晏红明. 2017. 一个新的东亚副热带夏季风指数的定义[J]. 气象学报, ():-, doi:10.11676/qxxb2017.020
一个新的东亚副热带夏季风指数的定义
Definition of a new East Asian subtropical summer monsoon index
投稿时间:2016-04-21  最后修改时间:2016-11-30
DOI:10.11676/qxxb2017.020
中文关键词:  东亚夏季风指数  中国夏季降水  三类雨型  西北太平洋环流异常
英文关键词:East Asian summer monsoon  summer rainfall in China  three kinds of rainfall pattern  circulation anomalies over northwestern Pacific
基金项目:
作者单位E-mail
晏红明 云南省气候中心 yanhongming2013@163.com 
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中文摘要:
      利用1958-2014年夏季NCEP/NCAR大气环流资料和中国486站降水观测资料,通过多种统计诊断方法,从与夏季中国东部三类不同雨型分布相联系的东亚高低层风场变化特征出发,依据与雨带变化密切联系的高层200hPa纬向风定义了一个新的东亚副热带夏季风指数。分析表明该指数不仅能反映夏季东亚大气环流的变化特征,兼顾北方冷空气活动和南方东亚夏季风环流变化,同时还能反映夏季中国东部降水南北差异的年际特征。强东亚副热带夏季风年,高层中纬度西风急流位置偏北,低层西太平洋副热带高压偏强偏北,有利于冷空气活动位置偏北和东亚东部西南暖湿气流向北推进,中国东部多以Ⅰ类雨型为主;弱东亚副热带夏季风年的环流变化刚好相反,中国东部多以Ⅲ类雨型为主。与现有东亚夏季风指数的对比分析表明,该指数在反映中国东部南北区域降水变化的差异方面有很大改进。
英文摘要:
      Based on precipitation data of 160 observation stations in China and NCEP / NCAR reanalysis atmospheric circulation data from 1958 to 2014, the relationship between summer precipitation in China and wind at low and high level is firstly investigated. Then a new East Asian subtropical summer monsoon index is defined using 200-hPa zonal wind closely relating to three kinds of summer rainfall in Eastern China. The results show that the new index may well reflect not only the integrated impact of the circulations over high and low latitudes, but also summer precipitation difference characteristic between northern and southern China. Strong East Asian summer monsoon years, strengthen high-level westerly, North position of cold air activity, strengthen the low-level West Pacific subtropical high pressure with position to the north resulting in strong south-west flow over Eastern East Asian, type I rainfall occurring to Eastern China; circulation changes is just the opposite in weak East Asian summer monsoon, type Ⅲ rainfall occurring to Eastern China. Compared with the existing East Asian summer monsoon index, the new index has a great advantage in reflecting the precipitation difference between eastern and southern China.
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