近50年珠江流域降雨多尺度时空变化特征及其影响

Multi-scale Spatio-temporal Characteristics and Influence of Precipitation Variation in Zhujiang River Basin During the Last 50 Years

利用珠江流域38个站点54 a日降水资料,采用Kendall非参数检验法、线性回归及空间克里格插值,对多种降雨指数时空变化及影响进行了研究。结果表明:1珠江流域西部年降雨有减少趋势,流域大部分的降雨日数则有增加趋势;2流域降雨具有季度、月份集中性,其中,季度集中性趋于空间均匀化,月份集中性趋向空间极端化;3极端降雨阈值东高西低,全区极端降雨在20世纪60、80年代末有突变现象,P0.01%设计值在21世纪达到最高。综合多尺度降雨时空变化结果进行分析,将珠江流域划分为广东(包括江西)、广西中北部(包括湖南)、广西西南及云贵4个降雨特征区,广东尤其是珠三角地区及广西中北部地区应注重防洪安全,广西西南与云贵地区应注重保障用水安全。

Basing on daily precipitation data from 1959-2012 in 38 gauging stations in Zhujiang River Basin(PRB), we have adopted Kendall test and linear regression method in studying the spatio-temporal characteristics of multiple precipitation indexes as studied time series, conclusions are drawn as follows: 1) In PRB, annual precipitation decreases towards west and declines along time; RRB drops from center to surroundings and keeps an increasing trend in most part of the basin; 2) Precipitation is seasonal and moderately concentrated in June; PCI becomeseven in the whole basin while differences between FI6 values expands; 3) Threshold value of extreme rainfall descends from east to the west and jumps are found in 1960 s and 1980s; volume of extreme rainfall with same recurrence interval comes to its peak in 21stcentury; 4) Four precipitation regions are divided as(a)Guangdong District,(b) north-central part of Guangxi District,(c) south-west of Guangxi District and(d) Yunnan-Guizhou District; flood prevention is crucial for aand b districts especially Pearl River Delta region, and water safety is major concern for c and d District.