Effect of Precipitation to the Wind Retrieval from Synthetic Aperture Radar

摘要

As one of the most powerful air-sea interaction in the weather system, typhoon always accompany with a wide range of heavy rainfall. Synthetic Aperture Radar(SAR) plays an importantrnrole in typhoon wind field retrieval, because it can work all-day, all-weather and has high spatial resolution. But due to the influence of the rainfall on the radar signal, the inversion precision of searnsurface wind field will decline. With the exploration of high wind speed inversion model, much more researchers focus on the influence of large precipitation to the wind field retrieval. Researchers havernproposed many different rain effect models applied to scatterometer data, but it is not sure weather they can also used on SAR data.rnIn this paper, one C band scatterometer rain effect model proposed by Congling Nie and David G. Long (TGRS 2007) was applied on typhoon Rammasun RADARSAT-2 ASAR data. Combined withrnthe sea wind direction information from European Center for Medium-Range Weather Forecasts (ECMWF) reanalysis data, high accuracy and high-resolution wind field was obtained by usingrngeophysical model function CMOD5.Then the result was validated with wind field retrieved from VH polarization data using C-band Cross-Polarization Ocean (C-2PO) model (Biao Zhang and WilliamrnPerrie, AMS, 2012), the comparison showed that there still need further correction based on by Nie and Long’s rain effect model.