Research for Time Variation of C20 Using GRACE and SLR Measurements

초록

The research of global-scale mass redistribution and it changed by Earth gravity filed variation observations,including Earth’s oblateness(also called low degree spherical harmonic coefficient), is in continuous progress. Recently, the comparative analysis of geodetic observation SLR can be made by the development of GRACE and other time-variable gravity measurements. In this study,time series changes in the value of comparative analysis was got by GRACE monthly Gravity filed model (CSR RL04) for the period April 2002 to May 2008. And comparative analysis the harmonic coefficients of was obtained from SLR observations. Signal analysis for two time-series data was made by wavelet transform, CWT(continuous wavelet transform), XWT(cross wavelet transform) and WTC(wavelet coherence) methods. The results indicate that GRACE and SLR values for had both decreasing trend, as well as SLR data represent the annual frequencies,and GRACE was semiannual variations. In addition, the results of GRACE and SLR had a strong correlation with the XWT and WTC in an annual cycle.

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