夏半年西南暴雨洪涝灾害变化特征及其与大气环流的关系

Flood disaster’s characteristic in Southwest China in summer and relationship with atmospheric circulation

利用中国气象科学数据共享服务网提供的1961—2017年间90个地面气象观测台站的逐日降水量,进行西南片区(四川、贵州、云南和重庆市)洪涝灾害时空变化特征的分析,再挑选其高、低值年与大气环流的关系进行讨论,最后制作高值年与低值年的差值图与相关系数图进行比较分析.研究结果表明:西南暴雨洪涝灾害主要发生在主汛期6—8月,但5月和9月也不容忽视,其中7月是洪灾发生次数最多的月份,8月其次;近57年来,20世纪70年代至80年代和21世纪10年代发生的洪灾次数整体呈明显上升趋势,而20世纪90年代整体呈下降趋势;小波分析主要存在8~9 a的年际周期变化和17 a左右及32 a左右的年代际周期变化;西南地区的洪灾高发区主要在四川盆地以东至贵州北部一带、贵州西南部和云南南部边缘地区,低值区主要在西南地区西北部;洪涝灾害与其高层、中层和低层的环流形势有较好的配置关系.

Choose the Southwest area(Sichuan,Guizhou,Yunnan and Chongqing)daily precipitation of 90 meteorological stations in the summer half year during 1961—2017,the characteristic’s temporal and spatial variation of flood and waterlogging disaster are analyzed.To select the high and low abnormal circulation situation discussion,and make differential diagram(both for high value minus low years)comparing with correlation coefficient structure diagram.The resuits showed that the torrential rain and flood disaster in Southwest China mainly occurred in the main flood season from June to August.But May and September should not be ignored.July was the most frequent month,followed by August.In the past 57 years,1970 s to 1980 s and 2010 s,the number of floods was on the rise,and the overall decline in the 1990 s,there was a decreasing trend.The wavelet analysis 8—9 a of the annual cycle changes,interdecadal cycle changes of about 17 and 32 years.The high flood risk areas in Southwest China are mainly located in the East of Sichuan Basin to the northern part of Guizhou,southwestern Guizhou and southern Yunnan marginal areas.The low value area is mainly in the Northwest of Southwest Region.Flood disaster and its abnormal circulation has good configuration.