An experimenal analysis for the impact of 2D variation assimilation of satellite data on typhoon track simulation

A series of test simulations are performed to evaluate the impact of satellite-derived meteorological data on numerical typhoon track prediction.Geostationary meteorological satellite(GMS-5) and NOAA's TIROS operational vertical sounder(TOVS) observations are used in the experiments.A twodimensional variation assimilation scheme is developed to assimilate the satellite data directly into the Penn State-NCAR nonhydrostatic meteorological model(MM5).Three-dimensional objective analyses fields based on T213 results and routine observations are employed as the background fields of the initialization.The comparisons of the simulated typhoon tracks are also carried out,which correspond respectively to the initialization scheme with two-dimensional variation(2D-Var),three-dimensional observational nudging and direct assimilation of satellite data.It is found that,comparing with the experiments without satellite data assimilation,the first two assimilation schemes lead to significant improvements on typhoon track prediction.Track errors reduce by 18% at 12 h for 2D-Var and from about 16% at 24 h to about 35% at 48 h for observational nudging.The simulated results based on assimilating different kinds of satellite data are also compared.