摘要
采用CMISS/MIMIC微波卫星产品,TCGP数据集和NECP/NCAR全球再分系资料,详细分析了超强台风"利奇马"(1909)的双眼墙过程中对流结构及动力结构的协同变化特征。结果表明:(1)在双眼墙形成前,"利奇马"内核对流雨带对称性增加,呈现环状包裹眼墙。在环状雨带和眼墙之间,下沉气流配合相对湿度干区在此发展,致使该区域对流受到抑制,最终发展为下沉晴空Moat区。而在内核环状对流雨带处,上升运动中心和次极大入流中心发展,增大绝对涡度的内输,促进次极大风速中心的形成,并有利于深对流发展。最终环状对流带发展成为外眼墙;(2)双眼墙结构形成后,次眼墙及其相伴的次级环流和对流雨带均增强并且内缩,Moat区变狭窄,对流抑制作用增强。相反,内眼墙对流强度及次级环流减弱,绝对涡度内输不足,导致"利奇马"强度减弱。
Based on CMISS/MIMIC microwave satellite images,Tropical Cyclone Guidance Project(TCGP)dataset and NECP Final Analysis(FNL)dataset,this paper analyzes the co-variation of convection and dynamical structure during concentric eyewall process of Typhoon“Lekima”.The results come as follows:(1)Before the formation of concentric eyewall,the symmetry of Lekima s inner-core convective rainbands increases rapidly,presenting a ring-shaped inner rainband enveloping surround the eyewall.Between the ring-like rainband and the eyewall,there is a zone where downward motion and low humidity develop,resulting in the suppression of convection,which finally develops into a moat region.On the other hand,updraft and radial inflow largely develop around the ring-like rainband,which strengthen the import of absolute vorticity and benefit the development of deep convection.This rainband finally becomes the outer eyewall.(2)After the formation of the concentric eyewall,the secondary eyewall is gradually strengthened and contracted.The moat region becomes narrow and the convection suppression is enhanced there.However,the primary eyewall is weaken during the development and contraction of the secondary eyewall,resulting in the intensity decrease of“Lekima”.
作者
郭晞
仇欣
李超
沈阳
陈圣劼
GUO Xi;QIU Xin;LI Chao;SHEN Yang;CHEN Shengjie(Jiangsu Meteorological Observatory,Nanjing 210008,China;Nanjing University,Nanjing 210014,China)
出处
《气象科学》
北大核心
2020年第3期315-324,共10页
Journal of the Meteorological Sciences
基金
国家自然科学基金资助项目(41805038,41575053)
江苏省气象学会青年基金(KQ201901)。
关键词
台风
双眼墙演变
风场结构
对流结构
typhoon
concentric eyewall
wind structure
convective structure
