GRACE反演南极冰盖质量变化的高斯与Wiener滤波比较

Comparison of Gaussian and Wiener filter by investigation on mass rates of ice sheet in Antarctic from GRACE

本文利用UTCSR 2003年1月到2008年8月间的GRACE Level-2 RL04重力场模型估计了南极冰盖质量变化。计算过程中分别采用高斯和Wiener滤波两种平滑方法,分别采用22、43和65个月重力场模型计算Wiener滤波信号与噪声函数,得出以下结论:在实际的计算过程中需要具体计算Wiener滤波平滑因子值,65个月GRACE重力场模型计算得到的Wiener滤波权值非常接近于平滑半径为540km高斯滤波权值;采用两种不同的滤波方法在相同区域质量变化率基本相同。

Gravity solutions from GRACE level-2 RL04 released by UTCSR for the period January 2003 to August 2008 were used to estimate the rates of Antarctic ice mass change. The Gaussian and Wiener filtering smoothing method were used respectively during the process. The signal and noise function of Wiener filtering were calculated respectively by 22, 43 and 65 months time gravity model, and the result was that the model signal and noise functions relate to the selected time period. Therefore smoothing factor values of Wiener filter need to be calculated during the process. The weights of Gaussian filter and Wiener filter computed by 65 GRACE gravity solutions were computed and it was very close to the Gaussian smoothing radius of 540km. The ice mass rates in the west Antartic Amundsen and the east Antartic Enderby land were computed and the mass rates at the same area were almost the same using the two different filtering methods.