7B.1    Assimilation of Microwave All-Sky Radiances and Hydrometeor Retrievals in HWRF

 

Wu, Ting-Chi, Milija Zupanski, Lewis Grasso, and Christian Kummerow,

Cooperative Institute for Research in the Atmosphere/Colorado State University, Sid-Ahmed Boukabara, National Aeronautics and Space Administration/Center for Satellite Applications and Research

 

Satellite all-sky radiances from the Advanced Technology Microwave Sounder (ATMS) and microwave hydrometeor retrievals from the Hurricane GPROF are assimilated into Hurricane Weather Research and Forecasting (HWRF) using the hybrid Gridpoint Statistical Interpolation (GSI). Hurricane GPROF is an algorithm that produces hydrometeor retrievals from the Global Precipitation Measurement mission (GPM) and the Tropical Rainfall Measuring Mission (TRMM) microwave imagers for hurricanes.  In order to improve the assimilation of cloud and precipitation information from the hydrometeor retrievals and all-sky radiances, cloud variables are included as additional control and state variables in GSI. That is, the above-mentioned observations are assimilated using observation operators that consider cloud variables and Jacobians with respect to cloud variables. As a consequence, the analysis will include cloud variable updates along with the default temperature, pressure, horizontal wind, and specific humidity updates. Results indicate that the assimilation of Hurricane GPROF hydrometeor retrievals and ATMS all-sky radiances showed an improvement of the analysis field. Synthetic satellite data from HWRF forecasts was used to show that there are too many cloud top pixels that are too cold compared to observations. In addition, several metrics were used to evaluate the forecasts.