基于三棱柱单元的青藏高原重力场地形效应计算

Calculation of Gravity Topographic Effect of Qinghai-Tibet Plateau Based on Triangular Prism Elements

地球是一个梨形的不规则椭球体,其表面起伏的地形产生的重力场地形效应对地球物理勘探布格重力异常校正、大地测量学地形校正和确定大地水准面起伏都具有十分重要的意义。青藏高原是全球地质情况最复杂、地形变化最大的区域之一,其产生的地形效应是我国重力勘探普查、反演解释的研究热点。为了计算该地区的重力场地形效应,对该区域进行基础网格建模是最重要的步骤,其次还需进行高精度正演计算。本文提出了一种基于不规则三棱柱单元的带曲率大规模区域网格构建方法,并使用重力场闭合解析公式对其进行了正演计算,我们的结果与前人研究高度一致,证明了建模方法的正确性,同时该方法也可以被用于任意复杂的陆地区域建模,因此也具有应用指导意义。

The earth is a pear-shaped irregular ellipsoid, and the topographic effect of the gravity field pro-duced by the undulating topography on its surface is of great significance to the correction of the Bouguer gravity anomaly in geophysical exploration, the topographic correction of geodesy and the determination of geoid fluctuations. The Qinghai-Tibet Plateau is one of the regions with the most complex geological conditions and the largest topographic changes in the world. The topo-graphic effect produced by this area is a research hotspot of gravity exploration census and inversion geological interpretation. In order to calculate the topographic effect of the gravity field the Qinghai-Tibet Plateau, the basic mesh construction of the area is the most important step, followed by high-precision forward calculation. In this paper, a method for constructing a large-scale regional grid with curvature based on irregular triangular prism elements is proposed, and the forward calculation is carried out using the closed analytical formula of the gravity field. The method which is verified correctly can also be used for arbitrarily complex land area modeling, so it also has the guiding significance.