2014年12月西北太平洋上一爆发性“气旋对”的分析

Analyses of a Pair of Explosive Cyclones over the Northwestern Pacific in December,2014

利用NCEP(National Centers for Environmental Prediction)提供的FNL (Final Analysis)再分析资料,JMA(Japan Meteorological Agency)提供的MTSAT-1R(Multi-functional Transport Satellites-1R)卫星红外波段云顶亮温资料和HYSPLIT(Hybrid Single Particle Lagrangian Integrated Trajectory Model)模式对2014年12月15—18日发生在西北太平洋上的一个"气旋对"的演变过程和相互作用进行分析。该"气旋对"由两气旋A、B组成,气旋A在15日00UTC生成,在"气旋对"发展初期占主导地位,并为12h后生成的气旋B的发展创造有利条件。气旋B生成后发展迅速,后期占据主导地位,直至气旋A衰亡。两气旋相互影响,在向东北方向移动的过程中围绕共同中心"互旋",两者相互吸引靠近,其中心连线逐渐由南北向转为东西向。天气形势分析表明,气旋A在高空为气旋B的发展提供了有利的背景涡度场,在低空通过环流将冷平流输送到气旋B内部,使气旋B低层斜压性增加,促使气旋B发展迅速。用前向轨迹追踪的方法证明在中低层两者之间存在动能传输通道,空气微团从气旋B向气旋A传递,湿焓沿动能通道从南到北向气旋A、B中心传递。在中后期,两气旋中低层的涡旋强度反向变化,即气旋A的涡度逐渐减小,而气旋B的涡度逐渐增大。过气旋A、B中心连线的垂直剖面分析表明,气旋A有利于气旋B发展加强。

This paper documented a pair of explosive cyclones over the Northwestern Pacific from 15 to 18 December,2014.The evolutionary and interaction processes of this pair of cyclones were investigated by using Final Analysis(FNL)data issued by National Centers for Environmental Prediction(NCEP),the Multi-functional Transport Satellites-1R(MTSAT-1R)infrared satellite data supplied by Japan Meteorological Agency(JMA),as well as the HYSPLIT(Hybrid Single Particle Lagrangian Integrated Trajectory Model)model.This pair of cyclones was consisted of two explosive extratropical cyclones A and B.Cyclone A formed around 00 UTC 15 December,2014,about 12 h earlier than cyclone B.During the initial stage,cyclone A played the dominant role and provided the favorable conditions for the generation and development of cyclone B.After formation,cyclone B intensified rapidly and dominated the pair of cyclones until the dissipation of cyclone A.When this pair of cyclones moved northeastwards,they had mutual rotation with each other,suggesting the strong interaction among of them.The orientation of the line connecting two cyclone centers changed from E-W direction to N-S direction gradually.Synoptic analyses indicated that cyclone A provided the upper-level positive vorticity for cyclone B.Cold advection at lower-level penetrated into the center of cyclone B,increasing the lower-level atmospheric baroclinicity and promoting the rapid development of cyclone B.With the help of forward trajectory simulation of HYSPLIT,it is found that,at the lower levels,there was a kinetic energy transmission channel among these two cyclones,and the air particles were transmitted from cyclone B to cyclone A.The enthalpy was transferred into the central region of cyclones A and B along the kinetic energy channel from south to north.In the later stage,the maximum vorticity related to cyclones A and B at the lower levels changed inversely,i.e.,the vorticity of the cyclone A decreased gradually,while the vorticity of cyclone B increased gradually.Finally,the vertical section analyses of equivalent potential temperature and potential vorticity(PV)along the line between cyclones A and B presented that there was a significant interaction among these two cyclones.