Physical Mechanism of Formation of the Bimodal Structure in the Meiyu Front System
Physical Mechanism of Formation of the Bimodal Structure in the Meiyu Front System作者机构：Laboratory of Cloud-Precipitation Physics and Severe Storms (LACS) Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 National Meteorological Centre China Meteorological Administration Beijing 100081 Liaoning Meteorological Observatory Liaoning Meteorological Bureau Shenyang 110016 joint Center for Satellite Data Assimilation and NOAA/NESDIS/Office of Research and Applications Camp Springs Maryland 21029 USA
出 版 物：《Chinese Physics Letters》 (中国物理快报（英文版）)
年 卷 期：2005年第22卷第12期
页 面：3218-3220页
核心收录：
学科分类：07[理学] 070601[理学-气象学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0706[理学-大气科学] 0704[理学-天文学]
基 金：中国科学院知识创新工程项目 国家自然科学基金 中国气象局中国气象科学研究院项目 卫星数据同化联合中心(JCSDA)资助 国家973计划 南京信息工程大学气象灾害省部共建教育部重点实验室基金
主 题：SLANTWISE VORTICITY DEVELOPMENT MOIST POTENTIAL VORTICITY ASIANSUMMER MONSOON EAST CHINA SEA SCALE STRUCTURE PART II REGION CONVERGENCE TRANSPORT FEATURES
摘 要：The bimodal structure of the Meiyu front system is readdressed after Zhou et al.（2005）. The physical mechanism of the formation of the bimodal distribution is discussed. The bimodal structure of the Melyu front system considerably results from atmospheric moisture gradients, though atmospheric temperature gradients are also not negligible. According to the definition of equivalent potential temperature, and by scale analysis, we find that atmospheric equivalent potential temperature gradients, which could be regarded as an indicator of the Meiyu front system, could be mainly attributed to the variations of atmospheric potential temperature gradients with a scaling factor of 1 and moisture gradients multiplied by a scaling factor of an order of about 2.5 × 10^3, which means that small variations of atmospheric moisture gradients could lead to large variations of equivalent potential temperature gradients, and thus large variations of the Meiyu front system. Quantitative diagnostics with a mesoscale simulation data in the vicinity of the Meiyu front system show that moisture gradients contribute to equivalent potential temperature gradients more than potential temperature gradients.
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