doi:  10.3878/j.issn.1006-9895.1811.18109
中国东部夏季风雨带向北推进与条件对称不稳定的关系研究

Research on the Relationship between Conditional Symmetric Instability and the Northward Jumping of the Summer Monsoon Rainbands in East China
摘要点击 96  全文点击 19  投稿时间:2018-01-17  修订日期:2018-08-07
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基金:  国家自然科学基金,国家重点研发计划,国家重点基础发展计划
中文关键词:  季风雨带  强降水 湿位涡通量  条件对称不稳定 对流有效位能  倾斜对流有效位能
英文关键词:  Monsoon  rainbands, Heavy  rainfall, MPV  flux , CSI, CAPE, SCAPE
        
作者中文名作者英文名单位
黄明策HUANG Mingce1、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合作联合实验室/气象灾害预报预警与评估协同创新中心;2、广西气象台
CAO ZuohaoCAO Zuohao加拿大环境和气候变化部
沈新勇SHEN Xinyong1、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合作联合实验室/气象灾害预报预警与评估协同创新中心;2、
引用:黄明策,CAO Zuohao,沈新勇.2019.中国东部夏季风雨带向北推进与条件对称不稳定的关系研究[J].大气科学
Citation:HUANG Mingce,CAO Zuohao,SHEN Xinyong.2019.Research on the Relationship between Conditional Symmetric Instability and the Northward Jumping of the Summer Monsoon Rainbands in East China[J].Chinese Journal of Atmospheric Sciences (in Chinese)
中文摘要:
      利用1981~2010年欧洲中期天气预报中心(ECMWF)ERA-interim再分析资料和中国741站日降水资料,分析了中国东部夏季风雨季期间,条件对称不稳定(CSI)与季风雨带季节性北推的关系。结果表明:逐月强降水距平场显示了雨带强降水中心从华南(4~6月份)先北跳到江淮(5-7月份),再到华北(7-8月份)的季节性进程,特别是用具有“北多南少”分布特征的7~8月份强降水距平场表征雨带季节北跳现象比对应的平均雨量场更显著。大气负湿位涡通量中心与雨带强降水中心4~6月份在华南停滞、然后逐渐北推,7~8月份到达华北停滞的季节性变化一致。CSI区在4~5月及9月份主要在925~600 hPa,而6~8 月份抬升到700~600hPa,CSI区也很好地表征了夏季风北进加强、南撤减弱及所伴随的雨带变化趋势。在春末夏初,夏季风建立初期的华南、江淮雨季集中期,热成风(垂直风切变)作用对倾斜对流有效位能(SCAPE)的贡献占绝对优势,华北雨季集中期则相反,重力作用项占主要作用;同时,热成风作用项的季节分布与强降水中心季节变化一致,但重力作用项却没有这种变化关系。条件性湿位涡通量指数(CMF index)可指示雨带强降水异常区。
Abstract:
      The summer monsoon rainbands in East China and their northward seasonal leap in relation to conditional symmetric instability (CSI) during the period of 1981 to 2010 is diagnosed through computing and analyzing moist potential vorticity (MPV) flux, CSI, slantwise convective available potential energy (SCAPE), and a newly developed index CMF (conditional MPV flux) , using the European Centre for Medium-Range Weather Forecasts reanalysis data and the daily precipitation data of 741 Chinese stations. The results demonstrate that the monthly-averaged anomaly fields show the northward leap of heavy rainfall centers from South China in April to June, Yangtze–Huaihe in May to July, to North China in July to August. The situation of numerous precipitation in North China and scanty rainfall in sounth of Yangtze–Huaihe during July to August is better represented by the rainfall anomaly fields than the mean fields.The negative MPV flux is in phase with the northward leap of heavy rainfall from South China (April to June) to North China (July to August). CSI zones within the rainbands centers are mainly located between 925 and 600 hPa in April, May, and September whereas they are vertically shifted to 700-600 hPa from June to August. CSI zones are also a good indicator of the northward leap of summer monsoon rainbands and their intensification as well as southward falling back and weakening.During the late spring and early summer when the monsoon starts, the thermal wind contribution of SCAPE is dominant over the CAPE in magnitude whereas from July to August, the opposite is true. Furthermore, the thermal wind contribution is in phase with the northward seasonal leap of heavy rainfall from South China in April to June, Yangtze- Huaihe in May to July, to North China in July to August while CAPE has no such relationship with heavy rainfall centers. The CMF index can be an indicator for the regional summer rainfall anomaly in East China.
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