大气重力信号的理论计算及其检测

THEORETICAL COMPUTATION AND DETECTION OF THE ATMOSPHERIC GRAVITY SIGNALS

基于标准大气定律和大气圆柱体分布模型，本文引进了大气重力格林函数，用离散格积方法求得了大气对重力场观测的影响，对台站高程、周围地形和地表温度变化等因素的影响问题进行了讨论．结果说明台站近区气压变化是大气重力信号的主要贡献者，考虑大气质量负荷引起的弹性地球形变效应后，对距台站0．5°的区域积分获得的大气重力导纳值为—0．3603μGal／hPa，占全球大气变化引起的总信号的90％以上，这一理论模型结果与超导重力仪实测结果相吻合，并能较有效地用于消除重力观测中的气压干扰成分．

Based on the standard atmospheric law and atmospheric colunm distribution model,the atmospheric gravity Green's functions are introduced in this paper, the atmospheric influence on gravity measurements is obtained using a discrete convolution method, the influence of the station height the topography around station and the temperature on gravity signal are discussed. The results show that the air pressure change near station is the main contributor to gravity signals. Considering the loading contribution due to the deformation of the elastic Earth, the atmospheric gravity admittance is obtained to be - 0.3603(Gal / hPa when integrating an area with an angular distance of 0.5°which occupies about 90% of the total atmospheric gravity signals due to the global change of the pressure. This model value coincides well with those observed with superconducting gravimeters and can be used effectively to remove the pressure perturbations appearing in the tidal gravity observations.