Multi platform Comprehensive Retrieval of Marine SC Microphysical and Geometrical Properties Including Cloud Base Height and Surface Coupling State

We developed a methodology for a complete description of the marine stratocumulus clouds geometrical and microphysical properties. These include, among others, coupling state, retrieval of cloud base heights, cloud geometrical depth and type of precipitation (initiated by giant CCN or drizzle). The methodology combines simultaneous observations from several A-TRAIN instruments (CALIPSO, CloudSat and MODIS) and co-locates it to produce secondary products. The methodology is packed into a tool that visualizes the clouds macrophysical and microphysical properties.

Some of the problems that can be solved by using the presented tool are (1) Disentangling the role of meteorology and aerosols on the development of precipitation (i.e., cloud depth versus droplet concentrations as a limiting factor for drizzle initiation). The cloud top heights are retrieved directly from CALIPSO, whereas the cloud bases are estimated by a reverse accumulation (top to bottom) of the adiabadic cloud water to achieve the MODIS retrieved liquid water path at the points where clouds have maximum optical depth. CloudSat radar reflectivity provides estimation of the drizzle rates. (2) Determining whether the cloud layer is coupled or decoupled from the ocean surface layer. This has implications regarding the dynamical feedbacks of drizzle on the cloud regimes. (3) Identifying the type of precipitation, i.e., initiation of precipitation from the main mode of the droplet size distribution by giant CCN or drizzle. Such discrimination is possible by the difference of the MODIS cloud top effective radius that is retrieved from channels 2.1 and 3.7 µm. Examples will be shown together with their physical interpretation.