近64年来南京夏季降水峰期变化及其异常环流分析
投稿时间: 2015-12-28  最后修改时间: 2016-04-18  点此下载全文
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作者单位E-mail
王羱 解放军理工大学气象海洋学院 wangyuanyjs@163.com 
张立凤 解放军理工大学气象海洋学院 Zhanglif_qxxy@sina.cn 
朱鹏 中国人民解放军95990部队  
基金项目:国家自然科学基金项目(面上项目,重点项目,重大项目);国家重点基础研究发展计划(973计划)
中文摘要:利用1951—2014年南京站逐日降水资料,NCEP逐日再分析资料和海温资料对南京夏季降水的逐候演变特征及其异常环流进行了分析。结果表明:南京夏季降水集中在6月第五候至7月第三候,在气候态上降水强度存在峰期位于6月第五候和7月第一候的双峰结构;降水峰期还存在准10年的年代际变化,不同年份降水的候演变特征呈现为峰期在6月第五候的单峰结构、峰期为7月第二候的单峰结构以及双峰结构三种状态之间的转换。当降水单峰出现在7月第二候(6月第五候)时,在6月第五候,西太副高偏弱(强)偏东(西),东亚大槽和贝加尔湖浅槽偏弱(强),南京附近对流层低层水汽异常辐散(辐合),中层盛行下沉(上升)运动,在7月第一和第二候,西太副高偏强(弱)偏西(东),东亚大槽和贝加尔湖浅槽偏强(弱),南京附近对流层低层水汽异常辐合(辐散),中层盛行上升(下沉)运动;降水的峰期变化与前期冬季(175癊-150癢,10癗-20癗)区域的SST异常有着较好的相关性。
中文关键词:南京  夏季降水  峰期变化  异常环流
 
Variability of summer precipitation peak time in Nanjing during recent 64 years and its abnormal circulation
Abstract:Based on the daily precipitation data from 1951 to 2014 in Nanjing, NCEP daily reanalysis data and SST data, the pentad evolution characteristics of summer precipitation in Nanjing and its abnormal circulation are analyzed. Results show that summer precipitation in Nanjing is concentrated between the 5th pentad of June and the 3rd pentad of July, and precipitation intensity shows a “double-peak” structure in climatology with peak time occuring in the 5th pentad of June and the 1st pentad of July. The precipitation peak time also has a decadal variation of ~10 years. The pentad evolution characteristics of precipitation shows a conversion between three states—a “single-peak” structure with peak time occuring in the 5th pentad of June, a “single-peak” structure with peak time occuring in the 2nd pentad of July and a “double-peak” structure—in different years. When precipitation’s “single-peak” occuring in the 2nd pentad of July (5th pentad of June), in the 5th pentad of June, West Pacific Subtropical High (WPSH) tends to be weak (strong) and eastward (westward), East Asia Trough and Baikal Shallow Trough tend to be weak (strong), the vapor in the lower troposphere around Nanjing tends to be abnormally divergent (convergent), and the vertical velocity in the middle troposphere tends to be downward (upward). On the contrary, in the 1st and 2nd pentad of July, WPSH tends to be strong (weak) and westward (eastward), East Asia Trough and Baikal Shallow Trough tend to be strong (weak), the vapor in the lower troposphere around Nanjing tends to be abnormally convergent (divergent), and the vertical velocity in the middle troposphere tends to be upward (downward). The preceding winter SST anomalies of (175癊-150癢,10癗-20癗) has a siginificant correlation with variability of precipitation peak time.
keywords:Nanjing  summer precipitation  peak time variation  abnormal circulation
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