Data Assimilation Studies on Typhoon Sinlaku (2008) Using the WRF-LETKF System

Data assimilation and predictability studies on Tropical Cyclones with a particular focus on intensity forecasts are performed with the newly-developed Local Ensemble Transform Kalman Filter (LETKF) system with the WRF model. Taking advantage of intensive observations of the internationally collaborated T-PARC (THORPEX Pacific Asian Regional Campaign) project, we focus on Typhoon Sinlaku (2008) which intensified rapidly before making landfall to Taiwan. This study includes a number of data assimilation experiments and sensitivity analysis which quantifies impacts of observations on forecasts. Recent achievements include higher-resolution data assimilation with two-way nested domains as well as improved forecasts due to including SST uncertainties in ensemble-based data assimilation. This presentation includes latest achievements up to the time of the conference.