Sea surface wind speed inversion method based on cross polarization model and CMOD5N

Abstract

The invention discloses a sea surface wind speed inversion method based on a cross polarization model and CMOD5N. The method comprises the steps of: according to the CP model and a C-2PO method, utilizing VV polarization and VH polarization SRA images to carry out inversion and obtain an initial wind speed U0 and an initial wind direction [phi]0 of a reconstruction resolution unit; determining wind field vectors (U, [phi]) according to the initial wind speed U0 and the initial wind direction [phi]0, using the wind field vectors (U, [phi]) as a first guess value, and utilizing a CMOD5N algorithm to gradually traverse and calculate normalized radar scattering cross sections NRCS of corresponding VV polarization in upper and lower limit ranges of the wind speed and the wind direction with the first guess value serving as a center; and finding out the wind speed and the wind direction which have the smallest differences with the normalized radar scattering cross sections NRCS of VV polarization SRA images, wherein the wind speed and the wind direction having the smallest differences are the wind field vectors obtained by inversion. According to the invention, the wind speed inversion precision of the existing C-2PO method is generally improved in different SAR image reconstruction resolution scale situations.

Description

technical field [0001] The invention relates to a sea surface wind speed inversion method, which belongs to the technical field of oceans. Background technique [0002] Sea surface wind speed retrieval is an important technical means for marine meteorological forecast and marine environment safety monitoring. [0003] At present, the remote sensing technology of sea surface wind field mainly includes scatterometer and synthetic aperture radar (SAR). SAR has a higher spatial resolution than scatterometers, so using SAR image remote sensing to retrieve sea surface wind field vectors has always been an international research hotspot. Document 1, F.Said and H.Johnsen, Ocean surface wind retrieval from dual-polarizedSAR data using the polarization residual Doppler frequency, IEEE Trans. Geosci. Remote Sens. 52(2014) 3980-3990. Document 2, G.K.Carvajal, L.E.B.Erikssonand L.M.H.Ulander, Retrieval and quality assessment of wind velocity vectorson the ocean with C-band SAR, IEEE Tr...

AI Technical Summary

Problems solved by technology

Although this method does not rely on external wind direction information and GMF, the accuracy of wind speed retrieval is greatly affected by the resolution scale of SAR image reconstruction, and it is difficult to determine the resolution scale of SAR image reconstruction corresponding to the highest accuracy.

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