摘要
利用NCEP/NCAR再分析资料 ,探讨夏季中国东部长江流域严重洪涝灾害发生时的天气气候异常特征。分析表明 :东亚夏季风环流偏弱是夏季长江流域发生严重暴雨洪涝灾害的气候特征。天气特征是东亚地区东、西、南、北天气尺度系统的最佳配合以及东亚大气环流出现较显著的 2 0～ 30天的低频振荡。东亚中高纬大气环流出现 2 0～ 30天的低频振荡 ,有利于青藏高原上空的低压系统沿着中纬度东传到 1 1 5～ 1 2 5°E附近 ,造成长江流域梅雨锋低压扰动加强 ;东亚低纬大气环流出现 2 0～ 30天的低频振荡 ,有利于印度洋、南海和热带西太平洋的水汽输送到长江流域 ,为长江流域暴雨提供持续充足的水汽来源。夏季西太平洋副热带高压西伸出现 2 0～ 30天的低频振荡 ,有利于低压系统在长江流域 ( 1 1 5～ 1 2 5°E)再生和维持。
The East Asian circulation characteristics of season and intraseason during summer for persistent heavy rainfall over the Yangtze River valley were investigated. It had been found that the climatic background of the persistent heavy rainfall over the Yangtze River valley in summer was that East Asian summer monsoon circulation weakened. However the persistent heavy rainfall should not occur over the Yangtze River valley when East Asian summer monsoon circulation weakened. The persistent heavy rainfall over the Yangtze River valley in summer was owing to the phase lock of the synoptic scale system over East Asia as well as the cyclone over the Tibetan plateau moved to 110～120°E. The 20～30 days intraseason oscillation of the circulation system over East Asia in summer caused that the phase of the synoptic scale system over East Asia locked and the cyclone over the Tibetan Plateau moved to 110～ 120°E.
出处
《大气科学》
CSCD
北大核心
2003年第6期1018-1030,共13页
Chinese Journal of Atmospheric Sciences
基金
国家重点基础研究规划项目G1 9980 40 90 0
中国科学院资源环境领域知识创新工程重要方向项目KZCX2 2 0 3共同资助
关键词
长江流域
暴雨
洪涝灾害
气候条件
季风环流
heavy rainfall
East Asian summer monsoon
20～30 days oscillation.
