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张元春, 孙建华, 徐广阔, 齐琳琳. 江淮流域两次中尺度对流涡旋的结构特征研究[J]. 气候与环境研究, 2013, 18(3): 271-287. DOI: 10.3878/j.issn.1006-9585.2012.11162
引用本文: 张元春, 孙建华, 徐广阔, 齐琳琳. 江淮流域两次中尺度对流涡旋的结构特征研究[J]. 气候与环境研究, 2013, 18(3): 271-287. DOI: 10.3878/j.issn.1006-9585.2012.11162
ZHANG Yuanchun, SUN Jianhua, XU Guangkuo, QI Linlin. Analysis on the Structure of Two Mesoscale Convective Vortices over Yangtze-Huaihe River Basin[J]. Climatic and Environmental Research, 2013, 18(3): 271-287. DOI: 10.3878/j.issn.1006-9585.2012.11162
Citation: ZHANG Yuanchun, SUN Jianhua, XU Guangkuo, QI Linlin. Analysis on the Structure of Two Mesoscale Convective Vortices over Yangtze-Huaihe River Basin[J]. Climatic and Environmental Research, 2013, 18(3): 271-287. DOI: 10.3878/j.issn.1006-9585.2012.11162

江淮流域两次中尺度对流涡旋的结构特征研究

Analysis on the Structure of Two Mesoscale Convective Vortices over Yangtze-Huaihe River Basin

  • 摘要: 对2003、2007年江淮梅雨期的中尺度对流涡旋(MCV)进行了统计分析,结果表明我国梅雨锋上MCV活跃,这些MCV与强降水有关。2003、2007年江淮梅雨期有9个MCV发生,大多数的MCV发生在32°N~35°N之间的江苏境内。采用ARPS(Advanced Regional Prediction System)的资料分析系统(ADAS)和WRF模式模拟了2个MCV的发展过程,并使用数值模拟结果分析了它们的结构特征。MCV一般发生在强对流系统的北侧,其涡旋环流一般在600 hPa以下,对应涡旋区域对流层高层为强辐散,涡度最强的中心在对流层中层,但正涡度区可伸展到300 hPa。初始阶段MCV的中心为上升运动和中性层结,成熟阶段MCV的中心转为下沉运动,同时其南侧有新的对流发生。发展型和不发展型的MCV对比发现,涡旋对流层高层有涡度增加以及二次对流的潜热释放多,可能是发展型MCV维持时间较长的原因。此外,MCV发展过程中南侧急流的增强对MCV中对流的触发和维持有一定作用。

     

    Abstract: The statistics of mesoscale convective vortices (MCVs) occurring in the Yangtze-Huaihe River basin during the Meiyu period of 2003 and 2007 show that MCVs along the Meiyu front were highly active and could have induced severe flooding. Most of the nine MCVs identified during Meiyu period of 2003 and 2007 were formed at 32°N-35°N near the Jiangsu Province. The WRF (Weather Research and Forecasting) model and the ARPS (Advanced Regional Prediction System) data analysis system (ADAS) are employed to simulate two MCVs, in order to study the development and structure of MCVs. It is determined that MCVs form to the north of convection system with a closed vortex circulation maintained below 600 hPa and a vorticity maximum in the middle troposphere. In addition, positive vorticity could reach 300 hPa. The evolution of MCVs can be divided into three stages: Initiation, maturity, and dissipation. During the initiation stage, an updraft can be found in the center of the MCV with neutral stratification. During the mature stage, a downdraft occurs in the center of the MCV, and secondary convections develop southeast region of the MCV. Compared with undeveloped MCVs, developed MCVs may result from the increase of vorticity in the high-level troposphere and more latent heating from secondary convections. Furthermore, the intensified jet is favorable for the triggering and development of new convections of the MCV.

     

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