Interpreting AMSR-E Liquid Water Path Products in Warm Precipitating Clouds using MODIS and CloudSat

Global observations of liquid water in the atmosphere have been available for decades yet significant differences still remain between products obtained from microwave radiometers, visible/infrared sensors and cloud radars. Among the largest differences occur in precipitating clouds where passive microwave sensors are sensitive not only to rain and cloud water but also large ice particles. For warm rain clouds at low latitudes, differences in cloud liquid water path (LWP) derived from the Moderate resolution Infrared Spectrometer (MODIS) and Advanced Microwave Scanning Radiometer-EOS (AMSR-E) have been found to be strongly correlated to rain water path observed by the CloudSat Cloud Profiling Radar (CPR). The cause of this relationship is unclear but is likely related to assumptions made in the rain drop size distribution and/or partitioning of cloud and rain water in the AMSR-E algorithm. This study aims to better understand the AMSR-E LWP products in warm rain clouds using a new merged MODIS/AMSR-E dataset matched to the CloudSat CPR. The merged dataset is based on the latest versions of the Level 2 MODIS cloud products (collection 6) and Level 2b AMSR-E swath ocean products (version 7) and was created from a fast collocation algorithm that averages the high resolution MODIS products using the effective antenna pattern of the lower resolution AMSR-E footprint. These latest versions of the datasets include new and improved products that will further aid in the interpretations. In our analysis, we plan to use the recently released CloudSat 2C-RAIN-PROFILE products, which include profiles of rain rate, rain water content and cloud liquid water content, and undertake radiative transfer modeling experiments. Results will be presented at the conference.