Impacts of Improved Quality Control and Ocean Emissivity Model for AMSR-E Radiance Assimilation in JMA

Since 2006, the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E), Special Sensor Microwave Imager (SSM/I), and Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) clear ocean radiance data have been utilized in Japan Meteorological Agency (JMA) operational global four dimensional variational (4D-Var) data assimilation system [1]. The quality control and bias correction to screen out cloud- and rain affected radiance data are crucial parts in the pre-process of the clear radiance data assimilation. Improved quality control and bias correction were developed and FAST emissivity model version 3 (FASTEM-3) [3] was employed for the assimilation. Experiments showed a reduction of bias in moisture field and improvements of 850 hPa temperature and 500 hPa geopotential height forecasts in the Southern Hemisphere. The results suggest the use of the new quality control and bias correction scheme can select clear radiance data effectively and accurate moisture analysis produce better global forecasts in the JMA operational Numerical Weather Prediction (NWP) system.