基于近岸海岛GPS数据反演海洋分潮负荷影响  

Inversion of ocean tidal loadings of marine constituents based on the GPS measurements in the offshore islands

作　　者：吴志露 刘焱雄[1,2] 何秀凤[1] 彭琳[2] 郑剑[2] 

机构地区：[1]河海大学地球科学与工程学院,江苏南京210098 [2]国家海洋局第一海洋研究所,山东青岛266061

出　　处：《地球物理学报》2017年第1期61-69,共9页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目(41374044);国家自然科学基金项目(41274011);国家海洋局预报减灾司项目-GNSS业务化运行(1511311700008)资助

摘　　要：本文探索了海潮负荷特征值的反演方法.基于中国近岸海岛GPS站(平潭与闸坡)观测数据,采用FFT方法提取了海潮负荷特征值,分析了反演特征值与全球海潮模型FES2004、NAO.99b和GOT4.7计算出的相关特征值之间的差异,评估了反演海潮分潮频率项的精度,并利用平潭站得到的海潮负荷特征值对附近的三沙站进行海潮改正以评价反演效果.结果表明:(1)频谱分析可精确提取4个半日分潮和4个全日分潮负荷的频率信息;与已知频率相比,P1分潮的反演频率误差为1.4%,其他7种分潮负荷反演频率误差均小于1%.(2)两个海岛分属不同的潮波入侵通道,反演分潮振幅和初相存在差异,但反演分潮频率几乎一致,间接证实它们属于同一潮波系统,也表明其潮差有别.(3)反演振幅与三种全球模型具有较好的一致性;其中S2、O1、P1、Q1四个分潮在水平方向互差为1~2 mm,高程方向上的互差均小于3 mm;K2、K1、M2、N2在水平方向振幅互差多数小于2 mm,个别差异高达4 mm,高程方向互差多为5~6 mm,个别超过10 mm.(4)反演得到海潮负荷改正模型相对于3种全球模型在三沙站的改正效果略佳,间接表明反演结果有效、可靠.(5)动态PPP结果中虽然存在多种误差,其时间序列仍可分离并提取海潮负荷的影响.The inversion method is studied and applied to acquire eigenvalues of the Ocean Tidal Loading （OTL） in this paper. Two offshore GPS sites EPTN and SZPO of China are adopted for the inversion based on FFT method, of which the results are compared with the global ocean tide models FES2004/NAO. 99b/GOT4.7. The accuracy of the inverted frequency of the OTL is also evaluated for a better correction of the OTL effect on DSSA, which is close to EPTN. Results are as follows. （1） The frequency extracted from FFT is nearly identical with the known value for the marine constituents, with maximum deviation of 1. identified in the other 7 sub tides. （2） The two islands 4%; and less than 1% frequency error is belong to different intrusion channels of ocean tides, their behavior of same tidal system but different tidal ranges is indirectly demonstrated by the differences in the inverted amplitudes and initial phases while the consistency in frequency. （3） The inverted amplitudes are in good agreement with the global model. Differences of the S2/O1/P1/Q1 constituents are 1-2 mm and 〈3 mm in the horizontal and vertical directions, respectively; while 〈2 mm and 5-6 mm differences are found for K2/K1/ M2/N2 in horizontal and vertical directions, respectively. （4） Compared with global models, the improvement achieved by the OTL correction on nearby GPS stations indirectly illustrated the reliability and effectiveness of the proposed method. （5） The dynamic PPP results can be used to separate the OTL effects, although they contain many kinds of errors.

关 键 词：精密单点定位 FFT 海潮负荷 时间序列 近岸海岛 

分 类 号：P228[天文地球—大地测量学与测量工程]