基于MCI指数的西南地区近60年夏季干旱特征  

Characteristics of Summer Drought in Southwest China in Recent 60 a based on MCI Index

作　　者：张皓 毛文书[1] 师春香[2] 粟运 高焕昕 ZHANG Hao;MAO Wenshu;SHI Chunxiang;SU Yun;GAO Huanxin(College of Atmospheric Sciences,CUIT,Chengdu 610225,China;National Meteorological Information Center,Beijing 100081,China)

机构地区：[1]成都信息工程大学大气科学学院,四川成都610225 [2]国家气象信息中心,北京100081

出　　处：《成都信息工程大学学报》2022年第4期442-448,共7页Journal of Chengdu University of Information Technology

基　　金：国家重点研发计划资助项目(2018YFC1506601);国家自然科学基金资助项目(41775079)。

摘　　要：为了对西南地区夏季干旱特征进行分析,利用西南地区381个气象站点1961-2019年6-8月的逐日MCI指数,采用经验正交函数分解方法、Morlet小波分析等方法对西南地区近60年夏季干旱的空间分布特征及时间变化特征进行讨论。结果表明:(1)平均连续干旱日数(Mean CDD)在23 d左右。最长连续干旱日数(Max CDD)平均为25.53 d。(2)轻、中、重旱多发生在四川北部,重庆及贵州的东部区域;特旱多发生在云南中部和贵州西南部。(3)西南干旱日数主要分为,南北反向变化的第一模态,西南与东北反向变化的第二模态,贵州南部和四川东部与呈反向变化特征的第三模态,由西向东“-+-”纬向变化的第四模态。(4)西南地区轻旱日数存在12~18 a尺度上的周期振荡;中旱日数存在一个准10 a的周期振荡,10~15 a尺度上有中旱日数“偏少—偏多—偏少”交替振荡;重旱日数存在15 a尺度上的周期振荡和准7 a尺度上的周期振荡及准5 a尺度上的周期振荡;20 a尺度上存在特旱日数的“偏少—偏多”的交替振荡和准5 a尺度上的周期振荡。In order to analyze the characteristics of summer drought in Southwest China was studied by the daily MCI drought index of 388 meteorological stations in summer from June to August during 1961-2019,the spatial and temporal characteristics of summer drought in Southwest China in recent 60 years were discussed in detail by using the empirical orthogonal function decomposition method and Morlet wavelet analysis.The results showed that:(1) The average continuous drought days(Mean CDD) is about 23 days.The longest continuous drought days(Max CDD) averaged 25.53 days.(2) Light,medium,and heavy droughts mostly occurred in northern Sichuan,Chongqing,and eastern Guizhou,and extreme droughts mostly occurred in central Yunnan and southwestern Guizhou.(3) Southwest drought days are mainly divided into the first mode of north-south reverse change;The second mode of southwest and northeast reverse change;The third model with reverse variation characteristics in southern Guizhou and eastern Sichuan;The fourth mode is the "Negative-Positive-Negative " latitudinal change pattern from west to east.(4) The number of days of light drought in Southwest China has periodic oscillation of 12-18 a scale.The number of days of medium drought has a periodic oscillation of quasi-10 a,and there is an alternating oscillation of "less-more-less" on the scale of 10-15 a.There are periodic oscillations at the 15 a scale,periodic oscillations at the quasi-7 a scale,and quasi-5 a scale in heavy drought days.On the 20 a scale,there are "less-more" alternating oscillations in the number of extreme drought days and periodic oscillations at the quasi-5 a scale.

关 键 词：气象学 夏季干旱 西南地区 EOF分解 小波分析 

分 类 号：P426.616[天文地球—大气科学及气象学]