青藏高原东北缘ALOS AW3D30高程模型和EIGEN-6C4自由空气重力异常模型精度分析

doi:10.12196/j.issn.1000-3274.2023.01.008

摘要/Abstract

摘要： 利用EGM96全球重力场模型对ALOS AW3D30全球数字高程模型的高程系统进行转换, 结合实测GNSS数据, 分析ALOS AW3D30模型在青藏高原东北缘地区的精度。利用实测重力数据计算青藏高原东北缘地区的自由空气异常, 并与EGIEN-6C4自由空气异常模型进行对比, 分析其精度。结果表明: 青藏高原东北缘地区ALOS AW3D30模型与264个GNSS测点的差异标准差为3.4 m, 该地区ALOS AW3D30精度优于4 m; 青藏高原东北缘地区自由空气重力异常整体呈负值, 局部为正值, 变化范围为-177×10^-5~166×10^-5 m·s^-2, 实测重力异常与模型结果空间分布基本一致, 存在局部差异; EIGEN-6C4自由空气重力异常变化范围为-163×10^-5~142×10^-5 m·s^-2, 实测结果与模型结果差异为-119×10^-5~63×10^-5 m·s^-2, 平均值为-20×10^-5 m·s^-2, 差异标准差为29×10^-5 m·s^-2, 实测结果与模型结果差异较大, 青藏高原东北缘地区真实地球重力场应该通过实测获得。最后, 本文基于青藏高原东北缘地区的实测重力异常与EGIEN-6C4重力异常模型, 利用消去—恢复法, 将实测重力异常与模型结果进行融合, 提高了青藏高原东北缘地区, 尤其是祁连山东缘、海原断裂及周边地区的重力异常精度, 可以为区域重力场研究提供参考。

关键词: ALOS AW3D30, EIGEN-6C4, GNSS, 青藏高原东北缘, 重力异常

Abstract: In this paper, we transferred the normal height of ALOS AW3D30 to GNSS ellipsoidal height based on the EGM96, and analyzed the precision of this digital elevation model in the northeastern Qinghai—Xizang Plateau (QXP) combining with the ground GNSS measurements. We also calculated the gravitational free air anomalies in the northeastern QXP based on the campaign gravity measurements, and evaluated the precision of the EIGEN-6C4 gravitational mode. The results showed that the standard deviation of the difference between ALOS AW3D30 and GNSS results is 3.4 m, which demonstrated that the precision of the ALOS AW3D30 in this region was better than 4 m. The measured gravity anomalies showed generally negative with local positive values, ranging from -177×10^-5 to 166×10^-5 m·s^-2. The modeled gravity free air anomalies of the EIGEN-6C4 changed from -163×10^-5 to 142×10^-5 m·s^-2. The difference between the EIGEN-6C4 gravity anomalies and measured results span from -119×10^-5 to 63×10^-5 m·s^-2, which indicated that the EIGEN-6C4 gravity anomalies were poorly constrained in the northeastern QXP and the measured gravity anomalies should be combined when analyzing gravity anomalies in this region. At last, we fused the EIGEN-6C4 modeled gravity anomalies with the measured ones by the “remove-restore” method, and improved the precision of gravity free air anomalies in the northeastern QXP, especially around the eastern Qilian— Haiyuan Fault and its surrounding areas. The improved regional gravity anomalies can provide a reference for the study of gravity field in the northeastern QXP.

Key words: ALOS AW3D30, GNSS, the northeastern Qinghai—Xizang Plateau, Campaign gravity, Gravity anomalies

中图分类号:

P312.1

张国庆, 梁伟锋. 青藏高原东北缘ALOS AW3D30高程模型和EIGEN-6C4自由空气重力异常模型精度分析[J]. 地震, 2023, 43(1): 93-104.

ZHANG Guo-qing, LIANG Wei-feng. Evaluation of the ALOS AW3D30 DEM and EIGEN-6C4 Gravity Anomalies in the Northeastern Qinghai—Xizang Plateau[J]. EARTHQUAKE, 2023, 43(1): 93-104.

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