北京地区长序列季节尺度降水研究

本文采用线性回归,11年滑动平均,Mann-Kendall,连续Morlet小波分析等方法对北京地区286年长降水序列在季节尺度上进行了趋势与周期分析。分析结果表明：（1）在过去的将近300年,北京地区四季除了冬季之外降水呈上升趋势;（2）夏季降水和年降水的上升趋势在17世纪80年代后上升的非常明显并且在很长的一段时间是显著的;（3）夏季降水和年降水的突变点发生分别发生在1764和1768年,这之后北京夏季降水和年降水从下降趋势变为上升趋势;（4）四季降水表现出不尽相同的周期特征。130–170年, 80–95年, 75–95年和 55–65年被认为是春夏秋冬四季降水的最主要周期;（5）153年,85年,83年,59年分别为北京地区春夏秋冬四季降水的第一主周期;（6）夏季降水与年降水变化阶段基本相似,夏季降水完全控制年降水;根据两者85年第一主周期判断北京地区在2009–2030年这个时段正处于一个少降水期。

Long-term Trend Analysis of Seasonal Precipitation for Beijing, China

A comprehensive precipitation trend and periodic analysis at the seasonal scale on a 286year data series （1724-2009） for Beijing are presented using linear regression, 11-year moving averages, Mann-Kendall test and continuous Morlet wavelet analysis. We found that in the past 300 years precipitation has increased except during winter. There were strong increasing trends after the 1780s in both summer and annual precipitation data series and the trend was significant for a longterm period. The abrupt points of summer and annual data series of precipitation are 1764 and 1768 respectively, after that, the trend changed from decreasing to increasing. It shows different periodic traits in four seasons respectively： 30–170 years, 80–95 years, 75–95 years and 55–65 years are considered to be the strongest period in spring, summer, autumn and winter. One hundred and fiftythree years, 85 years, 83 years and 59 years are the first order main periods in spring, summer, autumn and winter, respectively. The trend and period of annual precipitation are mainly impacted by rainfall in summe. According to the first main period of 85 years in both summer and annual precipitation data series, Beijing will experience a time period of less precipitation in 2009–2030.