Thursday, 13 January 2005
Characterization of global microwave surface emissivity over land
Microwave remote sensing of the atmosphere over land and ice is a great challenge. Traditionally microwave approaches have been severely limited over land, and are only routinely performed over ocean areas. This is due to the higher emissivity values over land and their dynamic behaviors on daily to seasonal timescales. The lack of reliable land surface emissivity knowledge has hindered full exploitation of the capabilities of operational microwave satellite sensors such as AMSU, SSM/I, and will continue to adversely impact the utilization of new sensors such as the DMSP SSMIS.
A global 1DVAR microwave emissivity retrieval algorithm is used with AMSU data to retrieve global microwave emissivities at frequencies from 23 to 183 GHz. A simultaneous retrieval of the temperature and water vapor profiles as well as cloud liquid water is also performed. Our emissivity results are compared with the NOAA NESDIS Microwave Emissivity Model for a variety of conditions. Application of the dynamic global emissivity database for data assimilation performance improvements will also be discussed.