球近似地形改正的研究分析

本文视大地水准面为球面，以计算点向径为半径，将地形分为布格球壳和球面粗糙地形，分别给出球坐标下对地面重力值的地形改正公式，并与局部地形和布格板对重力改正的计算值进行比较。结果表明，球近似粗糙地形改正与局部地形改正之间存在差异，平坦地区差异较小，在地形高超过1 000 m的山区，差异在05 mGal以上。球近似粗糙地形影响计算，易于扩展积分范围，比局部地形改正更能体现精细信息，并符合地球实际形状。布格球壳和布格板改正计算值趋势相近，幅度存在明显差异。

Study on Topography Correction based on Spherical Approximation

Assuming the geoid as spherical approximation，the topography correction was calculated by dividing the actual topography into the Bouguer shell and the rough terrain based on the radius of the calculated point.The comparison of the local terrain correction with the Bouguer planar shows that there is difference between the rough terrain correction and the local terrain correction；the difference is small in the even area.It is more than 0.5 mGal in the areas where the elevation is higher than 1 000 m.The integral range of the spherical rough terrain correction is easy to extend，so it can present the more signals than the local terrain correction，and it is more consistant with the actual earth shape.The regular topography correction calculated with the Bouguer shell and the Bouguer planar is the same in shape，but the difference of range is very large.