Observation Impact on Mesoscale Model Forecast Accuracy over South West Asia

An adjoint-based observation impact assessment tool for the Weather Research and Forecasting (WRF) model system is applied over South West Asia. The system is configured to assimilate a variety of conventional and remotely sensed observations including retrievals of ocean surface wind speed and total precipitable water derived from measurements taken by the Special Sensor Microwave Imager/Sounder (SSMIS) which flies onboard Defense Meteorological Satellite Program (DMSP) spacecraft. Brightness temperatures from select SSMIS temperature and moisture channels are also assimilated over ocean and land areas. The relative impact of assimilating the various observations types on 24-hour WRF model forecasts is determined. The assimilation of SSMIS data is shown to have a significant, positive impact on WRF model forecast accuracy.