【摘要】 2004年7月4日下午,甘肃河东出现强雷阵雨天气并伴有冰雹。从大尺度环境场、物理量场特征、多普勒雷达回波特征3方面综合分析本次强对流天气的成因。本次过程在500 hPa高空环流形势场上呈典型的西北气流型,冷平流随高度增加使不稳定层结得以建立和维持。干冷空气冲击高原东侧到甘肃中部的能量锋,触发了强烈的对流。根据雷达回波演变过程看出,冰雹是由多单体风暴造成的,在径向速度图上可分析出γ中尺度气旋性旋转流场。更多还原

【Abstract】 The causes of a heavy rain with hails and thunderstorm which occurred in the east part of Gansu province on July 4th 2004,were analyzed from three aspects of the synoptic environment,physical quantity field and the characteristics of Doppler radar echoes.Results show that it was a typical northwest flow pattern at the level of 500 hPa,and the intensity of cold advection increasing with height resulted in instability energy accumulation,the dry and cold air touching off the energy front from the east side of Tibet plateau to the middle part of Gansu province led to the strong convection.The evolution of radar echoes showed that the hailstones came from multi-cell storms and the meso-γ scale cyclone could be identified by the radial velocity products of Doppler radar.更多还原