重庆暴雨、热浪、干旱时空格局及聚类特征

Spatio-temporal pattern and clustering characteristics of heavy rain,heat waves and drought in Chongqing

基于1966—2021年重庆区域34个气象站观测日值数据,选择暴雨、热浪、干旱3种典型气象灾害,依据国家标准、采用Mann-Kendall和Sen趋势法分析了3种灾害的时空变化特征,采用SaTScan时空扫描统计法研究了3种灾害的时空聚类特征。结果表明:1966年以来重庆平均热浪频次呈增加趋势,2001年以来暴雨和热浪明显增多、干旱总体减轻;重庆大多数地区暴雨、热浪变化以上升为主,特别是热浪,44%的区县热浪显著上升。暴雨和热浪事件易在东北部偏东地区和西部、西南、中心城区三区交界处聚集,热浪和干旱事件易在西南、中部、东南三区交界处和典型年份聚集。暴雨和热浪灾害在20世纪80年代及以后东北部聚集增多,热浪和干旱灾害在20世纪90年代及以后聚集区向东北迁移;暴雨、热浪和干旱灾害在20世纪80年代以前主要在东南部和西部地区聚集、在20世纪80年代及以后聚集范围明显缩小。基于时空扫描统计法揭示的研究区暴雨、热浪、干旱灾害时空聚类特征与灾害发生事实及Moran’s I方法结果基本一致,该方法和结论对重庆区域多灾种并发的诊断和综合风险防范具有一定参考价值。

Based on the daily data of 34 meteorological stations in Chongqing from 1966 to 2021,three typical meteorological disasters of heavy rain,heat waves and drought were selected,and the spatio-temporal variation characteristics of the three disasters were analyzed according to the national standards and the Mann-Kendall and Sen trend methods,and the spatio-temporal clustering characteristics of the three disasters were studied by using the SaTScan spatio-temporal scanning statistical method.The results show that:Heat waves in Chongqing increased since 1966.Heavy rain and heat waves happened more,and intensity of drought became weaker since 2001.The changes of heavy rain and heat waves in most areas of Chongqing mainly increased,especially heat waves,and the heat waves in 44%of districts and counties increased significantly.Heavy rain and heat waves tended to gather at the east-northeast region and the junction of the western,southwestern,and central urban areas,while the heat waves and drought events tend to gather at the junction of the southwest,central,and southeast regions and in typical years.Heavy rain and heat waves gathered more in the northeastern since 1980s.Clusters of heat waves and drought migrated to the northeast since 1990s.Three disasters were mainly gathered in the southeastern and western regions before 1980s,while the clusters shifted to east and north since 1980s and the clustering scope was significantly reduced.The spatio-temporal clustering characteristics of heavy rain,heat waves and drought disasters in Chongqing revealed by the spatio-temporal scanning statistical method were basically consistent with the disaster occurrence facts and the results of Moran’s I method,which has certain reference value for the diagnosis and comprehensive risk prevention of multiple disasters in Chongqing.