基于CORS站网监测三峡地区陆地水负荷对地壳形变和重力变化的影响

三峡地区水资源丰富,加上三峡水库蓄放水的影响,水动力环境复杂,对该区域陆地水负荷变化影响的研究还比较薄弱.本文基于CORS站网,辅以少量重力台站数据,采用负荷形变和重力场球谐分析方法,研究了三峡地区陆地水负荷对地壳形变和重力变化的影响.本文研究发现:①基于CORS站网能够监测陆地水负荷引起的地壳形变和地面重力时空变化.②陆地水负荷对垂直形变的影响达厘米级,对水平形变的影响较小,对地面重力的影响可达数百微伽.③2011年1月至2015年6月陆地水负荷对垂直形变影响的年变化趋于平衡,对地面重力变化影响主要集中在三峡水库和重庆市附近.④基于CORS站网确定的三峡地区陆地水地壳垂直形变,与GRACE卫星重力成果在分布规律和趋势上具有较高的一致性,但在部分区域存在差异.本文研究成果可用于水动力环境监测与水资源保护利用,为高程基准和重力基准的动态维护提供支持.

Monitoring of crustal deformation and gravity variation from terrestrial water loading in the Three Gorges region by the CORS network

The impact of terrestrial water is not well understood due to the abundant water resources, the effect of the Three Gorges reservoir water-storage and drainage, and complex hydrodynamic environment in the Three Gorges area. We calculated the crustal deformation and gravity change caused by the variations of terrestrial water in the Three Gorges area based on CORS network, supplemented by gravity station data, using gravity field spherical harmonic analysis and loading deformation methods. This paper has drawn some conclusions as follows. First, it is able to use CORS network to monitor the crustal deformation and ground gravity variation, caused by terrestrial water loading. Second, the impact of terrestrial water loading on the vertical deformation is up to centimeter-level, less on the horizontal deformation, and up to hundreds of micro-gal on ground gravity. Third, from January,2011 to June, 2015,the vertical deformation annual variation caused by terrestrial water loading tends to be balanced, and the influence of gravity variation is mainly concentrated in the Three Gorges Reservoir and Chongqing area. Fourth, apart from some areas, crustal vertical deformation caused by terrestrial water based on CORS network is consistent with GRACE result in the distribution patterns and trends. The results can be applied to monitoring hydrodynamic environment, and protecting and utilizing of water resources, and supporting for maintaining the vertical datum and gravity datum.