基于模拟数据评估SWOT卫星KaRIn数据的测量误差对反演海洋重力场的影响  

Assessing the impacts of measurement errors in SWOT satellite KaRIn data on the inversion of marine gravity based on simulated data

作　　者：李杨 周江存 祝程程 孙和平 李宁 LI Yang;ZHOU JiangCun;ZHU ChengCheng;SUN HePing;LI Ning(State Key Laboratory of Geodesy and Earth’s Dynamics,Innovation Academy for Precision Measurement Science and Technology,Chinese Academy of Sciences,Wuhan 430077,China;University of Chinese Academy of Sciences,Beijing 100049,China;School of Surveying and Geo-Informatics,Shandong Jianzhu University,Jinan 250101,China)

机构地区：[1]中国科学院精密测量科学与技术创新研究院,大地测量与地球动力学国家重点实验室,武汉430077 [2]中国科学院大学,北京100049 [3]山东建筑大学测绘地理信息学院,济南250101

出　　处：《地球物理学报》2024年第11期4053-4064,共12页Chinese Journal of Geophysics

基　　金：湖北珞珈实验室开放基金资助项目(230100002);国家自然科学基金项目(42192535,42242015)资助.

摘　　要：地表水和海洋地形(Surface Water and Ocean Topography, SWOT)卫星搭载了Ka波段雷达干涉(Ka-band Radar Interferometer, KaRIn)测高计,其宽刈幅测高数据有望提升现有海洋重力场模型的精度和空间分辨率. 为评估KaRIn测高计的各类测量误差对反演海洋重力场的影响,本文基于模拟的KaRIn数据,使用逆Vening Meinesz公式反演了海洋重力异常. 单周期模拟数据的反演结果表明:相位误差和KaRIn噪声对重力异常的影响最大;利用数值差分计算KaRIn数据跨轨方向的垂线偏差无法消除相位误差、滚动误差和基线扩张误差,这导致垂线偏差的东西分量和反演的重力异常在空间上呈现明显的卫星地面轨迹特征;改正相位误差、滚动误差和基线扩张误差后,反演的重力异常不存在明显的卫星地面轨迹特征,主要误差源仅为KaRIn噪声. SWOT卫星执行精确重复轨道任务,其重复观测可以削弱测量误差对海洋重力场反演的影响,在反演中随着周期数的增加,相位误差和KaRIn噪声对重力异常的影响逐渐降低. 在不改正相位误差、滚动误差和基线扩张误差且不滤波削弱KaRIn噪声的情况下,本文利用3年53个周期的模拟数据反演了重力异常,结果显示本文讨论的各类测量误差对重力异常反演的综合影响仅为0.17 mGal.Surface Water and Ocean Topography (SWOT) satellite carries a Ka-band Radar Interferometer (KaRIn) altimeter, which is expected to improve the accuracy and spatial resolution of existing marine gravity models with its wide-swath altimetry data. To assess the influence of various measurement errors of the KaRIn altimeter on the inversion of marine gravity anomalies, this study used simulated KaRIn data and employed the inverse Vening Meinesz formula to calculate marine gravity anomalies. Based on the inversion results using a single cycle of simulated data, it was determined that phase error and KaRIn noise exert the most substantial influence on the inversion of gravity anomalies. Utilizing numerical differencing to calculate deflections of the vertical (DOV) in the cross-track direction does not eliminate the influence of phase error, roll error, and baseline dilation error. Consequently, distinct spatial patterns of satellite ground tracks emerge in the gravity anomalies and east components of DOV. However, after correcting phase error, roll error, and baseline dilation error, the gravity anomalies no longer exhibit noticeable spatial patterns of satellite ground tracks, and the primary source of error in gravity anomalies attributes to the KaRIn noise. The SWOT satellite performs an exact repeat mission, and its repeated observations can mitigate the influence of measurement errors on the inversion of marine gravity. As the data increases during inversion, the influence of phase error and KaRIn noise on gravity anomalies gradually diminishes. In the absence of correction for phase error, roll error, and baseline dilation error, and without applying filtering techniques to reduce KaRIn noise, gravity anomalies were calculated based on three years of simulated data comprising 53 cycles. The result indicates that the total influence of all measurement errors discussed in this study on the gravity anomalies is only 0.17 mGal.

关 键 词：SWOT卫星 宽刈幅测高计 最小二乘配置 逆Vening Meinesz公式 海洋重力异常 

分 类 号：P223[天文地球—大地测量学与测量工程]