基于CI指数的昔年地区1961-2012年春季干旱分布特征

_{选用1961-2012年西南片区(四川、贵州、云南和重庆市)90个地面气象观测台站的逐日降水、日平均气温的实测气象要素资料,运用综合气象干旱指数(CI) 来统计分析近52年来西南春季干旱的时空变化特征。研究得出：西南地区干旱主要发生在春季和冬季,其中春季干旱的频次最高,而冬季的干旱强度最强,春季干旱的频次和强度均为3级干旱(中旱)较偏多偏强；春季干旱的频次和强度均为略有下降趋势；年代距平均在20世纪60至80年代的为正,而后为负；频次在1980年左右有个突变,而强度在1981年左右有突变；频次主要在21世纪初之前具有8a的年际周期变化,有明显的缩短趋势,强度主要具有8a的年际周期变化和12a的年代际周期,也均具有明显缩短的趋势；频次和强度指数均在云南中部、贵州东部和四川西北部边缘有3个明显的高值中心,而四川南部和重庆东北部为低值中心。}

Temporal and Spatial Distribution Characteristics of Droughts in southwest Based on Meteorological Drought Composite Index

Choose the southwest area in 1961-2012 (sichuan, guizhou, yunnan and chongqing) daily precipitation of 90 meteorological stations in the ground, the measured data of meteorological elements of the average daily temperature using the integrated meteorological drought index (CI) to statistical analysis in recent 52 years southwest spatial and temporal variations of the spring drought. Study: southwest drought mainly happened in spring and winter, the spring drought frequency is highest, the strongest and the intensity of winter drought and the spring drought frequency and intensity are level 3 drought (drought) in a more strong; The spring drought frequency and intensity are slightly downward trend; Average s from 60 s to 80 s in the 20th century is positive, and negative; A mutation frequency around 1980, and the intensity of around 1981 mutation; Frequency before the main at the beginning of the 21st century has 8 a interannual cycle changes, have apparent shortening trend, mainly has the strength of interannual cycle and 8 a 12 a decadal cycle, also have significantly reduced trend; Frequency and intensity index in the eastern central yunnan, guizhou and sichuan northwest edge has three obvious high value center of northeast and southern sichuan and chongqing, for low value center.