根据珠江口伶仃洋三灶、赤湾、香港三个站的验潮记录,应用傅氏变换方法对月均验潮序列先做离散傅氏变换,并将周期小于4a的波动振幅设为零,再进行反傅氏变换,以消除小于4a的周期波动对确定海平面变化趋势的影响,最后由低通序列一元线性回归分析确定珠江口各站的海平面变化趋势。应用经验正交函数将区域的海平面变化分解为独立的时间特征函数和空间特征函数,据主要模态的特征函数分析珠江口海平面的时空变化规律,并由主要模态的时间特征函数估算珠江口伶仃洋海平面的平均变化趋势为0.89mm/a.。

Tidal gauge records are collected from three tidal stations in Lingdingyang Estuary. Fourier transform and inverse fourier transform are used to eliminate the components that periods are less than 4a from monthly mean time series. The secular trends of sea level are determined by means of linear regression of low passed time series. The empirical orthogonal function (EOF) is used to analyse the spatial and temperal characteristics of sea level change in Lingdingyang Estuary. The average rate of sea level change in Lingdingyang Estuary, which is estimated by the time series of the main mode, is 0.89 mm/a.