安徽春季连阴雨与不同类型厄尔尼诺/拉尼娜衰减年的关系  

Relationship between spring continuous rain over the Anhui province and different types of El Niño/La Niña decaying years

作　　者：罗连升[1] 吴蓉[1] 邓汗青[1] 何冬燕[1] LUO Liansheng;WU Rong;DENG Hanqing;HE Dongyan(Anhui Climate Center,Hefei 230031)

机构地区：[1]安徽省气候中心,合肥230031

出　　处：《暴雨灾害》2023年第2期170-178,共9页Torrential Rain and Disasters

基　　金：安徽省自然科学基金江淮气象联合基金项目(2208085UQ10);中国气象局创新发展专项(CXFZ2022J067);安徽省气象局预报员专项(KY202212)。

摘　　要：研究安徽省最近几十年春季连阴雨变化规律及其与厄尔尼诺/拉尼娜事件的关系,对提高春季连阴雨认识和防灾减灾具有重要意义。基于1961—2018年安徽省77站逐日降水量和日照时数、美国国家环境预报中心/美国国家大气研究中心(NCEP/NCAR)再分析资料,采用EOF、合成等方法分析了安徽省春季连阴雨的变化特征,并探讨不同类型厄尔尼诺/拉尼娜衰减年对春季连阴雨的可能影响。结果表明:近58 a安徽春季连阴雨日数、频次和最长连阴雨过程天数均呈北少南多的分布特征,其中江南南部是大值中心。连阴雨日数具有明显的减少趋势,平均每10 a减少1.0 d。连阴雨日数变化主要为全省一致型和南北反向型。东部型厄尔尼诺(拉尼娜)衰减年对应安徽春季连阴雨日数偏多(少),中部型厄尔尼诺/拉尼娜衰减年均有利于连阴雨日数偏少。东部型厄尔尼诺(拉尼娜)衰减年对应春季西太平洋副热带高压明显偏强(弱)偏北(南),厄尔尼诺衰减年日本海高压偏强,欧亚中高纬500 hPa高度场为两脊一槽(一槽一脊)形势,乌拉尔山高压脊(低压槽)明显,贝加尔湖为宽广低槽(高压脊),槽底部(脊前)冷空气持续南下,与西北太平洋异常反气旋(气旋)西侧的西南暖湿(东北)气流在江淮上空不断汇合,有利于安徽春季连阴雨日数偏多(少)。中部型厄尔尼诺衰减年西太平洋副热带高压偏强偏西偏南、外兴安岭为低压槽,中部型拉尼娜衰减年贝加尔湖和西太平洋均为异常气旋性环流,江淮地区均受偏北风控制,对应春季连阴雨日数偏少。It is a great significance to improve the understanding of spring continuous rain and to prevent and reduce disasters by studying the change rule of spring continuous rain over the Anhui province in recent decades and its relationship with El Niño/La Niña events.Based on the daily rainfall and sunshine hours at 77 stations in the Anhui province and the NCEP/NCAR reanalysis dataset,the variation characteristics of spring continuous rain over the Anhui province is studied and the possible impacts from different types of El Niño/La Niña decaying different years is discussed with the methods of EOF,composition analysis,and etc.The days,the frequency,and the longest days of spring continuous rain over the Anhui province during the past 58 years show similar distribution characteristics with less in the north,more in the south,and maximum in the south of Jiangnan.The number of spring continuous rainy days has an obvious decreasing trend and decreases by 1.0 day for every 10 years on average.The spatial distribution of continuous rain days includes two patterns:consistency in all areas and contrary in the north and south.The number of spring continuous rainy days over the Anhui province is more(less)during the years with eastern pattern El Niño(La Niña)decaying,and is less during the years with central pattern El Niño/La Niña decaying.During the years with eastern pattern El Niño(La Niña)decaying,the West Pacific subtropical high(WPSH)is obviously stronger(weaker)and abnormally northward(southward),and the high pressure in the Sea of Japan is obviously stronger.In addition,there is a pattern of two ridges-one trough(one trough-one ridge)for 500 hPa geopotential height at the mid-high latitudes of Eurasia.The high ridge(low trough)over the Ural mountains and the low trough over the Lake Baykal are evident.In the meantime,the cold air from the bottom(front)of the trough(ridge)continues flow ing southward,converging continuously with the southwest warm(northeast cold)air low from the Western North Pacific anomalo

关 键 词：春季连阴雨 厄尔尼诺 拉尼娜 衰减年 

分 类 号：P466[天文地球—大气科学及气象学]