大气变化对位移、重力和倾斜观测影响的理论计算

Theoretical computation of the barometric pressure effects on deformation,gravity and tilt

利用弹性地球负荷理论和流体静力学平衡假设条件下的干空气及其垂直温度梯度分布,理论计算了大气压力作用下地表位移、重力和倾斜格林函数.详细讨论了不同地球模型、台站高程、周边地形、地表大气温度和水汽含量等因素对计算结果的影响.数值结果说明大气效应弹性项影响主要来自于远离台站的区域;引力项对重力的影响主要贡献来自于台站近区,对倾斜的影响来自于远离台站的区域.各种因素对大气重力和倾斜格林函数的影响分别在0.1°和1°角距范围内,但其综合影响较为复杂.

Based on the loading theory of an elastic earth, and the distributions of dry air and its vertical gradients of temperature under hydrostatic equilibrium, we have theoretically modeled the effects of barometric pressure on the observations of deformation, gravity and tilt. The influences of many factors, such as the adopted earth models, station height, topography around station, surface temperature and water vapor in atmosphere, on the final results are taken into account and discussed in detail. The numerical results show that the elastic effects mainly come from the atmosphere in the area far away from the station. The direct effects on gravity come from the contribution of the air in the area near the station, while those on tilt from the contribution of the air in the area far away from the station. The influences of all these factors on the atmospheric gravity and tilt Green＇ s functions mainly occur in the range of the respectively, but their comprehensive influence is extremely angular distance less than 0.1 and 1 degrees, complicated.