本文基于拉格朗日观点,利用NCEP/NCAR再分析资料追踪了1979—2012年冬季欧亚大陆的反气旋活动,定义了冬季欧亚大陆反气旋强度指数,并据此分析了近30多年来欧亚大陆反气旋的活动特征及其与中国冬季气温的关系。结果表明,近30多年来冬季欧亚大陆反气旋强度有明显的年际、年代际变化,近10 a来其活动处于较强的位相;反气旋强度指数序列与中国大部分地区的冬季气温存在显著的负相关关系,当冬季欧亚大陆反气旋活动增强(减弱)时,中国大部分地区的冬季气温偏低(高);影响我国气温的反气旋生命期主要为1-3 d;蒙古高原是欧亚大陆反气旋活动的关键区域,每年有超过40%的反气旋经过该区域。这些反气旋多具有较强的移动性,其主要源地为斯堪的纳维亚半岛、地中海—黑海—里海—咸海附近以及中西伯利亚地区。
Over the past 10 years,due to the Arctic Amplification of global warming in the North Pole region,there have been situations of accelerated temperature rise and drastic decrease in sea ice area in the North Pole;nevertheless,the air temperature of continents in the north hemisphere continue to drop.Particularly in recent years,there have been abnormally cold winters in large areas.During the winter season in China,the cold air activity that causes temperature drop,including cold waves that can cause dramatic temperature drops throughout the entire country,often travels southward together with the cold high pressure on the ground.Therefore,winter temperature anomaly in China could be related to the anticyclone activities on the Eurasian continent.In this study,on the basis of Lagrange's theories,the NCEP/NCAR reanalysis data are used to trace anticyclone activities on the Eurasian continent from 1979-2012,and the strength index of the winter anticyclone on the Eurasian continent is defined.Based on this,we then analyze the features of anticyclone on the Eurasian continent for the past 30 years,as well as its relationship to winter temperature in China.The results show the following:1)The index of anticyclone intensity exhibits obvious inter-annual and inter-decades fluctuations in the winter during 1979-2012,and the ACI exhibits a pronounced intensification over the past 10 years.2) The winter temperature anomaly in China is negatively correlated to the strength of anticyclone activities on the Eurasian continent,i.e.when the anticyclone activities are strong,most part of China are colder,and vice visa.The negative anomalies of winter temperature increases in China in the past years were mostly related to the strong phase of anticyclone activities on the Eurasian continent.3) Anticyclones with short lifetime occur most frequently,and have a more apparent impact on the winter temperature in China in larger regions.Anticyclones with long lifetimes occur less frequently,and mainly affect the temperature