湿急流的结构及形成过程

利用比较稠密的无线电探空和气球测风观测网,通过对华北夏季一次暴雨过程的三维流场和湿度场的分析,揭示了湿急流的结构和形成过程.湿急流是指低层空气在湿不稳定大气的上升过程中,不断加速形成一支斜穿整个对流层的自下而上的急流.在湿急流附近,凝结饱和区的分布和发展过程,似乎表明水汽在急流形成过程中起了一种主动作用.湿急流在对流层顶附近和副热带急流合併,并使副热带急流的动能增加.这似乎启示,湿斜压过程可能是大气环流中的基本过程之一.

THE STRUCTURE AND FORMATION OF THE MOIST JET STREAM

By use of the fairly dense network of radio soundings and pilot balloons,the three dimensional structure and the formation process of the moist jet stream were shown by wind and humidity field in a case of heavy rain over north China in summer.The moist jet stream is a stream penetrating slantly through whole troposphere fxom Iow to high troposphere,which is formed as the air of the low level rises and accelerates in the moist unstable atmosphere.The distribution and the development process of the saturation and condensation area around the moist jet stream appears as if the water vapor plays a active role in the jet stream formation process.The fact,that the moist jet stream combines with the substropical jet stream near the tropopause and strenghtens the kenitic energy of the subtropical jet stream,shows that the moist baroclinic process is probably one of the essential processes in the atmospheric circulation.