云南西北地区近54年极端降水分析

Extreme Precipitation in Northwest Yunnan in Recent 54 Years

为了分析和揭示云南西北地区近54年极端降水的特点和规律,为其地区极端降水的研究与预防提供一些参考,笔者利用云南西北地区6个典型的气象站点1960—2013年的逐日降水数据,采用阈值检测方法计算出各站点极端降水阈值,并通过线性倾向、Morlet小波分析、Mann-Kendall突变检验、滑动t检验等研究了云南西北地区近54年极端降水的时空变化特征。结果表明:年极端降水量的范围在165.7~459.0 mm,自北向西南逐渐增大。云南西北地区的极端降水量趋势总体呈增加趋势,但并不显著。年极端降水量在20世纪80—90年代达最大。极端降水量主要有1个6~7年的短振荡周期,以及11~12年的中振荡周期和1个27~28年的长振荡周期。年极端降水量发生了2次突变,1966年由偏多转为偏少,1976年后极端降水量开始增加。

The paper aims to analyze the characteristics and regularities of the extreme precipitation for nearly 54 years in northwest Yunnan, and provide some references for the research and prevention of the extreme precipitation in the region. Based on daily precipitation data of 6 typical meteorological stations from 1960 to 2013 in northwest Yunnan, the thresholds of extreme precipitation were measured by the method of threshold detection, and the temporal and spatial distribution of change about the extreme precipitation were investigated by using climate diagnostic methods, such as linear trend, Morlet wavelet analysis, Mann-Kendall test and moving t-test. The results showed that： the annual extreme precipitation was 165.7-459.0 mm and had a trend of gradually increasing from north to southwest; the extreme precipitation of northwest Yunnan presented an increasing tendency which was not obvious; the annual extreme precipitation reached the maximum during the 1980＇s to 1990＇ s; the extreme precipitation had a 6-7 years short periodic oscillation, a 11-12 years medium periodic oscillation and a 27-28 years long periodic oscillation; the annual extreme precipitations had 2 abrupt change points, the precipitation changed from more to less in 1966, then began to increase in 1976.