大气科学学报2023，Vol.46Issue(6)：837-847,11.DOI:10.13878/j.cnki.dqkxxb.20230519001
1月北大西洋东部-乌拉尔山阻塞高压频次年际尺度偶极子模态特征
Dipole pattern characteristics of the blocking high frequency over eastern North Atlantic-Ural in January on an interannual scale
摘要
Abstract
Based on observational and reanalysis data,this study investigated the dominant mode characteristics of interannual variation in the January blocking high frequency over the eastern North Atlantic-Ural region in re-cent decades,along with their associated key atmospheric background fields.The results show that there are signif-icant inter-monthly differences in the dominant modes of the interannual variation of blocking high frequency in this region during the winter months(December to February)between 1980 and 2019.In December,the dominant mode is manifested as significant in-phase variation of blocking high frequency in the eastern North Atlantic-west-ern Europe region.In January,it shows significant out-of-phase variation of the blocking high frequency between the eastern North Atlantic-western Europe and the Ural region.The dominant mode in February exhibits significant in-phase variation of the blocking high frequency in the eastern North Atlantic-Ural region.Further studies show that the dipole pattern of the blocking high frequency in the eastern North Atlantic-Ural region in January is asso-ciated with the dipole variation of the simultaneous atmospheric background field,such as zonal wind,vertical shear of zonal wind,and meridional gradient of potential vorticity.When anomalies of the key atmospheric back-ground fields are negative in the Ural region and positive in the eastern North Atlantic-western Europe region,the blocking high frequency of the two regions respectively increases and decreases,showing a dipole pattern,and vice versa.The dipole pattern of the blocking high frequency and associated background atmospheric circulation a-nomalies can affect temperature and precipitation in northern Eurasia in January,and can also affect their frequen-cy of their extreme events by modulating horizontal temperature advection,vertical motion and water vapor trans-port.When the dipole pattern of the blocking high frequency is in the positive phase,the north(south)and south of the Ural region warms(cools),and the frequency of extreme warm and cold events increases(decreases)and decreases(increases),respectively.In northern Scandinavia,which cools,the frequency of extreme warm events decreases.Moreover,the frequency of precipitation and extreme precipitation decreases in the Ural region and northeastern Asia,but increases in parts of continental Europe,and vice versa.In addition,this paper discusses why,among the winter months,the dominant mode of interannual variation of the blocking high frequency exhibits a dipole pattern only in January.This may in part be caused by the inter-monthly differences in the key at-mospheric background fields'climatology and variations.关键词
1月阻塞高压频次/偶极子模态/北大西洋东部-乌拉尔山地区/大气环流/极端气候事件Key words
blocking high frequency in January/dipole pattern/eastern North Atlantic-Ural region/atmospheric circulation/extreme climate event引用本文复制引用
徐依梵,范可,徐志清..1月北大西洋东部-乌拉尔山阻塞高压频次年际尺度偶极子模态特征[J].大气科学学报,2023,46(6):837-847,11.基金项目
国家重点研发"政府间国际科技创新合作"项目(2022YFE0106800) （2022YFE0106800）
国家自然科学基金资助项目(42230603) （42230603）
南方海洋科学与工程广东省实验室(珠海)创新团队建设项目(311020001) （珠海）
