环境负载对区域GPS基准站时间序列的影响分析

Analysis of Environmental Loading Effects on Regional GPS Coordinate Time Series

基于1999—2011年中国地壳运动观测网络(CMONOC)及2007—2012年武汉市连续运行卫星定位服务系统(WHCORS)的观测数据,联合中国及周边35个IGS基准站数据,采用GAMIT软件解算,获得了ITRF2008框架下的GPS基准站坐标时间序列。然后采用QOCA计算了环境负载位移,并利用其对GPS时间序列进行改正。研究结果表明环境负载造成的中国区域基准站位移呈现显著的区域性特征,东北、华北、华中区域变化较为一致且较大,西南区域基准站(KUNM)垂直方向的负载位移均方根(RMS)最大值达6.09mm。通过对改正前后的数据进行时间序列分析,认为环境负载改正能够削弱中国区域大多数GPS基准站(约70%)垂直及水平东方向位移时间序列的非线性变化,其加权均方根(WRMS)减小量最大达1.5mm,但是对于水平北方向坐标时间序列的改善作用不明显。

In order to discuss environmental loading effects on regional GPS coordinate time series,the data which includes Crustal Movement Observation Network of China(CMONOC)measurements from 1999 to 2011and Wuhan Continuous Operational Satellite Positioning and Serving Syetem(WHCORS)measurements from2007 to 2012,together with China and around 35 IGS stations measurements are reprocessed by GAMIT,and the GPS fiducial stations coordinate time series under the ITRF2008 are obtained.The effects of environmental loading are then calculated by QOCA to correct the coordinate time series.It is found that the displacements of GPS stations inside China caused by environmental loading exhibit remarkable regional characteristics.Coherent and bigger variations exist in the northeast,north and central China,as well as the southwest regions,among which the biggest root mean square(RMS)of the vertical loading displacement for stations in southwest region(KUNM)reaches up to 6.09 mm.By comparing the corrected and the uncorrected time series,it is found that environmental loading correction could remarkably reduce the non-linear variations of most stations' vertical and east coordinate time series inside China(accounting for about 70%of the selected GPS fiducial stations),among which the biggest reduction in the weighted root mean square(WRMS)reaches 1.5mm.However,the improvement in the north components is quite limited.