诱发哈萨克斯坦暴雨的环流结构特征

The Characteristics of Circulation Structure Inducing Summer Heavy Rainfall in Kazakhstan

摘要:

采用FNL1°×1°和CPC0.5°×0.5°再分析资料，通过对比分析夏季哈萨克斯坦不同区域的3次强降水过程的环流特征，揭示了诱发强降水的环流结构。结果表明：哈萨克斯坦各区域出现强降水时，西部和东部的强降水中心位于高空急流带入口区右侧，北部位于出口区左侧，辐散抽吸作用利于上升运动发展；强降水的影响系统主要为500 hPa低涡，强降水中心位于低涡槽线前部西南气流带上，中层温度平流对强降水发生有促进作用，西部和北部强降水中心位于低层冷平流大值区，东部则位于东北冷平流南侧的气旋性辐合区；除哈萨克斯坦东部强降水受地形影响地面系统尺度较小外，西部和北部强降水时地面有明显的冷锋，并存在气旋性的辐合切变，冷暖汇合形成的辐合线是强降水的主要中尺度触发系统；哈萨克斯坦强降水的水汽源地主要为地中海、黑海、波斯湾和北冰洋，经长途输送在强降水区形成强的水汽辐合，辐合值＞40×10-6 g?cm-1?s-1。

Abstract:

By using FNL1 ° × 1 ° and CPC0.5 ° × 0.5 ° reanalysis data, the circulation characteristics of three heavy rainfall processes in different regions of Kazakhstan during summer were compared and analyzed, revealing the circulation structure that induced heavy rainfall. The results show that when heavy rainfall occurs in various regions of Kazakhstan, the centers of heavy rainfall in the western and eastern regions are located on the right side of the entrance area of the high-altitude jet stream, while the northern region is located on the left side of the exit area. The radiative suction effect is conducive to the development of upward movement. The main impact system of heavy rainfall is the low vortex at 500 hPa, with the center of heavy rainfall located on the southwest airflow belt in front of the trough line. The middle level temperature advection promotes the occurrence of heavy rainfall, while the western and northern heavy rainfall centers are located in the low level cold advection high value area, and the eastern part is located in the cyclonic convergence area on the south side of the northeast cold advection. Except for heavy rainfall in eastern Kazakhstan, which is affected by terrain, the surface system scale is relatively small. During heavy rainfall in western and northern Kazakhstan, there are obvious cold fronts on the surface and cyclonic convergence shear. The convergence line formed by the convergence of cold and warm is the main mesoscale triggering system of heavy rainfall. The main sources of water vapor for heavy rainfall in Kazakhstan are the Mediterranean, Black Sea, Persian Gulf, and Arctic Ocean. Through long-distance transportation, strong water vapor convergence is formed in heavy rainfall areas, with convergence values reaching over 40 ×10-6g?cm-1?s-1.