Environmental & Climate Sciences Department Seminar

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.