Alternation o...0-Year Period_Zhiwei ZHU.pdf

Alternation of the Atmospheric Teleconnections Associated with theNortheast China Spring Rainfall during a Recent 60-Year PeriodZhiwei ZHU*,Rui LU,Shanshan FU,and Hua CHENKey Laboratory of Meteorological Disaster,Ministry of Education(KLME)/Collaborative Innovation Center on Forecastand Evaluation of Meteorological Disasters(CIC-FEMD)/Joint International Research Laboratory of Climate andEnvironment Change(ILCEC),Nanjing University of Information Science and Technology,Nanjing 210044,China(Received 26 January 2022;revised 20 April 2022;accepted 6 May 2022)ABSTRACTNortheast China(NEC)is Chinas national grain production base,and the local precipitation is vital for agricultureduring the springtime.Therefore,understanding the dynamic origins of the NEC spring rainfall(NECSR)variability is ofsocioeconomic importance.This study reveals an interdecadal change in the atmospheric teleconnections associated withthe NECSR during a recent 60-year period(19612020).Before the mid-1980s,NECSR had been related to a Rossby wavetrain that is coupled with extratropical North Atlantic sea surface temperature(SST),whereas,since the mid-1980s,NECSRhas been linked to a quite different Rossby wave train that is coupled with tropical North Atlantic SST.Both Rossby wavetrains could lead to enhanced NECSR through anomalous cyclones over East Asia.The weakening of the westerly jet overNorth America is found to be mainly responsible for the alternation of the atmospheric teleconnections associated withNECSR during two epochs.Key words:Northeast China spring rainfall,Rossby wave train,interdecadal change,westerly jet streamCitation:Zhu,Z.W.,R.Lu,S.S.Fu,and H.Chen,2023:Alternation of the atmospheric teleconnections associated withthe Northeast China spring rainfall during a recent 60-year period.Adv.Atmos.Sci.,40(1),168176,https:/doi.org/10.1007/s00376-022-2024-3.Article Highlights:The linkage between Northeast China spring rainfall and tropical North Atlantic SST is unstable.The unstable relationship is caused by the alternation of the associated stationary equivalent barotropic Rossby wavetrains.The alternation of the barotropic Rossby wave trains is induced by the weakening of the westerly jet stream over NorthAmerica.1.IntroductionNortheast China(NEC)is one of Chinas key nationalgrain production bases,and the local precipitation has alarge impact on the grain yield.Therefore,understandingthe physical mechanism and improving the seasonal predic-tion of the precipitation variability over NEC are of great eco-nomic significance.Previous studies have documented the significant interan-nual and interdecadal variability of precipitation over NEC.The interannual variability of precipitation over NEC isrelated to the regional circulation systems such as the cold ver-tex over Northeast Asia,East Asian monsoon(Shen et al.,2011),and anomalous anticyclone over Japan(Han et al.,2018a),which are remotely driven by the sea surface tempera-ture(SST)variability over the Pacific,Atlantic(Zhang andSun,2020),and Indian Oceans(Gao et al.,2014;Zhao et al.,2022).Han et al.(2018b)found that the North Atlantic tri-polar SST anomaly (SSTA)could trigger a stationaryRossby wave propagating eastward from the North Atlanticto Northeast Asia,which would modulate the Okhotsk highand East Asian trough and influence NEC precipitation.They also found that SST warming in the tropical IndianOcean could stimulate the Eurasian wave pattern via induc-tion of upper-level convergence over northern Europe,influ-encing NEC precipitation.The long-term variability of SST over the Pacific,Atlantic,and Indian Oceans contributes to the interdecadal*Corresponding author:Zhiwei ZHUEmail:ADVANCES IN ATMOSPHERIC SCIENCES,VOL.40,JANUARY 2023,168176 Notes&Letters Institute of Atmospheric Physics/Chinese Academy of Sciences,and Science Press and Springer-Verlag GmbH Germany,part of Springer Nature 2023variability of NEC precipitation(Wang and He,2013;Zhouet al.,2021).NEC precipitation in early summer has had astrong relationship with the SSTA over the tropical IndianOcean since the late 1980s(Han et al.,2018a).NEC precipita-tion in winter was closely associated with the SSTA overthe Atlantic Ocean before 1990,whereas,it has been relatedto the SSTA over the Indian Ocean since 1990(Han et al.,2018b).The SST warming over the tropical North Atlanticcould induce an equivalent barotropic cyclonic anomalyover Northeast Asia,leading to a wetter NEC after 2000(Hu et al.,2021),whereas,the SST warming over the tropicalIndian Ocean could affect NEC precipitation by exciting azonal wave train pattern over the midlatitude Eurasian Conti-nent and by inducing local meridional cells over the westernPacific/East Asia sector(Zhang and Sun,2018).In addition,the transition of the Pacific decadal oscillation(PDO)froma negative to positive phase led to more NEC rainfall inApril through inducing anomalous southerly flow over theEast Asian coast(Chen et al.,2020).Furthermore,both theregime shift of the zonal dis