一种改进的尺度因子算法用于GRACE/GRACE-FO时变重力信号恢复  

An improved scale factor method for restoring GRACE/GRACE-FO time-variable gravity field

作　　者：陈威 钟敏[2] C.K.Shum 李权国 段淑娟 CHEN Wei;ZHONG Min;CKShum;LI QuanGuo;DUAN ShuJuan(College of Resource Environment and Tourism,Hubei University of Arts and Science,Xiangyang Hubei 441053,China;School of Geospatial Engineering and Science,Sun Yat-sen University,Zhuhai Guangdong 519082,China;School of Earth Sciences,The Ohio State University,Columbus 43210,USA;College of Mathematics and Information Science,Zhengzhou University of Light Industry,Zhengzhou 450002,China)

机构地区：[1]湖北文理学院,资源环境与旅游学院,湖北襄阳441053 [2]中山大学测绘科学与技术学院,广东珠海519082 [3]美国俄亥俄州立大学地球科学学院,哥伦布432104 [4]郑州轻工业大学数学与信息科学学院,郑州450002

出　　处：《地球物理学报》2025年第5期1633-1646,共14页Chinese Journal of Geophysics

基　　金：国家自然科学基金(12261131504);湖北省自然科学基金(2024AFB108,2023AFD060);湖北省教育厅青年人才项目(Q20232607)资助.

摘　　要：准确恢复GRACE(Gravity Recovery and Climate Experiment)及其后续任务GRACE-FO(GRACE Follow-On)卫星观测的时变重力信号,对于揭示全球陆地海洋水量交换过程、监测区域水量收支平衡及预测局部旱涝灾害等具有重要科学意义.尺度因子法作为恢复GRACE/GRACE-FO卫星观测信号中真实陆地水储量变化的一种常用手段,存在以下缺陷:不同水文模型推导出的尺度因子存在较大差异,缺乏一致性;即便在统一滤波处理条件下,传统方法往往未充分考虑GRACE/GRACE-FO数据中“条带”误差和高频信号的影响;滤波强度的选择具有主观性,难以保证恢复结果的最优性与稳定性.针对这些问题,我们提出了改进的尺度因子算法,主要包括:(1)引入贝叶斯三角帽方法,对多套水文模型加权融合,构建统一的融合后水文数据集,增强尺度因子的鲁棒性;(2)在水文模型滤波过程中考虑“条带”误差和高频信号的影响,提升滤波后信号的保真度;(3)引入评价性指标体系,从DDK1—DDK7滤波范围中确定了DDK4为最佳滤波方案,并基于迭代思想构建了改进尺度因子.改进尺度因子恢复的陆地水储量变化与CSR Mascon、JPL Mascon的结果吻合较好,相关系数分别为0.984和0.970,均方根误差分别为2.13 mm和3.54 mm.在线性趋势、周年振幅及相位值的时空分布上,改进尺度因子恢复的陆地水储量变化与CSR Mascon、JPL Mascon的结果基本一致.Accurately recovering the time-variable gravity from GRACE(Gravity Recovery and Climate Experiment)and GRACE-FO(GRACE Follow-On)is crucial for studying global land-ocean water exchange,monitoring regional water budget balance,and predicting local droughts and floods.However,the commonly used method of scale factor for recovering the true time-variable gravity signals has several limitations:different hydrological models yield different scale factors,the"striping"error and high-frequency signals are not considered when applying the same filtering process to hydrological models,and the subjective selection of filter strength.To address these issues,we propose an improved scale factor algorithm that includes:(1)integration of multiple hydrological models into a unified set of hydrological data using the Bayesian Three-Cornered Hat method;(2)consideration of the"striping"error and high-frequency signals in the filtering process of hydrological models;(3)introduction of evaluation metrics and iteration to determine DDK4 as the optimal filtering solution for GRACE/GRACE-FO level-2 time-variable gravity field data within the DDK1—DDK7 filtering range.The improved scale factor method shows good agreement with the results from CSR Mascon and JPL Mascon,with correlation coefficients of 0.984 and 0.970,and root mean square errors of 2.13 mm and 3.54 mm,respectively.Moreover,the spatiotemporal distribution of the recovered terrestrial water storage anomaly using the improved scale factor closely matches that of CSR Mascon and JPL Mascon in terms of trend,annual amplitude,and phase values.

关 键 词：尺度因子 GRACE/GRACE-FO 陆地水储量 贝叶斯三角帽方法(BTCH) 

分 类 号：P223[天文地球—大地测量学与测量工程]