基于Bjerhammar边值理论的似大地水准面计算模型改化及分析检验

Modification and Test of the Model for Computing Quasi-Geoid Based on the Bjerhammar Boundary-Value Theory

针对源自现代Bjerhammar边值理论的似大地水准面计算模型适用性问题,重点围绕地面重力异常向下延拓和似大地水准面计算两个解算阶段,分别提出了3种实用化的积分模型改化方法,同时设计了三阶段改化模型实验检验方案,使用超高阶位模型EGM2008作为数值模拟标准场,对两个解算阶段不同改化模型的计算效果进行了数值精度检核,并开展了数据观测噪声影响评估检验,得出了一些有参考和实际应用价值的研究结论。在一定条件下,使用改化Bjerhammar方法计算似大地水准面可获得1~2 cm的内符合度。

In order to improve the adaptability of computation model for the determination of quasi geoid based on the Bjerhammar boundary value theory we focus attention on the downward continuation of gravity data in the earth surface and the computation of quasi geoid and propose three practical modified approaches to the integral model.Then a three step numerical scheme for testing the modified computation models is designed.A numerical standard simulation gravity field is established using ultra high degree geopotential model EGM2008. The different modified models from the two computation steps are examined and evaluated by numerical tests. The influence of noise in observational data is studied through numerical experimentation. Some useful conclusions with reference significance are achieved.It is showed that the internal fitting accuracy of computing quasi geoid using the modified Bjerhammar models can reach 1~2cm under some conditions.