Linkage of the Decadal Variability of Extreme Summer Heat in North China with the IPOD since 1981  

作　　者：Tiejun XIE Ji WANG Taichen FENG Ting DING Liang ZHAO 

机构地区：[1]Beijing Municipal Climate Center,Beijing Meteorological Bureau,Beijing 100089,China [2]School of Atmospheric Sciences,Sun Yat-sen University,Zhuhai 528478,China [3]National Climate Center,China Meteorological Administration,Beijing 100081,China [4]State Key Laboratory of Numerical Modeling for Atmosphere Sciences and Geophysical Fluid Dynamics(LASG),Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China

出　　处：《Advances in Atmospheric Sciences》2023年第9期1617-1631,共15页大气科学进展（英文版）

基　　金：This work was jointly supported by the National Natural Science Foundation of China(Grant Nos.42130610,42075040,and 42175078);the Joint Research Project for Meteorological Capacity Improvement(Grant No.22NLTSQ002);Guangdong Major Project of Basic and Applied Basic Research(2020B0301030004);the Innovation and development project of China Meteorological Administration(Grant No.CXFZ2022J030).

摘　　要：Extreme summer heat can have serious socioeconomic impacts in North China.Here,we explore the decadal variability of the number of extreme heat days in early-to-mid summer(June and July)and a related potential mechanism consistent with the major seasonal occurrence period of extreme heat events in North China(NCSH).Observational analyses show significant decadal variability in NCSH for 1981–2021,potentially linked to the Indo-Pacific warm pool and Northwest Pacific Ocean dipole(IPOD)in early-to-mid summer.Dynamic diagnostic analysis and the linear baroclinic model(LBM)show that the positive IPOD in early-to-mid summer can excite upward vertical wind anomalies in the South China-East China Sea region,shifting the position of the western Pacific subtropical high(WPSH)to the east or weakening the degree of its control of the South China-East China Sea region,thus generating a positive geopotential height quadrupole(EAWPQ)pattern in the East Asia-Northwest Pacific region.Subsequently,the EAWPQ can cause air compression(expansion)over North China by regulating the tropospheric thickness anomalies in North China,thus increasing(decreasing)NCSH.Finally,an empirical model that incorporates the linear trend can better simulate the decadal NCSH compared to an empirical model based solely on the IPOD index,suggesting that the decadal variability of NCSH may be a combined contribution of the decadal IPOD and external linear forcing.

关 键 词：extreme heat early-mid summer North China Indo-Pacific warm pool and Northwest Pacific Ocean dipole(IPOD) decadal variability 

分 类 号：P423[天文地球—大气科学及气象学]