重力局部地形改正量的计算方法比较

Method comparison on calculation of local gravity terrain correction

重力局部地形改正是重力归算的一项重要内容,目前的算法多采用贴合地表的近似平面或球面,在其上的有限区域内积分计算。为了比较不同算法之间的差异,文中引入高精度地形模型,分别采用平面积分方法、平面FFT方法和球面积分方法计算西部典型山区局部重力地形改正值,并比较其结果。平面积分方法与平面FFT方法计算结果相近;近区地形起伏较大时,球面积分方法计算结果与前两者有较大差异。研究结果对在地形起伏较大的地区计算重力局部地形改正时的计算方法选择具有参考价值。

Local gravity terrain correction is an important part of gravity reduction,and the current algorithms use the approximate plane and sphere of the fitting surface,in finite areas of which the integral is calculated.In order to compare the differences between different algorithms,this paper introduces a high precision terrain model,and uses the plane integral method,the plane FFT method and the spherical integral method to calculate the local gravity topographic correction value in western mountainous of China,and to compare the results.It is concluded that the spherical integral has a better effect on the plane integration method and the plane FFT method.The calculation points of complex topography nearby have a great influence on the correction value,and its calculation needs to be improved from many aspects.