An Analysis Of The Structure Characteristics And Cause Of Two Kinds Of Deep Vortex

The thesis summarized the researches in characteristic and development of the vortex growing in southwestern China,pointed out the weakness of the knowledge in southwest vortex(SWV)which considered a shallow system before.The structure evolution characteristics of the deep SWV and its relation with upper circulation was analysed,the result shows that:(1)the two cases of deep vortex is closely related to South Asia High(SAH)and eastern trough,both two cases occurred during the period of the western movements of SAH and southern movement of eastern trough.(2)The deep vortex developed upward in dynamical structure with a vertical central axis and weak convergence in forming stage,the downward flow occupied the vortex area.The deep cold vortex development downwards,the central axis moved from slant to vertical gradually,the horizontal wind was asymmetric,the positive vorticity area leaned to southeast with the enhancement of ascending flow.(3)the two cases is layered in thermal structure,the vortex has a warm structure in 200 h Pa,the formation of warm core was related to the warm advection of SAH,below 200 h Pa,the vortex has a cold character,during the downward development,cold core has formed before the vortex development,then the vortex development towards the cold core which located in the west of vortex.The deep vortex has a warm structure in initial stage,and then turns into cold in succession on different layers.(4)Both two vortex enhanced the unstability of atmosphere,led to the severe convection weather which have different intensity because the different vapor and thermal condition.(5)There maybe some differences on the vortex's development factor,but they are all related to the horizontal convergence and the vertical transport(varies in different layers).(6)in the term of vortex energy,the release of latent heat during the heavy rain and the downward of the high momentum from the upper air is contributed to the development of Plateau Vortex.During the the development of cold deep vortex,the downward turbulence kinetic energy and turbulence available potential energy(TAPE),especially the TAPE,has contribute the most in the maintain of the high TAPE in the middle layer.The main reason of development of TKE and TAPE is different in different stage of deep clod vortex.