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Department Seminars

  1. JAN

    9

    Thursday

    Environmental & Climate Sciences Department Seminar

    Presented by Jeffrey Pierce, Colorado State University

    11 am, Large Conference Room, Bldg. 490

    Thursday, January 9, 2020, 11:00 am

    Hosted by: Art Sedlacek

  2. JAN

    16

    Thursday

    Environmental & Climate Sciences Department Seminar

    Presented by Alistair Rogers, Environmental & Climate Sciences Dept (BNL)

    11 am, Large Conference Room, Bldg. 490

    Thursday, January 16, 2020, 11:00 am

    Hosted by: Shawn Serbin

  3. JAN

    23

    Thursday

    Environmental & Climate Sciences Department Seminar

    Presented by Kyla Dahlin, Michigan State University

    11 am, Large Conference Room, Bldg. 490

    Thursday, January 23, 2020, 11:00 am

    Hosted by: Shawn Serbin

  4. JAN

    30

    Thursday

    Environmental & Climate Sciences Department Seminar

    Presented by Jimmy Radney, NIST

    11 am, Large Conference Room, Bldg. 490

    Thursday, January 30, 2020, 11:00 am

    Hosted by: Ernie Lewis

  5. FEB

    6

    Thursday

    Environmental & Climate Sciences Department Seminar

    Presented by Pierre Gentine, Columbia University

    11 am, Large Conference Room, Bldg. 490

    Thursday, February 6, 2020, 11:00 am

    Hosted by: Shawn Serbin

  6. FEB

    13

    Thursday

    Environmental & Climate Sciences Department Seminar

    "Tropical Deep Convection and Entrainment in Idealized Cloud-Resolving Models"

    Presented by Usama Anber, Environmental & Climate Sciences Dept (BNL)

    11 am, Large Conference Room, Bldg. 490

    Thursday, February 13, 2020, 11:00 am

    Hosted by: Mike Jensen

    Global Climate Models (GCMs) are depicted as the holy grail of climate science. However, they are far from reliably simulating the current and future climate. One of the components that represents a source of errors and biases in these models is the convective parametrization scheme and the ad-hoc treatment of deep convection and entrainment. In this talk, I will focus on two tropical atmospheric events that GCMs struggle to simulate: Amazonian deep precipitating convection, and the Madden Julian Oscillations. I will present how idealized cloud-resolving models (CRMs) coupled with simulated and forced large-scale circulation can capture the essential dynamics of these events. In particular, when diagnosed from the CRMs, I will show that entrainment is merely a response to the convective regime and cannot have a constant rate as GCMs suggest. If time allows, I will also point out to another potential source of biases in the simulated mean climate stemming from the representation of numerical noise damping in the model dynamical core.

  7. FEB

    20

    Thursday

    Environmental & Climate Sciences Department Seminar

    Presented by Danielle Way, Western University, Canada

    11 am, Large Conference Room, Bldg. 490

    Thursday, February 20, 2020, 11:00 am

    Hosted by: Alistair Rogers

  8. FEB

    27

    Thursday

    Environmental & Climate Sciences Department Seminar

    Presented by Steven Quiring, Ohio State University

    11 am, Large Conference Room, Bldg. 490

    Thursday, February 27, 2020, 11:00 am

    Hosted by: Mike Jensen

  9. MAR

    5

    Thursday

    Environmental & Climate Sciences Department Seminar

    Presented by Jian Wang, Washington University of St. Louis

    11 am, Large Conference Room, Bldg. 490

    Thursday, March 5, 2020, 11:00 am

  10. MAR

    9

    Monday

    Environmental & Climate Sciences Department Seminar

    Presented by Greg McFarquhar, University of Oklahoma

    11 am, Large Conference Room, Bldg. 490

    Monday, March 9, 2020, 11:00 am

  11. MAR

    19

    Thursday

    Environmental & Climate Sciences Department Seminar

    Presented by Virendra Ghate, ANL

    11 am, Large Conference Room, Bldg. 490

    Thursday, March 19, 2020, 11:00 am

    Hosted by: Mike Jensen

  12. MAR

    26

    Thursday

    Environmental & Climate Sciences Department Seminar

    Presented by Kevin Griffin, Lamont-Doherty Earth Observatory of Columbia University

    11 am, Large Conference Room, Bldg. 490

    Thursday, March 26, 2020, 11:00 am

    Hosted by: Alistair Rogers

  13. APR

    2

    Thursday

    Environmental & Climate Sciences Department Seminar

    Presented by Marjorie Lundgren, Lancaster University

    11 am, Large Conference Room, Bldg. 490

    Thursday, April 2, 2020, 11:00 am

    Hosted by: Angela Burnett

  14. APR

    9

    Thursday

    Environmental & Climate Sciences Department Seminar

    "Date Available"

    11 am, Large Conference Room, Bldg. 490

    Thursday, April 9, 2020, 11:00 am

  15. APR

    16

    Thursday

    Environmental & Climate Sciences Department Seminar

    "Non-Equilibrium Aerosol Dynamics across Length Scales: Addressing a Few Contemporary Challenges"

    Presented by Rajan Chakrabarty, Washington University, St. Louis

    11 am, Large Conference Room, Bldg. 490

    Thursday, April 16, 2020, 11:00 am

    Hosted by: Ernie Lewis

  16. APR

    23

    Thursday

    Environmental & Climate Sciences Department Seminar

    "Emergence of a New Chemical Regime at Whiteface Mountain: Growing Abundance of Water Soluble Organics in Cloud Water associated with a Growing Ion Imbalance"

    Presented by Sara Lance, SUNY Albany

    11 am, Large Conference Room, Bldg. 490

    Thursday, April 23, 2020, 11:00 am

    Hosted by: Ernie Lewis

  17. APR

    30

    Thursday

    Environmental & Climate Sciences Department Seminar

    "Date Available"

    11 am, Large Conference Room, Bldg. 490

    Thursday, April 30, 2020, 11:00 am

  18. MAY

    7

    Thursday

    Environmental & Climate Sciences Department Seminar

    Presented by Angie Burnett, Environmental & Climate Sciences Dept (BNL)

    11 am, Large Conference Room, Bldg. 490

    Thursday, May 7, 2020, 11:00 am

    Hosted by: Alistair Rogers

  19. MAY

    14

    Thursday

    Environmental & Climate Sciences Department Seminar

    "Date Available"

    11 am, Large Conference Room, Bldg. 490

    Thursday, May 14, 2020, 11:00 am

  20. MAY

    21

    Thursday

    Environmental & Climate Sciences Department Seminar

    "Date Available"

    11 am, Large Conference Room, Bldg. 490

    Thursday, May 21, 2020, 11:00 am

  21. MAY

    28

    Thursday

    Environmental & Climate Sciences Department Seminar

    "Date Available"

    11 am, Large Conference Room, Bldg. 490

    Thursday, May 28, 2020, 11:00 am

2019

  1. Environmental & Climate Sciences Department Seminar

    "Lagrangian Cloud Modeling: Foundations and Recent Developments"

    Presented by Fabian Hoffmann, NOAA Earth System Laboratory

    Thursday, November 14, 2019, 11 am
    John Dunn Seminar Room, Bldg. 463

    Hosted by: Fan Yang

    Although Lagrangian methods for the representation of cloud microphysics date back more than half a century, they have regained considerable attention in the last decade due to the advent of so-called Lagrangian cloud models (LCMs). Today, LCMs are not only considered a valuable alternative to commonly applied Eulerian cloud models (ECMs), but also the future of cloud microphysical modeling. The main difference between LCMs and ECMs is the representation of cloud microphysics, e.g., the cloud droplet size distribution (DSD): ECMs discretize the DSD by several bins or only predict a few statistical moments of it. LCMs, on the other hand, model the DSD by Lagrangian particles, each representing an ensemble of identical droplets. This talk will cover the fundamentals of LCMs, covering the implementation of warm-phase microphysical processes, the differences and advantages to ECMs, as well as novel analysis techniques only possible in LCMs. Subsequently, I will focus on a recent approach for the modeling of unresolved supersaturation fluctuations to be applied in LCMs. Since LCMs are typically coupled to a large-eddy simulation (LES) model for predicting dynamics and thermodynamics, supersaturation fluctuations are constrained by the LES resolution. Using the new approach, supersaturation fluctuations down to the Kolmogorov length scale may be considered, including their specific effects on cloud microphysics, most importantly typically unresolved inhomogeneous mixing. Results from warm-phase boundary layer cloud simulations will be presented, focusing on the entrainment process in stratocumulus clouds. Finally, an initial view toward the modeling of entrainment and mixing in mixed-phase clouds will be given, assessing the importance of inhomogeneous microphysical processes in these clouds.

  2. Environmental & Climate Sciences Department Seminar

    "Evaluating Land-Atmosphere Interactions during LAFE"

    Presented by Dave Turner, NOAA

    Thursday, November 7, 2019, 11 am
    John Dunn Seminar Room, Bldg. 463

    Hosted by: Allison McComiskey

    The turbulence and interactions between the land surface and the atmosphere needs to be represented in all numerical weather prediction and climate models. The Land-Atmosphere Feedback Experiment (LAFE) was conducted at the ARM SGP to collect a comprehensive dataset to evaluate the similarity relationships used to represent these processes in most numerical models. This seminar will present an overview of the LAFE campaign, present some observational results, and demonstrate how observations like this can be used to improve similarity relationships.

  3. Environmental & Climate Sciences Department Seminar

    "Observational insight into the relationships between large-scale conditions and the properties of boundary-layer precipitation"

    Presented by Katia Lamer, City College of New York (CCNY)

    Thursday, October 24, 2019, 11 am
    Large Conference Room, Bldg. 490

    Hosted by: Andy Vogelmann

    Reanalysis and observations collected at ENA are analyzed to document the properties of rain and boundary layer clouds during general subsidence conditions and following cold front passages. Clouds in the wake of cold fronts exhibit on average a 10% higher propensity to precipitate and higher rain-to-cloud fraction than clouds found in general subsidence conditions. The identification of monotonic relationships between rain-to-cloud fraction with surface forcing and boundary layer stability parameters as well as between virga base height with stability and humidity measures further supports that large-scale conditions impact precipitation variability. That being said, these relationships are less clear than those established between cloud and rain properties suggesting that cloud macrophysics have a more direct impact on the properties of rain than the large-scale environment.

  4. Environmental & Climate Sciences Department Seminar

    "What drives precipitation initiation in marine stratocumulus?"

    Presented by David Mechem, University of Kansas

    Thursday, October 17, 2019, 11 am
    Large Conference Room, Bldg. 490

    Hosted by: Mike Jensen

    The initial formation of precipitation in warm clouds remains shrouded in mystery. Precipitation initiation in bulk microphysical parameterizations is typically cast as a nonlinear function dependent on liquid water content and droplet concentration, which suggests two possible paths to precipitation initiation in actual clouds—high liquid water content or low droplet concentration. A bin-microphysics large-eddy simulation (LES) model is employed investigate the dominant microphysical precursor conditions influencing precipitation initiation for a case of marine stratocumulus over the eastern North Atlantic. Results suggest that new regions of precipitation are associated with fluid parcels that previously participated in the precipitation process.

  5. Environmental & Climate Sciences Department Seminar

    "Progress in quantifying the global effective radiative forcing due to aerosol-cloud interactions"

    Presented by Johannes Quaas, University of Leipzig

    Thursday, October 10, 2019, 11 am
    Large Conference Room, Bldg. 490

    Hosted by: Steve Schwartz

    The effective radiative forcing due to aerosol-cloud interaction, ERFaci, is composed of the radiative forcing due to aerosol-cloud interactions, RFaci (Twomey effect) that is the immediate response of cloud albedo to an increase in droplet number concentration, Nd. Previous satellite-based quantification of this effect was hampered by deficiencies in the retrieval of aerosol and also, of Nd. The talk will firstly discuss progress in this regard, which leads to a stronger estimated RFaci than previous satellite-based approaches. The other component of ERFaci is in the cloud adjustments. These can be split into adjustments of cloud fraction, f, and liquid water path, L. In terms of the latter, statistical relationships between L and Nd show on average negative adjustments of L (a positive forcing component). In turn, the analysis of ship-, volcano- and industry tracks leads to an estimated small overall effect on L; these results are trustworthy since a cause-effect relation is assured. In terms of the f adjustment, the current results point to an increase in cloud fraction at larger Nd. It is unclear which processes lead to this result. The talk will also briefly discuss how cloud-resolving simulations may help to better understand the remaining uncertainties. In the last part, a brief discussion will be presented on initial steps towards an estimate of the response of cirrus to anthropogenic aerosols.

  6. Environmental & Climate Sciences Department Seminar

    "Noise tolerance time-resolved photon counting: Prospects for atmospheric science applications"

    Presented by Yong Meng Sua, Stevens Institute of Technology

    Thursday, September 26, 2019, 11 am
    John Dunn Seminar Room, Bldg. 463

    Hosted by: Fan Yang

    Selective detection of signal over noise is essential to measurement and signal processing. Time-frequency filtering has been the standard approach for the optimal detection of non-stationary signals. However, there is a fundamental tradeoff between the signal detection efficiency and the amount of undesirable noise detected simultaneously. By tailoring the nonlinear process in a lithium-niobate waveguide, we demonstrate highly selective detection of picosecond single photons against broadband noise overlapping temporally and spectrally but in orthogonal time-frequency modes, with performance well exceeding the theoretical limit of the optimized time-frequency filtering. To this end, our technique can achieve signal to noise exceeding by far what's possible with linear optics filters even in the presence of strong background noise, which are highly desirable for many atmospheric remote sensing and imaging applications. Here, we present some feasibility studies in connecting our mode selective detection technique for applications in atmospherics science. Our results and visions may lead to enhanced resolution, sensitivity and detection limit for atmospheric instruments such as lidar and disdrometer.

  7. Center for Functional Nanomaterials Seminar

    "Ceria-based nanostructured biomimetic materials and interfaces for sensing and environmental remediation"

    Presented by Silvana Andreescu, Clarkson University

    Monday, September 23, 2019, 1:30 pm
    Bldg. 735, Conference Room A, 1st Floor

    Hosted by: Mircea Cotlet

    Cerium oxide nanoparticles or nanoceria have a unique structure and interesting physicochemical properties and reactivity that vary with the size, shape and surface coating. These particles have been traditionally used in catalytic applications in automotive combustion engines, and solid oxide fuel cells, and more recently have been proposed as therapeutic agents in biomedicine. This presentation will discuss properties, characterization and novel applications of a new type of biomimetic cerium oxide nanostructures with regenerative properties and illustrate their potential as active materials for sensing and environmental remediation applications. These materials have tunable redox activity, optical and catalytic properties and can be used to replace enzymes in biological sensing mechanisms, or amplify chemical and biological detection schemes when used in combination with biomolecules. The resulting nanostructures integrate biorecognition, signal amplification and detection capabilities and can function as all-in-one biosensing devices. Design and performance characteristics of several types of ceria-based sensing platforms developed in our lab for point-of-care diagnosis, food quality control and environmental monitoring will be described. The presentation will also show the capability of these materials to function as biomimetic degradation catalysts enabling their use in separation membranes and flow through reactors for environmental remediation. Within this framework, recent work focusing on the development of a mesoporous framework containing highly active ultrasmall cerium oxide nanoparticles will be discussed with an example of application for the degradation of organophosphate agents. These materials have high stability, can be produced in large quantities at a low cost and have demonstrated excellent performance when used in field-deployable devices. Due to their high stability, activity and reusability, the application of these materials can be extend

  8. Environmental & Climate Sciences Department Seminar

    "No Seminar Scheduled"

    Thursday, September 12, 2019, 11 am

  9. Environmental & Climate Sciences Department Seminar

    "Broadband Radiometry during EarthCARE: An Improved Solar Radiance-to-Flux Conversion"

    Presented by Florian Tornow, Freie Universitat Berlin

    Thursday, September 5, 2019, 11 am
    John Dunn Seminar Room, Bldg. 463

    Hosted by: Mike Jensen

    Outgoing radiative fluxes at top-of-atmosphere (TOA) are driven by the interaction of clouds, aerosols, and radiation. The upcoming EarthCARE mission aims to improve our understanding of this interaction and compares shortwave (SW) and longwave TOA fluxes from (1) radiative transfer simulations – acting on cloud and aerosol properties retrieved from onboard active and passive instruments – with (2) flux estimates based on broadband radiometer (BBR) measured radiances over horizontal domains of 10x10 km. To improve BBR-based TOA SW flux estimates, this talk explores a new approach that incorporates additional parameters (cloud-top effective radius and cloud-topped water vapor) and produces significantly different flux estimates when compared against state-of-the-art methodology.

  10. Environmental & Climate Sciences Department Seminar

    "Understanding bioaerosols atmospheric lifecycle, abundance dynamics and impacts"

    Presented by Arnaldo Negron Marty, School of Earth and Atmospheric Sciences, Georgia Tech

    Thursday, August 15, 2019, 11 am
    Conference Room Bldg 815E

    Hosted by: Art Sedlacek and Ernie Lewis

    Primary biological atmospheric particles (PBAP), also called bioaerosols, are ubiquitous in the atmosphere with potentially important impacts on human health1,2, cloud formation3, the hydrological cycle4,5, and biogeochemical cycles6. Measuring PBAP poses a challenge for established biological tools due to generally low atmospheric concentration. Bioaerosols are currently measured by light-induced fluorescence (LIF) instrumentation using the autofluorescence of cell macromolecules, but the frequency of misidentification of abiotic particles by LIF is unclear. As a result, a robust protocol using a state-of-the-art cyclone to collect liquid samples and subsequent flow cytometry analysis, a more specific single-cell detection technique, was effectively designed and applied to quantify the speciated abundance of PBAP7. Tests conducted in Atlanta, GA showed clearly defined low nucleic acid (LNA), high nucleic acid (HNA), and pollen PBAP populations. LNA dominated during dry days and HNA dominated warm and humid days. Our instrumentation pipeline has been deployed during the Biological and Oceanic Atmospheric Study (BOAS) and the Finokalia Aerosol Measurement Experiment (FAME) campaigns. BOAS results show bacteria enrichment at cloud formation altitudes in the marine free troposphere. FAME studied PBAP loadings reaching Crete from continental Europe and Africa air transport; concentrations reached 105 cells m-3 during dust events. Overall, the optimization of detection and quantification techniques has provided tools to study closely speciated bioaerosol populations over different environments and meteorology to better understand bioaerosols lifecycle. References: (1) Fröhlich-Nowoisky et al., Atmos. Res. 2016; (2) Pöschl, Angew. Chem., 2005; (3) Hoose et al., Environ. Res. Lett., 2010; (4) Morris et al., Glob Chang Biol, 2014; (5) DeLeon-Rodriguez et al., PNAS, 2013; (6) Myriokefalitakis et al., Biogeosciences, 2016; (7) Negron-Marty et al., ACP, in

  11. Environmental & Climate Sciences Department Seminar

    "Experimental and modeling investigation of the OH-initiated heterogeneous oxidation of semi-solid and aqueous saccharide aerosols"

    Presented by Hanyu Fan, Department of Chemistry, West Virginia University

    Monday, August 12, 2019, 11 am
    Conference Room Bldg 815E

    Hosted by: Art Sedlacek and Ernie Lewis

    Sugars (primary saccharides, saccharide polyols and anhydro-saccharides) are a major class of water-soluble organic carbon (WSOC) that significantly contribute to atmospheric organic aerosol particular matter (PM). [1] The heterogeneous oxidation of organic materials plays a significant role during the chemical aging of organic aerosols in the atmosphere. The kinetic of such heterogeneous reactions has been shown to be very dependent on the chemical component of the particle phase. [2] The experiments were performed using an atmospheric pressure aerosol flow tube coupled with Scanning Mobility Particle Sizer (SMPS), Gas Chromatography – Flame Ionization Detector (GC-FID) and Aerosol Mass Spectrometer or Teflon filter collection. The kinetics are determined from the loss of particle species as a function of OH exposure. We reported results on the OH-initiated heterogeneous oxidation of pure monosaccharide semi solid nanoparticles over a wide range of relative humidity (RH) conditions. The decay rate of the monosaccharide is found to strongly depend on the gas phase water concentration. [3] We recently report results on heterogeneous oxidation of OH radicals with ternary component of monosaccharide-disaccharide-water semi solid nanoparticles over a range of mole ratio of mixtures of monosaccharide and disaccharide. The presence of disaccharide slows down the decay rate of monosaccharide in semi solid phase. [4] Then we moved on to aqueous phase oxidation of saccharides by OH radicals study. Contrast to what we observed in semi solid phase study, the presence of monosaccharide slows down the kinetic of disaccharide in aqueous phase. [5] A reaction-diffusion kinetic model solved in Matlab software is developed in order to investigate the effect composition-dependent diffusion on heterogeneous reaction behaviors in solid phase study. [3,4] Molecular dynamics simulations and kinetic mechanism of the heterogeneous oxidation of aqueous droplets based

  12. Environmental & Climate Sciences Department Seminar

    "Accurate Multicomponent Fick Diffusion at the Cost of Mixture Averaged Transport"

    Presented by Manuel Arias Zugasti, Departamento de Física Matemática y de Fluidos Facultad de Ciencias, UNED

    Friday, August 9, 2019, 11 am
    Conference Room Bldg 815E

    Hosted by: Bob McGraw

    Two simple and efficient models for the description of multicomponent Fick diffusion in mixtures with high numbers of components have been recently developed [1]. Both models are based on the Kinetic Theory of Gases and make use of perturbation schemes in terms convenient dimensionless variables, leading to efficient algorithms for the calculation of mass diffusion fluxes in mixtures of interest in combustion science. The first model, termed Model 1, which is extremely simple, assumes that all components in the mixture are dilute in a single species, and provides an accurate description of the multicomponent fluxes by means of a perturbation scheme. In the second model, termed Model 1+M, the number of main species (those species which are not in the dilute limit) is increased from 1 to 1+M, with 1+M being at most an order O(10) number, and the perturbation strategy is only applied to the remaining dilute species, often in trace amounts. The performance of these two descriptions of multicomponent diffusion fluxes is compared to the formulation of Dixon-Lewis [2], used for instance in the Chemkin package [3], and also to the widely used mixture-average simplification. The results are illustrated with steady flamelets of hydrogen or dodecane, in order to compare computational costs when different number of species are involved. An unsteady auto-igniting counterflow diffusion flamelet of methane in a coflow of hot products is also considered. The different comparisons in terms of precision and cost show that Model 1+M can be more effective than the mixture-average approach in terms of computation time, while reproducing the results of Dixon-Lewis multicomponent diffusion [4]. REFERENCES [1] Arias-Zugasti, M., Garcia-Ybarra, P.L., Castillo, J.L., "Efficient calculation of multicomponent diffusion fluxes based on kinetic theory", Combust. Flame 163:540–556 (2016)

  13. Environmental & Climate Sciences Department Seminar

    "The Influence of Aerosol Chemical Composition, Morphology, and Phase State on Water and Ice Cloud Particle Formation"

    Presented by Yue Zhang, North Carolina State, MIT, and Aerodyne

    Thursday, May 30, 2019, 11 am
    Large Conference Room, Bldg. 490

    Hosted by: Ernie Lewis

    Aerosols and clouds effect Earth's radiative balance, and aerosol-cloud interactions are major sources of uncertainties in predicting future climate. The climate effects of water and ice cloud particles formed from atmospheric particulate matter are not well understood due to the complex physical and chemical properties of these aerosols. Measurements from fixed sites and field campaigns have shown that organic aerosols (OA) dominate the non-refractory aerosols in the free troposphere where clouds typically form, and cloud water and ice cloud residue both show the presence of organic materials. Despite the abundance of OA, their effects on both cloud condensation nuclei (CCN) and ice nucleation (IN) are not fully understood and even controversial. To probe into these issues, the CCN and IN properties of complex inorganic-organic aerosol mixtures that simulate ambient conditions were measured with a cloud condensation nuclei counter (CCNC, DMT, Inc.) and a spectrometer for ice nucleation (SPIN, DMT, Inc.) at a variety of laboratory conditions. Our studies suggest that the composition of the organic-containing aerosols, as well as their morphology and phase state, jointly impact their cloud forming potential. The results highlight the importance of combining aerosol physical and chemical properties to accurately understand cloud particle formation processes and their implications on the climate.

  14. Environmental & Climate Sciences Department Seminar

    "Radar Observations and Simulations of the Level of Maximum Detrainment"

    Presented by Gretchen Mullendore, Univ. North Dakota

    Thursday, May 23, 2019, 11 am
    Large Conference Room, Bldg. 490

    Hosted by: Mike Jensen

    Parcel theory is the basis for many of convective indices (e.g., CAPE, LNB) that are used extensively throughout the community. While it is widely known that parcel theory is only an approximation, and therefore the indices that derive from parcel theory are also just approximations, much more research is needed so that we can better link our theory to observations. One example is the relationship between the level of neutral buoyancy (LNB) and the level of maximum detrainment (LMD). Both models and observations show departures from LNB depend on storm morphology, season and geographical region.

  15. Environmental & Climate Sciences Department Seminar

    "High-throughput field phenotyping of photosynthetic capacity using hyperspectral imaging"

    Presented by Katherine Meacham, Univ. of Illinois

    Thursday, May 9, 2019, 11 am
    Large Conference Room, Bldg. 490

    Hosted by: Angie Burnett

    Improved photosynthetic rates have been shown to increase crop biomass, making improved photosynthesis a focus for driving future grain yield increases. Improving the photosynthetic pathway offers opportunity to meet food demand, but requires high throughput measurement techniques to detect photosynthetic variation in natural accessions and transgenically improved plants. Gas exchange measurements are the most widely used method of measuring photosynthesis in field trials but this process is laborious and slow, and requires further modeling to estimate meaningful parameters and to upscale to the plot or canopy level. In field trials of tobacco with modifications made to the photosynthetic pathway, we infer key photosynthetic parameters from imaging spectroscopy using a partial least squares regression technique. We used two hyperspectral cameras with resolution 2.1nm in the visible range and 4.9nm in the NIR. Ground-truth measurements from leaf-level photosynthetic gas exchange, full-range (400-2500nm) hyperspectral reflectance and extracted pigments support the model. The results from a range of wild-type cultivars and from genetically modified germplasm offer a high-throughput screening tool for crop trials aimed at identifying increased photosynthetic capacity.

  16. Environmental & Climate Sciences Department Seminar

    "Date Available"

    Thursday, April 25, 2019, 11 am
    Large Conference Room, Bldg. 490

  17. Environmental & Climate Sciences Department Seminar

    "Using High-Resolution Observations to Improve a Low-Resolution Global Climate Model"

    Presented by Greg Elsaesser, NASA GISS

    Thursday, April 18, 2019, 11 am
    Large Conference Room, Bldg. 490

    Hosted by: Mike Jensen

    This talk will begin with an overview of recent development in the representation of deep convection in the NASA Goddard Institute for Space Studies (GISS) General Circulation Model (GCM). Global satellite remote sensing products are important references for continual GCM development and evaluation, but such products often provide data at coarse temporal and/or spatial resolutions, thus making it difficult to conceptualize and evaluate "process representations" in a GCM. I will discuss the various approaches I am taking to average global satellite retrievals in new ways, coincident with efforts to use new DOE/ARM observations, to derive composite high-resolution evolutions of deep convection and the nearby environment. These depictions will not only inform future development, but they are also crucial for ensuring that recent improved mean-state representations are not the result of errors cancelling at the process level.

  18. Environmental & Climate Sciences Department Seminar

    "Simulating Mixed-Phase Clouds at High Latitudes: Model Evaluation, Improvement, and Interactions with Aerosol"

    Presented by Xiahong Liu, Univ. Wyoming

    Thursday, April 11, 2019, 11 am
    Large Conference Room, Bldg. 490

    Hosted by: Damao Zhang

    Mixed-phase clouds are frequently observed in the Arctic and Antarctic and over the Southern Ocean, and have important impacts on the surface energy budget and regional climate. Global climate models (GCMs), an important tool for studying the climate change still have large biases in simulating the mixed-phase cloud properties, including supercooled liquid amount and liquid and ice phase partitioning. In this talk, I will present our recent works on mixed-phase clouds: (1) improving the representations of subgrid mixing and partitioning between cloud liquid and ice in mixed-phase clouds in the DOE's Energy Exascale Earth System Model (E3SM). Model simulations are evaluated against observation data obtained in the DOE Atmospheric Radiation Measurement (ARM) Program's field campaigns and long-term ground-based multi-sensor measurements; and (2) investigating the effects of aerosols, including dust and sea spray aerosol, on mixed-phase clouds. We found that dust, as ice nucleating particles (INPs), induces a global net warming via its indirect effect on mixed-phase clouds with a predominant warming in the NH midlatitudes and a cooling in the Arctic. INP sources of sea spray aerosol vary with time and geographic location with the maximum contribution in the marine boundary layer over the Southern Ocean, where dust has a limited influence. Modeled INP concentrations are compared with observations from different campaigns (e.g., MARCUS, SOCRATES, CAPRICORN).

  19. Environmental & Climate Sciences Department Seminar

    "How Long Does Anthropogenic CO2 Stay in the Atmosphere?"

    Presented by Stephen Schwartz, Environmental and Climate Sciences Department, Brookhaven National Laboratory

    Thursday, April 4, 2019, 11 am
    John Dunn Seminar Room, Bldg. 463

    Hosted by: Mike Jensen

    Knowledge of the adjustment time of anthropogenic CO2, the e-folding time by which excess CO2 (above preindustrial) would decrease in the absence of anthropogenic emissions, is central to understanding the influence of anthropogenic CO2 on climate change and to prospective control of CO2 emissions to reach desired targets. Estimates of this adjustment time from current carbon-cycle models range from about 100 years to over 700 years. This talk examines the CO2 budget by a top-down, observationally based approach. Major stocks and fluxes are quantified. The net flux from the atmosphere and the ocean mixed layer, which are in near equilibrium, to the deep ocean and terrestrial biosphere is found to be proportional to the excess CO2 in these compartments throughout the Anthropocene. These observations, together with knowledge of the underlying physical and chemical processes, are used to develop a simple, transparent model that describes the transport of CO2 between major compartments — the atmosphere, the mixed-layer ocean, the deep ocean, and the terrestrial biosphere. This model compares well with observed atmospheric CO2 from 1750 to the present. The adjustment time of excess CO2, evaluated by multiple measures including the 1/e decay time and the negative inverse of the fractional annual transfer rate of excess CO2 into the terrestrial biosphere and the deep ocean, is found to be 54 ± 10 years. Such a short adjustment time, if correct, would mean that the atmospheric amount of CO2 would respond quickly and strongly to emission changes. For example, atmospheric CO2 could be immediately stabilized at its present value by decreasing anthropogenic emissions by about 50%.

  20. Environmental & Climate Sciences Department Seminar

    "Large-Scale Drivers And Local Processes Impacts On Post-Cold Frontal Cloud Properties Over The East North Atlantic ARM Site"

    Presented by Jimmy Booth, CCNY

    Thursday, March 28, 2019, 11 am
    John Dunn Seminar Room, Bldg. 463

    Hosted by: Mike Jensen

    Using observations collected at the ARM Eastern North Atlantic (ENA) site, we examine the relationship between the large-scale environment and the properties of low-level clouds that occur in conditions of subsidence. The cloud boundary cloud properties correlate well with the difference in potential temperature between the 800 hPa level and the surface, a measure of the degree of boundary layer instability. Moreover, consistent relationships are found between near-surface stability, surface energy fluxes, and cloud fraction, optical thickness, and top temperature in various regions of strong post-cold frontal activity. To help understand these mechanisms, we use the Weather Research Forecast (WRF) model to explore post-cold frontal clouds with a case study. The modeled cloud properties are sensitive to the interactions between the shallow convection and the boundary layer parameterizations. We will report how this sensitivity is related to boundary layer decoupling, vertical shear in the horizontal winds at cloud top, and drizzle. We also test the robustness of these conclusions by analyzing a perturbed initial conditions ensemble using WRF. A comparison of the perturbed physics and the perturbed initial condition ensembles explores the relative impact of circulation changes and physical processes on low-level cloud in the model.

  21. Environmental & Climate Sciences Department Seminar

    "Aerosol-Cloud Interactions: Buffers, Turbulence, and Knowledge Gaps"

    Presented by Yangang Liu, Environmental and Climate Sciences Department, Brookhaven National Laboratory

    Thursday, March 21, 2019, 11 am
    John Dunn Seminar Room, Bldg. 463

    Hosted by: Mike Jensen

    Despite progress in understanding of aerosol-cloud interactions (ACI) and their representation in climate models, climate models still suffer from large uncertainty in estimated aerosol indirect effects and large discrepancy compared to observations. This tenacious problem poses vital challenges to accurately represent aerosol-cloud interactions even in warm clouds, the apparently simplest of all clouds. In this talk, I will discuss several potentially important yet poorly understood factors that likely compensate/buffer aerosol-cloud interactions as conventionally represented in climate models (e.g., dispersion effect associated with the aerosol-induced changes of the spectral shape of the cloud droplet size distribution; regime dependence of cloud properties on aerosol concentration and updraft velocity; effect of turbulent entrainment-mixing processes; microphysics-turbulence interactions; scale-dependence; process coupling). I will explore the challenges and the main knowledge gaps that are needed to fill to address these challenges, and discuss the approaches that hold potentials to fill the knowledge gaps and address the ACI challenges.

  22. Environmental & Climate Sciences Department Seminar

    "Realistic Lagrangian Large Eddy Simulations of Boundary Layer Clouds"

    Presented by Jan Kazil, University of Colorado at Boulder and NOAA

    Thursday, March 14, 2019, 11 am
    Large Conference Room, Bldg. 490

    Hosted by: Allison McComiskey

    Large Eddy Simulations (LES) are the tool of choice to study the dynamics, microphysics, and aerosol-cloud interactions of boundary layer clouds. LES traditionally operate with idealized large scale meteorological conditions, derived from a snapshot of the atmospheric state, and leave aside the role of mesoscale organization. The need for better scientific understanding, supported by technical progress, has prompted the development of LES approaches geared towards greater realism. This seminar will introduce realistic Lagrangian LES, which capture boundary layer and cloud state development and mesoscale organization along reanalysis trajectories. The approach is applied, together with satellite observations and in-situ data, to study the impact of continental outflow on the transition from the closed- to the open-cell stratocumulus state, and the impact of long-range transport of biomass burning aerosol on a pocket of open cells in the South-east Atlantic. Furthermore, some fundamental questions on the dynamics of stratocumulus clouds with relevance for large scale modeling and satellite remote sensing are answered.

  23. Environmental & Climate Sciences Department Seminar

    "The Characteristics of Mesoscale Convective Systems as Revealed by Radar Wind Profilers"

    Presented by Die Wang, Environmental and Climate Sciences Department, Brookhaven National Laboratory

    Thursday, March 7, 2019, 11 am
    Conference Room Bldg 815E

    Hosted by: Scott Giangrande

    Deep convective clouds (DCCs) regulate the global energy and water cycles through their extensive cloud coverage and the exchange of latent heat. Through the influence of DCCs on the large-scale atmospheric Hadley and Walker circulations, DCCs affect the cloud and precipitation properties in remote tropical and subtropical environments. Unfortunately, current general circulation models (GCMs) do not properly simulate DCC role in our climate system, since relevant DCC processes operate across GCM resolved and parameterized scales. In addition, inadequate observational constraints inhibit high-resolution convective model process improvement. This talk will focus on the kinematic characteristics of DCCs using ARM ground-based observations (e.g., radar wind profiler), and the challenges faced in model evaluation (e.g., WRF). The convective up- and downdrafts of DCCs will be discussed in particular, which are the most fundamental property and are among the most difficult aspects of convection to measure.

  24. Environmental & Climate Sciences Department Seminar

    "Time evolution of aerosol optical properties a few hours downwind of wildfires as observed in BBOP"

    Presented by Larry Kleinman, Environmental and Climate Sciences Department, Brookhaven National Laboratory

    Thursday, February 28, 2019, 11 am
    Conference Room Bldg 815E

    Hosted by: Mike Jensen

    During the first phase of the Biomass Burn Operational Period (BBOP) field campaign, conducted in the Pacific Northwest, the DOE G-1 aircraft was used to follow the time evolution of wildfire smoke from near the point of emission to locations several hours downwind. In nine flights we made repeated transects of wildfire plumes at varying downwind distances and could thereby follow the plume's time evolution. We observed an active photochemistry: rapid depletion of NOx and O3 concentrations up to 170 ppb. The peak concentration of biomass burning aerosols was 16,000 μg/m3. On average there was little change in dilution-normalized aerosol concentration during 2-4 hours of pseudo-Lagrangian sampling. This consistency seemingly hides a dynamic system in which primary aerosols are evaporating and secondary condensing. Particle size increases with downwind distance causing the particles to be more efficient scatters. Aerosol light scattering increases by up to a factor of two even though aerosol mass is nearly constant. Near-fire aerosol had a single scatter albedo (SSA) of 0.8-0.85. After 1-3 hours of aging, SSAs were typically 0.9 and above. For average surface and atmospheric conditions, the observed increases in SSA change plumes from having a small warming effect due to light absorption, to a cooling effect due to the scattering of sunlight upwards, back to space.

  25. Environmental & Climate Sciences Department Seminar

    "Polar Stratiform Mixed-phase Clouds Observed with Remote Sensing Measurements"

    Presented by Damao Zhang, Environmental and Climate Sciences Department, Brookhaven National Laboratory

    Thursday, February 21, 2019, 11 am
    Conference Room Bldg 815E

    Stratiform mixed-phase clouds are prevalent at high latitudes and greatly impact regional radiative fluxes. Satellite and ground-based remote sensing measurements enable statistical analyses of mixed-phase cloud properties and their underlying processes. A comprehensive database is constructed of retrieved mixed-phase cloud microphysical properties using ground-based remote sensing measurements from the Atmospheric Radiation Measurement Program (ARM) West Antarctic Radiation Experiment (AWARE) campaign at the McMurdo station, and multiple years of measurements at the ARM North Slope of Alaska (NSA) Utqiagvik Facility. The database includes ice and liquid components of water content, average particle size and concentration, and dynamics including vertical air velocity and turbulence. With the database, polar stratiform mixed-phase cloud macro- and microphysical properties are analyzed and compared for the dramatically different environments. In addition, lidar backscattering and polarization measurements are used to study polar aerosol profiles that may impact stratiform mixed-phase cloud microphysical properties through aerosol-cloud interactions. Such long-term remote sensing observations of polar stratiform mixed-phase cloud properties may be used to evaluate and improve model simulations.

  26. Environmental & Climate Sciences Department Seminar

    "TRacking Aerosol Convection interactions ExpeRiment (TRACER) - An upcoming ARM field campaign"

    Presented by Michael Jensen, Environmental and Climate Sciences Department, Brookhaven National Laboratory

    Thursday, February 14, 2019, 11 am
    Conference Room Bldg 815E

    Despite their climatic importance, multi-scale models continue to have persistent biases produced by insufficient representation of convective clouds. To increase our understanding of convective cloud lifecycles and aerosol-convection interactions, the TRacking Aerosol Convection interactions ExpeRiment (TRACER) will take place in the Houson, TX region from April 2021 through April 2022 with an intensive observation period from June to September 2022. TRACER (currently) includes the deployment of the ARM Mobile Facility, a C-band scanning polarimetric radar, and additional aerosol and atmospheric state measurements within existing surface meteorology, air quality and lightning dection neworks. A unique component of TRACER is that a large number of individual, isolated convective cells will be tracked and measured in high spatial and temporal resolution for the purposes of: (i) Characterizing and linking convective cloud kinematic and microphysical lifecycles, (ii) Quantifying environmental thermodynamic and kinematic controls on convective lifecycle properties, and (iii) Isolating and quantifying the impacts of aerosol properties on convective cloud kinematic and microphysical evolution. The seminar will present the scientific motivation for the TRACER campaign, details on the deployment strategies, and evolving opportunities for participation. The unique combination of cloud, precipitation, lightning, aerosol, and atmospheric state measurements associated with tracked convective cells will ultimately improve our understanding of the convective cloud lifecycle and its interaction with individual environmental factors such that improved, next generation cumulus, microphysics, turbulence, and aerosol parameterizations can be designed.

  27. Environmental & Climate Sciences Department Seminar

    "What can we learn from cloudy convection in a box? Laboratory meets LES with cloud microphysics"

    Presented by Raymond Shaw, MTU

    Thursday, January 31, 2019, 11 am
    Conference Room Bldg 815E

    Hosted by: Fan Yang

    Inspired by early convection-tank experiments (e.g., Deardorff and Willis) and diffusion-chamber experiments, we have developed a cloud chamber that operates on the principle of isobaric mixing within turbulent Rayleigh-Bénard convection. The "Pi cloud chamber" has a height of 1 m and diameter of 2 m. An attractive aspect of this approach is the ability to make direct comparison to large eddy simulation with detailed cloud microphysics, with well characterized boundary conditions, and statistical stationarity of both turbulence and cloud properties. Highlights of what we have learned are: cloud microphysical and optical properties are representative of those observed in stratocumulus; aerosol number concentration plays a critical role in cloud droplet size dispersion, i.e., dispersion indirect effect; aerosol-cloud interactions can lead to a condition conducive to accelerated cloud collapse; realistic and persistent mixed-phase cloud conditions can be sustained; LES is able to capture the essential features of the turbulent convection and warm-phase cloud microphysical conditions. It is worth considering what more could be learned with a larger-scale cloudy-convection chamber. Turbulence Reynolds numbers and Lagrangian-correlation times would be scaled up, therefore allowing more enhanced role of fluctuations in the condensation-growth process. Larger vertical extent (of order 10 m) would approach typical collision mean free paths, thereby allowing for direct observation of the transition from condensation- to coalescence-growth. In combination with cloudy LES, this would be an opportunity for microphysical model validation, and for synergistic learning from model-measurement comparison under controlled experimental conditions.

  28. Environmental & Climate Sciences Department Seminar

    "Remote Sensing of Clouds and Precipitation and their Application to Model Evaluation"

    Presented by Xiquan Dong, Univ. Arizona

    Monday, January 28, 2019, 11 am
    Conference Room Bldg 815E

    Hosted by: Mike Jensen

    Cloud feedbacks and an appropriate representation of clouds in climate models have long been one of the largest sources of uncertainty in predicting any potential future climate change. Although it is already a great challenge to derive true cloud fractions (CFs) from both active and passive remote sensing observations, it is even more difficult to infer their vertical distributions. Here we use the NASA CERES) Edition 4 cloud products in conjunction with the availability of ARM ground-based and NASA CloudSat-CALIPSO (CC) spaceborne radar-lidar observations over four ARM sites (SGP, ENA, TWP, and NSA) to answer two questions: Can spaceborne and ground-based radar-lidar combinations observe the same types and amounts of clouds? Are clouds detected and analyzed using passive satellite remote sensing comparable to these actively sensed clouds? From the long-term satellite-surface comparisons over these four sites, we found that ARM missed some optically thin high-level clouds at ARM SGP and ENA and even more at TWP, while CC missed some low-level clouds at NSA but identified more low-level clouds at SGP and ENA, even more at TWP. Passive sensors could not detect optically thin clouds, which is beyond their limitation. Based on the results, we conclude that true CFs can only be estimated from multiple instruments on various platforms. At the end of talk, we will present some comparisons between satellite observed and model simulated cloud properties.

  29. Environmental & Climate Sciences Department Seminar

    "WRF-Solar: Model overview and ongoing developments"

    Presented by Pedro Jiminez Munoz, NCAR

    Thursday, January 24, 2019, 11 am
    Conference Room Bldg 815E

    Hosted by: Yangang Liu

    The WRF-Solar model is an augmentation of the Weather Research and Forecasting (WRF) model specifically designed for solar energy applications. The developments have focused on improving the representation of the aerosol-cloud-radiation physics. In this direction, WRF-Solar includes a fast radiative transfer parameterization to provide surface irradiance forecast only limited by the model time step; an improved representation of the aerosol-radiation feedback (aerosol direct effect); incorporation of the cloud-aerosol feedbacks (aerosol indirect effects); and improved cloud-radiation feedbacks. During this seminar I will provide an overview of the WRF-Solar model and present evaluations that illustrate the benefits of the augmentations. Ongoing developments including a better cloud initialization and extending the model to provide probabilistic forecasts will be also discussed.

2018

  1. Environmental & Climate Sciences Department Seminar

    "The relationship of atmospheric ice content and vertical velocities"

    Presented by Sylvia Sullivan, Columbia University

    Thursday, December 6, 2018, 11 am
    Conference Room Bldg 815E

    Hosted by: Laura Fierce

    The links of atmospheric vertical motions and the ice content within clouds are numerous. Vertical motions generate the supersaturation that allows ice nucleation; they determine whether mass transfer will occur from droplets to crystals by the Bergeron process; and they control the sedimentation rate from the cloudy layer to lower altitudes. I will present the ways in which we have tried to better understand this dynamic-microphysical relationship over the past few years. First, with an automatic differentiation-based attribution analysis, we see the importance of accurately representing updrafts for the number concentration of nucleated ice crystals on a global scale. Then we zoom in, using a parcel model to identify joint temperature-updraft regimes in which secondary ice production processes like rime splintering or frozen droplet shattering can significantly enhance ice content. Along with these direct connections via hydrometeor formation, the relationship of vertical velocity and cloud ice content affects surface precipitation. We illustrate this indirect hydrological impact with mesoscale simulation of a mid-latitude cold frontal rain band and satellite data analyses of cloud top phase and precipitation from mesoscale convective systems throughout the tropics.

  2. Environmental & Climate Sciences Department Seminar

    "In-situ measurements of aerosol composition in Nepal: linking aerosol sources to ambient concentrations"

    Presented by Pete DeCarlo, Drexel University

    Thursday, November 29, 2018, 11 am
    Conference Room Bldg 815E

    Hosted by: Laura Fierce

    The Kathmandu Valley in Nepal is home to over 4 Million people, and is one of the fastest growing metropolitan areas in South Asia. It is subject to extreme pollution events due to numerous unregulated localized pollution sources and regional transport from the Indo-Gangetic Plain (IGP). Previous field work has studied gas species, wintertime VOCs and PM in the valley. The Nepal Ambient Measurement and Site Testing Experiment [NAMaSTE] is the first deployment of an Aerosol Mass Spectrometer (HR-ToF-AMS and mini-AMS) in Nepal and allows for a more comprehensive analysis of aerosol species and their source contributions. Source and ambient measurements were made in April 2015, but were interrupted by the Ghorka earthquake. Source measurements were nearly complete, but ambient measurements required additional data. We returned in December and January of 2017-2018 for a multi-site measurement campaign, and again in April 2018 to make additional real-time mobile measurements of aerosol composition throughout the Kathmandu Valley. Clear meteorological influences are observed with regular diurnal wind patterns in the valley. These patterns are key in establishing the influence of regional brick kiln operation with urban air pollution burden in Kathmandu. While organic species dominate the submicron aerosol composition measured throughout Nepal, the inorganic component of the aerosol (e.g. sulfate and chloride) are key species to identify brick kiln emissions and biomass/trash emissions.

  3. Environmental & Climate Sciences Department Seminar

    "Global models for atmospheric new particle formation from the CERN CLOUD experiment"

    Presented by Hamish Gordon, Leeds

    Thursday, November 15, 2018, 11 am
    Conference Room Bldg 815E

    Hosted by: Laura Fierce

    In this seminar I will introduce the CERN CLOUD chamber experiment studying atmospheric new particle formation. I will then focus on work we have done to parameterize new particle formation and growth rates for atmospheric models. I will discuss the implementation of the parameterizations into the models, and the implications of the results from these models for estimated cloud condensation nuclei concentrations and indirect aerosol radiative forcing. The uncertainties in modelling new particle formation remain large, and I will outline how we are moving forward to try to reduce them.

  4. Environmental & Climate Sciences Department Seminar

    "From Case Studies to Operations: Severe Storm Observations Using Emerging Radar Technologies"

    Presented by Michael French, Stony Brook University

    Friday, November 9, 2018, 11 am
    Conference Room Bldg 815E

    Hosted by: Mike Jensen

    Over the past ~20 years, there has been a significant advancement in knowledge regarding severe thunderstorms and tornadoes through the use of high-resolution data from high-frequency, truck-mounted, mobile Doppler radar systems. Recently, two advanced radar technologies, phased-array radar (PAR) and dual-polarization radar, have offered promise as a way to learn even more about severe weather systems. PAR allows for the collection of increased temporal resolution data of the phenomenon being studied. In turn, the processes that a quickly-evolving feature undergoes can be analyzed more accurately. Dual-polarization radars scan with the same update times as conventional mobile Doppler radars, but provide information about several characteristics of the hydrometeors being sampled. This information also can provide insight into processes occurring within the phenomenon of interest. Recent past observational work that has used these radar technologies to better understand supercell thunderstorms and tornadoes will be summarized. In addition, new efforts to generalize results from past case studies to large numbers of storms will be motivated and some preliminary results discussed.

  5. Environmental & Climate Sciences Department Seminar

    "Investigation of cloud droplet growth in turbulence using digital in-line holography"

    Presented by Neel Uday Desai, Michigan Technological University

    Friday, November 2, 2018, 11 am
    Conference Room Bldg 815E

    Hosted by: Yangang Liu

    The cloud droplet 'growth gap' problem in warm rain formation has troubled the cloud physics community for a few decades now. Turbulence has been considered as one of the mechanisms to overcome this bottleneck between cloud droplet growth by diffusion and growth by collision-coalescence. Being able to better understand and predict droplet growth rates would mean better estimates of cloud properties such as lifetime, precipitation, albedo etc. In this study, we use digital in-line holography to obtain volume measurements of cloud droplets with sizes near this growth gap in a turbulent laboratory chamber. We find that turbulent fluctuations in droplet number concentrations may lead to fluctuations in local supersaturation. Droplet growth through this stochastic condensation process results in broader droplet size distributions with some droplets growing large enough to jump the growth gap. We find similar results for airborne measurements of warm clouds suggesting this process should occur in the atmosphere as well. This approach is then extended to mixed phase clouds, and our first results show the importance of aerosol properties in controlling cloud glaciation.

  6. Environmental & Climate Sciences Department Seminar

    "Modeling future changes in Mesoscale Convective Systems: will end-of-century floods be more severe than expected?"

    Presented by Andreas F. Prein, NCAR

    Thursday, November 1, 2018, 11 am
    Conference Room Bldg 815E

    Hosted by: Scott Giangrande

    Stationary mesoscale convective systems (MCSs) are responsible for most of the warm season major flood events. Recent examples in North America are the West Virginia and Louisiana flooding of 2016, or the Houston flooding after the landfall of hurricane Harvey in 2017. Observations showed that MCSs became more frequent, intense, and long-lived in the Central US during the past 30 years. State-of-the-art climate models are not able to simulate MCSs realistically due to their coarse grid spacing leading to significant errors in simulating convective precipitation and uncertainties in extreme precipitation projections. Convection-permitting climate simulations (CPCS), which are able to simulate deep convection explicitly due to their high resolution, are promising tools that improve the representation of convective extremes. Here we use the weather research and forecasting model (WRF) to perform a current and end-of-century business as usual CPCS with 4 km horizontal grid spacing over a North American domain. Tracking MCS precipitation with a Lagrangian storm tracking algorithm shows that the current climate simulation can realistically simulate MCSs including the size, intensity, movement speed, and dynamical evolution of MCS precipitation. The future intensification of peak MCS precipitation rates is with about 7 % per degree warming in line with expectations from the Clausius-Capayron relation. However, these intensity increases combined with the spread of heavy rainfall areas of up to 70 % and additional changes in MCS movement speed lead to an almost doubling of MCS rainfall volume. The aim of this study is to understand the processes that lead to the rapid response of MCS precipitation volume to global warming. We show that interactions in future storm dynamics, thermodynamics, and microphysics are responsible for the large response. We will discuss the importance of model grid spacings to capture these changes. Further, i

  7. Environmental & Climate Sciences Department Seminar

    Presented by Dr. Lukas Pfitzenmaier, Integrated Remote Sensing, Meteorology & Geophysics, University of Cologne, Germany

    Thursday, October 25, 2018, 11 am
    Buidling 815 Conference Room

    Hosted by: Pavlos Kollias

    Mixed phase clouds contain both ice particles and super-cooled cloud water droplets in the same volume of air. Currently, one of the main challenges is to observe and understand how ice particles grow by interacting with liquid water within the mixed-phase clouds. In the mid latitudes this process is one of the most efficient processes for precipitation formation. It is particularly important to understand under which conditions growth processes are most efficient within such clouds. The observation of microphysical cloud properties from the ground is one possible approach to study the liquid-ice interaction that play a role on the ice crystal growth processes. In the seminar I will give an overview on spectral polarimetric radar measurements and what the observations can tell us about ice particle growth within mid-latitude precipitation mid-latitude cloud systems.

  8. Environmental & Climate Sciences Department Seminar

    "Freezing of Supercooled Drops in Motion: Pressure Matters, Not Just Temperature"

    Presented by Fan Yang, Environmental and Climate Sciences Department, Brookhaven National Laboratory

    Thursday, September 27, 2018, 11 am
    Conference Room Bldg 815E

    Hosted by: Mike Jensen

    Ice nucleation is the crucial step for ice formation in atmospheric clouds, and therefore underlies climatologically-relevant precipitation and radiative properties. Progress has been made in understanding the roles of temperature, supersaturation and material properties, but an explanation for the efficient ice nucleation occurring when a particle contacts a supercooled water drop (contact nucleation) has been elusive for over half a century. This work considers what other factors can affect ice nucleation, e.g., can electric fields or the dynamics of multi-phase contact lines affect ice nucleation? I have investigated these questions using conceptually-simple laboratory experiments in which the nucleation and freezing of supercooled water droplets resting on a substrate are observed with high-speed video. Two serendipitous and surprising results suggest that ice nucleation is strongly related to the contact line motion and distortion and a possible mechanism is proposed. It might interpret long-mysterious observations related to contact nucleation and its efficiency relative to immersion nucleation.

  9. Environmental & Climate Sciences Department Seminar

    "Rapid Measurements of Aerosol Size Distribution and Hygroscopic Growth with a Fast Integrated Mobility Spectrometer (FIMS)"

    Presented by Yang Wang, Environmental and Climate Sciences Department, Brookhaven National Laboratory

    Thursday, September 13, 2018, 11 am
    Conference Room Bldg 815E

    Hosted by: Bob McGraw

    A Fast Integrated Mobility Spectrometer (FIMS) based on image processing was developed for rapid measurements of aerosol size distributions from 10 to 500 nm. The FIMS consists of a parallel plate classifier, a condenser, and a CCD detector array. Inside the classifier an electric field separates charged aerosols based on electrical mobilities. Upon exiting the classifier, the aerosols pass through a three-stage growth channel, where aerosols as small as 7 nm are enlarged to above 1 μm through water or heptanol condensation. Finally, the grown aerosols are illuminated by a laser sheet and imaged onto a CCD array. The images provide both aerosol concentration and position, which directly relate to the aerosol size distribution after data inversion, considering the FIMS transfer function, particle penetration efficiency, and multiple charging of aerosols. The parallel Comparisons between the FIMS and a scanning mobility particle sizer (SMPS) demonstrated excellent agreement when measuring aerosols with various size spectra, showing differences within 5% in average particle size and total number concentration. But by simultaneously measuring aerosols with different sizes, the FIMS provides aerosol size spectra nearly 100 times faster than the SMPS. Recent deployment onboard research aircraft demonstrated that the FIMS is capable of measuring aerosol size distributions in 1s, thereby offering a great advantage in applications requiring high time resolution. The deployment of the FIMS during the recent Aerosol and Cloud Experiments in the Eastern North Atlantic (ACE-ENA) campaign helped identify new particle formation in the decoupled layer of the marine boundary layer during cold air outbreak periods. The vertical profiles of the aerosol size distributions during these events further explained the fate and transport of the newly formed aerosols.

  10. Environmental & Climate Sciences Department Seminar

    "Invariant and insensitive: climate model microphysics as a scaling problem"

    Presented by Mikael Witte, National Center for Atmospheric Research

    Thursday, July 19, 2018, 11 am
    Conference Room Bldg 815E

    Hosted by: Yangang Liu

    Clouds are inherently multiscale phenomena: the particles that make up clouds are typically microns to millimeters, while the large-scale circulations that drive cloud systems can be hundreds of kilometers across. Limited computational power and the need to accurately represent the large-scale circulations in numerical simulations of the atmosphere make explicit inclusion of cloud microphysics a practical impossibility. In the last 20 years there has been a shift toward representing microphysics as scale-aware processes. Despite this shift, many unanswered questions remain regarding the scaling characteristics of microphysical fields and how best to incorporate that information into parameterizations. In this talk, I will present results from analysis of high frequency in situ aircraft measurements of marine stratocumulus taken over the southeastern Pacific Ocean aboard the NCAR/NSF C-130 during VOCALS-REx. First, I will show that cloud and rain water have distinct scaling properties, indicating that there is a statistically and potentially physically significant difference in the spatial structure of the two fields. Covariance of cloud and rain is a strong function of length/grid scale and this information can easily be incorporated in large-scale model parameterizations. Next I will show results from multifractal analysis of cloud and rain water to understand the spatial structure of these fields, the results of which provide a framework for development of a scale-insensitive microphysics parameterization. Finally, I compare observed microphysical scaling properties with those inferred from large eddy simulations of drizzling stratocumulus, applying the same analyses as applied to the aircraft observations. We find that simulated cloud water agrees well with the observations but the drizzle field is substantially smoother than observed, which has implications for the ability of limited-area models to adequately reproduce the spatial structure o

  11. Environmental & Climate Sciences Department Seminar

    "SKYPE Seminar: Development of microphysical schemes in CESM-CAM5 and WRF"

    Presented by Xi Zhao, Qinghua University, China

    Tuesday, July 17, 2018, 10 am
    Conference Room Bldg 815E

    Hosted by: Yangang Liu

    Realistic representation of cloud microphysical processes is of vital importance to the simulation of climate and weather in atmospheric model. In this talk, I am going to talk about my model development work in climate and regional models, especially with emphasis on the microphysical processes which consists of: 1) Developing a novel cloud microphysical scheme in the CESM-CAM5 aiming at improving the representation of ice-phase cloud process. Different from conventional microphysics schemes separating cloud ice from snow, a single prognostic category is used to represent the whole spectrum of solid hydrometeors in this scheme. Instead of using fixed physical properties for separate ice classes, e.g., the mass, area, and fall velocity, we consider the particle shape and riming impacts on ice properties. This scheme is notable for its improved representation of cloud and cloud radiative forcing with reduced the computational time in global simulation; 2) Optimizing physical process of the single-moment SBU_YLIN scheme aiming at improving convection simulation, and further developing it into a double-moment scheme and coupling it with WRF-Chem model in WRF model. The double-moment scheme is notable for its significant improvement in squall line simulation.

  12. Environmental & Climate Sciences Department Seminar

    "Deep convective outflow, level of neutral buoyancy, entrainment rate and convective core: new insights from space-borne cloud radar observations"

    Presented by Zhengzhao (Johnny) Luo, CUNY

    Wednesday, May 30, 2018, 11 am
    Conference Room Bldg 815E

    Hosted by: Mike Jensen

    Level of neutral buoyancy (LNB) is an important parameter for understanding convection because it sets the potential vertical extent for convective development. It can be estimated from the parcel theory using the ambient sounding without having to observe any actual convective cloud development. In reality, however, convection interacts with the environment in complicated ways; it will eventually find its own effective LNB and manifests it through detraining masses and developing cirrus anvils. In a series of recent papers, we investigated the relationship between the LNB and actual deep convective outflow using 5 years of CloudSat observations. Due to entrainment dilution, the actual outflow level is almost always lower than the LNB. The difference between the two can be interpreted as a proxy for entrainment rate. It was found that the entrainment rate as determined this way is larger over tropical ocean (e.g., TWP warm pool) than tropical land (e.g., Africa and Amazon). Analysis of radar reflectivity profiles further shows that land convection has wider and more intense cores than the oceanic counterpart. These findings lend observational support to a long-standing assumption in convection models concerning the negative relationship between entrainment rate and convective core size. Finally, we examined the environment conditions for the observed convection cases and found that convective outflow tends to occur at a higher level when the mid-troposphere is more humid and when convective system size is smaller. Application of similar analysis to ground-based radar observations (such as those from the DOE ARM program) will be discussed. ?

  13. Environmental & Climate Sciences Department Seminar

    "Monitoring thunderstorms through their lightning activity"

    Presented by Eric Defer, CNRS-Institute National des Sciences de'l Univers (INS), France

    Monday, May 7, 2018, 11 am
    Conference Room Bldg 815E

    Hosted by: Mike Jensen

    There are about 45 flashes per second worldwide. About 90% of the flashes occur in cloud. A lightning flash is triggered when the ambient electric field exceeds a threshold. The ambient electric field is due to zones of electrical charges spreading within the thundercloud. Electrical charges are exchanged during hydrometeor collisions and are carried by the hydrometeors which are transported within the cloud. Consequently the lightning properties (e.g. flash rate; lightning type, i.e. intra-cloud and cloud-to-ground; flash extension; triggering altitude...) are strongly related to the microphysical, dynamical and electrification processes occurring in the parent storms. At the flash scale, a lightning flash is not a continuous phenomenon but is in fact composed of successive events, also called flash components, with different physical properties in terms of discharge propagation, radiation type, current properties, space and time scales. First a brief description of lightning detection techniques will be given. Then examples of flashes observed simultaneously by different instruments and replaced in their cloud context will be presented. Properties of the lightning activity will be discussed according to the dynamical and microphysical characteristics of the parent thunderclouds based on observational and modeling-based studies. Finally the EXAEDRE (EXploiting new Atmospheric Electricity Data for Research and the Environment) project will be introduced with an emphasis on the airborne field campaign scheduled between mid-September and mid-October 2018 in Western Mediterranean Sea.

  14. Environmental & Climate Sciences Department Seminar

    "Nano-aerosol and Air Ion Measurement using Parallel Electrical Aerosol Spectrometry"

    Presented by Sander Mirme, University of Tartu/Airel Ltd., Estonia

    Thursday, March 15, 2018, 11:30 am
    Conference Room Bldg 815E

    Hosted by: Janek Uin

    A parallel electrical aerosol spectrometer is essentially a differential mobility analyzer with many output sections and measurement channels. Instead of varying the analyzer voltage to scan over a range of particle mobilities, the whole distribution is captured at once. The principle is used by the Neutral cluster and Air Ion spectrometer (NAIS) to measure ions in the size range from 0.8 nm to 40 nm and neutral particles from 2 nm to 40 nm. The instrument is used in many places around the world, from polluted downtowns to jungles and mountain tops, to study new particle formation and other aerosol phenomena. The talk will give an overview of the principles and designs of the NAIS and other aerosol instrumentation developed at the University of Tartu and the spin-off company Airel Ltd.

  15. Environmental & Climate Sciences Department Seminar

    "Deep convective outflow, level of neutral buoyancy, entrainment rate and convective core: new insights from space-borne cloud radar observations"

    Presented by Zhengzhao (Johnny) Luo, CUNY

    Thursday, March 8, 2018, 11 am
    Conference Room Bldg 815E

    Hosted by: Mike Jensen

    Level of neutral buoyancy (LNB) is an important parameter for understanding convection because it sets the potential vertical extent for convective development. It can be estimated from the parcel theory using the ambient sounding without having to observe any actual convective cloud development. In reality, however, convection interacts with the environment in complicated ways; it will eventually find its own effective LNB and manifests it through detraining masses and developing cirrus anvils. In a series of recent papers, we investigated the relationship between the LNB and actual deep convective outflow using 5 years of CloudSat observations. Due to entrainment dilution, the actual outflow level is almost always lower than the LNB. The difference between the two can be interpreted as a proxy for entrainment rate. It was found that the entrainment rate as determined this way is larger over tropical ocean (e.g., TWP warm pool) than tropical land (e.g., Africa and Amazon). Analysis of radar reflectivity profiles further shows that land convection has wider and more intense cores than the oceanic counterpart. These findings lend observational support to a long-standing assumption in convection models concerning the negative relationship between entrainment rate and convective core size. Finally, we examined the environment conditions for the observed convection cases and found that convective outflow tends to occur at a higher level when the mid-troposphere is more humid and when convective system size is smaller. Application of similar analysis to ground-based radar observations (such as those from the DOE ARM program) will be discussed. ?

  16. Environmental & Climate Sciences Department Seminar

    "The impact of organic aerosols partitioning on activated cloud number concentration"

    Presented by Chloe Y. Gao, NASA Goddard Institute for Space Studies

    Thursday, March 1, 2018, 11 am
    Conference Room Bldg 815E

    Hosted by: Laura Fierce

    We examined the impact of condensing organic aerosols on activated cloud number concentration in a new aerosol microphysics model, MATRIX-VBS. The model, which can be used as a box model or a module in a global model, includes the volatilitybasis set (VBS) framework in an aerosol microphysical scheme MATRIX (Multiconfiguration Aerosol TRacker of mIXing state) that resolves aerosol mass and number concentrations and aerosol mixing state. Parameters such as aerosol chemical composition, mass and number concentrations, and particle sizes which affect activated cloud number concentration were thoroughly evaluated via a suite of Monte-Carlo simulations. Results from the box model show that by including the condensation of organic aerosols, under most conditions, the new model (MATRIX-VBS) has less activated particles compared to the original model (MATRIX), which treats organic aerosols as non-volatile. When implemented in the global model GISS ModelE as a module, we expect that the improved box model in the global scale would more accurately represent aerosol-cloud interactions. Thus it would offer us valuable insights on how the addition of organic partitioning would change cloud activation in the global atmosphere and its implications for climate.

  17. Environmental & Climate Sciences Department Seminar

    "Understanding the Structure and Dynamics of Long-Duration Floods using Physics Informed Bayesian Multilevel Models"

    Presented by Naresh Devineni, CUNY

    Thursday, January 18, 2018, 11 am
    Conference Room Bldg 815E

    Hosted by: Bob McGraw

    Long duration floods cause substantial damage and prolonged interruptions to water resource facilities, critical infrastructure, and regional economic development. We present a novel physics-based model for inference of such floods with a deeper understanding of dynamically integrated nexus of land surface wetness, effective atmospheric blocking/circulation, and moisture transport/release mechanism. Diagnostic results indicate that the flood duration is varying in proportion to the antecedent flow condition which itself is a function of the available moisture in the air, the persistency in atmospheric pressure blocking, convergence of water vapor, and the effectiveness of divergent wind to condense the aforesaid atmospheric water vapor into liquid precipitation. A physics-based Bayesian inference model is developed that considers the complex interactions between moisture transport, synoptic-to-large-scale atmospheric blocking/circulation pattern, and the antecedent wetness condition in the basin. We explain more than 80% variations in flood duration with a high success rate on the occurrence of long duration floods. Our findings underline that the synergy between a large persistent low-pressure blocking system and a higher rate of divergent wind often triggers a long duration flood, even in the presence of moderate moisture supply in the atmosphere. This condition in turn causes an extremely long duration flood if the basin-wide surface wetness prior to the flood event was already high.

  18. Environmental & Climate Sciences Department Seminar

    "Satellite-based estimates of convective mass flux and large-scale mass flux a new approach and applications"

    Presented by Zhengzhao (Johnny) Luo, CUNY

    Thursday, January 4, 2018, 10:30 am
    Conference Room Bldg 815E

    Hosted by: Mike Jensen

    pending

2017

  1. Environmental & Climate Sciences Department Seminar

    "Application of a cloud-resolving model to climate-change problems"

    Presented by Marat Khairoutdinov, SUNY Stony Brook

    Thursday, November 30, 2017, 11 pm
    Conference Room Bldg 815E

    Hosted by: Bob McGraw

    Convection contributes significantly to the uncertainty of the climate feedbacks to the forcing due to increasing presence of anthropogenic green-house gases as simulated by the contemporary global climate models (GCMs). In nature, convection tends to self-organize on larger scales, from squall-lines to tropical cyclones (TCs), or even planetary-scale systems associated with the Madden-Julian Oscillation. Cloud-resolving models (CRMs) have been used to gain some insight into these important issues. In this talk, the results of application of a particular CRM, the System for Atmospheric Modeling, or SAM, to several problems involving self-organized tropical convection among others will be presented. In particular, preliminary results of global cloud-resolving simulations with a 4 km horizontal grid spacing will be shown. Also, a high-resolution building-resolving LES of pollutant transport over Manhattan and simulation of tsunami in New York Harbor will be introduced as examples of urban modeling.

  2. Environmental & Climate Sciences Department Seminar

    "Carbonaceous Gas and Aerosol Measurements to Validate Models and Verify Emissions"

    Presented by Manvendra Dubey, Los Alamos National Laboratory

    Monday, November 20, 2017, 11 am
    Conference Room Bldg 815E

    Hosted by: Steve Schwartz

    Earth system models rely on accurate representations of processes and emissions that are evaluated using observations. Iterative refinements are crucial for reliable and robust climate assessments, as I will illustrate with following recent case studies: Carbonaceous aerosol (CA) forcing in current models is prescribed as a balance between the warming by black carbon and the cooling by organic aerosol. However, data show that some organic aerosols called brown carbon absorb sunlight. Furthermore, transparent coatings on black carbon amplify their light absorbing potency by lensing. Such coatings could make black carbon more hydrophilic thereby reducing their lifetime and burden. I will use field and laboratory studies to uncover the fundamental chemistry controlling the optical properties and water affinity of CAs as they age to enable prognostic treatments. Atmospheric carbon dioxide (CO2) accumulation is moderated by its uptake by forests and oceans that soak up 25% each of the human emissions. How carbon sinks will respond to future climate change is uncertain. I will present observations of daily and seasonal variations of column CO2 and CO over the Amazon rainforest. I will show that both biomass burning and net ecosystem exchange that are out of phase control the seasonal CO2 cycle and are captured well by models. However, the daily CO2 drop driven by photosynthesis is biased low in models, a problem that needs to be fixed. Atmospheric Methane (CH4) that accounts for 25% of climate forcing is rising after a long hiatus. Potential causes include leaks from shale gas revolution, intensive agriculture, permafrost thaw, expand wetlands or shorter lifetime by higher Hydroxyl. I will review recent findings and focus on our discovery of the methane hot spot over Four Corners, NM attributed to fossil fuel that demonstrated reported emissions were low by a factor of 3. I will close with our development of an automated neural network methane leak detection

  3. Environmental & Climate Sciences Department Seminar

    "Microwave to millimeter wave radiometry from satellites for cloud characterization"

    Presented by Catherine Prigent, CNRS-Institute National des Sciences de'l Univers (INSU), France

    Tuesday, November 14, 2017, 11 am
    Conference Room Bldg 815E

    Hosted by: Mike Jensen

    Passive microwave observations from satellites are increasingly used for the quantification of cloud and precipitation parameters. The frequencies above 80 GHz are sensitive to the cloud and precipitation frozen phase, and can provide unique information on the ice water path as well as on the size and shape of the hydrometeors. On board the Global Precipitation Measurement (GPM) mission for instance, the Microwave Imager (GMI) includes channels up to 190 GHz for a better estimation of the snowfall, to complement the lower frequency channels that were already present on TRMM (Tropical Rainfall Measuring Mission). The meteorological observations from satellites in the microwave domain are currently limited to below 190 GHz. However, the next generation of the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) Polar System-Second Generation-EPS-SG will carry an instrument, the Ice Cloud Imager (ICI), with frequencies up to 664 GHz, to improve the characterization of the cloud frozen phase. This presentation will propose an overview of the application of the millimeter wave observations for cloud and precipitation estimation, insisting on the challenges that have to be faced and the methodology developed to exploit this wavelength range.

  4. Environmental & Climate Sciences Department Seminar

    "Marine dissolved organic matter reactivity and a possible aerosol sink? Insights from radiocarbon (14C) analyses"

    Presented by Steven R. Beaupré, School of Marine and Atmospheric Sciences, Stony Brook University

    Thursday, November 9, 2017, 11 am
    Conference Room Bldg 815E

    Hosted by: Ernie Lewis

    Marine dissolved organic matter (DOM) is a complex mixture of molecules comprising the largest reservoir of organic matter in seawater, yet its sources and sinks remain largely unconstrained. While radiocarbon (14C) is a powerful tracer of time and mass, the lack of specificity in bulk 14C measurements and the analytical costs of compound specific 14C analyses have limited our observations. As an alternative, monitoring the 14C content of CO2 evolved during quantitative oxidation in concert with chemical kinetics analyses provides rapid insights into the compositions, reactivities, and coarse 14C "age" spectra of complex natural mixtures. In this talk, I will first demonstrate how monitoring photochemical and thermal oxidation reinforces a long-standing, but confusing, two-component age model of marine DOM. That is, the 14C age of DOM throughout the water column can be described as a mixture of molecules that fall into just two distinct age groups: recently produced vs. refractory DOM (RDOM). Second, I will discuss a test of one recently hypothesized sink of RDOC: namely, that RDOC could be removed from the oceans through adsorption onto the surfaces of rising bubble plumes produced by breaking waves, ejection into the atmosphere via bubble bursting as a component of primary marine aerosol (PMA), and subsequent oxidation in the atmosphere. In this test, measured the 14C signatures of PMA produced in a high capacity generator at two biologically-productive and two oligotrophic hydrographic stations in the Northwest Atlantic Ocean during a research cruise aboard the R/V Endeavor (Sep – Oct 2016). The 14C signatures of PMA generated were compared with corresponding 14C signatures in seawater of near-surface dissolved inorganic carbon (DIC, a proxy for recently produced organic matter), bulk deep DOC (a proxy for RDOC), and near-surface bulk DOC. Preliminary results and their constraints on the selectivity of PMA formation from RDOC will be discusse

  5. Environmental & Climate Sciences Department Seminar

    "Desert Dust, Wildfire Smoke, Volcanic Ash, Urban and Industrial Pollution – Grasping the Role Particles Play in Global Climate and Regional Air Quality"

    Presented by Ralph Kahn, NASA Goddard Space Flight Center

    Thursday, October 19, 2017, 11 am
    Conference Room Bldg 815E

    Hosted by: Steve Schwartz

    Airborne particles are ubiquitous components of our atmosphere, originating from a variety of natural and anthropogenic sources, exhibiting a wide range of physical properties, and contributing in multiple ways to regional air quality as well as regional-to-global-scale climate. Most remain in the atmosphere for a week or less, but can traverse oceans or continents in that time, carrying nutrients or disease vectors in some cases. Bright aerosols reflect sunlight, and can cool the surface; light-absorbing particles can heat the atmosphere, suppressing cloud formation or mediating larger-scale circulations. In most cases, particles are required to collect water vapor as the initial step in cloud formation, so their presence (or absence) and their hygroscopic or hydrophilic properties can affect cloud occurrence, structure, and ability to precipitate. Grasping the scope and nature of aerosol environmental impacts requires understanding microphysical-to-global scale processes, operating on timescales from minutes to days or longer. Satellites are the primary source of observations on kilometer-to-global scales. Spacecraft observations are complemented by suborbital platforms: aircraft in situ measurements and surface-based instrument networks that operate on smaller spatial scales, some on shorter timescales. Numerical models play a third key role in this work — providing a synthesis of current physical understanding with the aggregate of measurements, and allowing for some predictive capability. This presentation will focus on what we can say about aerosol amount and type from space. Constraining particle "type" is at present the leading challenge for satellite aerosol remote sensing. We will review recent advances and future prospects, including the strengths and limitations of available approaches, and current work toward better integrating measurements with models to create a clearer picture of aerosol environmental impacts, globally.

  6. Environmental & Climate Sciences Department Seminar

    "Investigating Convective Dynamic Detrainment Heights in Observations and Model Forecasts"

    Presented by Mariusz Starzec, University of North Dakota

    Wednesday, September 20, 2017, 11 am
    Conference Room Bldg 815E

    Hosted by: Mike Jensen

    Deep moist convection plays a pivotal role ranging from daily weather impacts to long-term climatic feedbacks. The height and depth of deep convection are particularly important parameters for studies focusing on convective mass transport. Deep convection has the potential to rapidly transport mass and chemical constituents from the boundary layer into the upper tropospheric and lower stratospheric layer. Depending on whether convection is able to reach and penetrate the tropopause has significant implications on whether mass is rapidly transported into the troposphere or the stratosphere, where long residence times can alter the chemical budget and have important effects on climate. Nevertheless, accurately identifying the dynamic convective detrainment height is not easily achieved and commonly used methods contain considerable limitations or assumptions. Observations, such as taken by satellite or aircraft, are typical limited temporally and/or spatially. To account for limited observations, focus is either directed on the use of parcel theory or chemical modeling; however, assumptions in parcel theory are often invalid in observed convection and limited knowledge is available on the accuracy of simulated storm depths and heights. To enhance our understanding and enable more common retrievals of convective detrainment heights, a methodology utilizing the reflectivity field from ground-based radars is used to locate the detrainment envelope and level of maximum detrainment (LMD). A new radar classification algorithm that uses three-dimensional radar observations to stratify radar echo is used to identify suitable regions of convectively-generated anvil, which are used as a proxy for dynamic detrainment. The methodology is validated against dual-Doppler observations and preliminary results of applying the methodology to several months of volumetric radar composites are presented. Additionally, four months of convective forecasts are evaluated to determine the ac

  7. Environmental & Climate Sciences Department Seminar

    "Emission and Aging of Organic Aerosols from Wildfires in the Western US: Insights from the BBOP campaign"

    Presented by Qi Zhang, University of California, Davis

    Thursday, August 17, 2017, 11 am
    Conference Room Bldg 815E

    Hosted by: Bob McGraw

    Biomass burning (BB) is one of the most important contributors to atmospheric aerosols on a global scale and the environmental impacts of BB aerosols are strongly correlated with their chemical, optical, and microphysical properties. In this study, we investigated the properties and atmospheric aging of BB aerosols from wildfires in the Western US from the Mt. Bachelor Observatory (MBO; ~ 2700 m a.s.l.) in Central Oregon, as part of the DOE Biomass Burning Observation Project (BBOP) campaign in summer 2013. Plumes transported from forest fires in N California and SW Oregon were frequently observed. Organic aerosol (OA) dominated aerosol composition in BB plumes and three types of BBOA was identified: a less oxidized (O/C = 0.35), semivolatile BBOA-1 (~ 20% of OA mass) and two more oxidized BBOAs (BBOA-2 and BBOA-3). BBOA-1 was enriched of levoglucosan and was chemically similar to POA in fresh BB emissions. BBOA-3 was highly oxidized (O/C = 1.06; 31% of OA mass), contained no levoglucosan, showed very low volatility with only ~ 40% mass loss at 200°C, and had a similar mass spectrum as low-volatility oxygenated OA (LV-OOA) commonly observed in regional airmass. This finding highlights the possibility that the influence of BB emission could be significantly underestimated in regional air masses where highly oxidized BBOA (e.g., BBOA-3) might be a significant aerosol component. Increasing oxidation of BBOA was observed in more aged BB plumes but the enhancement ratios of BBOA relative to CO were nearly constant independent of plume aging. The chemical evolution of BBOA was examined for a BB plume event where fire plumes originated from a single fire source were sampled continuously for 36 hours. The average oxidation state of BBOA and the mass fraction of aged BBOA (= BBOA-2 + BBOA-3) in fire smoke increased with the increase of cumulative solar irradiance during transport, but the OA/CO ratios remained constant in the plumes. A possible explanation is that SOA f

  8. Environmental & Climate Sciences Department Seminar

    "Effects of Solar Geoengineering on Clouds, Energy Transport and the ITCZ"

    Presented by Rick Russotto, University of Washington

    Monday, July 31, 2017, 11 am
    Conference Room Bldg 815E

    Hosted by: Mike Jensen

    The polar amplification of warming and the ability of the inter-tropical convergence zone (ITCZ) to shift to the north or south are two very important problems in climate science. Examining these behaviors in global climate models (GCMs) running solar geoengineering experiments is helpful not only for predicting the effects of solar geoengineering, but also for understanding how these processes work under increased CO2. Both polar amplification and ITCZ shifts are closely related to the meridional transport of moist static energy (MSE) by the atmosphere. This study examines changes in MSE transport in 10 fully coupled GCMs in Experiment G1 of the Geoengineering Model Intercomparison Project, in which the solar constant is reduced to compensate for abruptly quadrupled CO2 concentrations. In this experiment, poleward MSE transport decreases relative to preindustrial conditions in all models, in contrast to the CMIP5 abrupt4xCO2 experiment, in which poleward MSE transport increases. Since poleward energy transport decreases rather than increasing, and local feedbacks cannot reverse the sign of an initial temperature change, the residual polar amplification in the G1 experiment must be due to the different spatial patterns of the simultaneously imposed solar and CO2 forcings. However, the reduction in poleward energy transport likely plays a role in limiting the polar warming in G1. The seasonal migration of the ITCZ is dampened in G1 relative to abrupt4xCO2 due to preferential cooling of the summer hemisphere by the solar reduction. The ITCZ shifts northward in G1 by 0.14 degrees in the annual, multi-model mean, with an inter-model range of -0.33 to 0.89 degrees. These shifts are anticorrelated with changes in cross-equatorial MSE transport. An attribution study with a moist energy balance model shows that cloud feedbacks are the largest source of uncertainty regarding changes in cross-equatorial energy transport under solar geoengineering. Analysis of cloud changes in

  9. Environmental & Climate Sciences Department Seminar

    "Classifying Aerosol Particles with a Centrifugal Particle Mass Analyzer (CPMA)"

    Presented by Kristen Okorn, Stevens Institute of Technology (SULI Student Summer 2017)

    Thursday, July 27, 2017, 11 am
    Conference Room Bldg 815E

    Hosted by: Ernie Lewis

    Although wood stoves are a carbon-neutral renewable energy source, they are the largest source of particulate matter (PM) emissions in New York State. A Differential Mobility Analyzer (DMA), which classifies particles by their mobility diameter, has traditionally been employed to characterize such particulate emissions. However, because the black carbon (BC) particles produced by combustion that contribute to PM are fractal, their mobility diameters are not equal to their mass-equivalent diameters. In contrast to the DMA, the Centrifugal Particle Mass Analyzer (CPMA) classifies aerosol particles by their mass, using two rotating cylinders and an electric potential; when the centrifugal and electrostatic forces on a particle are equal, it passes through. The CPMA can select particles with masses ranging from 2×10 4 to 1.05×103 fg (corresponding to diameters, for particles with density 1 g cm 3, ranging from 7 to 1300 nm). It can be operated in two different ways: the "Run" classification method can be used to select for a single particle mass, and the "Step Scan" method can be used to select particles over a set range of masses. A neutralizer must be used upstream of the CPMA to create a charge distribution on particles before they enter the instrument. A DMA can optionally be used to pre-select particles of a specific mobility diameter before entering the CPMA. Downstream of the instrument, a Condensation Particle Counter (CPC) must be used in order to determine the number concentration of particles that pass through the CPMA. The basic operating principles of the CPMA are discussed, and results are presented for its characterization of polystyrene latex (PSL) particles, ammonium sulfate particles, and emissions from a wood burning stove.

  10. Environmental & Climate Sciences Department Seminar

    "Cloud radiative fraction: Determination by high resolution photography from the surface looking upward"

    Presented by Stephen E. Schwartz, Environmental & Climate Sciences Department

    Thursday, June 1, 2017, 11 am
    Conference Room Bldg 815E

    Clouds greatly affect short- and longwave radiation transfer in the atmosphere and consequently climate. Hence it is essential that the amount and radiative influences of clouds be accurately represented in climate models. The conventional measure of the amount of cloud in a grid cell is cloud fraction, CF, the fraction of the surface area covered by cloud. CF is a commonly reported meteorological quantity, with a long record of surface observations, greatly augmented in the past several decades by satellite observations. Global cloud fraction determined from satellite measurements has systematically increased with time, a consequence not of secular increase in cloud fraction but of an increase with time in the sensitivity of active and passive satellite instruments. Such a situation raises the question of whether CF can be defined and how well it can be measured. Commercially available digital cameras provide an unprecedented opportunity for detailed study of cloud structure from the surface, looking upward. Key attributes of such cameras include large number of pixels, (e.g., 3456 x 4608; 16 M pixel) yielding rich detail of spatial structure, high spatial resolution, and high dynamic range (16 bit in each of three color channels at visible wavelengths). In the work reported here two cameras were pointed vertically, typically with field of view FOV 21 × 29 mrad and 120 × 160 mrad, respectively, denoted here narrow field of view, NFOV, and wide field of view WFOV, corresponding, for cloud base at 1 km, to 21 × 29 m (NFOV) and 120 × 160 m (WFOV). For perspective, the FOV for the NFOV camera is 2 × 3 sun diameters and for the WFOV camera 11 × 15 sun diameters. Nominal angular dimension of a single pixel is 6 μrad for the NFOV camera and 34 μrad for the WFOV camera, corresponding, again for cloud height 1 km, to 6 mm and 34 mm, respectively. Such single-pixel resolution is some 3 to 5 orders of magnitude finer than that avai

  11. Environmental & Climate Sciences Department Seminar

    "Direct Measurements of Absorbing Aerosols to Reduce Uncertainties in Climate Models"

    Presented by Allison C. Aiken, Los Alamos National Laboratory

    Wednesday, May 10, 2017, 11 pm
    Conference Room Bldg 815E

    Hosted by: Janek Uin

    Aerosols and their climate forcing represent one of the largest uncertainties in global climate models (GCMs) today. Despite being tiny in size (~1nm - ~10 µm in diameter), ambient aerosols have large impacts through their microphysical interactions and climate feedbacks. For these reasons, direct in situ measurement of aerosol chemical, physical and morphological properties is a high priority to reduce these uncertainties. Absorbing aerosols that absorb light and contribute to atmospheric warming are of particular interest due to their anthropogenic sources, potential to increase in the future due to climate change, and impacts on human health. Large uncertainties exist on the extent of the warming that absorbing aerosols cause, specifically due to morphology and mixing state as black carbon physical and optical properties change as particles are transported in the atmosphere due to oxidation, coagulation, and condensation. For this reason, black carbon and organic carbon aerosol species that are emitted from combustion sources such as biomass burning and diesel sources will be presented. Emission ratios, physical and optical properties will be compared to those from controlled laboratory studies to understand carbonaceous aerosols and their transformations in the atmosphere. Laboratory measurements are used as a framework to understand the ambient observations and to improve model treatment of aerosols and aging in global climate models.

  12. Environmental & Climate Sciences Department Seminar

    "Sub 2 nm Particle Characterization in Systems with Aerosol Formation and Growth"

    Presented by Yang Wang, Washington University

    Wednesday, March 8, 2017, 10 am
    Conference Room Bldg 815E

    Hosted by: Jian Wang

    Aerosol science and technology enable continual advances in material synthesis and atmospheric pollutant control. Among these advances, one important frontier is characterizing the initial stages of particle formation by real time measurement of particles below 2 nm in size. Sub 2 nm particles play important roles by acting as seeds for particle growth, ultimately determining the final properties of the generated particles. Tailoring nanoparticle properties requires a thorough understanding and precise control of the particle formation processes, which in turn requires characterizing nanoparticle formation from the initial stages. This work pursued two approaches in investigating incipient particle characterization in systems with aerosol formation and growth: (1) using a high-resolution differential mobility analyzer (DMA) to measure the size distributions of sub 2 nm particles generated from high-temperature aerosol reactors, and (2) analyzing the physical and chemical pathways of aerosol formation during combustion. Part. 1. Particle size distributions reveal important information about particle formation dynamics. DMAs are widely utilized to measure particle size distributions. However, our knowledge of the initial stages of particle formation is incomplete, due to the Brownian broadening effects in conventional DMAs. The first part of this presentation discusses the applicability of high-resolution DMAs in characterizing sub 2 nm particles generated from high-temperature aerosol reactors, including a flame aerosol reactor (FLAR) and a furnace aerosol reactor (FUAR). Comparison against a conventional DMA (Nano DMA, Model 3085, TSI Inc.) demonstrated that the increased sheath flow rates and shortened residence time indeed greatly suppressed the diffusion broadening effect in a high-resolution DMA (half mini type). The incipient particle size distributions were discrete, suggesting the formation of stable clusters that may be intermediate phases betw

  13. Environmental & Climate Sciences Department Seminar

    "The Impact of Organic Aerosol Volatility on Aerosol Microphysics for Global Climate Modeling Applications"

    Presented by Yuchao 'Chloe' Gao, NASA Goddard Institute for Space Studies, China

    Thursday, February 9, 2017, 11 am
    Conference Room Bldg 815E

    Hosted by: Robert McGraw

    A newly developed box model, MATRIX-VBS [Gao et al., 2017], includes the volatility-basis set (VBS) framework in an aerosol microphysical scheme MATRIX (Multiconfiguration Aerosol TRacker of mIXing state) [Bauer et al., 2008], which is a module within GISS ModelE that resolves aerosol mass and number concentrations and aerosol mixing state. By including the gas-particle partitioning and chemical aging of semi-volatile organic aerosol in MATRIX, we were able to examine its effects on the growth, composition and mixing state of particles. MATRIX-VBS is unique and advances the representation of organic aerosols in Earth system models by greatly improving the traditional and very simplistic treatment of organic aerosols as non-volatile and with a fixed size distribution. Idealized cases representing Beijing, Mexico City, a Finnish and a Southeast U.S. forest were simulated, and we investigated the evolution of mass concentrations and volatility distributions for organic species across the gas and particle phases, as well as their mixing state among aerosol populations. To test and simplify the model, a Monte-Carlo analysis is performed to pin point which processes affect organics the most under varied chemical and meteorological conditions. Since the model's parameterizations have the ability to capture a very wide range of conditions, all possible scenarios on Earth across the whole parameter space, including temperature, humidity, location, emissions and oxidant levels, are examined. These simulations provide information on which parameters play a critical role in the aerosol distribution and evolution in the atmosphere and which do not, and that will facilitate the simplification of the box model, an important step in its implementation in the global model GISS ModelE as a module.

  14. Environmental & Climate Sciences Department Seminar

    "SURF Project: Understanding Urban Convection and Haze"

    Presented by Shiguang Miao, Beijing Institute for Urban Meteorology, China

    Thursday, February 2, 2017, 11 am
    Conference Room Bldg 815E

    Hosted by: Jorge Gonzalez/Alice Cialella

    Half the global population will be in cities by 2025, many having more than 10 million people. Urbanization modifies atmospheric energy and moisture balances, forming local climates, e.g. urban heat islands (UHIs) and enhanced precipitation. These produce significant challenges to science and society, e.g. flooding, heat waves strengthened by UHIs, and air pollutant hazes. The Beijing megacity experiences such severe events, e.g., 2012 flooding killed 79 and caused losses of $2B. Despite significant research into urban effects on weather and air quality, important science issues remain, e.g., urban-thermodynamic and aerosol impacts on summer convective precipitation and interactions between urban and regional climate changes. Observations are fundamental for understanding these interactions, improving forecasts, and providing useful information to end-users. Previous large urban field campaigns have not been coordinated by a group such as the Beijing Institute of Urban Meteorology (IUM), with its responsibilities for both boundary layer research and real time urban weather forecasting. The overall science objective of the 2014-8 SURF Project is thus a better understanding of urban, terrain, convection, and aerosol interactions for improved forecast accuracy. Beijing is a test case, but the improved understandings are transferable to many large cities globally. Specific objectives include: Promote cooperative international-research to improve understanding of urban weather-systems via summer thunderstorm-rainfall and winter aerosol field studies; Improve high-resolution (∼1 km grid) urban weather and air quality forecast-models; and, Enhance urban weather forecasts for societal applications, e.g., health, energy, hydrologic, climate change, air quality, urban planning, emergency-response management.

  15. Environmental & Climate Sciences Department Seminar

    "What's happening in near-road air quality? Insights from a recent field study near a North Carolina Interstate freeway"

    Presented by Provat Saha, North Carolina State University

    Thursday, January 12, 2017, 11:45 am
    Conference Room Bldg 815E

    Hosted by: Jian Wang

    Motor vehicles emit gas- and particle-phase air pollutants, including organic and inorganic gasses, black carbon (BC), organic aerosols (OA) and other species, which are linked with adverse human health effects, visibility reductions, and climate effects. There are steep gradients in concentrations of these species within 10s to 100s of meters from the roadway. The mechanistic evolution of vehicle emissions downwind of a roadway involves complex physicochemical processes and varies spatially and temporally. Exposure concentrations of different pollutants in a near-road environments are influenced by the complex dispersion process, built environments and meteorological factors which lead to physicochemical transformations of primary reactive species. For a better understanding of exposure and evolution of near-road air pollutants, we conducted a comprehensive field study at a site near Interstate 40, near Durham, North Carolina. The specific aims of this study were: 1) characterizing the spatio-temporal and seasonal trends of multiple air pollutant concentrations in a near highway setting, 2) characterizing near-road submicron aerosol volatility and mixing state, and 3) determining the extent to which motor vehicles contribute to ambient secondary OA production. Results from this study show strong seasonal and diurnal differences in downwind concentration gradients with a less-sharp near-road gradients in winter in many species, decreasing of the semi-volatile fraction in ultrafine particle with downwind distance, and a substantial seasonal differences in secondary OA (SOA) formation due to oxidation of near-highway air in an oxidation flow reactor. Details observations from this field study will be discussed. This talk may also briefly address two other projects those are part of my Ph.D. work, (i) improve quantification of gas-particle partitioning parameter values of organic aerosol using a dual-thermodenuder system, and (ii) laboratory aging of wood smoke from d

2016

  1. Environmental & Climate Sciences Department Seminar

    "Stochastic ice nucleation and its effect on the microphysical properties of mixed-phase stratiform cloud"

    Presented by Fan Yang, Michigan Technological University

    Monday, November 21, 2016, 11 am
    Conference Room Bldg 815E

    Hosted by: Mike Jensen

    Mixed-phase stratiform clouds can persist with steady ice precipitation for hours and even days. The origin and microphysical properties of the ice crystals are of interest. Vapor deposition growth and sedimentation of ice particles along with a uniform volume source of ice nucleation lead to a power law relation between ice water content (wi) and ice number concentration (ni) with exponent 2.5. The relation is confirmed by both a large-eddy simulation cloud model and Lagrangian ice particle tracking with cloud volume source of ice particles through a time-dependent cloud field. Initial indications of the scaling law are observed in data from the Indirect and Semi-Direct Aerosol Campaign (ISDAC). Based on the observed wi and ni from ISDAC, a lower bound of 0.006 m-3s-1 is obtained for the volume ice crystal formation rate. Results from Lagrangian ice particle tracking method also show that more than 10% of ice particles have lifetimes longer than 1.5 h, much longer than the large eddy turnover time or the time for a crystal to fall through the depth of a nonturbulent cloud. An analysis of trajectories in a 2-D idealized field shows that there are two types of long-lifetime ice particles: quasi-steady and recycled growth. For quasi-steady growth, ice particles are suspended in the updraft velocity region for a long time. For recycled growth, ice particles are trapped in the large eddy structures, and whether ice particles grow or sublimate depends on the ice relative humidity profile within the boundary layer. Some ice particles can grow after each cycle in the trapping region, until they are too large to be trapped, and thus have long lifetimes. The relative contribution of the recycled ice particles to the cloud mean ice water content depends on both the dynamic and thermodynamic properties of the mixing layer. In particular, the total ice water content of a mixed-phase cloud in a decoupled boundary layer can be much larger than that in a fully coupled boundary la

  2. Environmental & Climate Sciences Department Seminar

    "Observational constraints on mixed-phase clouds imply higher climate sensitivity"

    Presented by Ivy Tan, Yale Univ.

    Thursday, November 10, 2016, 11 am
    Conference Room Bldg 815E

    Hosted by: Robert McGraw

    Mixed-phase clouds are comprised of both liquid droplets and ice crystals. For a given total water content, mixed-phase clouds with higher liquid water contents are optically thicker and therefore more reflective to sunlight compared to those with higher ice water contents. This is due to the fact that liquid droplets tend to be smaller in size and more abundant than ice crystals in Earth's atmosphere. Given the ubiquity of mixed-phase clouds, the ratio of liquid to ice in these clouds is expected to be important for Earth's radiation budget. We determine the climatic impact of thermodynamic phase partitioning in mixed-phase clouds by using five pairs of simulations run with CAM5/CESM. Of the five pairs of simulations, the thermodynamic phase partitioning of two of the simulations were constrained to better agree with observations from CALIPSO. The other three pairs of simulations include a control simulation, as well as an upper and lower bound simulation with maximally high and low amounts of mixed-phase cloud liquid fractions. An analysis of the simulations shows that a negative "cloud phase feedback" that occurs due to the repartitioning of cloud droplets and ice crystals under global warming is weakened when mixed-phase clouds initially contain a higher amount of liquid. Simulations that exhibited weaker cloud phase feedbacks also had higher climate sensitivities. The results suggest that an unrealistically strong cloud phase feedback leading to lower climate sensitivities may be lurking in the many climate models that underestimate mixed-phase cloud liquid fractions compared to observations.

  3. Environmental & Climate Sciences Department Seminar

    "Sea Level Lies: Ethics and Policy Realities for Coastal Communities"

    Presented by Keith Rizzardi, St. Thomas University School of Law, Miami Gardens, FL

    Thursday, November 3, 2016, 11 am
    Conference Room Bldg 815E

    Hosted by: Tom Watson

    Discussion of the harsh truths of rising seas, and the ethical and policy challenges, with a focus on Florida.

  4. Environmental & Climate Sciences Department Seminar

    "Using satellite observations to evaluate the representation of clouds in climate models"

    Presented by Gregory Cesana, Jet Propulsion Laboratory

    Friday, October 28, 2016, 11 am
    Conference Room Bldg 815E

    Hosted by: Mike Jensen

    The ubiquitous presence of clouds within the troposphere (global total cloud frequency about 70%) strongly characterizes the radiative balance of the earth-atmosphere system. Knowledge of the distribution of clouds and their response to a warmer climate are crucial to anticipate the evolution of our future climate. Yet, this challenge remains subject to large uncertainties in climate modeling, wherein the vertical structure of clouds plays a crucial role. Due to the potential for significant variations in the height, temperature and microphysical properties of a cloud, there is a significant range of radiative impacts from clouds. In this presentation, I will take advantage of active sensor observations from the CALIPSO satellite and recent climate simulations from multi-model experiments to characterize systematic biases in the representation of clouds and cloud microphysics in contemporary climate models. To this end, I will introduce the satellite simulator approach, which reduces uncertainties related to instrument biases and ensures a consistent comparison between models and observations. Then, I will show a couple of examples of model biases focused on the vertical structure of clouds and the transition between supercooled liquid clouds and ice clouds. Finally, I will determine whether these biases are systematic or not, and explore their origin.

  5. Environmental & Climate Sciences Department Seminar

    "Intercontinental smog: how and why global models fail to resolve intercontinental chemical plumes"

    Presented by Sebastian Eastham, Harvard University Center for the Environment

    Thursday, October 27, 2016, 11 am
    Conference Room Bldg 815E

    Hosted by: Laura Fierce

    Air quality exceedances in California are frequently attributed to Asian pollution, but global Eulerian models consistently fail to reproduce the intercontinental chemical plumes which are responsible. This has been attributed to excessive numerical diffusion. We apply a global model over a wide range of horizontal resolutions in both 2-D and 3-D to isolate the specific causes and effects of this diffusion on the representation of intercontinental pollution. Our results show that the vast increases in computation power required to increase model horizontal grid resolutions are wasted if the aim is to better represent intercontinental transport of pollution. We instead provide motivation for modelers and researchers to experiment with higher vertical grid resolution if they wish to reproduce the ubiquitous quasi-horizontal plumes observed in atmospheric measurements.

  6. Environmental & Climate Sciences Department Seminar

    "Viscous organic aerosol particles and water uptake: From observations of internal diffusion fronts in single, levitated particles to estimating kinetic limitations under atmospheric conditions"

    Presented by Dr. Ulrich Krieger, Institut für Atmosphäre und Klima, Zürich, Switzerland

    Friday, September 30, 2016, 11 am
    Conference Room Bldg 815E

    Hosted by: Robert McGraw

    Field measurements in the recent past have shown that secondary organic aerosol (SOA) particles are often amorphous glasses or highly viscous liquids under dry and/or cold conditions. Chemical and physical processes occurring in the interior of the aerosol particle and at the gas/particle interface are influenced by the viscous state in which condensed-phase diffusion is slows down considerably. I will discuss measurements of water diffusion in single, levitated aerosol particles for a number of model systems of SOA. In particular, I will show how Mie-resonance spectroscopy allows to "image" diffusion fronts within these particles and discuss atmospheric implications of kinetic limitations of water uptake.

  7. Environmental & Climate Sciences Department Seminar

    "Multi-sensor Remote Sensing of Midlevel Stratiform Cloud Macro- and Microphysical Properties"

    Presented by Damao Zhang, University of Wyoming

    Thursday, September 8, 2016, 11 am
    Building 815 Conference Room

    Hosted by: Michael Jensen

    Mid-level stratiform clouds (MSCs) are not well studied and their macrophysical, microphysical, and radiative properties are poorly documented. A comprehensive view of MSCs is presented with four years of collocated CALIPSO/CloudSat measurements and with long-term ground-based remote sensing measurements. Algorithms are developed for identifying MSCs and for detecting ice particle occurrence by combining lidar and radar measurements. A global view of MSCs in terms of their occurrence frequencies, day-night and seasonal variations, and vertical distributions is provided. Multi-sensor remote sensing measurements are also used to quantify the impacts of dust on heterogeneous ice generation in supercooled MSCs over the 'dust belt'. Furthermore, algorithms are developed to retrieve ice number concentration (Ni) in stratiform mixed-phase clouds by combining cloud radar reflectivity (Ze) measurements and 1-D ice growth model simulations at given cloud top temperature (CTT) and liquid water path (LWP). Evaluations of the retrieved Ni in stratiform mixed-phase clouds with in situ measurements and with the simulations from a 3-D cloud-resolving model with bin microphysical physics scheme show that the retrieved Ni are within an uncertainty of a factor of 2, statistically.

  8. Summer Sunday

    "Family Fun Day: The Science Learning Center and Environmental Protection"

    Sunday, July 10, 2016, 10 am
    Lobby in Berkner

    A fabulous day of hands-on family fun with the Science Learning Center and Environmental Extravaganza, both ready for you to explore.

  9. Environmental & Climate Sciences Department Seminar

    "Observed and modeled sensitivity of trade-wind clouds to changes in the large-scale flow"

    Presented by Louise Nuijens, MIT

    Tuesday, June 28, 2016, 11 am
    Conference Room, Bldg 815E

    Hosted by: Mike Jensen

    Large areas over subtropical and tropical oceans experience neither strong subsidence nor strong ascent. In these regions shallow trade-wind clouds prevail, whose vertical distribution has emerged as a key factor determining the sensitivity of our climate in global climate models. But how susceptible are trade-wind clouds in our current climate? Do we understand the role of the large-scale flow in observed variations in these clouds? And do global models represent those patterns of variability? Using long time series of ground-based and space-borne remote sensing in the trades (the Barbados Cloud Observatory), combined with Large-Eddy Simulation, I will analyze how shallow cumuli and their associated cloudiness respond to changes in the large-scale atmospheric state, providing constraints on modeled cloud feedbacks. Unlike climate models, the major component of trade-wind cloudiness, which is cloudiness near the saturation level, appears remarkably robust to variability in the thermal structure of the lower atmosphere, and I will explain how convection itself plays an important role in that robustness. Variability in cloudiness is far more pronounced at levels further aloft, related to the deepening of shallow convection on mesoscale and synoptic time scales. This mesoscale variability explains, in part, why cloudiness is poorly predicted by large-scale factors on longer time scales. However, variations in vertical motion and wind speed are shown to play an important role, suggesting that we should be mindful of how the large-scale flow conditions the lower atmosphere. Global models underestimate the strength of a relationship with wind speed and diverge in particular in their response to large-scale vertical motion. I will explain why models overestimate the low cloud feedback in these regions, and discuss possible pathways through which these seemingly persistent clouds are critical to climate, even if their feedback on global mean temperature is small

  10. Environmental & Climate Sciences Department Seminar

    "Large-eddy simulation of complex turbulent flows in energy and environmental applications"

    Presented by Dr. Fotis Sotiropoulos, Dean, College of Engineering and Applied Sciences, Stony Brook University

    Wednesday, June 22, 2016, 11 am
    Conference Room, Bldg 815E

    Hosted by: Alice Cialella

    Large-eddy simulation (LES) has emerged as a powerful simulation-based engineering science tool in a broad range of engineering applications involving complex turbulent flows. In my talk I will review computational advances that have enabled the LES of multi-physics flows in arbitrarily complex domains and with flow-structure interaction. I will highlight the predictive power of these algorithms by presenting simulations of: 1) atmospheric turbulence past land-based and offshore wind farms; 2) complex floating structures in the ocean under the action of broadband waves; 3) marine and hydrokinetic energy harvesting devices in real-life waterways, and 4) flow, sediment transport and scour in large rivers during extreme flooding events. I will also discuss the potential of coupling such computational power with field-scale experiments with DNA-based flow tracers to study pathogen and pollutant transport in indoor and outdoor environments.

  11. Environmental & Climate Sciences Department Seminar

    "High-Resolution Photography of Clouds from the Surface: Retrieval of Cloud Optical Depth down to Centimeter Scales"

    Presented by Stephen Schwartz, Environmental and Climate Sciences Department

    Thursday, June 16, 2016, 11 am
    Conference Room, Bldg 815E

    Initial results are presented of a analysis of high resolution photographs of clouds at the ARM SGP site in July, 2015. A commercially available camera having 35-mm equivalent focal length up to 1200 mm (nominal resolution as fine as 6 µrad, which corresponds to 12 mm for cloud height 2 km) is used to obtain a measure of zenith radiance of a 40 m x 40 m domain as a two-dimensional image consisting of 3456 x 3456 pixels (12 million pixels). Downwelling zenith radiance varies substantially within single images and between successive images obtained at 4-s intervals. Variation in zenith radiance found on scales down to about 10 cm is attributed to variation in cloud optical depth (COD). Attention here is directed primarily to optically thin clouds, COD less than roughly 3. A radiation transfer model used to relate downwelling zenith radiance to COD and to relate the counts in the camera image to zenith radiance, permits determination of COD and cloud albedo on a pixel-by-pixel basis. COD for thin clouds determined in this way exhibits considerable variation, for example, an order of magnitude within the 40 m domain examined here and 50% over a distance of 1 m. An alternative to the widely used areal or temporal cloud fraction, denoted radiative cloud fraction, also evaluated on a pixel-by-pixel basis, is introduced. This highly data-intensive approach, which examines cloud structure on scales 3 to 5 orders of magnitude finer than satellite products, opens new avenues for examination of cloud structure and evolution.

  12. Environmental & Climate Sciences Department Seminar

    "title pending"

    Presented by Kimmo Neitola, Finnish Meteorological Institute

    Monday, May 16, 2016, 11 pm
    Conference Room, Bldg 815E

    Hosted by: Jian Wang

    pending

  13. Environmental & Climate Sciences Department Seminar

    "Orographic Convection and Precipitation in the Tropics: Wind Speed Control and Aerosol Interactions"

    Presented by Alison Nugent, UCAR

    Tuesday, April 26, 2016, 11 am
    Conference Room, Bldg 815E

    Hosted by: Jian Wang

    Mountains around the globe control precipitation patterns and water resources. Here the focus is on understanding orographic precipitation in the tropics over a small island. An aircraft dataset from the Dominica Experiment (DOMEX) which took place in the eastern Caribbean is utilized. The aircraft measured upstream and downstream airflow properties as well as the properties of the convective clouds over the island. These flight data along with an idealized numerical model are used to understand the role of wind speed in controlling the transition from thermally to mechanically forced orographic convection. When the convection is thermally driven, DOMEX observations show clear evidence of aerosol-cloud-precipitation interactions; the aerosol-aware Thompson microphysics scheme in WRF is used to investigate. Using this framework of understanding from an orographic case, a broader view of marine cloud microphysics can be gained.

  14. Environmental & Climate Sciences Department Seminar

    "Improved Tandem Measurement Techniques for Gas Phase Nanoparticle Analysis"

    Presented by Vivek Rawat, University of Minnesota

    Wednesday, April 20, 2016, 11 am
    Conference Room, Bldg 815E

    Hosted by: Jian Wang

    Non-spherical, chemically inhomogeneous nanoparticles are encountered in a number of natural and engineered environments, including combustion systems, reactors used in gas-phase materials synthesis, and in ambient air. To better characterize these complex nanoparticles, tandem measurement techniques are well suited, in which analytes are characterized by two orthogonal properties (e.g. size and mass). Tandem measurement techniques have been applied in a number of situations; however, there are still a considerable number of fundamental developments needed to advance these approaches. Specifically, new instrument combinations (with existing instruments) and appropriate data inversion routines need to be developed to determine combined two-dimensional mass-size distribution functions, pure mass distribution and for mobility-mass analysis for sub 2-nm clusters (ions). With this motivation, we first develop and apply a data inversion routine to determine the number based size-mass distribution function (two dimensional distribution) from tandem differential mobility analyzer-aerosol particle mass analyzer (DMA-APM) measurements, while correcting for multiple charging, instrument transfer functions and other system efficiencies. This two dimensional distribution can be used to calculate the number based size distribution or the mass based size distribution. We employ this technique to analyze various spherical and non-spherical nanoparticles and examine the validity of this approach by comparing the calculated size distribution functions and mass concentrations with direct measurements of these quantities. In a second study, we utilize a transversal modulation ion mobility spectrometer (TMIMS) coupled with a mass spectrometer (MS) to study vapor dopant induced mobility shifts of sub 2 nm ion clusters. Isopropanol vapor is introduced into the TMIMS, shifting the mobilities of ions to varying extents depending on ion surface chemistry, which provides an improved separa

  15. Environmental & Climate Sciences Department Seminar

    "Response of Arctic Temperature to Changes in Emissions of Short-Lived Climate Forcers"

    Presented by Maria Sand, NASA-GISS

    Thursday, April 7, 2016, 11 am
    Conference Room, Bldg 815E

    Hosted by: Laura Fierce

    Over recent decades temperatures in the Arctic have increased at twice the global rate, largely as a result of ice–albedo and temperature feedbacks. Although deep cuts in global CO2 emissions are required to slow this warming, there is also growing interest in the potential for reducing short-lived climate forcers (SLCFs). Politically, action on SLCFs may be particularly promising because the benefits of mitigation are seen more quickly than for mitigation of CO2 and there are large co-benefits in terms of improved air quality. This study systematically quantifies the Arctic climate impact of regional SLCFs emissions, taking into account black carbon, sulphur dioxide, nitrogen oxides, volatile organic compounds, organic carbon and tropospheric ozone, and their transport processes and transformations in the atmosphere. Using several chemical transport models we perform detailed radiative forcing calculations from emissions of these species. We look at six main sectors known to account for nearly all of these emissions: households (domestic), energy/industry/waste, transport, agricultural fires, grass/forest fires, and gas flaring. To estimate the Arctic surface temperature we apply regional climate sensitivities, the temperature response per unit of radiative forcing for each SLCF. We find that the largest Arctic warming source is from emissions within the Asian nations owing to the large absolute amount of emissions. However, the Arctic is most sensitive, per unit mass emitted, to SLCFs emissions from a small number of activities within the Arctic nations themselves. A stringent, but technically feasible mitigation scenario for SLCFs, phased in from 2015 to 2030, could cut warming by 0.2 (±0.17) K in 2050.

  16. Environmental & Climate Sciences Department Seminar

    "Coupled Air-Sea Modeling in Coastal Regions"

    Presented by Julie Pullen, Stevens Institute of Technology

    Thursday, March 17, 2016, 11 am
    Conference Room, Bldg 815E

    Hosted by: Bob McGraw

    This talk will highlight modeling efforts focused on probing the dynamics of the air and sea in the complex coastal zone utilizing high-resolution (~1 km) coupled models. Results will cover the ocean response to atmospheric flows around island topography (Philippines and Madeira), as well as sea breeze interactions with city morphology (New York and Tokyo) - and associated transport & dispersion applications. Dr. Julie Pullen is an Associate Professor in Ocean Engineering at Stevens Institute of Technology. She uses high-resolution coupled ocean-atmosphere modeling in order to understand and forecast the dynamics of coastal urban regions throughout the world. Applications include predicting chemical, biological, radiological and nuclear (CBRN) dispersion in coastal cities in the event of a terrorist or accidental release. She has served on the steering team for field studies in urban air dispersion (DHS/DTRA NYC Urban Dispersion Program) and archipelago oceanography (ONR Philippines Straits Dynamics Experiment). She is a member of the international GODAE Coastal Ocean and Shelf Seas Task Team and is the physical oceanography councilor for The Oceanography Society. Dr. Pullen earned her Ph.D. in Physical Oceanography at Oregon State University and did postdoctoral work at the Naval Research Laboratory's Marine Meteorology Division. She is an Adjunct Research Scientist at Columbia's Lamont Doherty Earth Observatory.

  17. Environmental & Climate Sciences Department Seminar

    "Plant respiration: lessons from high latitudes for ecosystem carbon balance modelling"

    Presented by Paul P. Gauthier, Princeton University

    Wednesday, March 9, 2016, 11 am
    John Dunn Seminar Room, Bldg. 463

    Hosted by: Alistair Rogers

    Climate-mediated changes in ecosystem C balance are accepted as an important component of the biosphere response to climate change. Plant respiration and photosynthesis are major drivers of this balance but our lack of understanding of the controls and constrains surrounding their interaction stalls our capacity to predict future ecosystem changes. Using a new O2 isotopes method for measuring leaf functional traits, I will present a new approach to estimate the rate of leaf respiration in the light and its biochemical origin in temperate and arctic plants. The role of plant respiration as a key player for plant adaptation will also be discussed in the context of plant respiration modelling.

2015

  1. Biological, Environmental, & Climate Sciences (BECS) Department Seminar

    "Molecular Mechanism of the Assembly of PKD1/TRPP2 Receptor-Ion Channel Complex, the Cellular Sensor in Autosomal Dominant Polycystic Kidney Disease"

    Presented by Yong Yu, Department of Biological Sciences, St. John's University, Queens, NY

    Friday, August 28, 2015, 11 am
    John Dunn Seminar Room, Bldg. 463

    Hosted by: Chang-Jun Liu

    Mutations in TRPP2 and PKD1 account for almost all clinically identified cases of autosomal dominant polycystic kidney disease (ADPKD), one of the most common human genetic diseases. TRPP2 and PKD1 form a receptor-ion channel complex on primary cilia and couple extracellular stimuli to cellular responses in renal cells. We found that this complex contains three TRPP2 subunits and one PKD1 subunit, and this 3:1 stoichiometry is determined by a coiled-coil domain on the C-terminus of TRPP2. Our data also suggested that PKD proteins may be involved in channel pore-forming, in addition to signal reception. Furthermore, by generating a gain-of-function TRPP2 mutant, we investigated the functional property of TRPP2, which was largely unknown due to the lack of the knowledge on the activation mechanism of this ion channel.

  2. Biological, Environmental, & Climate Sciences (BECS) Department Seminar

    "ORANGE Interacts with TCP14 in Regulating Etioplast Development in Arabidopsis"

    Presented by Shan Lu, School of Life Sciences, Nanjing University, Nanjing, China

    Monday, August 3, 2015, 10 am
    John Dunn Seminar Room, Bldg. 463

    The ORANGE (OR) protein regulates carotenoid accumulation and plastid development. Our work showed that OR is dually targeted to the nucleus and the chloroplasts. The expression level of Or regulates transcript abundances of genes for carotenoid and chlorophyll metabolism and accumulation in etiolated cotyledons. We demonstrated that OR physically interacts with a bHLH transcription factor, TCP14, which binds directly to promoter regions of its target genes, such as CAB4, ELIP1 and AtOr itself. OR-regulated gene expression relies on TCP14. Taken together, we proved that OR regulates etioplast development via its physical and genetic interactions with TCP14.

  3. Biological, Environmental, & Climate Sciences (BECS) Department Seminar

    "Evaluation of Cloud Parameterisations in Climate Models Using Satellite Observations"

    Presented by Johannes Quaas, NASA GISS

    Monday, May 11, 2015, 1:30 pm
    Conference Room, Bldg 815E

    Hosted by: Stephen Schwartz

    Fractional cloudiness in climate models is parameterised in terms of the subgrid-scale variability of humidity. This variability is expressed explicitly or implicitly as the probability density function (PDF) of the total-water specific humidity. No large-scale high-resolved observations of water vapour exist. I will present four approaches to evaluate the humidity PDF despite this observational shortcoming, and show their application to evaluate different cloud schemes. I will then discuss the implications for other cloud processes, and the subsequent improvements within the ECHAM climate model. If time permits, I will also briefly summarise one recent study on an observational constraint on the aerosol radiative forcing.

  4. Biological, Environmental, & Climate Sciences (BECS) Department Seminar

    "Structural Mechanism of a Conserved Calcium Leak in Protection of Life"

    Presented by Qun Liu, New York Consortium on Membrane Protein Structure, New York Structural Biology Center, New York, NY

    Friday, May 1, 2015, 11 am
    John Dunn Seminar Room, Bldg. 463

    Hosted by: Huilin Li

    Ca2+ is a ubiquitous intracellular messenger that regulates cellular activities in plants, animals and humans. Cytosolic Ca2+ is kept at a low level, but subcellular organelles such as the endoplasmic reticulum (ER) maintain Ca2+ stores. Under resting conditions, Ca2+ homeostasis is dynamically regulated to equilibrate between active calcium uptake and passive calcium leak. Ca2+ homeostasis is cytoprotective. An overloaded ER Ca2+ content promotes cell death. We determined crystal structures of a Ca2+ leak channel and characterized its biochemical functions. The structure has a novel seven-transmembrane-helix fold consisting of a centralized C-terminal helix wrapped by two triple-helix sandwiches. Lateral displacement of transmembrane helix TM2 by change of pH leaves a transmembrane pore, allowing a leak of Ca2+ across membranes. The leak is regulated by a di-aspartyl pH sensor consisting of two conserved aspartate residues. The leak is intrinsic to all kinds of cells and is cytoprotective for life.

  5. Biological, Environmental, & Climate Sciences (BECS) Department Seminar

    "Leveraging Isotopic Tracers and Imaging in the Model Grass, Setaria viridis, to Unravel the Mechanisms for Plant Growth Promotion via Associated N2-Fixing Rhizobacteria"

    Presented by Rich Ferrieri, Biological, Environmental & Climate Sciences Department

    Friday, April 24, 2015, 11 am
    John Dunn Seminar Room, Bldg. 463

    Though management of essential macronutrients, including nitrogen, phosphorous and potassium and water is crucial in any cropping system, it is of particular concern for sustaining future bioenergy crops that will be grown on sub-optimal soils lacking these essential resources. Use of fertilizers and applied irrigation will improve upon this, but at a significant increase in the net cost for energy derived from bioenergy fuels. In recent years, an increasing number of reports have appeared documenting healthy plant growth under nutrient limitation and drought conditions by applying plant growth promoting rhizobacteria (PGPB). Even so, most aspects of these unique plant-microorganism associations have been little studied at a systems-level and from a detailed mechanistic perspective. Knowledge gained from more intensive research on PGPB and their effects should increase their utility and field application in future bioenergy cropping systems. What is lacking is a genetically tractable, model system that can be employed to make more rapid progress toward understanding PGPB function. Our recent work in Setaria viridis (Pankievicz et al., The Plant Journal, 2015) using Azospirillum brasilense and Herbaspirillum seropedicae bacteria, has shown that it is a robust model C4 grass system for studying PGPB attributable to biological nitrogen fixation and other phytostimulatory actions. Leveraging several imaging approaches, including radioluminescence, optical and nanoSIMS in combination with radiotracer metabolic fluxomics and proteomics, we are beginning to get a clearer picture into the physiological and metabolic basis for plant growth promotion via these microbial associations - and with a sequenced genome for S. viridis and plant transformation efforts underway, this system promises to provide even greater insight that should help accelerate translation and deployment of new strategies for future bioenergy crop sustainability.

  6. Biological, Environmental, & Climate Sciences (BECS) Department Seminar

    "High-resolution CAM5 simulations of varying complexity"

    Presented by Kevin Reed, Stony Brook University

    Friday, April 24, 2015, 10 am
    Conference Room, Bldg 815E

    Hosted by: Ernie Lewis

    In our continued effort to understand the climate system and improve its representation in general circulation models (GCMs) it is crucial to develop new methods to evaluate these models. This is certainly true as the GCM community advances towards high horizontal resolutions (i.e., grid spacing less than 50 km), which will require interpreting and improving the performance of many model components. Idealized, or reduced complexity, frameworks can be used to investigate how model assumptions impact behavior across scales. This work makes use of a range of National Center for Atmospheric Research and Department of Energy Community Atmosphere Model version 5 (CAM5) simulations, ranging from simplified global radiative-convective equilibrium (RCE) simulations to full decadal simulations of present-day and future climate. The various CAM5 configurations provide useful insights into the model's ability to simulate extreme precipitation events and tropical cyclones. Furthermore, the impact of horizontal resolution and the choice of CAM5 dynamical core on the simulation of extreme events will be explored. Finally, time slice experiments using the Representative Concentration Pathway (RCP) 8.5 scenario for greenhouse gas concentrations are assessed and compared to present-day simulations. Overall, this work is part of a continued effort to understand how weather extremes may vary in a changing climate using next-generation high-resolution climate models.

  7. Biological, Environmental, & Climate Sciences (BECS) Department Seminar

    "Atmospheric Ice Formation: What can be Learned from Ice Nucleation Studies"

    Presented by Daniel Knopf, Stony Brook University

    Friday, April 17, 2015, 11 am
    Conference Room, Bldg 815E

    Hosted by: Ernie Lewis

    Ice formation represents one of the biggest challenges in atmospheric sciences for prediction of mixed-phase and cirrus clouds with subsequent consequences for the global radiative budget and hydrological cycle. The reasons for this are manifold: ice nucleation can occur via different pathways with each mechanism depending on the ambient thermodynamic conditions such as temperature and relative humidity; only a small fraction of particles nucleates ice as low as one in a million; the physicochemical complexity of ice nucleating particles (INPs); the ice nucleation efficiency of ambient particles. This seminar will introduce a multi-modal methodology approach allowing optical, micro-spectroscopy, and chemical imaging of individual identified field-collected and laboratory generated INPs active in immersion freezing and deposition ice nucleation. Ice formation pathways are studied for temperatures as low as 200 K covering typical atmospheric conditions. In the first part of this presentation a new model of immersion freezing will be presented. It is based on droplet water activity and accounts for INP surface area and nucleation time. Its application and implications for cloud modeling will be discussed. The second part is concerned with the unique ability to quantitatively characterize the individual INP among hundred thousands of particles not nucleating ice. These findings raise a new perspective on the parameters governing atmospheric ice nucleation. The data demonstrates that the INPs are not necessarily exceptional particles in comparison to the ambient population with regard to composition and mixing state. However, particle surface area, besides ice nucleation kinetics, may also constitute a crucial factor for our predictive understanding of the ice nucleation process. Lastly, a stochastic model is applied to re-analyze laboratory immersion freezing data demonstrating that statistically insufficient freezing experiment numbers and inaccurate estimates of INP s

  8. Biological, Environmental, & Climate Sciences (BECS) Department Seminar

    "Theories of the Ice Ages"

    Presented by Gerald R. North, Texas A&M University

    Thursday, April 9, 2015, 11 am
    Conference Room, Bldg 815E

    Hosted by: Wei Wu

    Many think the timing and intensity Pleistocene Glaciations have been solved. There remain many problems explaining these grand events. This talk will review some past attempts and how they have failed. Energy balance climate models are useful in this class of problems. I will show some recent results that do not settle the case, but get part of the way there and may point the way to a satisfactory solution.

  9. Joint Department Seminar: Biological, Environmental and Climate Sciences & Sustainable Energy Technologies

    "Lessons Learned from Energy Storage Pilots at Pacific Gas and Electric"

    Jon Eric Thalami, Pacific Gas and Electric

    Monday, March 30, 2015, 11 am
    Bldgh. 734, Room 201

    Hosted by: J. P. Looney

    Pacific Gas and Electric has piloted the use of 6MWs of Sodium Sulfur batteries on their distribution system. These projects have tested the bulk system use of energy storage on a variety of applications including renewable smoothing, load shifting, local islanding and frequency regulation. In the case of the frequency regulation the projects are the first energy storage device to participate in the California Independent System Operator (CAISO).

2014

  1. Biological, Environmental, & Climate Sciences (BECS) Department Seminar

    "Plant Systems Biology: From Predictive Network Modeling to Trait Evolution"

    Presented by Gloria M. Coruzzi, Department of Biology, Center for Genomics & Systems Biology, New York University, New York, NY

    Friday, November 7, 2014, 11 am
    John Dunn Seminar Room, Bldg. 463

    Hosted by: Ben Babst

    Main Research Interests — Dr. Coruzzi's lab initiated systems biology approaches in Arabidopsis and other species to study gene regulatory networks. Using network integration and machine-learning approaches, her lab generated the first dynamic and predictive regulatory networks in plants, a hallmark of Systems Biology. These networks uncovered novel hypotheses including nutrient control of the clock, and a Hit-and-Run transcription model. These informatic tools are embodied in a systems-biology enabling software platform VirtualPlantv1.3 (www.virtualplant.org), developed with NYU's Courant Inst. of Mathematical Sci. Dr. Coruzzi also leads a collaborative NSF Plant Genome Project - "Comparative Genomics of Seed Evolution" with co-PIs at the NY Botanical Garden, the American Museum of Natural History, and CSHL. This generated the largest genome-scale phylogeny of 150 seed plants, the BigPlantv1.0 matrix (http://nypg.bio.nyu.edu/bp/) available as an interactive browser, "PhyloBrowser." This resource enables researchers to explore the genomic underpinnings of plant diversification across a wide range of species. Selection of four major recent publications: [1]Para A, Li Y, Marshall-Colon A, et al., and Coruzzi GM (2014) Hit-and-run transcriptional control by bZIP1 mediates rapid nutrient signaling in Arabidopsis. PNAS 111(28):10371-6. [2]Ruffel S, Krouk G, Ristova D, et al., and Coruzzi GM (2011) Nitrogen economics of root foraging: Transitive closure of the nitrate-cytokinin relay and distinct systemic signals for N supply vs. demand. PNAS 108(45):18524-9. [3]Lee EK, Cibrian-Jaramillo A, Kolokotronis S-O, et al., Coruzzi G, and DeSalle R (2011) A functional phylogenomic view of the seed plants. PLoS Genetics 7(12):e1002411. [4]Krouk G, Mirowski P, et al., and Coruzzi GM (2010) Predictive network modeling of the high-resolution dynamic plant transcriptome in response to nitrate. Genome Biology 11(12):R123.

  2. Environmental Sciences Department Seminar

    "CWRF Physics Representation and Climate Prediction at Regional Scales"

    Presented by Prof. Xin-Zhong Liang, University of Maryland

    Friday, June 20, 2014, 11 am
    Bldg 815E Conference Room

    Hosted by: Wei Wu

    The CWRF is developed as a Climate extension of the Weather Research and Forecasting model (WRF) by incorporating numerous improvements in representation of physical processes and integration of external (top, surface, lateral) forcings that are crucial to climate scales, including interactions between landâ€"atmosphereâ€"ocean, convectionâ€"microphysics and cloudâ€"aerosolâ€"radiation, and system consistency throughout all process modules. As a result, the CWRF has demonstrated great capability and excellent performance in simulating the regional climate over U.S. This presentation will focus on the development of CWRF representation of physical processes at regional scales and its added values over the driving general circulation model outputs for seasonal-interannual climate prediction and possible impacts of the present-day model fidelity on future climate projection.

  3. Environmental Sciences Department Seminar

    "Observation and simulation of coastal urban atmospheres in a changing climate, with an emphasis on NYC"

    Presented by Robert Bornstein, Department of Meteorology & Climate Science, San Jose State University

    Tuesday, June 3, 2014, 10:30 am
    Bldg 815E Conference Room

    Hosted by: Wei Wu

    Urban areas alter atmospheric energy and moisture balances to create unique weather patterns and local climates. During periods of global change, urban climates can amplify adverse impacts from larger scale changes. This presentation thus reviews processes creating urban climates and also recent advances in numerical mesoscale modeling in general and in urban modeling in particular, with an emphasis on simulations over NYC. Possible model developments are discussed, as are implications for human heat-stress, energy consumption, and air quality.

  4. Environmental Sciences Department Seminar

    "Long-path Quantum Cascade Laser-based Sensor for Environmental Sensing and Ambient Detection of Methane and Nitrous Oxide"

    Presented by Paulo Castillo, City College of New York

    Thursday, May 22, 2014, 10 am
    Bldg 815E Conference Room

    Hosted by: Arthur Sedlacek

    Methane (CH4) and nitrous oxide (N2O) are long-lived greenhouse gases (GHGs) in the atmosphere with large global warming effects. These gases also are known to be produced in a number of anthropogenic settings. One example is manure management systems, which release substantial GHGs and are mandated by the EPA to be continuously monitored. Such monitoring can be easily done remotely using open-path methods. Most open-path methods for quantitative detection of trace gases utilize either Fourier Transform Infrared Spectroscopy (FTIR) or near-infrared Differential Optical Absorption Spectroscopy (DOAS). Although FTIR is suitable for ambient air monitoring measurement of more abundant gases such as CO2 and H2O, the lack of spectral resolution makes retrieval of more weakly absorbing species such as N2O difficult. As alternative, a quantum cascade laser (QCL) operating in the mid-infrared, has been successfully employed for sensing atmospheric abundance of such species. In this presentation I will discuss the use of an open-path QCL-based sensor for simultaneous detection of multiple GHGs, specifically CH4 and N2O. Spectra for these gases were recorded by tuning a QCL over the wavenumber range 1299-1300 cm-1 using a thermal down-chirp technique to achieve rapid sweeping. Careful optimization of the spectral window for absorption features of CH4 and N2O and interfering gases has enabled this technique to be incorporated into a cost-effective, robust, and rapid-response open-path laser-based monitor that can detect ambient concentrations of CH4 with ~1% accuracy and N2O with <1% accuracy over a 500 m path length. Long-time performance and other applications of the system will also be discussed.

  5. Environmental Sciences Department Seminar

    "To BC or not to BC"

    Presented by Mary Gilles, LBNL

    Monday, May 19, 2014, 11 am
    Bldg 815E Conference Room

    Hosted by: Martin Schoonen

    In the past decade, the use and applications of microscopies in aerosol science have grown significantly. This talk focuses on the evolution of scanning transmission x-ray microscopy in aerosol science over the last decade. It will cover the fundamental characterization of black carbons and soot to developing compositional mapping routines. This has now matured to a state that the information and evolution of the mixing states is beginning to be incoroporated into mixing state information into models. While microscopic methods are highly complementary and much of our work has utilized multiple micro and spectroscopic techniques, here, scanning transmission x-ray microsocpy will be highlighted. This will provide an overview of the studies focused on light absorbing particles (biomass burn, black carbon reference standards, soots) and how they are charaterized and used for mapping techniques to obtain mixing state information and work focused on sea salts and sea salt processing or metals will not be presented. As part of showing the evolution and applications of this method there will be some illustrative examples of current and future studies focussed on phase transitions, phase separation, and viscosity changes associated with water vapor uptake.

  6. Environmental Sciences Department Seminar

    "A revisit of climate feedbacks: Understanding processes responsible for the pattern of forced climate change"

    Presented by Jianhua Lu, Environmental Sciences Department, BNL

    Thursday, March 20, 2014, 11 am
    Bldg 815E Conference Room

    Hosted by: Ernie Lewis

    In the talk, a new perspective on the basic concept of climate feedback, which is not based on the radiative balance at the top of the atmosphere (TOA), but on the 3-D energy cycle of the coupled climate system, will be presented. Its relationship with traditional TOA-based view will be discussed. In the talk, the new framework with its application in understanding, at process level, the vertical and horizontal structure of anthropogenic climate change will be illustrated.

2013

  1. Environmental Sciences Department Seminar

    "Signal Processing for Weather Radar Polarimetry: Removing the Bias induced by Antenna Coherent Cross-Channel Coupling"

    Presented by Michele Galletti, Brookhaven National Laboratory

    Wednesday, September 11, 2013, 11 am
    Building 815E Conference Room

    We present a novel digital signal processing procedure, named Eigenvalue Signal Processing (henceforth ESP), patented by the author with Brookhaven Science Associates in 2013. The method enables removal of antenna coherent cross-channel coupling that can occur in the LDR mode, the ATSR mode and the STSR orthogonal mode of weather radar measurements. In this work we focus on the LDR mode and consider copolar reflectivity at horizontal transmit (ZHH), cross-polar reflectivity at horizontal transmit (ZVH), linear depolarization ratio at horizontal transmit (LDRH) and degree of polarization at horizontal transmit (DOPH). The eigenvalue signal processing method is substantiated by an experiment carried out in November 2012 using a C-band weather radar with a parabolic reflector located at the Selex Systems Integration (Selex SI) facilities in Neuss, Germany. The experiment involved comparison of weather radar measurements taken 1.5 minutes apart in two hardware configurations, namely with cross-coupling on (cc-on) and cross-coupling off (cc-off). It is experimentally demonstrated that eigenvalue-derived variables are invariant with respect to antenna coherent cross-channel coupling. This property had to be expected, since the eigenvalues of the Coherency matrix are SU(2) invariant.

  2. Environmental Sciences Department Seminar

    "Land Surface Impacts on Convective Precipitation Development over the United States Great Plains"

    Presented by Thomas W. Collow, Rutgers University

    Thursday, August 22, 2013, 10:30 am
    Conference Room, Bldg 815E

    Hosted by: Wei Wu

    A series of modeling experiments was conducted using the Weather Research and Forecasting Model to assess the sensitivity of mesoscale convective precipitation patterns to vegetation and soil moisture on a short time scale. For vegetation, runs were done over the Southern Great Plains of the United States using current vegetation cover, a uniform forest cover, a uniform barren land surface, and a pre-farming scenario in which cropland was changed to native grassland. The goal was to determine how vegetation impacts precipitation and whether pre-farming conditions would result in any meaningful alterations. Individual case studies were chosen to include days with both strong and weak synoptic forcing. Extreme changes in vegetation impacted precipitation, 2 m temperature, 2 m dewpoint, and the convective available potential energy (CAPE). Barren land decreases dewpoint, minimally affects temperature, and decreases CAPE. Forested land decreases temperature, increases dewpoint, and increases CAPE. Changes were more extreme for cases with little synoptic forcing but still substantial in all cases. Strong precipitation reductions occur with a barren land surface while some increases occur on a forested surface. Pre-farming conditions had little impact on the evolution of convective precipitation systems, showing that while vegetation cover is an important component in mesoscale precipitation, the switch from grassland to cropland was insignificant at this scale over this particular region. This means we found no evidence that "rain follows the plow." A similar procedure was followed for soil moisture in which initial model soil moisture at all levels was set to the porosity (very wet) and wilting point (very dry). The feasibility of using soil moisture data from the Soil Moisture Ocean Salinity (SMOS) Satellite was also analyzed. SMOS data were directly inserted into the WRF model and it was found that the changes were minimal compared to using orig

  3. Environmental Sciences Department Seminar

    "Particle-Resolved Model Analysis of Black Carbon Aging"

    Presented by Laura Fierce, University of Illinois at Urbana-Champaign

    Wednesday, August 14, 2013, 11 am
    Conference Room, Bldg 815E

    The size and composition of particles containing black carbon (BC) are modified soon after emission by condensation of secondary aerosol and coagulation with other particles, known collectively as "aging" processes. Although this change in particle properties is widely recognized, the timescale for transformation is not well constrained. In this work, we simulated aerosol aging with the particle-resolved model PartMC-MOSAIC and extracted aging timescales based on changes in particle cloud condensation nuclei (CCN) activation. We simulated nearly 300 scenarios and, through a regression analysis, identified the key parameters driving the value of the aging timescale. We show that the value of the aging timescale spans from hours to weeks, depending on local environmental conditions and characteristics of the fresh BC-containing particles. Although the simulations presented in this study included many processes and particle interactions, through a regression analysis we show that 80% of the variance in the aging timescale is explained by only a few key parameters. The condensation aging timescale decreased with the flux of condensing aerosol and was shortest for the largest fresh particles, while the coagulation aging timescale decreased with the total number concentration of large (D>100 nm), CCN-active particles and was shortest for the smallest fresh particles. Therefore, both condensation and coagulation play important roles in aging, and their relative impact depends on the particle size range.

  4. Environmental Sciences Department Seminar

    "Smoke and Mirrors: Is Geoengineering a Solution to Global Warming?"

    Presented by Alan Robock, Rutgers University

    Monday, August 12, 2013, 4 pm
    Conference Room, Bldg 815E

    Hosted by: Wei Wu

    In response to the global warming problem, there has been a recent renewed interest in geoengineering "solutions" involving "solar radiation management" by injecting particles into the stratosphere, brightening clouds, or blocking sunlight with satellites between the Sun and Earth. While volcanic eruptions have been suggested as innocuous examples of stratospheric aerosols cooling the planet, the volcano analog actually argues against geoengineering because of ozone depletion and regional hydrologic responses. In this talk, I describe different proposed geoengineering designs, and then show climate model calculations that evaluate both their efficacy and their possible adverse consequences. No such systems to conduct geoengineering now exist, but a comparison of different proposed stratospheric injection schemes, using airplanes, balloons, and artillery, shows that using airplanes to put sulfur gases into the stratosphere would not be expensive. Nevertheless, it would be very difficult to create stratospheric sulfate particles with a desirable size distribution. Our GeoMIP project, conducting climate model experiments with standard stratospheric aerosol injection scenarios, is ongoing, but has already shown that temperature and precipitation responses would be uneven globally. If there were a way to continuously inject SO2 into the lower stratosphere, it would produce global cooling, stopping melting of the ice caps, and increasing the uptake of CO2 by plants. But there are at least 26 reasons why geoengineering may be a bad idea. These include disruption of the Asian and African summer monsoons, reducing precipitation to the food supply for billions of people; ozone depletion; no more blue skies; reduction of solar power; and rapid global warming if it stops. Furthermore, the prospect of geoengineering working may reduce the current drive toward reducing greenhouse gas emissions, there are concerns about commercial

  5. Environmental Sciences Department Seminar

    "Atmospheric Aerosol Research at UEF"

    Presented by Jussi Malila, University of Eastern Finland, Finland

    Thursday, July 11, 2013, 11 am
    Conference Room, Bldg 815E

    University of Eastern Finland (UEF) was formed in 2010 merging previously independent universities of Kuopio and Joensuu. At the former University of Kuopio, atmospheric aerosol research dates back to the earliest years of the university, when the emphasis was on the atmospheric hygiene and health effects of air pollution both to humans and ecosystems. Since then, atmospheric aerosol reserach has expanded to cover areas of cloud microphysics, global climate effects, remote sensing of aerosols and clouds, and new measurement techniques, just to mention few examples. In this talk I will give an overview of active research areas and recent results of atmospheric aerosol research at the UEF, concentrating on the research conducted at the Aerosol Physics Group at the Department of Applied Physics (professors Laaksonen, Lehtinen and Virtanen). I will also shortly discuss on the related education at the UEF.

  6. Environmental Sciences Department Seminar

    "Fast physics testbed: development, demo, and applications"

    Presented by Wuyin Lin, Environmental Sciences Department

    Tuesday, July 2, 2013, 11 am
    Conference Room, Bldg 815E

    Hosted by: Ernie Lewis

    Clouds and their associated physical processes exert strong influences on the climate system through the couplings with dynamical, hydrological and radiative processes. Representation of cloud-related fast physics in climate models however has long been a challenging task, and primarily responsible for the large uncertainty in climate projections. The BNL's Fast-Physics System Testbed and Research (FASTER) project is tasked to develop a comprehensive cloud modeling testbed to enhance and accelerate evaluation and improvement of cloud representation in climate models. In this talk, I will go over the rationales behind the development of the testbed with a focus on the single column model (SCM) testbed. Applications of the online SCM testbed for interactive model evaluation and cloud parameterization development will also be demonstrated.

  7. Environmental Sciences Department Seminar

    "Exoplanets"

    Presented by Warren Wiscombe, NASA Goddard Space Flight Center

    Friday, June 14, 2013, 11 am
    Conference Room, Bldg 815E

    Hosted by: Ernie Lewis

    Exoplanets are being discovered at an accelerating rate since 1995. Beginning with Jupiter-sized and larger planets, the gallery has enlarged to include super-Earths (1.5 to 2x the radius of Earth) and bodies smaller than Earth as well. There are no less than four different methods used to detect exoplanets, although the transit method, exemplified by the Kepler telescope in space, has bagged by far the largest number of detections. The watchword in exoplanet research has become "we can predict nothing" since many of the discoveries have defied traditional theories. Categories of exoplanets have been discovered that "should not" exist, for example hot Jupiters and planets around binary stars. This talk shall attempt to overview the methods used to detect exoplanets, a few of the important discoveries, and what lies ahead.


  8. Environmental Sciences Department Seminar

    "A Direct Statistical Approach for Cloud Radiation Interaction"

    Presented by Dong Huang, Environmental Sciences Department

    Thursday, June 13, 2013, 2:30 pm
    Conference Room, Bldg 815E

    Direct numeric simulations (the approach adopted by current climate models) accumulate statistics by cumbersome numerical integrations and usually offer little insight into complex systems. Direct statistically approaches, on the other hand, directly predict the statistics. Along this line, we present a simple one-dimensional stochastic transport theory for complex three-dimensional medium. The heart of the theory is using a spatial autocorrelation function that encodes information about the spatial arrangement and morphology of the medium. Numerically, we show that the stochastic theory is able to faithfully reproduce various three-dimensional effects traditionally only captured by expensive three-dimensional simulations.

  9. Environmental Sciences Department Seminar

    "Temperature Dependent Yields of Minor Mono- and Di- Substituted Carbonyl Compounds from the Oxidation of Isoprene under Near-zero and High NOx Conditions"

    Presented by Dr. Ryan Thalman, University of Colorado

    Wednesday, June 12, 2013, 11 am
    Conference Room, Bldg 815E

    Hosted by: Jian Wang

    Isoprene emitted by the biosphere is the largest biogenic portion of the global budget of volatile organic compounds (VOC). Isoprene in the atmosphere is predominantly oxidized by the hydroxyl radical (OH). The oxidation of VOCs in the atmosphere contributes to the creation of ozone and secondary organic aerosol (SOA). Recent theoretical predictions and measurements have shown that small carbonyl compounds such as glyoxal, methyl glyoxal, hydroxyacetone and glycolaldehyde may be produced as co-product pairs from rapid isomerization of peroxy radicals in the first generation of isoprene oxidation. We investigated the temperature (260K, 298K and 330K) and NOx (near-zero NOx and high NOx (ppm level)) dependence of the first generation product yields from these isomerization pathways, and the implications of these findings on our understanding of the oxidation mechanism. Experiments combine the atmospheric simulation chamber at the National Center for Atmospheric Research with the CU Light Emitting Diode Cavity Enhanced Differential Optical Absorption Spectroscopy (CU LED-CE-DOAS) for the detection of glyoxal and methyl glyoxal; as well as Proton Transfer Reaction Mass Spectrometry for the detection of other isoprene oxidation products.

  10. Environmental Sciences Department Seminar

    "DISCOVER-AQ and the uses of remote sensing in air quality and climate studies"

    Presented by Russell Dickerson, University of Maryland

    Thursday, May 16, 2013, 11 am
    Conference Room, Bldg 815E

    Hosted by: Stephen Schwartz

    In July 2011, NASA conducted the DISCOVER-AQ campaign over Maryland. Several aircraft and a ship were deployed with the goal of bridging the gap between space-based observations and surface concentrations. Along the way, substantial insight was gained into the chemistry, physics, and meteorology of smog events over the eastern US. This talk will summarize these findings and discuss broader uses of existing instruments such as OMI (SO2, NO2) and MOPITT (CO) and plans for the Geostationary Infrared Pollution Sounder, GRIPS, for trace gases and aerosols.

  11. Environmental Sciences Department Seminar

    "To Be Announced"

    Presented by Xiaojie Zhu, Texas A&M University

    Monday, January 7, 2013, 11 am
    Bldg. 815E Conference Room

2012

  1. Environmental Sciences Department Seminar

    "Precipitation measurement using a dual Ka-band radar system for GPM/DPR algorithm development"

    Presented by Masanori Nishikawa, Hydrospheric Atmospheric Research Center (HyARC), Nagoya University, Japan

    Monday, December 10, 2012, 2 pm
    Bldg 815E Conference Room

    The core satellite of Global Precipitation Measurement (GPM), which is scheduled to launch in 2014, has a dual-wavelength precipitation radar (DPR). DPR consists of Ku and Ka radars. Ka-band radiowave suffers from strong attenuation for rain and strong Mie scattering effect for snow. Because ground measurements of precipitation (rain and snow) at Ka-band are limited, measurements of backscattering and extinction characteristics of precipitation are necessary for the GPM/DPR algorithm development. For the ground validation of the GPM/DPR, a dual Ka-band radar system was developed by the Japan Aerospace Exploration Agency (JAXA). The Ka radar system consists of two identical Ka radars. When the Ka radars face each other and observe the same precipitation system between the radars with opposite direction, both the equivalent radar reflectivity factor (Ze) and specific attenuation (k) can be measured at each range bin of the path. The measured k-Ze relations of rain, snow, and the melting layers can be used to develop the "scattering table" for the improvement of the GPM/DPR algorithm performance. Observations for both rain and snow using the dual Ka-radar system are ongoing in several locations in Japan. Results of measurements of k-Ze relations of rain and snow are presented. Performance of the system are evaluated by comparing measured Ze and k of rain with those estimated from the disdrometer. Although some biases in Ze exist, the measured k-Ze relations are reasonable. Among snow events, different tendencies of k-Ze plots appear depending on surface temperature. The difference of k-Ze relations of snow is attributed to the difference of the backscattering and attenuation characteristics between wet and dry snow. Moreover, as a transformation of the dual Ka observation, a vertical-slant direction observation for melting layer is proposed. The configuration is that one radar was directed in vertical and the other was in

  2. Environmental Sciences Department Seminar

    "Observation of the Young-Bedard Effect during the 2010 and 2011 Atlantic Hurricane Seasons"

    Presented by Philip Blom, University of Mississippi

    Wednesday, October 10, 2012, 11 am
    Bldg 815E

    Infrasonic acoustic energy is known to be generated during the collision of counter propagating ocean surface waves of like periods. The acoustic signals produced by such collisions are known as microbaroms. One significant source of microbarom radiation is the interaction of waves produced by large maritime storms with the background ocean swell. The region in which the microbaroms associated with a large storm are produced tends to be hundreds of kilometers from the eye of the storm. It was suggested by Young and Bedard that, when observed along propagation paths that pass through the storm, the microbarom signal can be severely refracted by the storm itself. Such refraction has been observed in data from the 2010 and 2011 Atlantic hurricane seasons. A data processing algorithm has been developed and implemented using the Capon minimum variance beamforming method. The results of this analysis will be presented and compared with predictions of the refraction using a geometric acoustics propagation model.

2011

  1. Photon Sciences Seminar

    "Soft X-ray Spectromicroscopy on Environmental and Biological Samples"

    Presented by Julia Sedlmair, University of Gottingen, Germany

    Friday, August 26, 2011, 1:30 pm
    Seminar Room, Bldg. 725

    Hosted by: Juergen Thieme

  2. Photon Sciences Directorate Seminar

    "Nanoparticle Behavior in Environmental and Test Media: Conclusions from Static and Dynamic Stability Testing"

    Presented by Frank Von Der Kammer, University of Vienna, Austria

    Friday, June 3, 2011, 11 am
    Seminar Room, Bldg. 725

    Hosted by: Juergen Thieme

    The appearance and behavior of engineered nanoparticles in the environment determine their distribution, their fate and the exposure of organisms. This behavior is governed by several well-known parameters as surface potential of the particles, particle size and shape and of course the water chemistry. However a detailed understanding how the inter-connected processes of aggregation, transport, settling and transformation are influenced by these parameters is still missing. From the perspective of risk assessment it would be essential to be able to predict behavior, fate and transformation, but meaningful predictions derived from first principles remain difficult, even in fairly simple systems. For certain engineered nanoparticles like citrate stabilized Gold-NPs for example, which come with a fairly simple surface chemistry, the prediction of reactions may be more straight forward than for others, especially metal-oxide particles. Hence as long as process understanding remains underdeveloped empiric approaches will be necessary. We have addressed this issue by developing a testing approach to generate empiric data for the dispersion stability of nanoparticles in a wide variety of conditions. The testing procedure itself and the comparison of conditions and materials will be presented and discussed with respect to the application to real world conditions including analytical challenges in real surface waters and soils, limitations due to reduced complexity of the set-up, and the problem of heterogeneity and property distributions of the nanoparticles.

  3. Office of Educational Programs Event

    "Environmental Education Summit"

    Wednesday, April 13, 2011, 9 am
    Berkner Hall, Room B

    Hosted by: Melvyn Morris

    Bring together individuals interested in environmental education to porduce a white paper concerning the state of environmental education on Long Island. To also discuss the proposed NY State Environmental Literacy Standards

2010

  1. Center for Functional Nanomaterials Seminar

    "Application of the Environmental Transmission Electron Microscopy Technique to Address Chirality Control and Growth Termination in Carbon Nanotubes"

    Presented by Dmitri Zakharov, Purdue University

    Thursday, October 14, 2010, 10 am
    Bldg. 735 - Conf Rm B

    Hosted by: Eric Stach

    Environmental Transmission Microscopy (ETEM) is a technique that has attracted substantial recent interest, and has significant potential to advance research in the field of catalysis. The Birck Nanotechnology Center at Purdue University installed the first ETEM version of the Titan 80-300 TEM/STEM. A number of experimental modifications to the microscope vacuum system, heating holders and gas delivery systems were carried out to improve overall system performance and repeatability of experiments. The above modifications will be discussed along with scientific results and observations of carbon nanotube nucleation, chirality selection and growth termination. The benefits attained from linking controlled real time in-situ observations of catalyst morphological evolution with equivalent quantitative measurements derived from more standard approaches will be presented.

  2. Medical Department Seminar

    "Single Cell Environmental Microbiology with Nano Secondary Ion Mass Spectrometry"

    Presented by Jennifer Pett-Ridge, Ph.D., Lawrence Livermore National Laboratory

    Monday, May 17, 2010, 1:30 pm
    Large Conference Room, Bldg. 490

    Hosted by: Joanna Fowler

    Understanding single cell environmental microbiology is a key challenge in fields ranging from medicine to biofuel development to C sequestration. Isotope-labeling experiments provide a useful means to investigate the ecophysiology of microbes in the environment and allow measurement of nutrient transfers between cell types, symbionts and consortia. The combination of Nano-Secondary Ion Mass Spectrometry (NanoSIMS) analysis, in situ labeling and high resolution microscopy allows isotopic analysis to be linked to phylogeny and morphology and holds great promise for fine-scale studies of microbial systems. In NanoSIMS analysis, samples are sputtered with an energetic primary beam (Cs+, O-) liberating secondary ions that are separated by the mass spectrometer and detected in a suite of electron multipliers. Five isotopic species may be analyzed concurrently with spatial resolution as fine as 50nm. A high sensitivity isotope ratio "map" can then be generated for the analyzed area. NanoSIMS analyses are particularly powerful when used in combination with analysis techniques such as TEM, STXM, CARD-FISH and high density oligonucleotide microarrays. These newly developed approaches provide correlated oligonucleotide, enzymatic and metabolic image data and can help unravel the metabolic processes of complex microbial communities in soils, biofilms and aquatic systems.

  3. Environmental Sciences Department Seminar

    "Growing Giant Grass: Why Bigger is Better for Energy Crops"

    Presented by Emily Heaton, Dept. of Agronomy, Iowa State University

    Friday, April 16, 2010, 1 pm
    John Dunn Seminar Room, Bldg. 463

    Hosted by: Dr. Alistair Rogers

    Among renewable energy sources, only biomass can provide fuel and electricity in a form and scale that is compatible with existing transportation and power generation infrastructure. Unlike wind and solar energy, biomass can be converted directly into liquid fuel by a variety of conversion routes, as is current practice with petroleum, or it can be stored to generate electricity on-demand, as is current practice with coal. Further, lignocellulosic biomass can be produced in such a way as to balance the three pillars of sustainability: economic, social and environmental sustainability. This presentation will discuss a portfolio of high-yielding biomass crops including Miscanthus spp., switchgrass (Panicum virgatum), prairie cordgrass (Spartina pectinata) and other grasses that, if managed appropriately, can be integrated into the US agricultural system with little impact on food production in many regions. Importantly, the technology for implementing biomass energy from these crops exists today.

2009

  1. National Synchrotron Light Source Lunch Time Seminar

    "Environmental Significance of Bauxite Residues"

    Presented by Markus Grafe, Commonwealth Scientific Industrial Research Organization, Australia

    Friday, November 13, 2009, 12 pm
    Seminar Room, Bldg. 725

    Hosted by: Christie Nelson

  2. National Synchrotron Light Source Lunch Time Seminar

    "Quantification of Organochlorine Concentrations by X-ray Absorption Spectroscopy with Environmental and Public Health Applications"

    Presented by Alessandra Leri, Marymount Manhattan College

    Friday, October 2, 2009, 12 pm
    Seminar Room, Bldg. 725

    Hosted by: Elaine DiMasi

  3. NSLS-II Seminar

    "Crystal growth and ion exchange in environmentally important materials"

    Presented by Aaron Celestian

    Wednesday, July 22, 2009, 2 pm
    NSLS-II Seminar Room, Bldg. 817

    Hosted by: Eric Dooryhee

    Materials capable of selectively sieving cations from aqueous media are extremely useful for environmental applications like remediation. The molecular processes leading to ion selectivity in zeolites and other porous materials under extreme environmental conditions are not well understood. This is in part due to the fast rates of exchange reactions and the experimental difficulty probing crystal structures under adverse conditions. By understanding the mechanisms that govern crystal growth and ion selectivity in zeolitic materials, we can learn how to optimize ion exchange for specific environmental conditions. I will present time-resolved X-ray diffraction studies demonstrating how structural transformations that occur during ion exchange serve to enhance the exchange capacity and/or ion selectivity . I will also describe current work on in situ crystal growth and decomposition in highly acidic and basic solutions. The primary goal of this research is to understand the mechanistic and dynamic nature of cation diffusion and crystallization processes for materials in harsh environments.

  4. NSLS-II Seminar

    "Application of X-ray Diffraction Techniques to materials under various environmental conditions"

    Presented by Dr. Sanjit Ghose, Stony Brook University

    Tuesday, June 16, 2009, 2:30 pm
    Large Conference Room, Building 703

    Hosted by: Qun Shen

    Understanding the behavior of novel materials and minerals at various environmental conditions requires the understanding of its atomic and molecular structure on long-range, intermediate-range and short-range scale. Information on all these length scales could be possible with the application of state-of-the-art X-ray diffraction techniques. In this presentation I will be talking on Crystal Truncation ROD (CTR) a surface sensitive diffraction technique and its application in determining the structure of geochemical interfaces. I will also be discussing on some of the results of the application of Angle and Energy Dispersive X-ray Diffraction (ADXD & EDXD) and Total X-ray Scattering (PDF analysis) techniques in geosciences and materials science.

  5. Environmental Sciences Department Seminar

    "XemI Lab, Giving Old Data a New Life"

    Presented by Yves Gibon, Institut National de la Recherche Agronomique, Villenave d’Ornon, France

    Friday, March 20, 2009, 11 am
    John Dunn Seminar Room, Bldg. 463

    Hosted by: Alistair Rogers

    Abstract: We have developed Xeml Lab, a platform with a graphical interface, which helps the user to plan experiments and concomitantly generate machine-readable metadata files, based on different ontologies. We performed meta-analyses of a large set of experiments that were carried out during 5 years. This revealed that Arabidopsis achieves a remarkable metabolic homeostasis across a wide range of photoperiod treatments, and that adjustment of starch turnover and the leaf protein content contribute to this metabolic homeostasis.

  6. Chemistry Department Seminar

    "Nano-Scale Environmental Effects on the Reactivity of Platinum Clusters"

    Presented by Ye Xu, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory

    Wednesday, March 11, 2009, 11 am
    Room 300, Bldg. 555

    Hosted by: Alex Harris

    Advances in synthesis techniques for size-defined metal clusters have brought uniform and potentially size-tunable nano-catalysts closer to reality. The versatility of platinum catalysts in many important industrial and energy applications and the high cost of the metal make Pt an excellent candidate for going “nano.” However, the response of such tiny objects to the chemical environment will need to be thoroughly understood before this type of novel catalyst can be productively deployed. The ability of theory and computational modeling to elucidate the properties of objects in the angstrom size regime makes it an ideal tool for nano-catalysis research. Therefore we have performed density functional theory calculations to explore the interaction of a series of small Pt clusters with prototypical environmental elements. Non-bulk-like, size-dependent phase behavior and accompanying changes in the molecular and electronic structures are identified for the isolated clusters when they are exposed to an oxygen atmosphere, and size- and composition-dependent reactivity is found for two model oxidation reactions, CO and NO oxidation. In addition, we have investigated how adsorption on a MgO(100) support surface affects the structures and oxidation of the Pt clusters and analyzed the mechanism of adhesion. Our results shed light on the intricate coupling between particle size, chemical environment, and reactivity in the surface chemistry of finite supported metal clusters.

2008

  1. Environmental Sciences Department Seminar

    "Hubbert's Peak, The Coal Question, and Climate Change"

    Presented by Dave Rutledge, California Institute of Technology

    Tuesday, September 2, 2008, 1:15 pm
    Hamilton Seminar Room, Bldg. 555

    Hosted by: Stephen Schwartz

    There is a vigorous debate now about whether our oil, natural gas, and coal resources will be sufficient in the future. At the same time, there is an intense effort to predict the changes in climate that will result from consuming these fossil fuels. There has been surprisingly little effort to connect these two. Do we have a fossil-fuel supply problem? Do we have a climate-change problem? Do we have both? Which comes first? We will see that the trend for future fossil-fuel production is less than what is assumed in the United Nations climate-change assessments. The implication is that an understanding of producer limitations could help us do a better job of predicting climate change. We will also see that the time scale for exhausting fossil fuels is much smaller than that for global temperature change. This means that to reduce the future temperature rise, it is critical to reduce the total fossil-fuel production, not just slow it down. One possible approach for reducing total production would be to establish fossil-fuel preserves on federal lands that would be off limits for new leases for drilling and mining.

  2. Biology Department Seminar

    "Plants and Environmental Challenges"

    Presented by Lee Newman, Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, SC

    Friday, August 1, 2008, 11 am
    John Dunn Seminar Room, Bldg. 463

    Hosted by: Niels van der Lelie

    Plants have been used for several years for the remediation of hazardous chemicals in the environment. During that time we have had some understood what they did with the hazardous material, but not necessarily how they did it. But as the science has progressed, and as new environmental challenges have emerged, there is an increasing need to expand our thoughts on how to use plants to meet these challenges. This presentation will include our use of genetic tools to understand how plants degrade ‘traditional’ pollutants such as trichloroethylene as well as the plant interactions with new environmental contaminants such as nanoparticles. We will also present work we have done to identify multiuse bioenergy plants that would be suitable for use in the southeast, and the use of endophytes to increase both degradation potential for environmental contaminants while increasing production of biomass. And finally, we will present how native biological and physical degradation pathways can be combined for the degradation of light sensitive compounds, and discuss ongoing work to develop novel sensors to identify plants that have been in contact with contaminants.

  3. BSA Distinguished Lecture

    "Unraveling the Mystery of an Environmental Disease"

    Presented by Arthur Grollman, Stony Brook University, Dept. of Pharmacology

    Thursday, May 15, 2008, 4 pm
    Berkner Hall Auditorium

    Hosted by: Peter Wanderer

    A progressive, invariably fatal kidney disease, Balkan endemic nephropathy, and the upper urothelial tract cancer associated with it, occur among residents of farming villages in the Danube river basin. Dr. Arthur Grollman and his colleagues began epidemiologic and clinical studies that resulted in the discovery that home-baked bread, a dietary staple of farm families living in the endemic area, was contaminated with aristolochic acid, a powerful kidney toxin and human carcinogen that was present in Aristolochia weeds that grow in local wheatfields.

  4. Life Sciences Seminar

    "Toxicogenomics of an Environmental Disease"

    Presented by Arthur Grollman, Laboratory of Chemical Biology, Department of Pharmacological Sciences, Stony Brook University

    Thursday, May 15, 2008, 11 am
    John Dunn Seminar Room, Bldg. 463

    Hosted by: Carl Anderson

    An interdisciplinary approach (chemistry, molecular/cell biology and functional genomics) was used to establish the molecular and genetic mechanisms by which aristolochic acid exerts its profound nephrotoxic and genotoxic effects in humans. We have identified several genes involved in the cytotoxic effects of this ubiquitous phytotoxin on human renal proximal tubular and urothelial cells. Molecular epidemiologic and toxicogenomic methods have been used to investigate the etiology of endemic nephropathy and its associated urothelial cancer (PNAS, 104:12129, 2007), and to identify genes that confer susceptibility and resistance to this devastating environmental disease.