7月不同形态南亚高压与北半球大气环流的关系  

Relationships between different types of South Asian high and atmospheric circulation in the Northern Hemisphere in July

作　　者：孙照渤[1] 周航[1] 彭丽霞[1] 倪东鸿[1] 

机构地区：[1]南京信息工程大学气象灾害教育部重点实验室/气候与环境变化国际联合实验室/气象灾害预报预警与评估协同创新中心,江苏南京210044

出　　处：《大气科学学报》2016年第5期577-588,共12页Transactions of Atmospheric Sciences

基　　金：国家自然科学基金资助项目(41105059;41575070);科技部公益性行业(气象)科研专项(GYHY201306028)

摘　　要：利用NCEP/NCAR月平均高度场和风场再分析资料,分析了1948—2013年7月南亚高压多中心特征及其与北半球大气环流的关系。结果表明:1)南亚高压存在1至5个中心不等,其中以双中心类和三中心类为主,占总样本数的82%,其次是单中心类,占总样本数的14%,四中心类和五中心类仅占总样本数的3%。2)根据高压中心个数、经向位置和环流特征,将不同类高压分成了不同型,其中单中心类分为Ⅰ1型和Ⅰ2型,分别占该类的44%和56%,双中心类分为Ⅱ1型、Ⅱ2型和Ⅱ3型,分别占该类的66.7%、18.5%和14.8%,三中心类仅考虑了Ⅲ1型,占该类的67%。3)Ⅰ1型高压中心在伊朗高原上空,Ⅰ2型高压中心在青藏高原上空,Ⅱ1型两高压中心分别在伊朗高原和青藏高原上空,Ⅱ2型两高压中心分别在伊朗高原和我国东部西太平洋上空,Ⅱ3型两高压中心分别在青藏高原和我国东部西太平洋上空,Ⅲ1型三个高压中心分别在伊朗高原、青藏高原和我国东部西太平洋上空。4)不同类型的高压中心所在地区高层位势高度场和对流层中上层温度场都表现为显著正异常,且不同区域温度场异常的维持机制不相同。The South Asian high （SAH） in summer is a strong anticyclone over the Tibetan Plateau and adjacent areas. It is an important component of the Asian summer monsoon.The east-west oscillation of the SAH is an important characteristic and is closely related to the weather situation and climate change of Asia-especially the distribution of drought and flood.It is found that the east-west oscillation of the SAH is not only manifested as the zonal ex- pansion of the area,but also the adjustment of different forms.The climatological mean center position of the SAH is usually located over the Tibetan Plateau, and the SAH has multiple centers in general. The different centers often appear over the Iranian Plateau, the Tibetan Plateau, eastern China, or the western Pacific.The SAH can be classified into different forms according to the number and location of these SAH centers.Identifying the circula- tion features and maintenance mechanisms of the different forms can help research the mechanism of the east-west oscillation of the SAH.In this paper,based on NCEP-NCAR monthly mean height and wind field reanalysis data from 1948 to 2013 ,the SAH is classified into several forms according to its center numbers and center location u- sing composite analysis.In addition,the relationship between the circulation characteristics of different SAH forms and the atmospheric circulation in the Northern Hemisphere is discussed.The results obtained are as follows： （1） The SAH can have between one and five centers, among which having two or three centers constitutes the majority, accounting for 82% of the total samples.Next,is the SAH with a single center,accounting for 14% of the total samples,and the remainder comprises SAHs with four or five centers,accounting only for 3% of the total samples. （2） The SAH can be classified into different forms according to the number of centers,the meridional posi- tion and the circulation features.SAHs with only one center can be classified into I 1 form and I2 form,account- ing for 44%

关 键 词：南亚高压 多中心特征 青藏高原 伊朗高原 

分 类 号：P424[天文地球—大气科学及气象学] P434