Assimilation of GBVTD-Retrieved Winds from Single-Doppler Radar for Short-Term Forecasting of Super Typhoon Saomai (0608) at Landfall Kun Zhao1, 2, Ming Xue2,3 and Wen-Chau Lee4 1Key Laboratory for Mesoscale Severe Weather/MOE and School of Atmospheric Sciences, Nanjing University, Nanjing, 210093, China 2Center for Analysis and Prediction of Storms and 3School of Meteorology University of Oklahoma, Norman Oklahoma 73072 4Earth Observing Laboratory, National Center for Atmospheric Research*, Boulder, CO 80307 July, 2010 Revised and resubmitted in April 2011 Quarterly Journal of Royal Meteorological Society Corresponding author address: Ming Xue Center for Analysis and Prediction of Storms University of Oklahoma, 120 David L. Boren Blvd, Norman OK 73072
[email protected] *The National Center for Atmospheric Research is sponsored by the National Science Foundation. Abstract A single-Doppler wind retrieval method called the Ground-Based Velocity-Track Display technique (GBVTD) has been developed in recent years to retrieve horizontal circulations of tropical cyclones. The technique is able to retrieve axisymmetric tangential and radial winds, asymmetric tangential winds for wavenumbers 1 through 3, and along-beam mean winds in tropical cyclones. It has been successfully applied to tropical cyclone monitoring and warning. This study explores, for the first time, the assimilation of GBVTD-retrieved winds into a tropical cyclone prediction model, and examines its impact relative to that of directly assimilated radial velocity data. Super Typhoon Saomai (2006), the most intense landfalling typhoon ever recorded in China, is chosen as the test case, and data from the coastal operational radar at Wenzhou, China are used. The ARPS 3DVAR system is used to assimilate either the radial velocity data directly or the GBVTD-retrieved winds, at 30-min intervals for 2 hours.