盆地环流型及冷湖的形成和消散的数值研究

本文建立了一个三维原始方程数值模式，模拟三维盆地中的环流，重点讨论在热力强迫环流型的转变过程中能量场的动量场的配置情况及环流演变过程。模拟结果表明，夜间地面强烈的辐射冷却过程引起盆地各坡面冷迳流的发展，盆地中成为冷空气湖，逆温层结建立。日出后对流边界层从大气低层向上发展，逆温从底部随之消蚀，仅在上层存在了夜间逆温残余，即所谓稳定核，上坡风在对流边界层发展，而稳定核内仍维持夜间下坡风环流。

NUMERICAL STUDY OF CIRCULATION IN BASIN WITH FORMATION AND DISSAPATION OF COLD AIR LAKE

In this article, we set up a three-dimensional numerical model to simulate circulation in basin especially when thermal forcing is reversed. Model results show that radiative cooling at night time can cause cold air flow along sides of basin and cold air lake forms with inver sion lapse rate appearing in center of the basin. After sunrise convective boundary layer (CBL) begins to develop upward from bottom and inversion layer is gradually invaded. Only a part of layer stable is remained above the CBL which is the so-called 'stable core'. Ups lope wind develops in CBL and downward wind remains in stable core. Vertical motion in basin affords effective mechanism to spread heating and cooling. Inversion layer is complete ly disapeared when CBL develops strongly after sunrise and circulation begins to change to daytime pattern. Upslope wind develops along every side of basin. Around sunset time sta ble layer begins to form again with downslope wind in this layer. Inversion lapse rate devel ops rapidly after sunset.