水文气象因素对中国北疆流动重力变化的影响

水文气象因素引起的重力变化是影响地震重力变化成果解释的重要因素。以中国北疆地区为研究区域，借助全球陆地数据同化系统（global land data assimilation systems，GLDAS）全球水文模型数据、大气模型数据，计算2016-01—2017-12时段内水文气象因素对研究区域的重力影响。计算结果表明，陆地水影响的年变化为1.3 μGal，两期陆地水影响空间分布的差异低于1 μGal；大气影响的年变化为8 μGal，两期大气影响空间分布的差异达到6 μGal。利用2016-04、2016-08和2017-06三期流动重力测量数据，对比扣除水文气象因素前后的重力变化，可以看出，在中国北疆流动重力数据处理中，大尺度水文因素可以不予考虑，气象因素应予考虑。同时，为更好分析流动重力变化，建议流动重力测量过程中同时开展测点附近的土壤湿度、大气气压等观测。

Influence of Hydrometeorological Factors on Mobile Gravity Variation in the Northern Xinjiang,China

  Objectives  The gravity variation caused by hydrometeorological factors is an important factor affecting the interpretation of seismic gravity variation results. However, quantitative analysis of gravity field changes caused by hydrometeorological factors is rarely carried out.  Methods  This paper takes the north?ern Xinjiang, China as the research area and uses the global hydrological model data of global land data assimilation system (GLDAS) and an atmospheric model to calculate the gravity influence of hydrometeorological factors on the research area from January 2016 to December 2017.  Results  The results show that the annual change of terrestrial water influence is 1.3 μGal, and the difference in spatial distribution of terrestrial water influence between two adjacent periods is lower than 1 μGal. The annual change of atmospheric influ?ence is as high as 8 μGal, and the difference in spatial distribution of atmospheric influence between two adjacent periods is up to 6 μGal.  Conclusions  The gravity variations before and after deducting hydrometeorological factors were compared using the mobile gravity measurement data of three periods, i.e., April 2016, August 2016 and June 2017. The comparison results show that in the processing of mobile gravity data in the northern Xinjiang, the large-scale hydrological factor can be ignored and the meteorological factor should be taken into account. Meanwhile, for a better analysis of the mobile gravity variation, soil moisture and atmospheric pressure near the measuring point should be observed during the mobile gravity measurement.