汪子琪,张文君,耿新. 2017. 两类ENSO对中国北方冬季平均气温和极端低温的不同影响[J]. 气象学报, ():-, doi:10.11676/qxxb2017.038
两类ENSO对中国北方冬季平均气温和极端低温的不同影响
Different influences for the two types of ENSO on average temperature and cold extremes in winter over Northern China
投稿时间:2016-09-23  最后修改时间:2017-01-21
DOI:10.11676/qxxb2017.038
中文关键词:  东部型ENSO,中部型ENSO,冬季平均气温,极端低温,中国北方
英文关键词:Eastern Pacific ENSO,Central Pacific ENSO,Winter mean air temperature,Cold extremes,Northern China
基金项目:全球变化与海气相互作用专项资助(GASI-IPOVAI-03);国家自然科学基金项目(41475086、41675073); 江苏省六大人才高峰、333高层次人才工程和优势学科建设工程(PAPD)项目
作者单位E-mail
汪子琪 南京信息工程大学气象灾害教育部重点实验室/气候与环境变化国际合作联合实验室/气象灾害预报预警与评估协同创新中心 momingziqi@126.com 
张文君 南京信息工程大学气象灾害教育部重点实验室/气候与环境变化国际合作联合实验室/气象灾害预报预警与评估协同创新中心 zhangwj@nuist.edu.cn 
耿新 南京信息工程大学气象灾害教育部重点实验室/气候与环境变化国际合作联合实验室/气象灾害预报预警与评估协同创新中心 1036677086@qq.com 
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中文摘要:
      利用1961-2012年观测、再分析资料以及全球大气环流模式数值试验,探讨了中国北方冬季平均气温对于不同类型(即东部型和中部型)ENSO事件的气候响应,并分析了不同类型ENSO对极端低温事件的可能影响,重点关注了北大西洋涛动(NAO)在其中的桥梁作用。结果表明,ENSO信号能通过调制北大西洋地区的大气环流改变欧亚中高纬的纬向温度平流输送和西伯利亚高压的强度,进而影响中国北方冬季气温,由于不同类型ENSO海温分布的差异,这种影响具有明显的非线性特征。在两类El Ni?o和东部型La Ni?a冬季,NAO都呈现负位相,不利于北大西洋的暖湿空气向欧亚大陆输送,西伯利亚高压偏强,因而中国北方地区较气候态偏冷,具体地,中部型El Ni?o和东部型La Ni?a冬季气温负异常的显著区域分别位于东北大范围地区、内蒙古河套附近;东部型El Ni?o冬季显著的冷异常信号仅局限于黑龙江北部与大兴安岭地区;而中部型La Ni?a冬季虽伴随NAO正位相,但其空间结构向西偏移,对下游中国北方地区气温的直接影响并不显著,可能受局地信号干扰较大。数值试验再现了NAO以及中国北方冬季气温对不同类型ENSO的响应,进一步佐证了上述结论。此外,两类El Ni?o冬季中国东北地区日平均气温容易偏低,极端低温事件的发生频次增多;而两类La Ni?a事件对极端低温的影响较弱。
英文摘要:
      The responses of surface air temperatures (SAT) over northern China to eastern Pacific (EP) and central Pacific (CP) ENSO events during boreal winter season are analyzed by using reanalysis and observational data as well as specific atmospheric general circulation model (AGCM) experiments.Possible influences of ENSO events on the regional cold extremes are also discussed.The North Atlantic Oscillation (NAO) is identified as a bridge connecting ENSO signal and northern Eurasian temperature anomalies.Results show that ENSO influences the northern China winter SAT mainly through modulating the atmospheric circulations over the North Atlantic region and thus changing the zonal temperature advection over northern Eurasia as well as the intensity of Siberian High.Moreover, the effect display prominent nonlinear characteristics due to the different distributions of the tropical Pacific sea surface temperature (SST) anomalies during the two types of ENSO events.During the two types of El Ni?o and EP La Ni?a winters,negative NAO-like atmospheric anomalies are evident over the North Atlantic region,which tend to inhibit the warm and moist air transporting from Atlantic Ocean towards Eurasian continent and thus favor a colder than normal winter in Northern China.In particular,the significant negative temperature anomalies during CP El Ni?o and EP La Ni?a winter are located over Northeast China,and Hetao and its vicinity area,respectively.The significant cold signal are confined in the north of Heilongjiang Province and Greater Khingan Range during EP La Ni?a winter.In comparison,a positive NAO-like atmospheric anomaly pattern occurs over the North Atlantic region during the CP La Ni?a winter,but its positive anomaly center shifts to the westward,as a result,the significant temperature anomalies are mainly confined in Europe and little significant signal can be observed over downstream northern China.These observed results can be realistically reproduced by AGCM experiments.In addition,the daily temperature over northeastern China tends to be colder than normal during EP El Ni?o and CP El Ni?o winters,which suggests that the more frequent cold extremes are favored.However,the linkage between La Ni?a events and cold extremes seems to be negligible.
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