Cloud Processes Group Field Campaigns
Midlatitude Continental Convective Clouds Experiment
Convective processes play a critical role in the Earth's energy balance through the redistribution of heat and moisture in the atmosphere and their link to the hydrological cycle. Accurate representation of convective processes in numerical models is vital towards improving current and future simulations of Earths climate system. Despite improvements in computing power, current operational weather and global climate models are unable to resolve the natural temporal and spatial scales important to convective processes and therefore must turn to parameterization schemes to represent these processes. In turn, parameterization schemes in cloud-resolving models need to be evaluated for their generality and application to a variety of atmospheric conditions
The Midlatitude Continental Convective Cloud Experiment (MC3E), a joint field program involving ARM and NASA Global Precipitation Measurement Program investigators, was conducted in south-central Oklahoma during the April to June 2011 period. BNL scientists performed the roles of Principal Investigator (Jensen), Co-Investigator (Giangrande, Kollias) mission scientists (Jensen, Kollias), forecasting leads (Giangrande) and instrument Principal Investigators (Jensen, Kollias, Bartholomew). The experiment leveraged the unprecedented observing infrastructure available in the central United States, combined with an extensive sounding array, remote sensing and in situ aircraft observations, and new ARM radar instrumentation purchased with funding from the American Recovery and Reinvestment Act.
Experimental Goals
The overarching goal was to provide the most complete characterization of convective cloud systems and their environment that had ever been obtained, providing constraints for model cumulus parameterizations that had never before been available. Several different components of convective processes tangible to the convective parameterization problem were targeted, such as pre-convective environment and convective initiation, updraft/downdraft dynamics, condensate transport and detrainment, precipitation and cloud microphysics, influence on the environment and radiation, and a detailed description of the large-scale forcing.
Operational highlights of the MC3E campaign
- Sampling a variety of convective cloud conditions with both aircraft and ground-based radar including: strong convective line with trailing stratiform (7), widespread stratiform rain (3), elevated or weak convection (3), boundary layer clouds (9), mid- or high-level clouds (6)
- Launched more than 1400 radiosondes from six different sites to capture environmental conditions within which convection occurs for use in deriving a model-forcing data set
- Multiple coordinated missions with ARM surface-based observations (radar, radiosonde, etc.), NASA surface-based observations (N-Pol, disdrometer network), NASA ER-2 aircaft, and the UND Citation Cessna
- Sampling of convective clouds by multiple scanning radar systems providing opportunities for multi-Doppler analysis of atmospheric motions
- Flexible scanning radar modes (C-band, X-band) to fill observational gaps during campaign operations
- Dedicated cloud missions with UND Citation flying over scanning cloud radar
- Excellent sampling of large precipitation drops by 2D video disdrometers and accompanying NASA disdrometer array