长江河口水位极值分析

本文根据长江河口的吴淞及其支流黄浦公园两个验潮站1912/1915～1985年年最高高潮位序列资料,应用Weibull分布方法计算了极值水位的重现期.长江口年最高高潮位近70多年来显示有明显的上升趋势,特别是近30多年来有加速上升的趋势,并且与平均海平面的变化趋势具有相同的量级.通过对Weibull分布进行简单地调整,从而来处理有线性趋势分量的年最高高潮位.这样使得在计算极值水位重现期时能够考虑到线性趋势分量.同时,再将这种方法外推,考虑到未来100年海平面上升0.5、1.0和2.0米三种方案,对长江口今后水位极值重现期重新进行了分析计算.结果表明,用上述方法计算得到的不同重现期的极值明显大于在不考虑线性趋势情况下所得到的极值,而且极值重现期明显缩短,千年一遇将成为百年一遇.

Analysis of Maximum Water Level in the Changjiang Estuary

A series of data of annual maximum water levels observed in the Wusong and Huangpu Park tidal gauge stations over the past 70 years have been analysed.The Weibull method of analysis is used to compute the return period of extreme levels.The result shows that there is a significant rise trend in the annual maximum water levels, whereas the rise trend accelerates according to the same order as the mean sea level.The Weibull method is simply adjusted to cope with the annual maximum water levels having a linear trend component so that it can be used to compute the return period of extreme levels under the consideration of linear trend components.Suppose the sea level rise within the next century to be 0.5, 1.0 and 2.0 meters, the extreme levels and their return periods are obviously higher and shorter, respectively, than those of under no considerations of linear trend components.