Tropical Ice Cloud Features from 4-year CloudSat and CALIPSO observations

Most tropical precipitating cloud systems consist convective and stratiform elements. Currently most models produce too much convective and too little stratiform precipitation over most of the low latitudes. Thus, observational guide for model improvement is critical. While the CloudSat radar detects the heavy precipitation as well as optically thick anvil clouds the CALIPSO lidar provides the upper part of deep convective system including optically thin wide spreading anvil. Based on the combined CloudSat and CALIPSO measurements, an algorithm is developed to partition a tropical ice clouds into four regions: convective core (characterized by high reflectivity and reflectivity gradients), stratiform clouds (indicated by radar bright band at the melting layer), anvil cirrus, and apparent isolated ice clouds. First, the spatial coverage of the four regions is investigated. Second, with the CloudSat 2C-ICE product, the ice cloud property distributions within tropical deep convections are examined. From a microphysical point of view, cloud and precipitation particles may grow through vapor diffusion or through particle interactions. On the other hand, the size of a particle may also be reduced due to breakup into smaller pieces, caused by instability or collisions, or sublimation. Ice microphysical properties within the four regions are investigated to understand the microphysical and dynamical processes responsible for the differences.