近日，中国科学院上海天文台李进团队研究了从GRACE月解的不同版本分析2004年苏门答腊-安达曼地震的同震重力变化。2025年11月10日出版的《大地测量与地球动力学》杂志发表了这项成果。

重力恢复与气候实验卫星（GRACE）的二级产品，即以球谐（SH）系数表示的月度重力场模型，自2002年起已发布多个版本。

研究组分析了利用德克萨斯大学奥斯汀分校空间研究中心（CSR）提供的四个版本（RL01、RL04、RL05、RL06）的GRACE数据提取2004年苏门答腊-安达曼MW_9.1级地震同震信号的效果。结果显示：后期版本提取的同震信号受噪声影响更小；最早期的RL01版本仍可反映该地震的同震重力变化信号。特别地，RL04版本提取的同震信号空间分布存在显著畸变，可能源于重力场反演过程中大气与海洋模型处理引入的较大误差。

断层位移模型预测与GRACE观测的对比表明，后期版本数据与模型预测更一致；且在断层滑动反演中采用更多近场测量约束的模型预测与GRACE观测也更吻合。全球海洋区域的GRACE数据不确定性评估显示，噪声水平从早期到后期版本逐步降低，RL01、RL04、RL05、RL06版本经300公里空间平滑后的均方根误差（RMS）分别为7.1、4.9、2.4和2.1微伽。

附：英文原文

Title: Co-seismic gravity changes of the 2004 Sumatra-Andaman earthquake from different releases of GRACE monthly solutions

Author: Jin Li a b

Issue&Volume: 2025/11/10

Abstract: The Gravity Recovery and Climate Experiment (GRACE) Level-2 products, i.e., monthly gravity field models expressed in spheric harmonic (SH) coefficients, have been released in several versions since 2002. In this study, we analyze the extraction of co-seismic signals associated with the 2004 Sumatra-Andaman MW9.1 earthquake, using GRACE data from four versions, namely the RL01, RL04, RL05, and RL06, provided by the Center for Space Research (CSR), University of Texas at Austin. Results indicate that the co-seismic signals extracted from later versions of GRACE data are less affected by noise. Moreover, the earliest RL01 vision can also reflect the co-seismic gravity-change signals of the 2004 Sumatra-Andaman earthquake. In particular, we find that the spatial pattern of the co-seismic signals extracted from the RL04 version of GRACE data exhibits significant distortion, which is probably due to the large errors introduced in the processing of the atmosphere and ocean models in the gravity field inversion. Comparison between the dislocation model prediction and GRACE observation suggests that the GRACE results from later versions are more consistent with the model prediction. In addition, the dislocation models with stronger constraints from near-field measurements during the fault-slip inversion provide a more consistent prediction with the GRACE observation. The uncertainty estimation of GRACE data over the global oceanic region reveals that the noise levels gradually decrease from the earlier to later versions, with the RMSs of 7.1, 4.9, 2.4, and 2.1 μGal (with 300 km spatial smoothing) for the RL01, RL04, RL05, and RL06 versions, respectively.

DOI: 10.1016/j.geog.2025.07.005

Source: https://www.sciencedirect.com/science/article/pii/S1674984725000862