全球正向建模恢复法改正南极泄漏误差探讨

Discussion on Global Forward Modeling Recovery Method in Correcting Antarctic Leakage Errors

全球正向建模恢复法改正南极泄漏误差的效果取决于初始信号的准确性。球谐系数的截断和滤波导致南极周边海洋信号内泄漏至相邻的南极陆地,造成相应区域初始信号不准确。以美国德克萨斯大学的空间研究中心(Center for Space Research,CSR)Mascon数据为模拟数据,讨论周边海洋信号对南极泄漏误差改正的影响。结果表明,海洋信号内泄漏对南极冰盖的质量变化及其空间分布影响显著,造成东南极Coats Land、Queen Maud Land、Enderby Land和Kemp Land等沿海地区反演结果不准确。引入“流域”函数分离海洋信号,利用全球正向建模恢复法改正南极泄漏误差,通过CSR RL05 GSM(glacial systems model)数据估算出南极冰盖的质量变化速率为-180.66 Gt/a,且质量变化空间分布与Mascon数据一致性较好。

The effect of global forward modeling recovery method in correcting the Antarctic leakage errors depends on the accuracy of the initial signal. The truncation and filtering of the spherical harmonic coefficient cause the leakage of the ocean signal around the boundary of Antarctic into the adjacent Antarctic land,resulting in the inaccuracy of the initial signal in the corresponding area. Mascon data of Center for Space Research(CSR)in the United States is used as simulated data to analyze the influence of ocean signal on the correction of Antarctic leakage error. The results show that the leakage of ocean signal has a significant influence on the change of Antarctic ice sheet mass and its spatial distribution,which results in inaccurate inversion results in coastal areas such as Coats Land,Queen Maud Land,Enderby Land and Kemp Land.The“basin”function is introduced ito separate ocean signal,and the global forward modeling recovery method is also used to correct the Antarctic leakage errors. The change rate of the Antarctic ice sheet mass calculated by CSR RL05 GSM data is-180.66 Gt/a,which is in good agreement with the Mascon result.