1617号鲇鱼台风登陆后引发不同性质暴雨的成因对比分析
投稿时间:2019-01-21  修订日期:2019-02-16  点此下载全文
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作者单位E-mail
王毅 国家气象中心 yiwang@cma.gov.cn 
张晓美 中国气象局公共气象服务中心 492783709@qq.com 
杨寅 国家气象中心  
曹勇 国家气象中心  
张芳华 国家气象中心  
中文摘要:2016年9月28日1617号台风“鲇鱼”登陆后由台风本体环流和外围环流引发了不同性质的暴雨,是本次秋季登陆台风暴雨预报的难点。本文利用常规气象观测资料以及NCEP的1o×1o 客观再分析等资料对不同性质暴雨的成因进行了诊断对比分析,结果表明:浙江东南部对流性降水和江西南部稳定性降水的大气层结结构具有明显的差异。中高纬度低槽距离台风较远,冷空气主要从低层入侵台风西北侧,破坏了台风低层暖心结构。台风外围中层干冷空气沿东南风向浙江东南部输送,并叠加在低层暖湿气流之上,形成上冷下暖的不稳定层结,同时在对流层上层有干冷空气下沉至台风环流中下层(干侵入),导致浙江文成附近出现了局地特大暴雨。江西南部由于低层被湿冷空气占据,层结较为稳定,降水发展平缓。低空东南急流为台风外围环流暴雨提供了充足的水汽,浙江东南部地形对降水起到了增幅作用。不稳定层结及中层冷空气的输送对对流性暴雨的激发作用可以为登陆台风降水性质和强度预报提供参考依据。
中文关键词:登陆台风  暴雨  冷空气  干侵入  层结特征
 
Comparative analysis of cause of different types of heavy rainfall induced by typhoon Megi (1617) after its landfall
Abstract:The typhoon Megi (1617) was a large-scale and strong tropical cyclone. Heavy rainfall with different character were induced by typhoon own circulation and outer circulation after landfall of typhoon Megi on 28 September 2016. The different types of heavy rainfall make the forecasting of the heavy rainfall for landing typhoon in autumn difficult. By using convectional meteorological observation data and NCEP objective reanalysis data (1o×1o) etc, comparative cause analysis is conducted for different types of heavy rainfall in Zhejiang and Jiangxi province. It is showed that: there are obvious differences between convective precipitation over southeast of Zhejiang province and stable precipitation over south of Jiangxi province in the atmospheric stratification. Trough at middle level of troposphere in the mid-high latitude was far from Typhoon Megi. Cold air intrusion was occurred at the lower level towards northwest of the typhoon which destroyed the warm-core structure of the typhoon. The dry and cold air at middle level was transported by southeast winds towards southeast of Zhejiang province. This cold air overlaid on the warm and wet airflow at lower level thus forming the so called “cold on the top and warm on the bottom” unstable stratification. Meanwhile, dry and cold air from the upper troposphere sank into the middle and lower level of typhoon circulation (dry intrusion) which caused local extreme heavy rainfall near Wencheng in Zhejiang province. It is also found that south of Jiangxi province was occupied by wet and cold air at lower level which resulted in the stable stratification. Consequently, the evolvement of rainfall in south of Jiangxi province was more gentle compared to that in Zhejiang province. Low-level southeast jet stream provided abundant moisture to the heavy rainfall associated with outer typhoon circulation. The mountain topography in southeast of Zhejiang province played an amplification effect to the heavy rainfall in this area. The trigger effect of the unstable stratification and transport of cold air at middle level on convectional heavy rainfall can be used as the reference for forecasting of character of rainfall associated with landing typhoon as well as forecasting of its magnitude.
keywords:anding typhoon  heavy rainfall  cold air  dry intrusion  stratification characteristic
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