宁夏冬季极端低温事件特征及其与秋季北极海冰异常的联系  

Characteristics of the Winter Extreme Low Temperature Events in Ningxia and their Relationship with the Arctic Sea Ice Coverage Anomalies in Autumn

作　　者：王璠 李清泉[2,3] 孙银川[1] 王岱 郑广芬[1] 朱晓炜[1] WANG Fan;LI Qingquan;SUN Yinchuan;WANG Dai;ZHENG Guangfen;ZHU Xiaowei(Ningxia Hui Autonomous Region Climate Center,Yinchuan 750002,Ningxia,China;Laboratory for Climate Studies,National Climate Center,China Meteorological Administration,Beijing 100081,China;Key Laboratory of Meteorological Disaster,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&Technology(NUIST),Nanjing 210044,Jiangsu,China)

机构地区：[1]宁夏回族自治区气候中心,宁夏银川750002 [2]国家气候中心中国气象局气候研究开放实验室,北京100081 [3]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,江苏南京210044

出　　处：《高原气象》2021年第4期887-897,共11页Plateau Meteorology

基　　金：国家自然科学基金项目(41790471);第二次青藏高原综合科学考察研究项目(2019QZKK0208);中国科学院战略性先导科技专项(XDA20100304);国家重点基础研究发展计划项目(2016YFA0602200);中国气象局旱区特色农业气象灾害监测预警与风险管理重点实验室指令性项目(CAMP-201905)。

摘　　要：利用1961-2018年我国宁夏全区平均逐日观测最高和最低气温数据,英国哈德莱(Hadley)中心的逐月海冰密集度资料,美国国家环境预报中心/国家大气研究中心(NCEP/NCAR)的逐月大气再分析资料以及中国气象局国家气候中心的逐月东亚冬季风指数和西伯利亚高压指数系统地研究了宁夏冬季极端低温事件的特征及其与北极关键影响区域海冰异常的联系。结果表明:20世纪60年代以来,宁夏冬季冷日与冷夜频次呈现明显的减少趋势,极端低温事件强度总体趋于减弱,日极端低温升高趋势较为明显。秋季北极海冰异常与之后冬季海冰异常显著相关,前秋海冰异常通过季节持续性实现对后期冬季大气环流的影响,进而影响冬季气温。前期秋季拉普捷夫海-东西伯利亚海海冰密集度偏小、格陵兰海海冰密度偏大时,冬季西伯利亚高压指数和冬季风指数偏强,有利于宁夏日极端低温事件频次偏多;500 hPa高度场上,极地-欧亚大陆-阿留申地区有一个显著的“L”型的位相波列形态,使得北极与欧亚大陆中高纬地区的位势高度差减弱,中高纬地区西风气流偏弱,减弱的西风使得经向活动加强,利于北极的冷空气向低纬地区侵袭;在海平面气压场上,西伯利亚地区气压偏高,冷空气由极地挤压至中高纬度地区,造成冷空气南下,有利于宁夏冬季发生极端低温事件。Based on daily maximum and minimum temperature in Ningxia of China,monthly sea ice concentration from the Hadley Centre of UK,monthly atmospheric reanalysis data from the National Centers for Environmental Prediction/National Center for Atmospheric Research of US,and the East Asian Winter Monsoon Index and Siberia High Index from National Climate Center of China Meteorological Administration,the characteristics of extreme winter low temperature events in Ningxia and their relationship with autumn sea ice concentration in the key region of the Arctic from 1961 to 2018 were systematically studied.The results show that the frequency of cold day and cold night in winter in Ningxia has decreased significantly since 1960s.The intensity of extreme low temperature events generally tends to weaken,and the daily extreme low temperature increases obviously.The Arctic sea ice anomaly in autumn is significantly related to the sea ice anomaly in the following winter.The sea ice anomaly in autumn influences the atmospheric circulation in the following winter through the seasonal sustainability,and then affects the winter temperature.When the sea ice concentration is low in the Lapjev-East Siberian Sea and high in Greenland Sea in the previous autumn,the Siberian High Index and the East Asian Winter Monsoon Index become stronger,which is benefit to more extreme temperature events occurring in Ningxia in winter.The 500 hPa geopotential height Arctic-Eurasia-Aleutian region's"L"like phase wave pattern decreased the height difference between the Arctic and Eurasia in the mid-high latitudes,the mid-high latitude westerly airflow is weakened,and the zonal activity is weakened,that’s conducive to the cold air of the Arctic to the low latitudes.Correspondingly,the sea level pressure is high in Siberia and cold air is squeezed from the polar region to the middle and high latitudes in the Northern Hemisphere,which makes the cold air easy to reach in Ningxia and results in more extreme cold weather days there.

关 键 词：极端低温事件 北极海冰 冬季风 西伯利亚高压 

分 类 号：P423.36[天文地球—大气科学及气象学]