利用改进的动态PPP技术建立中国香港区域海潮负荷位移模型

Estimation of Displacements Caused by Ocean Tide Loading Using Improved GPS Kinematic Precise Point Positioning Technique:A Case Study in Hong Kong,China

利用GPS技术反演海潮负荷信息,相比传统重力及甚长基线干涉测量,有着全球覆盖、测站数多、全天候、成本低等诸多优势,为海潮模型的建立提供了有效的技术手段,也对海潮负荷效应的研究有着重要的理论意义和参考价值。利用动态精密单点定位技术(precise point positioning, PPP)反演海潮负荷位移,同时构建了区域海潮负荷位移模型。利用香港连续运行参考站8 a的GPS观测数据,精密测定了11个测站的三维海潮负荷位移参数,与高精度海潮模型提供的海潮负荷位移参数进行比较,发现除K_2、K_1潮波外,其他潮波的均方根误差均小于2 mm。与已有的动态PPP及静态PPP结果对比发现,采用改进的重叠时段动态PPP算法可有效改善K_1潮波的反演精度;该方法反演的海潮负荷位移精度可达到静态PPP反演海潮负荷位移的精度,且对于K_1潮波,在东西方向,动态PPP算法的反演精度较静态PPP略有改善。利用最小二乘曲面拟合法可有效建立中国香港地区GPS区域海潮负荷位移模型,可有效弥补沿海地区因验潮站稀少而导致的海潮模型适应性差的问题。

Compared with very long baseline interferometry(VLBI)and superconducting gravimeter(SG)techniques,Global Positioning System(GPS)technique has the advantages of global high-resolution coverage,long-term continuous observations,and low environmental impact to determine the ocean tide loading(OTL)displacement,which can provide a technical means to establish the ocean tide models and theory significance and reference for studying the OTL effect.In order to establish the regional OTL displacement model,the GPS kinematic precise point positioning(PPP)was used to determine the OTL displacement parameters.Three-dimensional ocean tide loading displacements of eight constituents at 11 sites in Hong Kong with eight years of continuous GPS observations are estimated.Comparing the RMS misfit of the model values,we found that the accuracy of K2 and K1 constituents are worst and the others’RMS are smaller than 2 mm.Comparing our results with the kinematic PPP and static PPP results,we found that our improved kinematic PPP can significantly improve the accuracy of K1 constituent.And the accuracy of 8 constituents derived by our method can reach the same accuracy as the kinematic PPP results,for K1 constituent,the accuracy of our method results is slightly better than the kinematic PPP results.Finally,using the least square quasi method to establish the GPS regional OTL displacement model can provide the reference for OTL effect correction in the coastal area which are lack of high accuracy local tide model.