联合GRACE重力卫星与GPS研究区域陆地水储量变化

发布时间：2019-02-28 13:02

【摘要】：自2002年地球重力场恢复和气候试验卫星GRACE(Gravity Recovery and Climate Experiment)发射至今,已连续运行15余年,积累了大量宝贵的科学观测数据,在地球重力场特别是在时变重力场、静态重力场,地表质量变化、地表负荷形变、陆地水储量变化、冰川海洋变化及强震形变等研究中做出了巨大的贡献。陆地水储量的变化会引起地球重力场的改变,而这种变化恰好可被GRACE重力卫星有效监测到。通过GRACE卫星提供的时变重力场,可以反演陆地水文信号得到大尺度陆地水储量变化,进一步结合水文模型即可探测出地下水变化特征,这不仅可为研究区域水资源动态变化和防控管理等提供了新的思路与方法,而且可为因开采地下水造成地面沉降灾害机理研究提供有价值的参考。为此,本文选取我国大陆板块内部地下水开采典型华北区域以及美国洋——陆板块交界处地下水开采最为严重的加州中央山谷区域,利用GRACE重力场模型开展了区域陆地水文信息变化特征的研究,对联合GPS观测形变数据恢复区域陆地水储量真实信号做了尝试分析,主要研究内容包括与成果如下:(1)详述了利用GRACE重力场位模型系数反演陆地水储量研究现状与关键技术,推导了利用GRACE重力场模型反演地表质量变化的公式原理,并基于GSM数据对重力场后处理过程中经典滤波方法使用不同参数做了对比试验分析,给出了有关采用何种滤波方法有效性的有价值的参考。(2)针对利用重力场模型反演过程中会存在高阶截断、滤波、泄露误差等带来真实信号损失的问题,提出了“附加GPS时序约束恢复区域水文信号”的新算法:通过频谱分析法比较由重力场模型反演出的地表负荷形变与GPS监测形变,得到反演过程中产生的信号损失比,从而依据该“比例”即可恢复出质量变化的真实信号。(3)利用GRACE重力场模型CSR_RL05数据,反演获得了华北平原陆地水储量变化信息,并结合水文模型数据计算获得了华北平原地下水动态变化特征。研究表明:华北平原地区地表水变化量较为微弱,变化周期稳定,而GRACE观测到的陆地水总储量变化主要是由于地下水变化所致;在2002—2016年华北平原地区陆地水储量约以37.32mm/a速率减少,地下水年损失速率约为34.6±3.2 mm/a,地下水损失量约为660.5亿吨。(4)利用GRACE重力场模型数据、GLDAS水文模型数据及美国PBO监测网GPS形变信息,采用附加GPS时序约束方法反演获得了美国加州中央山谷地下水的动态变化特征。研究表明:加州中央山谷区域陆地水储量整体呈下降趋势,地表水变化长期呈现出均衡状态但略有下降,并且变化趋势与陆地水储量变化相近;2003—2015年加州中央山谷地下水年损失率约为16.43±1.98 mm/a,该结果与前期研究结果基本一致,从而也验证了附加GPS时序约束方法的可行性。
[Abstract]:Since 2002, when the Earth's gravity field recovery and climate test satellite GRACE (Gravity Recovery and Climate Experiment) was launched, it has been operating continuously for more than 15 years, and has accumulated a great deal of valuable scientific observation data, especially in the time-varying gravity field, static gravity field, and the earth's gravity field, especially in the time-varying gravity field, static gravity field. Great contributions have been made in the study of surface mass change, surface load deformation, land water reserve change, glacier ocean change and strong earthquake deformation. Changes in land water reserves will cause changes in the earth's gravity field, which can be effectively monitored by GRACE gravity satellites. Through the time-varying gravity field provided by GRACE satellite, the large-scale change of land water reserves can be obtained by inversion of land hydrological signals, and the characteristics of groundwater variation can be detected by further combining hydrological model. It can not only provide new ideas and methods for studying the dynamic change of regional water resources, prevention and control, but also provide valuable reference for the study of the mechanism of land subsidence disasters caused by the exploitation of groundwater. For this reason, this paper selects the typical North China area and the California Central Valley, where groundwater exploitation is the most serious at the junction of the ocean-land plate of the United States of America, in the interior of the continental plate of China. Based on the GRACE gravity field model, the variation characteristics of regional land hydrologic information are studied, and the real signal of regional land water reserves can be recovered from the deformation data observed by GPS, and an attempt is made to analyze the real signal of regional land water reserves. The main research contents and achievements are as follows: (1) the research status and key techniques of inversion of land water reserves by using GRACE gravity field potential model coefficient are described in detail, and the formula principle of using GRACE gravity field model to invert land surface mass change is deduced. Based on the GSM data, the classical filtering methods in the post-processing process of gravity field are compared and analyzed with different parameters. The valuable reference about the effectiveness of the filtering method is given. (2) in view of the problems of high-order truncation, filtering, leakage error and so on, the real signal loss will be caused in the inversion process of gravity field model. In this paper, a new algorithm for restoring regional hydrological signals with GPS time series constraints is proposed. The ground load deformation retrieved from gravity field model is compared with the deformation monitored by GPS by means of spectrum analysis, and the loss ratio of signal generated in the inversion process is obtained. According to the "scale", the real signal of mass change can be recovered. (3) using CSR_RL05 data of GRACE gravity field model, the change information of land water reserves in North China Plain is obtained. Combined with hydrological model data, the dynamic characteristics of groundwater in North China Plain are obtained. The results show that the change of surface water in North China Plain is relatively weak and the period of change is stable, while the change of total land water reserves observed by GRACE is mainly due to the change of groundwater. In 2002-2016, the reserves of land water in North China Plain decreased at the rate of 37.32mm/a, and the annual loss rate of groundwater was about 34.6 卤3.2mm/a,. (4) using the GRACE gravity field model data, the loss of groundwater was about 66.05 billion tons. GLDAS hydrologic model data and GPS deformation information of American PBO monitoring network are used to retrieve the dynamic variation characteristics of groundwater in the Central Valley of California by using GPS time series constraint method. The results show that the total land water reserves in the central valley of California show a downward trend, and the surface water changes show a long-term equilibrium but a slight decline, and the trend of change is similar to that of land water reserves. The annual loss rate of groundwater in the Central Valley of California from 2003 to 2015 is about 16.43 卤1.98 mm/a, which is basically consistent with the results of previous studies. Therefore, the feasibility of the method with GPS time series constraints is also verified.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P22;P332

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