The impact of assimilation of microwave radiance in HWRF on the forecast over the western Pacific Ocean

We investigated the impact of assimilating microwave radiances from the Advanced Microwave Sounding Unit-A (AMSU-A) and the Microwave Humidity Sounder (MHS) into the Hurricane Weather Research and Forecasting (HWRF) model on the forecast of typhoon tracks over the western Pacific Ocean. The assimilation of MHS observations has positive impacts on the track forecast, but the assimilation of AMSU-A leads to mixed results. In the forecast experiments, the bias correction coefficients created from the regional model data assimilation system are found to be superior to those produced by the global modeling system, even though the background fields in both cases are derived from the global model predictions.