摘要
云南是我国干旱灾害高发区,为增进厄尔尼诺/南方涛动(El Niño/Southern Oscillation,ENSO)对云南干旱影响的认知,提升云南秋季气象干旱预测能力,采用1979—2022年云南125个气象站逐日降水资料、英国国家气象局哈德莱中心(Hadley Center)逐月海表温度(Sea Surface Temperature,SST)资料及欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts,ECMWF)第五代再分析资料(the Fifth Generation of European Reanalysis,ERA5),揭示两类ENSO事件对导致云南秋季气象干旱的降水异常影响及相应的物理过程。结果表明:(1)中部(Central Pacific,CP)型El Niño或La Niña事件同期,云南秋季降水以偏少为主;东部(Eastern Pacific,EP)型El Niño或La Niña事件同期,云南秋季降水则以偏多为主,且EP型El Niño是云南秋季降水偏多的强信号。(2)EP型El Niño年和La Niña年,500 hPa位势高度场在欧亚大陆中低纬呈负距平,西太平洋副热带高压偏西,西南暖湿气流与冷空气在云南交汇,中低层以上升运动为主,有利于降水产生。CP型El Niño年和La Niña年,500 hPa位势高度在云南附近为正距平,加之向外长波辐射正异常,对流活动较弱,不利于云南地区的降水。(3)ENSO事件SST异常激发的赤道西北太平洋气旋(反气旋)环流的位置东西偏移是导致云南秋季降水异常的重要因素。
Yunnan Province is frequently affected by drought catastrophes,in order to enhance the understanding of the influence of El Niño/Southern Oscillation(ENSO)on drought and to improve the prediction ability of meteorological drought in autumn in Yunnan Province,the paper revealed the influence of two types of ENSO events on precipitation anomalies resulting in autumn meteorological drought in Yunnan and the associated physical processes based on monthly average sea surface temperature(SST)data from the Hadley Center,the fifth generation of European reanalysis data(ERA5)from the European Centre for Medium-Range Weather Forecasts(ECMWF),and daily precipitation data from 125 meteorological stations in Yunnan Province from 1979 to 2022.The results are as fol⁃lows:(1)During the period of Central Pacific(CP)type El Niño or La Niña events,the autumn precipitation in Yunnan is mainly less.Conversely,during the period of Eastern Pacific(EP)type El Niño or La Niña events,the autumn precipitation in Yunnan is mainly more.Furthermore,the EP type El Niño event is a strong signal of more autumn precipitation in Yunnan.(2)In the years of the EP type El Niño and La Niña,the 500 hPa geopotential-height field presents a negative anomaly over the middle and low latitudes of Eurasia,the Western Pacific subtropical high is westward,the warm and humid air from the southwest meets cold air in Yunnan,and the rising movement is mainly in the middle and low levels,which is conducive to precipitation generation in Yunnan.In the years of the CP type El Niño and La Niña,the 500 hPa geopotential height field in Yunnan is positive anomaly.In addition,there is the positive anomaly of outgoing longwave radiation(OLR),and the convective activity is weak,which is not conducive to the precipitation in Yunnan.(3)When ENSO event occurs,The east-west shift of the position of the equatorial northwest Pacific cyclonic(anticyclonic)circulation ex⁃cited by the SST anomaly of ENSO event is an important factor leading to the autumn precipitation
作者
马思源
金燕
张思
王楚钦
马志敏
MA Siyuan;JIN Yan;ZHANG Si;WANG Chuqin;MA Zhimin(Yunnan Climate Center,Kunming 650034,China;Yunnan Meteorological Observatory,Kunming 650034,China;Yunnan Key Laboratory of Meteorological Disasters and Climate Resources in the Greater Mekong Subregion,Kunming 650034,China)
出处
《干旱气象》
2023年第6期860-872,共13页
Journal of Arid Meteorology
基金
中国气象局气象能力提升联合研究专项(22NLTSZ005)
云南省基础研究专项重点基金项目(202201AS070069)
云南省重点研发计划-社会发展专项(202203AC100005、202203AC100006)
云南省自然科学基金项目(202302AN360006)共同资助。
关键词
云南
秋季
气象干旱
两类厄尔尼诺/南方涛动事件
西北太平洋气旋
Yunnan
autumn
meteorological drought
two types of El Niño/Southern Oscillation
Northwest Pacific cyclone
