小波变换在相对海平面变化研究中的应用

根据广东沿岸14个验潮站的月均序列，应用小波分析方法将其进行时域-频域分解，分析了近40多年来月平均潮位序列的多层次尺度结构，进而研究相对海平面的周期变化和趋势变化。结果表明，用小波变换研究相对海平面在时域-频域中的周期分布及变化时，能较好地揭示周期变化的局部特征；广东沿岸相对海平面变化包含着0．5年、1年、2～4年、10～11年及18～20年左右等周期变化，且周期变化在时间域中具有明显的局部化特征；据实测资料计算，周期变化对海平面的趋势变化影响明显，未消除周期变化的趋势分析结果偏大，用小波变换有效地消除周期变化后得出粤西及珠江口地区沿岸相对海平面变化率，一般而言，广东沿岸海平面呈上升趋势，上升幅度约为0．36～1．2mm/a。

Application of Wavelet Transform to Relative Sea Level Research

This study is concerned with wavelet transform for relative sea level research. The abnormalities of monthly mean sea level of 14 stations in Guangdong coastland for the last 40 years are analyzed by the Morlet wavelet transformation to study the periodic variances and the variances of relative sea level variation with time domain. The results show that the periodic variances of relative sea level comprise half year period, one year period, (2-4) years period, (10-11) years and 18-20 years long term variances and are localized in time domain. The periodic variances has a significant effect on the trends of relative sea level change. Yet before removing periods in the records, the trend change of relative sea level is overestimated, and after eliminating the effects of periodic components significantly determined by wavelet transform, the variances of relative sea level vary with time domain and rise in (0.36-1.2) mm/a at all in Guangdong coastland.