| 两类ENSO对中国北方冬季平均气温和极端低温的不同影响 |
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| 引用本文： | 汪子琪,张文君,耿新.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,2017,75(4):564-580. |
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| 作者姓名： | 汪子琪 张文君 耿新 |
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| 作者单位： | 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, 南京, 210044 |
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| 基金项目： | 全球变化与海气相互作用专项（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。 |
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| 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度地区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事件海温分布的差异，这种影响具有明显的非线性特征。在两类厄尔尼诺和东部型拉尼娜事件冬季，北大西洋涛动均呈现负位相，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。中部型厄尔尼诺和东部型拉尼娜事件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；东部型厄尔尼诺事件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；而中部型拉尼娜事件冬季虽伴随北大西洋涛动正位相，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。数值试验再现了北大西洋涛动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，两类厄尔尼诺事件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；而两类拉尼娜事件对极端低温的影响较弱。
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| 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 |
| 收稿时间： | 2016/9/26 0:00:00 |
| 修稿时间： | 2017/3/27 0:00:00 |
Different influences of two types of ENSO on winter temperature and cold extremes in northern China |
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| WANG Ziqi,ZHANG Wenjun and GENG Xin.Different influences of two types of ENSO on winter temperature and cold extremes in northern China[J].Acta Meteorologica Sinica,2017,75(4):564-580. |
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| Authors: | WANG Ziqi ZHANG Wenjun and GENG Xin |
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| Institution: | Key Laboratory of Meteorological Disaster of Ministry of Education, Joint International Research Laboratory of Climate and Environment Change, Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science and Technology, Nanjing 210044, China |
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| Abstract: | The responses of surface air temperature (SAT) in northern China to the eastern Pacific (EP) and central Pacific (CP) ENSO events during boreal winter are analyzed using reanalysis and observational data as well as specific atmospheric general circulation model (AGCM) experiments. Possible influences of ENSO events on regional cold extremes are also discussed. The North Atlantic Oscillation (NAO) is identified to be a bridge connecting ENSO signal and northern Eurasian temperature anomalies. Results show that ENSO influences northern China winter surface air temperature mainly through modulating the atmospheric circulation over the North Atlantic region, and thus changing the zonal temperature advection over northern Eurasia and the intensity of Siberian High. Moreover, the ENSO effects display prominent nonlinear characteristics due to different distributions of the tropical Pacific sea surface temperature (SST) anomalies during the two types of ENSO events. Corresponding to the two types of El Niño and EP La Niña winters, negative NAO-like atmospheric anomalies are evident over the North Atlantic region, which tend to inhibit the transport of warm and moist air from the Atlantic Ocean to Eurasian continent and thus favor a colder than normal winter in northern China. In particular, significant negative temperature anomalies during CP El Niño and EP La Niña winters are located in northeast China and the Ordos Loop and its vicinity area, respectively. The significant cold signal is confined in the north of Heilongjiang Province and the Greater Khingan Range during EP La Nia winters. In contrast, a positive NAO-like atmospheric anomaly pattern occurs over the North Atlantic region during the CP La Niña winter, but its positive anomaly center shifts westward. As a result, significant temperature anomalies are mainly confined in Europe and few significant signals can be observed in northern China. These observed results can be realistically reproduced by AGCM experiments. In addition, daily temperature in northeastern China tends to be colder than normal during EP El Niño and CP El Niño winters,indicating more frequent cold extremes. However, the linkage between La Niña events and cold extremes seems to be negligible. |
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| Keywords: | Eastern Pacific ENSO Central Pacific ENSO Winter mean air temperature Cold extremes Northern China |
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