利用卫星云图、常规地面观测资料和逐6 h的1°×1°NCEP再分析资料, 对2003-2006年春季滇黔准静止锋背景下, 出现的5次贵州暴雨天气过程进行了诊断分析和总结。结果表明: 在准静止锋背景下, 贵州春季暴雨是由高低空急流、高空槽、冷空气与准静止锋的共同作用产生的。低空急流将大量的水汽从孟加拉湾和北部湾输送到贵州, 不断积累对流有效位能; 高空急流的加速增强了"高层辐散、低层辐合"的大尺度上升运动, 并通过急流下侧的正环流圈带动冷空气南下, 使得准静止锋活跃锋生, 是暴雨天气过程的触发机制。锋生现象分析表明, 高空急流加速导致对流层中高层极锋锋区内锋生和对流层中层正环流圈的形成, 加强了准静止锋附近的水平变形和垂直运动, 进而促使锋生加强。水平变形和垂直运动对暴雨的产生也有直接影响: 水平变形项范围越大则降雨强度越强, 与垂直运动相关的倾斜项移动与在准静止锋附近生成的强对流云团的移动方向一致。准静止锋与贵州春季的暴雨过程关系密切, 暴雨落区集中分布在准静止锋南侧1个纬距带内。高空急流加速度、冷锋附近的水汽辐合强度以及对流有效位能的高能舌区范围对暴雨范围和强度有指示作用。基于以上锋生机制, 提炼了滇黔准静止锋诱发贵州春季暴雨的物理模型。

Using satellite images, observational data and the 6-hour-inteval reanalysis data with 1°×1° resolution from NCEP, five spring rainstorm processes in Guizhou Province under the background of Dian-Qian quasi-stationary front from 2003 to 2006 are analysed. The results show: In the setting of quasi-stationary front, the spring rainstorm in Guizhou Province is impacted together with the upper and low jet stream, upper trough, cold air and the quasi-stationary front. The rich water vapor is transported from the Bay of Bengal and Beibu Gulf to Guizhou province by low level jet stream, and the convective available potential energy is accumulated continuously. The acceleration of high jet stream strengthens the large-scale ascending motion with divergence in high level and convergence in low level, and drives the cold air southward via the positive circulation below the jet stream, then makes the quasi-stationary front active and frontogenesis, which is the trigger mechanism of the rainstorm processes. The frontogenesis phenomenon shows that the acceleration of high level jet stream results in the frontogenesis in the polar front in the mid-upper troposphere and the formation of the positive circulation in the middle troposphere. The latter strengthens the horizontal deformation and vertical motion and then enhances the frontogenesis. The horizontal deformation and vertical motion impact the rainstorm directly: The range of the horizontal deformation is in proportion to the rainfall intensity, and the convective cloud generating near the quasi-stationary moves along the direction of the inclined item related to vertical motion. Quasi-stationary front is close to spring rainstorm in Guizhou province. The heavy rainfall area is distributed mainly southward one latitude zone from the quasi-stationary front. The acceleration of high jet stream, the intensity of the moisture convergence around the cold front and the region of high-energy tongue have an indicative function to the extent and intensity of heavy rainfall. Based on above frontogenesis mechanism, a physical model about spring rainstorm in Guizhou province induced by the quasi-stationary front is epurated.