贵州省主汛期暴雨的气候特征分析

利用1981—2010年30 a贵州省83个地面气象观测站月降水量和月暴雨日数资料,采用合成、方差分析和经验正交函数（EOF）分解,着重讨论贵州省主汛期6-7月暴雨日数的空间分布及其时间演变特征,进而对6-7月暴雨日数EOF第一模态的时间序列作小波分析、趋势分析及突变检验,分析贵州省6-7月暴雨日数时间序列的短期气候特征。结果表明：近30 a贵州省6-7月暴雨日数与降水量的时空分布一致,并对降水量有主要贡献。暴雨日数的空间分布存在3个暴雨多发区和2条暴雨少发带,范围最广、强度最大的暴雨多发区位于省之西南部,大值中心在六枝、晴隆和镇宁附近。暴雨日数时间序列的变化在20世纪90年代是偏多时期,20世纪80年代和21世纪至今是偏少时期。贵州省6-7月暴雨日数EOF第一模态时间序列在20世纪90年代存在显著的3～5 a年际震荡,在1981—2010年间总体变化趋势分为3个时段：1981—1990年、1991—2000年和2001—2010年,呈＂降—升—降＂变化,没有明显的突变点。

Climatic characteristics of rainstorms in main flood seasons of GuiZhou

Based on the monthly precipitation and the rainstorm days data at 84 ground meteorological observation stations in Guizhou during 1981-2010,this paper uses compose,variance and EOF for analysising the spatial and temporal distribution from June to July in Guizhou,and then using the wavelet analysis,trend analysis and mutation test for discussing climatic characteristics of the rainstorm days data from June to July in Guizhou.The results show that： there is a consistent spatial and temporal distribution between the rainstorm days and precipitation,and the rainstorm account the amount of precipitation for the major present from June to July in Guizhou in recently 30 years.The spatial distribution has the characteristics which contain three heavy rainstorms centers and two storm-prone areas.The heaviest rainstorm centers locate in the southwestern Guizhou,around the Liuzhi,Qinglong and Zhenning.The change of the rainstorm days is a more period in 1990’s and a less period in 1980’s and 2000’.The time series of EOF mode1 has the significant 3-5 a interannual period.The trend has three stages（1981-1990,1991-2000 and 2001-2010）,which shows was down-up-down changes,and has no mutation point.