珠江三角洲洪水位重现期变化研究

针对近年来珠江三角洲大洪水频频发生,洪水重现期发生变化的情况,它采用GEV分布模型对珠江三角洲35个潮位站50年左右的极端高水位值进行频率分析,在此基础上将50年左右的时间序列分成若干时间段,通过Monte-Carlo模拟随机方法在每个时间段里建立概率密度函数曲线以及水位与洪水重现期关系的函数曲线,进一步研究洪水重现期随时间的变化规律并分析其机理。结果表明：珠江三角洲中部腹地洪水重现期水位明显有增大的趋势,而上游以及口门区变化则不大,产生这种变化的一个重要原因是上部地区大规模的挖沙活动对河道及周边环境带来负面影响。

Research on changes of flood level return period in Pearl River

Since big flood occurred frequently in the Pearl River Delta in recent years and the return period of flood has changed,this article uses the GEV distribution model to get the frequency analysis of extreme high water level values of 35 tide stations in the Pearl River delta for about 50 years. On this basis this article divides the time series of about 50 years into several small time periods and establishes the probability density function curve and function curve of relationship between water level and the flood return period in each time period by Monte-Carlo random simulation to study the changing rule of the return period of flood further and analyze the mechanism. The result shows that there is an obvious increasing trend in water level of flood return period in the central hinterland of the Pear River Delta, but a little change in the upstream and entrance areas. An important reason for this change is that large-scale sand-excavating activities in the upper region have a negative impact on the river and the surrounding environment.