摘要
应用T2 13数值预报产品的分析场和 6h预报场资料对山东省春季一次暴雨天气的成因进行了分析 ,结果表明 :这次春季暴雨主要是受 85 0hPa低涡和地面气旋影响产生的 ,低涡中心和气旋中心北部的辐合上升运动触发对流不稳定能量释放 ,产生暴雨。低空西南风急流为暴雨提供了充足的水汽和不稳定能量。暴雨区低层有较大的正螺旋度和非地转 Q 矢量辐合 ,说明暴雨区有中尺度和大尺度上升运动相叠加。与夏季暴雨的不同在于副热带系统较弱而西风带系统起主导作用 ,暴雨前后冷暖空气活动剧烈。
By using the analyzed and 6-hour prediction data provided by the T213 model, the causes of a heavy rain and the energy and moisture conditions were analyzed. The dynamic trigger mechanism was studied through analyzing the features of helicity and Q* vectors. The result shows that the heavy rain was influenced mainly by the low vortex at 850 hPa and the surface cyclone; the convergence and ascending motion in the center of the vortex and north of the cyclone center triggered convective instability energy release, resulting in the heavy rain. The low-level Southwest Jet provided sufficient moisture and instability energy. The strong positive helicity and the intensive convergence of Q* vectors at the low level in the raining area indicate that there was superposition of mesoscale and synoptic-scale ascending motions. Differing from summer heavy rains, the systems in the westerly belt played a dominant role in spring heavy rain formation, but the subtropical systems are weaker and cool and warm air motions were very active before and after the heavy rain.
出处
《气象科技》
2005年第1期45-49,67,共6页
Meteorological Science and Technology
