摘要
伴随全球变暖和有卫星观测记录以来北极秋季海冰密集度的下降,近几年,东亚地区极端降温事件频繁发生。基于北极涛动指数、北极海冰密集度及温度、位势高度和风场等大气环流数据,研究2021年1月和2024年1月我国极端寒潮的时空变化特征及其原因机制。2021年1月1日至9日,2024年1月17日至24日,我国东部地区(115°00′~120°00′E,20°00′~37°30′N)均出现极端寒潮,最低温异常分别达到-9.028℃和-7.574℃,降温中心分别集中在蒙古高原南部和秦岭北部。2021年1月我国东部地区平均气温降至-3.8℃,达到21世纪以来的次低温纪录。本文基于美国国家环境预报中心(National Centers for Environmental Prediction,NCEP)的再分析资料,得出西风带的异常减弱致使西风带对高纬度冷空气的阻拦作用减弱。2021年、2024年寒潮爆发时位于西伯利亚、太平洋西北部的高压中心和华北地区低压中心均出现显著增强,导致位于西伯利亚的冷空气的南移,致使我国东部地区出现寒潮现象。2024年1月极端寒潮现象显示于气温经验正交分解(Empirical Orthogonal Function,EOF)的第一模态(29.33%),而EOF分解的第二模态(14.92%)显示2021年出现降温现象。回归分析表明北极涛动指数和北极海冰的下降与1月我国东部地区气温之间存在较强的关系,北极涛动负相位及北极海冰的减少也是促使北极冷空气南下的重要因素。异常强劲的北风、减弱的西风急流及对应高压中心的移动共同作用导致了极地寒流入侵我国大陆地区,是造成2021年1月和2024年1月我国大陆地区极端天气事件的主要原因之一。
With the global warming and the decreasing of Arctic autumn sea ice density since the onset of satellite observations,extreme cooling events in East Asia become more frequent in recent years.Based on the atmospheric circulation data such as the Arctic Oscillation Index,Arctic sea ice density and temperature,geopotential height and wind field,the causes and the spatiotemporal variations of the extreme cold waves occurred in China in January 2021 and 2024 are studied.The extreme cold waves occurred in the eastern part of China(115°00'-120°00'E,20°00'-37°30'N) from January 1 to 9 in 2021 and from January 17 to 24 in2024,with the lowest temperature anomalies being-9.028 °C and-7.574 °C respectively and the cooling centers being concentrated in the southern Mongolian Plateau and the northern Qinling Mountains respectively.In January 2021,the average temperature in the eastern part of China dropped to-3.8 °C,being the secondary lowest temperature record since the 21st century.According to the reanalysis data from the National Centers for Environmental Prediction(NCEP),USA,the abnormal weakening of the westerlies has made the obstruction effect of the westerlies on the cold air at high latitude weakened.When the cold waves broke out in 2021 and2024,the cold waves located both in the high-pressure centers in Siberia and the northwest Pacific Ocean and in the low-pressure center in North China exhibited significant enhancement,which led to the cold air moving southward from Siberia,resulting in the cold wave phenomenon in the eastern part of China.The extreme cold wave in January 2024 was manifested in the first mode of the Empirical Orthogonal Function(EOF)(29.33%),while the second mode of the EOF decomposition(14.92%) indicated a cooling trend in 2021.Regression analysis demonstrates a strong correlation among the Arctic Oscillation Index,the decline in Arctic sea ice and the air temperature in the eastern part of China in January.The negative phase of the Arctic Oscillation and the decrease of the Arctic sea ice
作者
李欣轩
崔红艳
陈宝旭
张子群
李品
LI Xinxuan;CUI Hongyan;CHEN Baoxu;ZHANG Ziqun;LI Pin(College of Mathematics and Physics,Qingdao University of Science and Technology,Qingdao 266061,China;Institute of Mathematics and Interdisciplinary Sciences,Qingdao University of Science and Technology,Qingdao 266061,China;Qingdao Innovation Center of Artificial Intelligence Ocean Technology,Qingdao 266061,China;First Institute of Oceanography,MNR,Qingdao 266061,China)
出处
《海岸工程》
2024年第2期116-128,共13页
Coastal Engineering
基金
国家重点研发计划政府间国际科技创新合作重点专项项目(2022YFE0140500)
国家重点研发计划课题(2022YFA1004403)
大学生创新创业训练计划项目(X202310426198)
国家自然科学基金项目(42130406)。
关键词
极端寒潮
西风急流减弱
EOF
回归分析
extreme cold events
weakening of westerly jet stream
EOF
regression analysis
