1961-2015年吉林省极端降水指数时空变化特征

Spatiotemporal change characteristics of extreme precipitation indices in Jilin Province from 1961 through 2015

利用1961-2015年吉林省50个气象站的逐日降水量资料,通过RClim Dex v1.1软件计算11个极端降水指数,采用线性倾向估计和Morlet小波分析等方法,分析了吉林省极端降水指数的时空变化规律。结果表明:1961-2015年吉林省最长连续无雨日数(CDD)自西向东逐渐降低,其他极端降水指数均呈自西向东逐渐增加的趋势分布。吉林省CDD呈极显著的下降趋势,下降速率为-1.99 d·(10a)-1,其他极端降水指数波动变化,线性趋势不显著。吉林省各极端降水指数均在20世纪70年代达到最小值。绝大多数极端降水指数存在3 a和12 a左右的周期变化,3 a左右的主周期通过了0.05的显著性水平检验。吉林省极端降水指数除CDD随经度、海拔的增加而显著降低,随纬度的增加而显著增加外,其他大部分极端降水指数随经度、海拔的增加而增加,随纬度的增加而降低。

In this paper, the features of eleven indices of extreme precipitation over Jilin Province were examined broadly through the RClimDex vl. 1 software based on daily precipitation data from 50 meteorological stations from 1961 through 2015. The methods of inverse distance weighted （IDW）, linear trend estimate and Morlet wavelet analysis were employed to delineate the spatiotemporal change, statistical significance and periodicity of extreme precipitation indices. The results showed that consecutive dry days （CDD） decreased from west to east, and other extreme precipitation indices increased from west to east. The CDD showed a significant decline trend by - 1.99 d · （10a）^ -1. However, the linear trends of other extreme precipitation indices were not obvious. Each extreme precipitation indices in the province reached its minimum in the 1970s. Most extreme precipitation indices had periodic variations about 3 and 12 years, and the main cycle around 3 years has passed the test of 0.05 significance level. Apart from the CDD, which reduced dramatically with longitude and altitude and increased with latitude, most of the extreme precipitation indices increased with longitude and altitude and decreased with latitude.