Water vapor profile retrievals from satellite microwave sounding instruments

Results from a 1DVAR simultaneous retrieval of atmospheric water vapor, temperature, cloud liquid water, and microwave surface emissivity using passive satellite microwave observations are presented. The method is tested on data from the Advanced Microwave Sounding Unit (AMSU) and compared with coincident radiosonde observations over coastal and island sites. The sensitivity of the retrieval system to a number of variables (antenna pattern corrections, first guess fields, and assumed error covariances) is discussed. This work explores several improvements, including the application of an AMSU-B antenna pattern correction, and improvements to the error covariance estimates. The method is quite general in its applicability. Preliminary results over land are also shown. Remaining research challenges are discussed in the context of creating an observationally-based global land/ocean microwave water vapor profiling capability.