北半球冬季110°—120°E垂直经向环流的年际变化及其与中国东部同期降水的关系  

INTERANNUAL VARIATION OF NORTHERN HEMISPHERE MERIDIONAL CIRCULATION BETWEEN 110-120°E IN WINTER AND ITS INFLUENCE ON PRECIPITATION IN EASTERN CHINA

作　　者：王玉 庄亮 黄丽芬[2] 朱会芸 

机构地区：[1]永安市气象局,福建永安366000 [2]福建省气象台,福建福州350001

出　　处：《气象与减灾研究》2013年第2期14-20,共7页Meteorology and Disaster Reduction Research

摘　　要：利用NCEP/NCAR再分析月平均风场资料和中国东部120个站的降水资料,分析了1951—2010年北半球冬季110°—120°E经向环流的气候特征,定义了北半球冬季110°—120°E低纬Hadley环流和中高纬气流强度指数,并分析了其强度的长期变化趋势以及对中国东部同期降水的影响。结果表明:(1)北半球冬季110°—120°E经向环流主要包括低纬Hadley环流和中高纬度从高层到低层较一致的偏北下沉气流。(2)北半球冬季110°—120°E Hadley环流和中高纬气流强度有明显的年际和年代际变化,二者在长期变化趋势上表现一致,即在1990年以前呈约20 a的振荡周期,且波动更大,而在1990年以后呈约10 a的振荡周期,波动相对较小。(3)北半球冬季110°—120°E经向环流强度指数对中国东部同期降水的年际变率具有较高的解释率,二者在统计上呈显著的负相关关系。北半球冬季110°—120°E Hadley环流强度和中国东部同期降水相关程度大值区集中在江南、华南及江淮地区,中高纬气流强度和中国东部同期降水相关程度大值区集中在西北、江淮及江南地区。(4)东亚地区冬季经向环流异常的显著差异主要表现在中高纬度反向的异常气流和中低纬度反向异常环流圈的变化。强(弱)经向风年,北半球中高纬度从高层到低层为异常的偏北(南)气流,中低纬度对流层存在顺时针(逆时针)方向闭合的异常经向环流,对应中国东部降水显著减少(增多)。Based on the monthly NCEP/NCAR reanalysis wind data and the rainfall data from the 120 stations in eastern China, the climatological characteristics, intensity variation of the meridional circulation and its influence on precipitation in eastern China are analyzed. The resuhs are as follows： （1） Northern hemisphere meridional circulation between 110-120°E in winter contains Hadley cell and northerly subsidence airflow in the whole troposphere at mid-high latitude; （2） The 110-120°E Hadley cell and the airflow intensity at mid-high latitude vary interannually and interdecadally, which presented 20-year period and vibrated largely before 1990 and showed 10-year period and vibrated slightly after 1990; （3） The precipitation in eastern China could be explained well by the variations of 110-120°E winter meridional wind intensity, and there exist some positive correlation between them over the past 60 years, with the higher correlation areas centralizing in the eastern and southern part of China; （4） In the strong （weak） meridional wind year, there exists anomalous northerly （southerly） in troposphere at mid-high latitude and clockwise （anticlockwise） meridional circulation at lower latitude, and precipitation over southeastern China decreases （increases） accordingly.

关 键 词：经向环流 变化趋势 同期降水 中国东部. 

分 类 号：P434[天文地球—大气科学及气象学]