Studies on the Initialization and Simulation of Hurricane Lili(2002): Assimilation of QuickScat, GOES-8 and Terra Data Using MM5 4D-Var System

QuickScat Winds, GOES-8 Winds, and Terra temperature and dewpoint profile data are assimilated using MM5 4D-Var system, to study the Hurricane Lili's rapid intensification and weakening episodes before landfall on Louisiana. Two assimilation and simulation experiments are conducted in this study for intensification, and for weakening period separately. In each assimilation experiment, there are two 6-h 4D-Var cycling of the satellite-retrieved data. Since the satellite-retrieved data are not available over the hurricane center area, the vortex bogus data are also assimilated with the satellite data together. The optimal initial condition of 4D-Var cycling experiments have more realistic hurricane structure than the experiment without data assimilation. Therefore, the simulations of track and intensity based on the optimal condition are improved. The impact of satellite data on Hurricane Lili's initialization and simulation is examined by data-denying experiments. The results show that the satellite data have positive impacts both on initialization and simulation.