Session 4: Atmospheric retrieval over land and sea ice: impact of surface information on cloud and rain retrieval Session Chair: Sid Boukabara 24. On the Sensitivity of TRMM Microwave Imager Channels to Over-Land Rainfall Author： Y. You and G. Liu Affiliation： Florida State University Current passive microwave rain retrievals over land are known to contain large uncertainties. A major setback for over land rain retrieval is its reliance on ice scattering information. The relation between ice aloft has variable relations with rainfall at the surface. In some cases, problems arise since rainfall is not directly proportional to ice. By analyzing TRMM data and performing radiative transfer modeling, here we argue that a combination of TMI channels does contain liquid information. Additionally, it is found that land surface type and 2-meter air temperature have significant skills in characterizing rain cloud types. An effective use of such information can lead to significant improvement for land rain retrieval.