Assimilating GPM/GMI and TRMM/TMI Microwave Radiance Data With GEOS-5

The Global Precipitation Mission (GPM) Core Observatory satellite was launched on February 27, 2014. Observations from its two instruments, the GPM Microwave Imager (GMI) and the dual-frequency radar, aim to advance scientific understandings of Earth's water and energy cycle. GMI conically scans 13 channels between 10 – 183 GHz between 65° S – 65° N latitude. This instrument is in many ways a successor to the Tropical Rainfall Measurement Mission (TRMM) Microwave Imager (TMI). The TMI has been observing 9 channels at frequencies ranging 10 – 85 GHz between 40° S – 40° N latitude since 1997. Information about clouds, rain, snow, and sea surface temperature can be extracted by assimilating GMI and TMI level 1 brightness temperatures. The Global Modeling and Assimilation Office (GMAO) has developed procedures to incorporate these radiance data into its Goddard Earth Observation System model, version 5 (GEOS-5) atmospheric analysis via an all-sky radiance data assimilation methodology. Initial experiments have shown that clear-sky GMI and TMI data assimilation lessens the model's precipitation, moving it towards retrieved rainfall products. The GEOS-5 atmospheric data assimilation algorithm now has the capability to assimilate near-real-time GMI radiance observations and is under testing. The procedures of assimilating these observations and the impact of these data on GEOS-5 atmospheric analysis will be presented in this talk.