锡林河下游河谷平原区降水时序演变规律研究

Research on the Precipitation time-series Evolution Rules of the Valley plain in the downstream of Xilin River

锡林河下游河谷平原区属典型草原区,生态系统脆弱,对降水时序变化十分敏感,分析和研究该区域降水时序演变规律意义重大。基于四个站点1958-2013年逐日降水资料,分别采用趋势分析法、Mann-Kendall检验法、Morlet小波分析法对锡林河下游河谷平原区降水量年尺度和季尺度时间序列变化进行了丰枯对比和多周期分析。研究表明:1958年以来锡林河下游河谷平原区年降水量以4.5 mm/10 a的速度递减,该区域降水量在不同时间尺度上发生了不同程度的偏丰-偏枯的循环交替过程,发生震荡变化的周期主要为3、5、8、19 a;在季尺度上,呈春季微增-夏季强减-秋季微减-冬季微增的特点,其中夏季降水量与年降水量存在高度一致性。

The Valley plain in the downstream of Xilin River located in typical steppe zone with a fragility ecosystem and very sensitive to the variation of the precipitation. The study of the variation of the precipitation time-series is of great significance. According to the daily precipitation data from 1958 to 2013, the interannual and seasonal variation characteristics of precipitation and cycle conditions were obtained by u- sing climate trend analysis method, mann-kendall test method and morlet wavelet analysis method. The result show that the annual preciptita- tion has a weak reducing trend by 4.5 mm/10 a, The area precipitation in different time scales had different degrees of wet and dry circulation process and the cycle of oscillation are mainly 3, 5, 8, 19 a. On seasonal-time scale, the precipitation characteristic show a mild increase in spring, a strong decrease in summer, a mild decrease in autumn and a mild increase in winter, the summer precipitation show a highly consistency with the annual precipitation.