冷锋雨带中湿物理过程与非绝热锋生的相互作用

利用包含冰相微物理过程参数化方案的三维非静力中尺度／云模式（ARPS）模拟了与冷锋有关的冷锋雨带（NCFR）结构，着重分析了锋面云系发展演变的主要特征。模拟结果表明，锋面云系是由位于锋面前沿处的锋面次级环流的上升运动激发的；锋面强度与冷锋云（雨）带中的潜热释放之间的正反馈引起的持续非绝热锋生是锋面以及冷锋雨带得以长时间维持的主要物理机制。进一步分析表明，锋区两侧位温梯度的增加是与沿着冷锋表面的倾斜上升运动引起的云水及水汽的再分布密切相关的，即在冷气团中由云水蒸发发冷却形成冷池，而在暖气团中由水汽凝结以及雨滴冻结等形成暖池，这种冷／暖池在冷／暖气团上的叠加是引起非绝热锋生的关键。

Interaction of diabatic frontogenesis and moisture processes in cold-frontal rain-band

Three-dimensional simulation of cold-front rain-band (NCFR) associated with a straight cold front has been studied by use of a non-hydrostatic, full compressible storm-scale model (ARPS) including multi-phase microphysical parameterization. The dynamical and physical features of the frontal cloud de velopment have been well simulated and analyzed. It is in evidence that the frontal cloud is triggered by the updraft of the secondary frontal circulation. However, the long persistence of diabatic frontogenesis onlycan be attributed to positive feedback between the frontal baroclinicity and the prefrontal latent heat release. The simulations indeed demonstrate that the potential temperature gradient enhancement in front zone is strongly related with the re-distribution of cloud moisture, by the action of tilted updraft. In conse.quence, the splice of cooling and heating pool that is respectively created from the evaporation of cloud water and condensing / freezing of water vapor / rain droplet, wich is in favor of the strong contrast of cool and warm air mass across the frontal zone to diabatic frontogenesis.