1961—2017年四川省夏季长周期旱涝急转演变特征及环流影响分析  

Evolution characteristics of long-term drought and flood alternation in summer and analysis of the circulation influence in Sichuan Province from 1961 to 2017

作　　者：甄英[1] 董雪峰 何静[2] ZHEN Ying;Dong Xuefeng;HE Jing(School of Geography & Resource Science,Neijiang Normal University,NeiJiang 641199,China;School of Atmospheric Sciences,Chengdu University of Information Technology,ChenDu 610225,China)

机构地区：[1]内江师范学院地理与资源科学学院,四川内江641199 [2]成都信息工程大学大气科学学院,四川成都610225

出　　处：《大气科学学报》2021年第3期355-362,共8页Transactions of Atmospheric Sciences

基　　金：四川省教育厅项目(16ZB0303);内江师范学院校级科研项目(2020YB28)。

摘　　要：基于NECP/NCAR再分析资料和四川省38个站点降水资料,结合长周期旱涝急转指数,分析了四川省夏季旱涝急转的时间演变特征及其与典型年份大气环流的联系。结果表明:1)四川省夏季旱涝急转指数年际变化差异较大,旱转涝事件多于涝转旱事件,但发生旱转涝事件的可能性和强度降低,而涝转旱年强度更强;2)旱转涝年的旱期与涝转旱的涝期相比,前者西太平洋副高位置偏西、偏强,不易将南海及西太平洋的水汽输送到四川,降水偏少偏旱,而后者中高纬槽脊波动剧烈,在高原东南侧低值系统与副高的配合下,有利于暖湿气流向北输送,在四川地区形成降水;而旱转涝年涝期与涝转旱年旱期相比,环流经向运动偏强,中高纬槽脊波动明显,有利于中高纬冷空气南下与低纬北上的暖湿气流相遇形成降水,降水偏多偏涝。In this study,based on the NECP/NCAR reanalysis data and statistical data from 38 stations located in Sichuan Province,and combined with the Long-term Drought and Flood alternative index(LDFAI),the relationship between the time evolution characteristics of long-term drought and flood alternative in summer and atmospheric circulation of typical years in Sichuan Province was analyzed.The results show the following:1)The interannual variation of summer drought and flood alternative index in Sichuan Province differs greatly,the occurrence of the drought to flood being greater than that of flood to drought;however,the drought to flood alternative is declining,while the intensity for flood to drought is quite high.2)Comparing the drought season of drought to flood with flood season of flood to drought,the western Pacific subtropical high is located westward,and is quite strong.The water vapor transport in the South China Sea and western Pacific cannot easily reach Sichuan,and the precipitation level is lower,with more frequent drought.Comparing the flood season of drought to flood with drought season of flood to drought,the circulation warp direction movement is stronger,while the mid-high latitudes ridges are clearly fluctuating,which is conducive to the formation of precipitation when the cold air in the middle and high latitudes traveling south meets the warm and humid air in the low latitude going north,thereby resulting in greater precipitation and increased floods.

关 键 词：四川省 旱涝急转指数 大气环流 标准化降水量 

分 类 号：P45[天文地球—大气科学及气象学]