卫星重力和水文模型联合研究陆地水变化对地心参考框架精度和稳定性影响

The ability to assign accurate and stable time-dependent coordinates to points on the Earth’s surface is fundamental for many Earth observation applications, for example sea level rise estimations, global plate tectonics, co/post-seismic deformation studies. Conversely, the knowledge of the expected displacements from geophysical theories and external measurements allows providing constraints on the error budget of the Terrestrial Reference Frame (TRF) defining parameters. For an accurate and stable TRF, an estimation model should take into account the geocentric movement and a more complex modelling of the non-linear movement on the stations, including seismic displacements, hydrology loading displacements, etc. The seasonal variations caused by continental hydrology loadings are not distinguished in the newly release International Terrestrial Reference Frame (ITRF) models (ITRF2014), which can bias all coordinates in the user’s solution, we mainly focus on the effect of hydrology loading on the ITRF realization and maintenance. With the development of satellite gravity, especially the Gravity Recovery and Climate Experiment (GRACE), the time-variable gravity field and mass variations from hydrologic loading now can be quantitatively estimated, but the excessive spatial smoothing in the GRACE measurements could probably cause the GRACE model to under-predict the hydrology signals. Continental hydrology model from the global hydrology model, for example Global Land Data Assimilation System (GLDAS), cannot modify the effect of hydrology loading quite well. On the basis of analysing the characteristic and common mode errors of reference stations, we try to combine the GRACE measurements and GLDAS data to model the continental hydrology loading signal, and evaluated the effect on the precision and stability of TRF realization and maintenance.

高精度及稳定的地心参考框架对大地测量学、地球物理学、地球动力学、海洋学、冰川学以及气候变化等研究具有非常重要的物理意义，因此，构建高精度、高稳定性的地心参考框架一直是当前地球科学研究的前沿课题。本课题围绕陆地水变化对地心参考框架的影响，以全球分布的基准站网、卫星重力观测和水文模型为基础，探索GRACE、大地测量观测和地球负荷变形模型融合的理论与方法，评估这一技术途径的有效性及限制条件。本课题涉及卫星重力和水文模型联合估算陆地水变化、基准站陆地水负荷变形的时空特征以及基准站时间序列中陆地水信号识别三项内容，目标是构建融合GRACE观测、水文模型以及连续基准网观测分析陆地水符合变形的理论与方法，既能满足高精度、高稳定性的全球参考框架的实现与维持，也服务于全球水文模型的逐步完善。

高精度及稳定的地心参考框架对大地测量学、地球物理学、地球动力学、海洋学、冰川学 以及气候变化等研究具有非常重要的物理意义，因此，构建高精度、高稳定性的地心参考框架 一直是当前地球科学研究的前沿课题。本课题围绕陆地水变化对地心参考框架的影响，以全球 分布的基准站网、卫星重力观测和水文模型为基础，探索GRACE、大地测量观测和地球负荷变 形模型融合的理论与方法，评估这一技术途径的有效性及限制条件。本课题涉及卫星重力和水 文模型联合估算陆地水变化、基准站陆地水负荷变形的时空特征以及基准站时间序列中陆地水 信号识别三项内容，目标是构建融合GRACE观测、水文模型以及连续基准网观测分析陆地水符 合变形的理论与方法，既能满足高精度、高稳定性的全球参考框架的实现与维持，也服务于全 球水文模型的逐步完善。