非潮汐海洋负载效应对近海岸IGS测站坐标时间序列的影响

根据均匀分布在全球各大洲的IGS测站信息，选取105个数据质量良好的近海岸测站以及29个内陆测站，利用ECCO发布的海底压力数据计算得到由非潮汐海洋负载引起的IGS测站位置N、E、U方向上的位移。分析了由地理位置差异导致的测站受非潮汐海洋负载效应的影响存在的差异，并修正了SOPAC提供的IGS测站坐标时间序列，探讨了非潮汐海洋负载效应引起的测站位移对近海岸测站坐标时间序列的影响。结果表明，近海区域（<50 km）测站受到非潮汐海洋负载影响U方向平均量级为5 mm，远大于内陆（>500 km）测站U方向的影响；经过非潮汐海洋负载修正，71%的测站高程坐标时间序列RMS值得以减小，其中最大可使RMS值降低13%；大西洋、太平洋西海岸受其影响比东海岸大，考虑到其受非潮汐海洋负载效应影响显著，使用大西洋与太平洋西海岸地区测站坐标时间序列前必须进行非潮汐海洋负载修正。

Effects of Non-Tidal Ocean Loading on IGS Stations in Coastal Areas

Based on information on evenly distributed IGS stations, the paper selects 150 healthy IGS stations distributed in coastal areas and 29 inland IGS stations. Displacements of IGS stations caused by non-tidal ocean loading are calculated using an ocean bottom pressure grid provided ECCO, results of which are used to analyze differences of effects of non-tidal ocean loading on IGS stations between coastal and inland areas. Finally, to investigate its effects on IGS station coordinate time series, the calculated displacements are used to correct coastal IGS station time series provided by Scripps orbit and permanent array center(SOPAC). Results indicate that U components of stations in coastal areas (less than 50 km) are affected on average by 5 mm, compared to only 1 mm for inland stations. After non-tidal ocean loading correction is applied, the RMS of height time series of 71% coastal area stations are reduced, with a maximum reduction of 13%. Furthermore, non-tidal ocean loading effects along the west coasts of the Atlantic and the Pacific ocean are more obvious than along the east coasts. Considering the obvious effects in these areas, it is strongly recommended that when using station coordinate time series in west coast areas of the Atlantic and the Pacific oceans, that non-tidal ocean loading corrections must be applied.