海洋负荷潮汐对地球重力场时变特征影响的理论研究

The Theoretical Research for Influence of Ocean Loading Tide on Time Variations of Gravitational Field

地球重力场的海潮效应可以看作足一种负荷影响,海潮负荷对重力场的影响在某些台站(例如大洋中的岛屿以及沿海岸地区)可达微伽的量级,因此在高精度的地球重力场的研究中必须加以改正.从理论和方法上研究了海洋负荷潮汐对地球重力场的影响,在推导过程中回避了将点负荷密度展开为球谐函数,而是直接以负荷引力位为基础,并将海潮潮高引入表达式中,推导出了海潮对地球重力场影响的有关公式,同时探讨了在毫微伽精度上需要注意的一些问题.

Ocean tide effects on gravitational field can be recognized as a kind of loading influence. In some sites, for example, group of islands in the ocean and coastland, the ocean tides loading influence on gravitational field can reach to magnitude of μgal, therefore, it must be taken into account in research of high precision gravitational field. This paper studied the theory and method for influence of ocean loading tides on gravitational field. In the process of deducing the formula, on avoided to develop the density of point loading into spherical harmonics, but directly to take the gravitational potential of ocean loading as a foundation and to contain the height of ocean tides in this expression, the relevant formulas for ocean tide's influence on gravitational field are deduced out. At the same time, some problems which should be noticed when the accuracy reaches magnitude of ngal are discussed. This study can provide reference and bases for theoretical research of space geodesy.