摘要
0509号台风"Matsa"和0712号台风"Wipha",均在中国大陆发生变性成为温带气旋。但前者变性后再度加强,后者变性后减弱消亡。用日本JRA25再分析资料,对其变性过程对比分析。表明:"Matsa"和"Wipha"均是在登陆后北上与中高纬西风槽相互作用的过程中,受到冷空气入侵后变性,从垂直对称分布演变为倾斜的非对称分布,且在北上过程中与中纬度高空锋区作用,但"Matsa"中心嵌入中纬度高空锋区,有再加强过程;而"Wipha"仅外围环流与锋区接触,中心未进入锋区,无再加强过程。通过对大气稳定度和垂直螺旋度等进一步分析表明:"Matsa"变性过程是系统性冷空气的南侵,而Wipha的变性只有弱冷空气的入侵;台风中心所在的垂直涡度ζp的增长大值区是否落在△θe<0的大气对流性不稳定的区域内,对台风变性后是否再加强有一定影响。此外,垂直螺旋度的高低空配置及正涡度柱与上升运动的相互配合是使台风变性加强的重要因素。
Both of typhoon Matsa（0509）and Wipha（0712） underwent extratropical transition（ET） over mainland of China, but only Matsa was re-intensified as an extratropical system. Using Japanese 25 years re-analysis data, this article compared and examined their ET processes. Results showed that Matsa and Wipha all penetrated into mid-latitude zone and was affected with an upper-level westerly trough dur- ing their ET. ET re-intensification was related to the interactions between typhoon remnant circulation, front zone and anomaly potential vorticity downward transported from the upper troposphere. Furthermore, this article analysed the equivalent potential temperature, atmospheric stability and the vertical helicity of both two typhoons, the results showed that during extratropical transition process, in the case of Matsa strong and systematic cold air invaded from north, while Wipha was just affected by weak cold air. Mean- while, the coincidence of central vertical vorticity＇s great increment area with △ θe 〈 0 atmospheric con- vective instability area, positive vorticity column＇s coupling with upward motion and vertical helieity con- dition were important factors in typhoon extratropical transition and reintensification.
出处
《气象科学》
CSCD
北大核心
2013年第6期685-692,共8页
Journal of the Meteorological Sciences
基金
江苏省重大科技支撑与自主创新示范工程项目(BE2008618)
关键词
台风
相当位温
大气稳定度
垂直螺旋度
Typhoons
Equivalent potential temperature
Atmospheric stability
Vertical helicity
