2017年盛夏7—8月浙江省高温热浪特征及环流背景分析  

Analysis on the climatic characteristics of extreme heat-wave during July-August,2017 and associated large-scale circulation background

作　　者：马浩[1] 刘昌杰 钱奇峰 葛敬文 强玉华 殷悦 MA Hao;LIU Changjie;QIAN Qifeng;GE Jingwen;QIANG Yuhua;YIN Yue(Zhejiang Climate Center,Hangzhou 310017,China;School of Earth Sciences,Zhejiang University,Hangzhou 310027,China;Lishui Meteorological Observatory,Lishui 323000,China)

机构地区：[1]浙江省气候中心,浙江杭州310017 [2]浙江大学地球科学学院,浙江杭州310027 [3]丽水市气象台,浙江丽水323000

出　　处：《自然灾害学报》2021年第5期85-99,共15页Journal of Natural Disasters

基　　金：浙江省基础公益研究计划项目(LGF19D050001);浙江省气象局重点项目(2020ZD14);国家重点研发计划项目(2018YFC1505601);浙江省自然科学基金项目(LQ20D050004)。

摘　　要：2017年盛夏7—8月浙江省发生了大范围、持续性极端高温热浪事件,省内大部地区高温日数达到30 d以上,多数区域极端最高气温达到39℃以上、39站达40℃以上,多站平均气温、高温日数和极端最高气温破历史纪录,高温累计日数和有效积温仅次于2003年和2013年。要素特征和高温强度分析表明该年是有观测以来盛夏高温热浪最突出的年份之一。西太平洋副热带高压(西太副高)偏强偏西是造成此次极端事件的直接原因;对流层低层中国东南部—西北太平洋区域形成了强大的反气旋式风场异常,下沉增温与辐射增温共同推动浙江气温不断升高;全球变暖是极端高温热浪形成的重要气候背景;出梅偏早和影响台风偏少也有潜在贡献。西太副高位置和强度的变化与热带、副热带和中高纬度环流系统密切相关。热带海洋性大陆和南海—中南半岛区域潜热释放增强有利于通过经向环流加强副高;副热带30°N附近的北太平洋对流旺盛、与西太副高之间形成纬向热力梯度,激发出异常纬向垂直环流从而增强副高;中高纬度200 hPa西风急流轴略偏北、极涡明显偏向西半球削弱了中高纬地区对副热带系统的影响,有利于副高的稳定维持。最后提出了未来值得开展的极端高温研究工作。An extensive and persistent extreme heat-wave(HW) occurred over Zhejiang province during July-August,2017.The number of high-temperature days(HD) in most regions exceeded 30 d.Extreme maximum temperature(EMT) of a large proportion of provincial stations was higher than 39℃,and even could reach 40℃ in 39 stations.Average temperature,number of HD,and EMT in many stations broke historical records.The accumulated stational high-temperature days and effective accumulated high temperature were both only next to that of 2003 and 2013.Therefore,the HW in midsummer of 2017 was identified as one of the most serious HW events in Zhejiang provincial meteorological observation when a comprehensive consideration of the performance of both meteorological variables and high-temperature intensity is given.A persistently enhanced and westward-extended western Pacific subtropical High(WPSH) was the direct cause for such extreme HW event.Wide anticyclonic horizontal wind anomaly formed in the region of Southeast China-Northwest Pacific at lower layer of troposphere,and anomalous downward flow and positive radiation worked together to promote the elevation of temperature.In addition,global warming,shorter Meiyu season and less typhoon invasion had potential contributions on temperature rising.The change of intensity and location of WPSH is intimately linked with tropical,subtropical and mid-high latitude circulation systems.In tropics,more supervital convection in Marine Continent and South China Sea-Indo-China Peninsula acted jointly to enhance WPSH through meridional adjustment,while in the subtropical region latent heating was strengthened over North Pacific around 30°N,which built zonal thermal gradient between WPSH and the North Pacific Ocean,and further reinforced WPSH through anomalous zonal-altitudinal circulation.In mid-high latitude,northward-placed westerly jet at 200 hPa and westward-extended polar Vortex were able to damp the impact of mid-high latitude circulation on subtropical areas and favor stable maintenance o

关 键 词：极端高温热浪 高温日数 极端最高气温 高温热浪强度 西太平洋副热带高压 大尺度环流系统相互作用 大气遥相关 

分 类 号：P423.3[天文地球—大气科学及气象学] P434