强热带风暴“莲花”(0903)非对称降水结构分析  

Analysis of asymmetric rainfall structure due to strong tropical storm Linfa(0903)

作　　者：石顺吉 林秀斌 吴陈锋 陈德花 郑礼新 李金建[2] 

机构地区：[1]厦门市气象局,福建厦门361012 [2]四川省气候中心,四川成都610072

出　　处：《海洋预报》2010年第5期64-71,共8页Marine Forecasts

摘　　要：利用雷达回波和NCEP分析资料,本文从水汽条件、环境风垂直切变和风暴移动状态等方面诊断分析了0903号强热带风暴"莲花"非对称降水结构形成的可能机制。结果表明:"莲花"南侧充足的水汽输送为强降水的发生提供了基本的水汽条件,同时水汽通量在水平空间上的非对称分布也在一定程度上导致了降水的非对称分布。环境风垂直切变是导致"莲花"降水结构改变并最终形成一波非对称降水结构的主要动力因子。随着垂直切变的增强,同时配合风暴南侧充足的水汽条件,一波非对称降水结构逐渐形成,在较强垂直切变长时间的作用下,强降水最终集中于顺切变方向左侧。在较强垂直切变的作用下,逆切变一侧的下沉运动抑制了陆地摩擦和地形抬升所形成的对流的发展。相对于较强的垂直切变而言,"莲花"相对稳定的移速和移向条件难以主导强热带风暴降水的空间分布。Using radar reflectivity and NCEP analysis data, the possible mechanism to form asymmetric rainfall structure of Linfa was diagnosed and analyzed from water vapor condition, environmental vertical wind shear and storm moving aspects. The result demonstrated that the abundant water vapor transportation in south part of Linfa provided basic water vapor condition to the happening of heavy rainfall. The asymmetric water vapor flux distribution contributed to asymmetric rainfall in some degree. Environmental vertical wind shear was the major dynamic factor to lead to the change of rainfall structure and form wavenumber-1 asymmetric rainfall structure finally. As the shear enhanced, and with the abundant water vapor condition in south part of Linfa, wavenumber-1 asymmetric rainfall structure formed gradually. Then the heavy rainfall concentrated in downshear left ultimately as the longtime effect of strong shear. Under strong shear condition, the sink motion around upshear restrained the development of convection, which induced by the friction of land and uplift of terrain. Compared to strong shear, the relative stable moving speed and direction of storm was difficult to be the leading role to rainfall structure.

关 键 词：强热带风暴“莲花” 非对称降水 水汽条件 环境风垂直切变 地形 风暴的移动 

分 类 号：P444[天文地球—大气科学及气象学]