GRACE时变重力场条带误差的加权平均去相关滤波方法

Analysis on GRACE Gravity Data Based on a Simple Weighted Average De-Correlation Filter

提出一种简单、快速的加权平均去相关滤波方法,以滤除GRACE时变重力场存在的显著的南北条带误差,并可以处理球谐位系数中的两端点系数。基于CSR RL05和Tongji-GRACE01时变重力场模型,采用加权平均去相关滤波求得2003~2011南极区域的质量变化速率为-78.35±41.08 Gt/a和-78.06±40.75Gt/a,与多项式拟合去相关滤波求得的结果-81.91±40.75Gt/a和-79.31±40.46Gt/a极为接近。在亚马逊流域,这两种滤波方法求得的结果也极为接近,从而验证了本文方法的有效性。

The time-variable gravity field model derived from GRACE contains large north-south strip errors.This paper presents a simple and fast weighted average de-correlation filter method that can effectively remove the north-south strip errors and can be applied to the end points of the spherical harmonic coefficients.Based on CSR RL05 data and Tongji-GRACE01 data from 2003 to 2011,the mass change rates in Antarctica are-78.35±41.08Gt/a and-78.06±40.75Gt/a by the weighted average filter method,which are very close to-81.91±40.75Gt/a and-79.31±40.46Gt/a by the polynomial fitting de-correlation filter.The results derived from the two filters also agree with each other in Amazon,which validates the efficiency of our weighted average filtering method to suppress the north-south strip errors.