Abstract:
Objectives Backscatter coefficient ( \sigma _0 ) is one of observations of satellite radar altimetry, which is widely used in the processes of surface state monitoring, snow thickness inversion, data calibration and verification of satellite altimeters, and other fields. The geophysical data record data of Jason-2 is used to extract and isolate the Ku-band \sigma _0 data of the Tibetan Plateau (TP).
Methods Taking the GlobeLand30 2020 version data as the basis for surface classification, \sigma _0 is given surface attributes by latitude and longitude data. And we obtain the time-varying sequences of \sigma _0 under different types of surface features from December 2008 to September 2016. The singular spectrum analysis principle is used to extract the \sigma _0 time change trend and period information, and the period results are analyzed by fast Fourier transform.
Results The results show that the \sigma _0 is higher in waters and wetland areas, and is lower in permanent snow and ice areas. There are multiple period signals of \sigma _0 in the TP.
Conclusions The surface properties of the artificial surfaces, bare land, and shrubland area are stable, and the annual \sigma _0 change is not significant. The other regions have significant annual and semi-annual cycles of \sigma _0 variability, and the amplitude of variability is not consistent across regions, with different regions corresponding to different changes in \sigma _0 trends.
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