地形与双冷锋的锋生过程  

Topography and Frontogenetical Process of Double Cold Front

作　　者：吕克利[1] 农尚尧[1] 

机构地区：[1]南京大学大气科学系

出　　处：《大气科学》1995年第2期183-191,共9页Chinese Journal of Atmospheric Sciences

基　　金：国家攻关项目85-906资助

摘　　要：本文利用半地转模式，讨论了双冷锋的锋生过程及其越过山脉的演变。结果显示，在变形场作用下，双冷锋在移行过程中会发生上层锋合并的现象。在锋生过程中，下层前一条冷锋加强远大于后一条，在上层则是后一条冷锋的加强远大于前一条。地形对双冷锋有重大影响，山的迎风坡对冷锋移行有阻挡作用，并削弱锋的强度，背风坡则加速锋的移行，并加强锋的强度。山对双冷锋的上层锋的合并有促进作用，并造成近地面锋区呈现鼻状突出；地形促使锋区垂直速度大大增大，并导致其产生跳跃式变化；地形对锋的影响限于下层锋区。The frontogenetical process and development of a double cold front over a mountain are studied by using a semi-geostrophic model. The results show that the upper level part of the double cold front may be merged in the movement under the effect of deformation factor. In frontogenetical process, the intensity of the ahead front is strengthened much more than that of the back front in lower level. On the contrary, the back front is strengthened more than the ahead front in uPPer level. The influence of topography is importmant on the double cold front. Front movement is retarded and intensity is weakened on windward side of a mountain, and there is an accelaration of the front movement and an enhancement of the intensity on the lee side. Mountain has a promoting effect on the upper level part of double cold front, and causes the cold front to form a nose-shape lobe near the surface, topography increases greatly the vertical velocity in the front zone, and leads to a jump in vertical velocity. The impacts of mountains on fronts are limited within the lower troposphere.

关 键 词：地形 双冷锋 锋生 

分 类 号：P441[天文地球—大气科学及气象学]