基于局部基函数反演区域地表质量变化的Mascon方法研究

Temporal gravity field can reveal the mass transport in and on the earth’s surface which caused by the geophysical processing. The spatial-temporal resolution and the accuracy of temporal gravity field could be improved by using the satellite gravimetric measurements recovering regional gravity filed. This project aims at determining high accuracy and high spatial-temporal resolution regional surface mass variations from the Mascon approach based on the regional basic function which was constrained by regional tectonic features. Firstly quantifying the leakage errors while recovery regional mass variations from earth’s gravity field and the spectral signal features associate with different tectonic feature region, and establishing the regional spherical orthogonal base function combined with the regional prior characteristic. Secondly, introducing the regional basic function into the Mascon approach which recovering the mass variations directly and deducing the directly expression between regional mass variations and satellite gravimetry measurements via the regional basic function. And finally the software of recovering the regional mass variation by Mascon approach will be developed. The anticipated results will not only provide efficient scientific significance and practical value for coping with the water resources shortage, extreme climate changes, natural disasters and other environmental problems but also supply the processing experiment of satellite measurements for the China’s autonomous satellite program in the future.

时变重力场可揭示地球表层及内部构造运动等地球物理过程造成的物质迁移，基于卫星重力观测数据直接反演局部地球重力场能够有效提高区域地表质量变化的精度和时空分辨率。本项目以获取高精度高时空分辨率的区域地表质量变化信号为目标，在定量分析地球重力场反演区域地表质量变化中的信号泄漏影响以及不同构造特征区域对应的频谱分布特性的基础上，结合区域构造特征等先验信息构建真实合理的局部球面正交基函数；将局部基函数引入到区域地表质量变化的直接反演方法中，通过局部最优基函数建立区域地表质量变化与卫星观测数据的直接关系，完善基于卫星观测数据直接反演区域地表质量变化的Mascon方法。预期研究成果不仅可以为人类认识和解决自然资源、气候环境及自然灾害等问题的研究提供基础地学信息和科学依据，还可为将来我国自主重力卫星观测数据的处理积累经验。

卫星重力观测数据直接反演局部地球重力场能够有效提高区域地表质量变化的精度和时空分辨率。以获取高精度高时空分辨率的区域地表质量变化信号为目标，本项目深入研究了基于GRACE卫星重力数据反演区域地表质量变化的Mascon方法。主要成果包括：（1）比较分析了利用GRACE卫星观测模式下模拟卫星重力观测数据的动力学反演方法，探讨了参考重力场模型和各类保守力模型精度对反演结果的影响；（2）通过数值仿真模拟研究验证了卫星跟踪数据反演区域地表质量变化的Mascon方法的有效性，实现了基于GRACE实测卫星重力数据的Mascon方法，并给出了2005-2009年亚马逊流域的时空变化结果；（3）利用GRACE时变重力场揭示了中国区域两个大型流域的水储量变化时空特征，研究了两大流域的水文学效应，主要包括长江流域的陆地水储量变化和蒸散发量变化、黄河流域的径流变化、鄱阳湖水储量变化等。