大气科学2016，Vol.40Issue(4)：703-718,16.DOI:10.3878/j.issn.1006-9895.1601.15258
梅雨雨带北跳过程研究
A Study on Northward Jump of the Meiyu Rainbelt
摘要
Abstract
This study has exploited daily reanalysis data and high-resolution precipitation data for the period of 1979 to 2007 to investigate the northward jump of the Meiyu rainbelt and its possible physical mechanisms. The northward jump dates of the Meiyu rainbelt are determined. Results show that the northward jump dates of the Meiyu rainbelt vary greatly from year to year. Composite results of the Meiyu northward jump process revealed in this study are consistent with results of previous studies. Water vapor transport and vertical motions in the middle troposphere play a crucial role in determining the spatial distribution of Meiyu rainbelt. Diagnostic results of the Omega equation indicate that anomalous circulations in the upper troposphere induce descending motion anomalies over the Yangtze−Huaihe River basin, which inhibit the northward jump of the Meiyu rainbelt. Meanwhile, diagnostic results of a vorticity equation suggest that the anomalous diabatic cooling associated with the anomalous descending motions over the Yangtze−Huaihe River basin produces anomalous anticyclonic vorticity tendency over East China in the lower troposphere, which is favorable for the westward shift of the subtropical high and the northward jump of the Meiyu rainbelt. The above results show clearly that <br> the sudden northward jump of the Meiyu rainbelt is attributed to anomalous ascending motions over the Yangtze−Huaihe River basin, which are associated with circulation anomalies in the upper troposphere (primarily driven by zonal vorticity advection).关键词
梅雨雨带/北跳/大气环流变化/涡度诊断Key words
Meiyu rainbelt/Northward jump/Variations of atmospheric circulation/Vorticity diagnosis分类
天文与地球科学引用本文复制引用
陈艳丽,宋洁,李崇银..梅雨雨带北跳过程研究[J].大气科学,2016,40(4):703-718,16.基金项目
国家自然科学基金项目41275086、41490642，国家重点基础研究发展计划（973计划）项目2015CB453202Funded byNational Natural Science Foundation of China (Grants 41275086 and 41490642), the National Basic Research Program of China (Grant 2015CB453202) （Grants 41275086 and 41490642）
