P7     Improved Hurricane Forecast through GSI-Hybrid Data        Assimilation: A Case Study

Zhou, Chunhua, Hui Shao, National Center for Atmospheric Research, Ming Hu, Ligia Bernardet, NOAA/ESRL, Xiang-Yu Huang and Brian Etherton, NCAR

Hybrid 3DVAR incorporates flow-dependent information from the ensemble perturbations into the static background error covariances used in 3DVAR, and has been shown to have positive impact on global forecasts and some regional applications. In this study, GSI (Gridpoint Statistical Interpolation) - Hybrid is being tested for the HWRF (WRF for Hurricanes) system. A case study is performed for Bret 2011 and positive impact from the GSI-Hybrid data assimilation is shown for the hurricane forecast, especially with the track forecast, in comparison with pure GSI 3DVAR applied for HWRF. Further studies are being conducted to assess the impact of satellite radiance data in the framework of GSI-Hybrid and preliminary results will be presented.