武汉九峰站地下水变化对重力场观测的影响  

The influence of groundwater changes on gravity observations at Jiufeng station in Wuhan

作　　者：贺前钱 罗少聪[1] 孙和平 徐建桥[1] 陈晓东[1] 

机构地区：[1]中国科学院测量与地球物理研究所大地测量与地球动力学国家重点实验室,武汉430077 [2]中国科学院大学,北京100049

出　　处：《地球物理学报》2016年第8期2765-2772,共8页Chinese Journal of Geophysics

基　　金：国家重点基础研究发展计划(973计划)(2014CB845902);国家自然科学基金(41321063;41274085;41374084;41574072)联合资助

摘　　要：本文从地下水渗透过程的物理机制出发,采用一维水动力学模拟,利用井水位和降雨数据模拟计算了武汉九峰站附近的土壤含水率变化,在此基础上估计了地下水变化导致的重力效应.其峰对峰变化幅度达到15.94μGal,说明当利用精密重力观测研究长周期效应时实施台站地下水改正的必要性;频域分析表明,地下水重力效应在周年频段上的振幅最大,说明地下水变化对重力的最大影响来自季节性变化.对比模拟计算的地下水重力效应和经过潮汐、大气、极移等改正后的高精度超导重力残差(峰对峰变化幅度为12.73μGal),发现两者在时域和频域均具有良好的一致性,说明超导重力残差信号主要来源于局部地区地下水的变化,同时也验证了本文使用的水动力学模拟方法的正确性.In this paper, following the physical mechanism of groundwater infiltration, water level of a monitoring well and precipitation data were combined to simulate the water content variations of the soil surrounding the Jiufeng superconductivity gravity （SG） station in Wuhan by using an one-dimensional hydrodynamic simulating method. Then, based on the variations of soil water content, the hydrological effects on gravity induced by groundwater changes were estimated. Its peak-to-peak variation reaches up to 15.94 μGal, which implies the necessity of correction for local groundwater changes when precise gravity observations are used to study long-periodic effects. The analysis in the frequency domain shows that the largest influence of groundwater changes on gravity appears in the annual band. Good agreements are yielded between the estimated groundwater hydrological effects on gravity and the SG residuals （with a peak-to-peak variation of 12.73 μGal） after correction for earth tides, atmospheric pressure, polar motion, etc., both in the time and frequency domains. This demonstrates that signal of the SG residuals is mainly from the local groundwater changes, and also validates the applicability of the hydrodynamic simulating method used in this paper.

关 键 词：地下水变化 水动力学模拟方法 超导重力仪观测信号 

分 类 号：P312[天文地球—固体地球物理学]