摘要
利用NCEP(National Centers for Environmental Prediction)提供的FNL(Final Analyses)资料和WRF模式(Weather Research Forecast Model)对2009年0920号超强台风LUPIT变性后再次爆发性发展的现象进行了研究,详细分析了潜热加热在热带气旋变性为温带爆发性气旋过程中的作用。研究发现:潜热释放是气旋快速发展阶段的重要影响因素,潜热通过影响环流促使气旋的爆发性发展,较为深厚的对流系统使潜热释放的位置发生在对流层的中高层。热量释放之后,地面气旋上空高空槽前的西南气流向槽前高压脊内输送热量,造成高层等压面坡度增大,涡度平流随高度增加,涡度平流的增加又进一步促进了上升运动加强,有利于更多水汽凝结,释放潜热,使得气旋海平面中心气压快速降低。天气尺度低压系统与对流活动相伴随的潜热释放之间的相互促进的正反馈过程类似于热带气旋的CISK机制,这可能是热带气旋变性后爆发性发展的一种重要机制。
Using reanalysis data, FNL （Final Analyses） from NCEP （National Centers for Environ- mental Prediction） and WRF （Weather Research Forecast） model, the structure, evolutionary process and physical mechanism of an explosive extratropical cyclone transformed from supper typhoon LUPIT over the Northwestern Pacific from 26 to 30 October 2009 were investigated. WRF modeling results showed latent heat influenced the circulation indirectly to contribute to the explosive development of cyclone： plenty of water vapor condition and relatively deep convection system made the position of latent heat release occurred in the upper troposphere. Due to the cyclone locating in the upper trough, southwest airflow might convey heat to the northeast. When the heat accumulation attended to a certain extent, geopotential height above the heating center of the upper atmosphere would increase and low-level geopotential height would decrease. It would make vorticity advection above cyclonic location increase with height, and then prompt rapid depressurization of cyclone. This is a positive feedback. Although this positive feedback mechanism and the CISK （Conditional Instability of the Second Kind） mechanism are similar, both of them develop by convective condensation, latent heat release and synoptic-scale system promote each other, the main difference is that the structure of explosive cyclone is sloping.
出处
《中国海洋大学学报（自然科学版）》
CAS
CSCD
北大核心
2017年第5期10-18,共9页
Periodical of Ocean University of China
基金
国家自然科学基金项目(41275049)资助~~
关键词
变性台风
爆发性气旋
WRF模式
潜热释放
发展机制
transformed typhoon
explosive extratropical cyclogenesis
WRF
latent heat release
physical mechanism
