近40年云南省极端降水时空变化特征分析

Analysis of Spatial and Temporal Variability of Extreme Precipitation in Yunnan Province in the Last 40 Years

为了研究云南省降水及极端降水变化趋势,基于1979—2019年云南省气象站点日降水数据及10种极端降水指标,采用Mann-Kendall(M-K)突变检验、小波分析及Hurst分析等方法,对近40年内降水及极端降水的变化趋势及空间格局进行探讨。结果表明:1979—2019年云南省年降水整体呈下降趋势,降水总量下降最大倾向率达到-24.52 mm/10 a,存在24 a、9 a及其他变化尺度,干旱半干旱区突变显著性最强。在空间变化趋势中,强降水量在湿润区出现快速下降,倾向率达到-5.161 mm/10 a。其他极端降水事件频率、强度及极值出现不同程度下降;Hurst指数均小于0.5,显示未来各地区间极端降水频率、强度指数变化趋势将会减弱;降水总量能够较好的指示其他极端降水指标变化,相关性达到0.8,降水强度其次,相关系数达到0.7,且均通过0.01显著性检验。研究结果能够为科学研究极端降水趋势变化机制提供依据。

In order to study the trend of precipitation and extreme precipitation in Yunnan Province,based on the daily precipitation data of meteorological stations in Yunnan Province from 1979 to 2019 and ten extreme precipitation indicators,the Mann-Kendall(M-K)mutation test,wavelet analysis and Hurst analysis were used to analyze the precipitation and extreme precipitation in the past 40 years.The change trend and spatial pattern of precipitation were discussed.The results show that the annual precipitation in Yunnan Province from 1979 to 2019 show a downward trend as a whole,and the maximum trend rate of total precipitation decline reach-24.52 mm/10 a.There are 24 years,9 years and other scales of change,and the arid and semi-arid regions have the strongest mutation.In the trend of spatial change,the amount of heavy precipitation decreased rapidly in the humid area,and the tendency rate reach-5.161 mm/10 a.The frequency,intensity and extreme value of other extreme precipitation events have decreased to varying degrees.The Hurst index is less than 0.5,indicating that the trend of extreme precipitation frequency and intensity index will weaken in the future.Total precipitation can better indicate the changes of other extreme precipitation indicators.The correlation reached 0.8,followed by precipitation intensity,and the correlation coefficient reached 0.7,and both passed the 0.01 significance test.The research results can provide a basis for scientific research on the mechanism of extreme precipitation trend changes.