Research on an improved NRCS model based on spaceborne SAR observation
The Normalized Radar Cross Section(NRCS)calculation formula is derived by analyzing the echo paths of the scattering attenuation characteristics of rainfall particles in different phases.Using the vertical profiles of convective rainfall measured over low-latitude tropical land and ocean in 1998,the optimization of NRCS is val-idated based on the Model-Oriented Statistical(MOS)surface rainfall retrieval algorithm of Synthetic Aperture Radar(SAR).The results show that the optimized NRCS model can improve the echo attenuation by about 6.17% .The improvement of echo attenuation indicates that the optimized NRCS model can improve the surface rainfall retrieval accuracy of MOS algorithm in the range of surface rainfall underestimated by MOS algorithm,and the average retrieval error is reduced by about 1.56% .However,in the range of surface rainfall overestimated by MOS algorithm,the optimized NRCS model will increase the retrieval error of MOS algorithm.Therefore,the im-proved NRCS model is only applicable to the case where the MOS algorithm underestimates the surface rainfall.
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