四川普格县一次暴雨天气过程成因分析

Analysis of Puge County, Sichuan a Rainstorm Weather Process

利用气象自动站的降水资料、数值预报产品,再结合卫星云图、雷达回波产品综合诊断、分析了普格县2014-08-17T20:00—2014-08-18T20:00出现的暴雨、局部大暴雨天气过程。结果表明,中高纬长时间维持"两槽一脊"型是造成不稳定天气的原因;盆地中部、南部有西南涡,且凉山自治州有切变辐合,为强降水天气过程提供了有利的动力条件;盆地内主要受西南气流控制,大气相对湿度高,为强降水天气提供了充足的水汽条件。通过相关分析,为今后该县暴雨预报提供有效的依据和清晰的思路:暴雨出现在强上升运动和非常暖湿的不稳定空气中。与暴雨有直接关系的是中、小尺度上升运动和地形引起的上升运动。大尺度的上升运动是暴雨发生、发展的重要先决条件。大形势稳定水汽的输送和辐合对流不稳定能量的释放和再生。由此可知,形成暴雨必须满足3个条件,即暖湿气团的输送、辐合和不稳定性;强烈的上升运动;稳定环流形势下较长的持续时间。

Using the meteorological automatic station precipitation data, numerical forecast products, combined with satellite images, radar echo, comprehensive diagnosis analysis of 2014-08-17T20：00- 2014-08-18T20：00 in Puge County appear rainstorm, local big rainstorm weather process. The results show that in high latitudes, long time to maintain the ＂two troughs and one ridge＂ type is the cause that causes erratic weather; in the central part of the basin, south of the southwest vortex, and the Liangshan autonomous prefecture has shear convergence, provides favourable condition for strong precipitation weather process; the basin is mainly affected by the southwest airflow control, air relative humidity and high, provided sufficient water vapor condition for strong precipitation weather. Through correlation analysis, offer the effective basis and clear thinking for the future development of the rainstorm forecast： rain occurred unstable air in the strong ascending motion and very warm in the. There is a direct relationship with the rainfall is in small scale, ascending motion and the ascending motion caused by terrain. Large scale upward motion is rainstorm, development an important prerequisite. Convective transport and convergence situation of stable water unstable release and regeneration energy. Therefore, the formation of rain must satisfy 3 conditions, that is, warm air mass transport, convergence and instability; strong ascending motion; continuous time stable circulation situation longer.