影响武汉台重力和垂直位移观测的环境因素

ENVIRONMENTAL EFFECTS ON GRAVITY AND VERTICAL DISPLACEMENT OBSERVATION AT WUHAN STATION

利用武汉台超导重力仪和同址的GPS连续观测数据,研究重力变化和垂直位移与主要环境因素之间的关系。采用经典的弹性地球表面负荷理论,模拟计算大气、非潮汐海平面变化(海底压力)和陆地水等环境负荷对重力和垂直位移的贡献。结果表明,3种环境因素对重力和垂直位移的周年振幅贡献分别为90%和75%。目前采用的全球陆地水同化模型LaD及GLDAS,不能客观地反映台站局部水储量的实时变化,由此得到的理论模拟结果与实际观测结果之间存在明显的时间延迟。

The relation between gravity variations, vertical displacement variations and the major environment factors is studied by using the continuous observational data with superconducting gravimeter and GPS at Wuhan station. According to the surface loading theories of classical elastic-earth the contributions to the gravity and vertical displacement from atmosphere loading, non-tidal oceanic mass and continental water loading were simulated and calculated. The numerical results show that the annual amplitude variations of gravity and vertical displacement are mainly caused by aboved-metioned three kinds of environment factors, the contributions are 90% and 75% respectively. At present the global assimilation models of land water such as LaD and GLDAS carmot objectively reflect real-time changes in water storage in the site of local stations, as there is time-delay between calculated values and observations.