联合GPS和GRACE研究青藏高原南部地区垂直形变的季节性波动

Vertical Deformation of Seasonal Hydrological Loading in Southern Tibet Detected by Joint Analysis of GPS and GRACE

  • 摘要: 利用青藏高原南部地区GPS站点近10 a(2004年至2014年)的观测资料,结合重力场恢复与气候实验卫星(Gravity Recovery and Climate Experiment,GRACE)同时期观测数据反演得到的该区域水文负荷变化引起的垂向位移,发现该地区利用GPS和GRACE获取的垂向位移时间序列存在一定相关性,多数站点的相关系数在0.7左右,特别是沿喜马拉雅造山带区域内的站点相关性更高;此外,大部分站点(例如CHLM、KKN4)拟合的周期项振幅和相位也较为一致。计算GRACE估算垂直信号改正GPS结果前后的加权均方根误差(weighted root mean square,WRMS),并定义RWRMS来表征GRACE改正GPS垂向季节性波动的有效性,其数值越接近1表明GPS和GRACE数据具有越大的一致性。研究发现GPS站点的RWRMS有明显差异:最大和最小值分别是0.96(TPLJ)和0.24(XZGE),平均值为0.64,这与青藏高原南部地区垂直运动的复杂性有关,存在多种因素(构造运动、冰川均衡调整、大气和非潮汐海洋负荷,水文负荷、GPS交点年误差等)的共同作用。

     

    Abstract: Using the observation data of GPS sites in southern Qinghai-Tibet plateau in recent 10 years (2004-2014) and combing with the observation data inversion of the GRACE period regional hydrological load changes caused by the vertical displacement, it can be found by GPS and GRACE that there is a vertical displacement time series in a certain correlation. The correlation coefficient of most sites is around 0.7; especially the site of Himalayan orogenic belt, the correlation is higher than others. Most sites, such as CHLM and KKN4, the fitting cycle amplitude and phase are in consistent. Defining RatioWRMS to characterize of GRACE to correct the effectiveness of the GPS vertical hydrological load, the value closing to 1 indicates that GPS and GRACE data have a greater consistency; The study showed that the different areas of GPS sites RWRMS have obvious differences:maximum and minimum value are respectively 0.96 (TPLJ) and 0.24 (XZGE), while the average is 0.64. This is associated with the south Tibetan region of the complexity of the vertical movement, there are many factors (tectonic movement, GIA, the non-tidal atmosphere and ocean, Seasonal Hydrological Load, the tides, etc.) work together.This article research results to further study the south Tibetan region of tectonic movement has important reference value.

     

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