大港验潮站潮汐分析与国家高程基准面变化

利用1980—2011年小时潮位数据和1952—2007年月平均潮位数据,对大港验潮站处海洋潮汐以及国家高程基准面近60年的变化进行了分析和研究。首先利用傅里叶变换对两组数据进行频谱分析,获得了影响海水面变化的180个较短周期分潮以及6个长周期分潮;然后对小时潮汐数据进行最小二乘调和分析,获得影响海水面变化的主要分潮的振幅及其变化,发现Q1、O1、M2、K1、K2的振幅具有非常明显的约19年的周期变化;并利用调和分析和18.61年移动平均对国家高程基准面的变化进行了估算,分别获得基准面1952—1980年的下降速率为1.07mm/a和0.76mm/a,1980—2011年的上升速率为1.59mm/a和1.62mm/a;最后,通过18.61年移动平均对1985高程基准进行了检核,发现两者相差0.14cm。

Analysis of Tidal Data for Dagang Tidal Gauge and Study of the Changes for the National Height Datum

The main tides affecting Dagang sea level are analyzed and the national height datum is studied by analyzing 1980—2011 hourly tidal data and 1952—2007 monthly mean tidal data .Firstly ,the frequencies and amplitudes of main tides including 180 short‐period tides and 6 long‐period tides are gained by the Fouirer transform .Then the actual amplitudes and their vari ations of main tides are obtained by the harmonic analysis of the 1980—2011 hourly tidal data ,and the changes with about 19 year period can easily be found in the amplitudes of Q1 、O1 、M2 、K1 、K2 .And then the changes of the mean sea level at Dagang tidal gauge defining national height datum during the period of 1952—2011 are studied by the harmonic analysis and the shifting average of 18 6.1 year tidal heights .The results of these methods show that the mean sea l evel at Dagang ti dal gauge descended wi th the speed of 1 0.7 mm/a and 0 7.6 mm/a respectively during 1952—1980 ,and that it ascended with the speed of 1 5.9 mm/a and 1 6.2 mm/a respec‐tively during 1980—2011 .And finally the difference of 0 1.4 cm is achieved by the shifting average of 18 6.1 year ti dal hei ghts for 1985 Nati onal Hei ght Datum .