附加空间约束的径向点质量模型方法反演区域地表质量变化

径向点质量模型反演方法本质上是空间扰动重力的向下延拓，属于病态问题，通常采用正则化方法求解。针对该问题，对径向点质量模型方法进行改进，提出附加空间约束的径向点质量模型方法，引入符合实际的空间约束条件，建立空间约束条件的虚拟观测方程，并采用赫尔默特方差分量估计确定原始观测方程和虚拟观测方程的合理权比，使反演结果更加稳定。以南美大陆区域为研究区域进行陆地水储量变化反演，试验结果表明：增加空间约束后，法方程组条件数明显减小、病态程度降低，反演结果与球谐系数法反演结果、GLDAS模型结果整体相一致，验证了方法的正确性，说明该方法可有效应用于区域地表质量变化反演，为利用卫星重力监测地表质量变化提供了一种新途径。

Regional Ground Surface Mass Variations Inversed by Radial Point-mass Model Method with Spatial Constraints

Radial point-mass model method is the disturbance gravity downward continuation in essence, which is an ill-posed problem.In general,the regularization method is an efficient way to get the reliable solution.To solve this problem,the radial point-mass model method is improved by using Helmert variance component estimation with adding spatial constraints from a practical point of view.Taking South America continent as study area, radial point-mass model method with spatial constraints is verified by experimental results.The experiments results show that the condition number of normal equations is decreasing obviously after adding spatial constraints.The inversion results of radial point-mass model method with spatial constraints are consistent with results of other methods.Furthermore,the radial point-mass model method with spatial constraints provides an alternative way to monitor regional surface mass variations by satellite gravimetry.