GRACE时变重力场模型的自适应正则化滤波方法  

An Adaptive Regularized Filtering Approach for Processing GRACE Time-Variable Gravity Field Models

作　　者：嵇昆浦 沈云中 陈秋杰 JI Kunpu;SHEN Yunzhong;CHEN Qiujie(College of Surveying and Geo-informatics,Tongji University,Shanghai 200092,China)

机构地区：[1]同济大学测绘与地理信息学院,上海200092

出　　处：《武汉大学学报（信息科学版）》2024年第11期2101-2112,共12页Geomatics and Information Science of Wuhan University

基　　金：国家自然科学基金(42274005,42192532,41974002)。

摘　　要：由于东西方向采样不足、背景力模型误差以及解算策略不完善等因素,导致GRACE(gravity recovery and climate experiment)时变重力场模型存在明显的南北条带误差,严重限制了其应用。尽管官方滤波器DDK(decorrelation and denoising kernel)正则化滤波已广泛应用,但仍存在以下不足:(1)正则化参数由经验确定,且未考虑不同月份的异质性,每月采用相同参数;(2)Tikhonov正则化方法在低频分量中过度正则化,而在高频分量中欠正则化。为此,提出采用一种自适应正则化滤波算法:低频部分采用最小二乘估计(不正则化),中频部分采用Tikhonov正则化,高频部分进行截断处理。各频段及正则化参数均依据最小均方误差准则确定,并且每月的数据分别处理。应用所提方法处理时间跨度为2002-04—2017-06的96阶ITSG-Grace2018时变重力场数据,结果表明,相比于经典DDK滤波,所提方法能够得到更强的质量变化信号,与官方3种mascon产品更为一致。模拟实验进一步验证了所提方法获得的质量变化信号与模拟真值更为接近。Objectives:The gravity recovery and climate experiment time-variable gravity field model suf⁃fers from significant north-south striping errors due to insufficient east-west sampling,background force model errors,and inadequate solving strategies.These errors severely limit its application.While the offi⁃cial decorrelation and denoising kernel(DDK)regularization filtering algorithm is widely used,it has nota⁃ble shortcomings:(1)The regularization parameters are empirically determined and do not account for monthly variability,using the same parameters for each month.(2)The Tikhonov regularization method over-regularizes low-frequency components and under-regularizes high-frequency components.To address these issues,we propose an adaptive regularization filtering method.Methods:This method estimates low-frequency components using least squares(without regularization),applies Tikhonov regularization to mid-frequency components,and truncates high-frequency components.Each frequency band and its regulariza⁃tion parameters are optimized based on the minimum mean square error criterion and processed separately each month.Results:The proposed method is applied to the ITSG-Grace2018 time-variable gravity field data with a maximum degree of 96,spanning from April 2002 to June 2017.Experimental results show that our proposed method achieves higher spatial resolution of mass anomalies and aligns more closely with the three official mascon products compared to the classic DDK filtering.Conclusions:Simulation experiments further validate that the mass anomalies obtained by this method are closer to the simulated true values.

关 键 词：GRACE 南北条带噪声 自适应正则化滤波 病态观测模型 

分 类 号：P223[天文地球—大地测量学与测量工程]