冬季东亚副热带急流和温带急流协同变化与我国冷空气活动的关系  

Association of Concurrent Variation between the East Asian Polar Front and Subtropical Jets with Winter Cold Air Activity in China

作　　者：叶丹[1] 张耀存[1] 

机构地区：[1]南京大学大气科学学院,南京210093

出　　处：《大气科学》2014年第1期146-158,共13页Chinese Journal of Atmospheric Sciences

基　　金：国家自然科学基金重点项目41130963;公益性行业(气象)科研专项GYHY201006019;高等学校博士学科点专项科研基金20100091110003

摘　　要：利用NCEP/NCAR再分析资料和地面台站气温观测资料,分析了冬季东亚副热带急流(EASJ)和东亚温带急流(EAPJ)强度变化特征及其与我国境内冷空气活动的关系。以(45°N^60°N,70°E^110°E)和(27.5°N^37.5°N,130°E^160°E)区域平均的300 hPa全风速分别表征冬季EAPJ和EASJ的强度,将两支急流的强度变化分为四种情况:EAPJ和EASJ同强(SS)、同弱(WW)、以及强弱(SW)、弱强(WS)。分析四种急流强度变化情形下中国境内冷空气活动强度、路径、持续时间以及源地的不同特征,发现当EAPJ和EASJ均强时,冷空气从内蒙古中东部入侵,主要影响华北、东北和东部沿海地区,强度较弱,持续时间短,冷空气源地位于新地岛以东的洋面及陆地上;当EAPJ和EASJ均弱时,冷空气从新疆北部入侵,影响我国大部分地区,强度强,持续时间长,冷空气源地位于巴尔喀什湖西部;当EAPJ强,EASJ弱时,冷空气从我国东北入侵,主要影响我国东北部,中国南部降温不明显,冷空气强度较强,持续时间短,冷空气源地位于中、西西伯利亚地带;当EAPJ弱,EASJ强时,冷空气从内蒙古中部入侵,进而影响华北和我国东部地区,但冷空气强度较弱,冷空气源地位于贝加尔湖的西侧。进一步分析急流强度四种变化情形下的环流特征发现,EAPJ、EASJ均弱时,西伯利亚高压偏强,阿留申低压偏弱,东亚大槽偏深,中国东部的偏北风强,而EAPJ弱、EASJ强时,尽管西伯利亚高压和阿留申低压偏强,东亚大槽偏深,但中国东部的偏北风并不是很强,而另两种情况时,西伯利亚高压较弱,东亚大槽也较弱,中国东部的偏北风偏弱。Winter cold air activity was examined in terms of the concurrent intensity variation between the East Asian polar front jet （EAPJ） and subtropical jet （EASJ） using NCEP/NCAR reanalysis dataset and observed daily temperature datasets from stations in China. The regional averages of 300-hPa wind over two domains （45°-60°N, 70°-110°E; 27.5°-37.5°N, 130°-160°E） were used to measure the strength of the East Asian polar front and subtropical jets. The results were classified into four situations based on jet intensity changes： strong EAPJ corresponding to strong EASJ（SS）; weak EAPJ corresponding to weak EASJ （WW）; strong EAPJ corresponding to weak EASJ（SW）; and weak EAPJcorresponding to strong EASJ （WS）. Then, the features of the winter cold air activity were analyzed with respect to cold air intensity, route, duration, and origin, taking the jet intensity changes into account. During the SS situation, it was found that relatively weak cold air activity with short duration intrudes into the inland and coastal regions of northeastern China from Inner Mongolia. The genesis of the cold air can be traced back to the region to the east of Novaya Zemlya. During the WW situation, strong cold air activity with long duration intrudes into most parts of China from northern Xinjiang. The genesis of this cold air can be traced back to the west of Lake Balkhash. During the SW situation, relatively strong cold air activity with short duration intrudes into North China from the northeast, with no obvious temperature drop . The genesis of the cold air in this situation can be traced back to western Siberia. During the WS situation, relatively weak cold air activity intrudes from Inner Mongolia, affecting almost all of eastern China. The genesis of this cold air can be traced back to the west of Lake Baikal. Circulation features corresponding to the different jet intensity changes were also analyzed. During the WW situation, the Siberian high and Aleutian low are relatively strong and weak, respect

关 键 词：温带急流 副热带急流 两支急流协同变化 冷空气活动 

分 类 号：P466[天文地球—大气科学及气象学]