气候变暖前后我国西北区域冬季极端低温事件的关键影响因子  

Key Influencing Factors of Winter Extreme Cold Events in Northwest Chinabefore and after Global Warming

作　　者：邵伟玲 陈颖 田书婷 刘精 刘艳 林文实[1] SHAO Weiling;CHEN Ying;TIAN Shuting;LIU Jing;LIU Yan;LIN Wenshi(Sun Yat-sen University,School of Atmospheric Sciences,Guangzhou 510275,China;Xinjiang Uygur Autonomous Region Climate Center,Urumqi 830002,China)

机构地区：[1]中山大学大气科学学院,广东广州510275 [2]新疆维吾尔自治区气候中心,新疆乌鲁木齐830002

出　　处：《沙漠与绿洲气象》2024年第6期64-71,共8页Desert and Oasis Meteorology

基　　金：新疆气象局引导性项目YD2022007。

摘　　要：利用中国地面气象站基本气象要素日值数据集(V3.0)、美国NCEP/NCAR再分析数据和中国国家气候中心环流指数资料,通过百分位法定义西北区域极端低温事件,分析其时空分布特征及关键影响因子。结果表明:西北区域极端低温事件呈显著减少趋势,在1985年发生突变;1961—1985年,极端低温事件日数与500 hPa位势高度场显著相关区位于泰米尔半岛以南、黑海上空和中国上空,极端低温事件日数与海平面气压显著相关区位于西伯利亚和青藏高原;1986—2016年,极端低温事件日数与500 hPa位势高度场显著相关区位于黑海至中国上空和大西洋上,极端低温事件日数与海平面气压显著相关区位于中亚至西伯利亚和大西洋上;北极涛动负位相时,极涡偏强,乌拉尔山易建立长波脊,利于极地冷空气南下,导致西北区域冬季极端低温日数异常偏多。45°N以北的纬向风风速也是影响极端低温日数的关键因子之一,风速强时,高纬度的冷空气不易南下影响西北区域,冬季极端低温事件日数偏少;反之偏多。Based on the daily dataset of basic meteorological variablesof China National Surface Weather Station(V3.0),NCEP/NCAR reanalysis data and NCC circulation index data,the extreme cold events(ECE)in northwest China were defined by percentile method.Thespatiotemporal distribution characteristics and key influencing factors were analyzed.The results revealed a significant decreasing trend in extreme cold events,with a noticeable shift occurring in 1985.From 1961 to 1985,the number of ECE days and 500hPa geopotential height field were significantly correlated overthe south of the Taymyr Peninsula,the Black Sea,and China.Additionally,sea-level pressure exhibited a strong correlation over Siberia and the Tibetan Plateau.From 1986 to 2016,the number of ECE days and 500hPa geopotential height field were significantly correlated over the region extending from the Black Sea to China,as well as over the Atlantic Ocean,and ECE days and sea level pressure were significantly correlated over the Central Asia to Siberia and acrossthe Atlantic Ocean.When the Arctic oscillation was in negative phase,the polar vortexintensified,and itwas easy to establish long wave ridges over the Ural Mountains,which is conducive to the southward movement of polar cold air,resulting in an abnormal increase of the number of ECE days in winter in the northwest region.The speed of the zonal wind in the north of 45°Nwasalso one of the key factors affecting the number of ECE days.When the wind speed is strong,the cold air at high latitude wasnot easy to move southward to affect the northwest region,and the number of ECE days was less in winter;conversely,weaker wind speeds allowed more frequent occurrences.

关 键 词：西北区域 极端低温事件 关键影响因子 

分 类 号：P461[天文地球—大气科学及气象学]