2022年江南盛夏持续高温干旱事件成因诊断分析  

Diagnosis of Persistent High-Temperature and Drought Events over the South of Yangtze River Valley in Midsummer of 2022

作　　者：马依依 潘欣 刘建勇 孙杭媛 Ma Yiyi;Pan Xin;Liu Jianyong;Sun Hangyuan(Quzhou Meteorological Bureau,Quzhou 324000,China;Zhejiang Quzhou Airport Management Co.,Ltd.,Quzhou 324000,China)

机构地区：[1]衢州市气象局,浙江衢州324000 [2]浙江省衢州机场管理有限公司,浙江衢州324000

出　　处：《气象与减灾研究》2024年第3期194-204,共11页Meteorology and Disaster Reduction Research

基　　金：2022年衢州市科技局指导性项目“衢州市近50年不同季节高温热浪典型气候特征及关键环流背景分析”;2023年浙江省气象局青年项目“浙江省7—8月极端高温事件环流分型及未来预估”。

摘　　要：利用1979—2022年江南地区279个气象台站逐日降水、最高气温资料和NCEP/NCAR提供的第二套再分析资料等,计算了1个月和3个月的标准化降水指数(SPI-1、SPI-3),分析了2022年江南盛夏持续高温干旱事件的特征,并通过诊断分析的方法探究了持续高温干旱事件的环流特征及异常成因。结果表明:1) 2022年江南盛夏降水异常偏少超5成,高温维持时间长,江西东部、浙江大部最长连续高温日数达30 d以上;2)高温少雨导致后续伏旱事件出现。SPI-1显示8月江南地区达特旱,SPI-3则显示7—8月江南大部由正常发展为轻旱,尤其是浙江沿海出现中旱;3)西太平洋副热带高压异常偏强偏西、南亚高压偏北及水汽辐合偏北是此次事件的主要原因。7—8月江南地区存在显著地表净辐射收入,其主要由地表加热贡献,地表热量向上输送进而维持高温天气;4) mega-El Ni1o/Southern Oscillation(mega-ENSO)是此次高温干旱事件的主要海温异常信号,其激发的反位相东亚太平洋遥相关波列为高温干旱提供有利的环流背景。此外,mega-ENSO信号在前期冬季甚至更早就出现,其可作为江南盛夏高温少雨事件的前期预测因子。Based on the daily precipitation,maximum air temperature data of 279 stations and NCEP/NCAR reanalysis data from 1979 to 2022,the standardized precipitation index for 1 month and 3 months(SPI-1,SPI-3) were calculated,the circulation characteristics and possible causes of the persistent high-temperature and drought events over the south of Yangtze River Valley in midsummer of 2022 were diagnosed.The results showed that:1) the rainfall was more than 50% below the historical average,the longest continuous high-temperature days reached more than 30 days in the east of Jiangxi,and most areas of Zhejiang broken the historical records.2) High temperature and less rainfall led to the occurrence of subsequent drought events.SPI-1 showed the extreme drought appeared over the south of Yangtze River Valley in August,while SPI-3 displayed most regions developed from normal to slight drought during July and August,particularly with moderate drought along Zhejiang coast.3) More intensive West Pacific Subtropical High and westward position of its west ridge point,the northward position of the South Asian High and its weaker moisture convergence were responsible for the high-temperature and drought events.High temperature was sustained by upward transport of surface heat,which mainly derived from a significant net surface radiation income over the south of Yangtze River Valley from July to August.4) mega-El Ni1o/Southern Oscillation(mega-ENSO) was the main SST variability affecting the high-temperature and drought events,which induced the anomalous anti-cyclone and corresponding downdraft over the south of Yangtze River by triggering the out-of-phase East Asia-Pacific(EAP) teleconnection.In addition,the mega-ENSO signal appeared even earlier in the early winter,indicating that it can be used as a prediction factor for high-temperature and less rainfall events in midsummer over the south of Yangtze River valley.

关 键 词：高温干旱 mega-ENSO 地表能量平衡 江南 

分 类 号：P466[天文地球—大气科学及气象学]