香溪河流域近60年来降雨量变化趋势及突变分析

为研究香溪河流域多年降雨特征，以流域1952—2011年10个雨量站日降雨资料为基础，得到流域面雨量序列。分别采用线性回归、滑动平均、Mann-Kendall趋势检验、M-K突变检验、Sen’s斜率估计和小波分析等方法，对流域60 a来降水量的年、季变化趋势和突变进行了检验。结果表明:香溪河流域年降水量以0.66 mm/a速率减少；春、秋季节降水量呈下降趋势，下降速率分别为0.33，0.81 mm/a，冬季降水量轻微下降趋势，夏季降水量呈上升趋势，速率为0.5 mm/a；年均和四季变化均未通过5%的显著性检验。研究时段内，年降水量发生了三次突变，分别在1954年，1989年，2006年。夏季降雨突变发生时间与年突变发生时间一致；春、秋、冬三季降雨在60 a内发生突变的时间分散、多变。

Analysis of Characteristics of Variation and Abrup Change of Precipitation in Xiangxi River Watershed over the Past 60 Years

The change trend of precipitation over the past 60 years in the Xiangxi River watershed was investigated using observed time series data from ten available rain gauges. Based on the ways of non-parametric trend test (linear regression,moving average method,Sen’s slope estimator and Mann-Kendall trend test), the change trend was analyzed. Mann-Kendall rank statistic test was also used to examine abrupt change for precipitation (using the 5% significance level). The results showed that precipitation had presented the decreasing trend at the rate of 0.66 mm per year in general. The precipitation in spring and autumn presented the decrease trend with the magnitude of 0.33,0.81 mm per year, respectively; while the summer precipitation increased at the rate of 0.5 mm per year. The obvious abrupt change points of annual and summer precipitation happened in the year of 1954,1989 and 2006. The abrupt change points in other three reasons are complex.