一次冷涡过程降水的微物理机制分析

该文分析了一次冷涡天气过程中云微物理量的分布特征、降水粒子的增长机制及云下雨滴的蒸发效应。主要结果为:云系由低层暖性Sc云和冷性主体As云组成。As云底高2 km，云顶高大于5 km，云中存在比较大的过冷水区，–11.2 ℃时的过冷水含量0.21 g·m-3，但过冷水的含量分布极不均匀，大于0.05 g·m-3的过冷水区连续分布的宽度87%小于2.4 km，不利于云中冰晶的连续凇附增长；同时云下雨滴的蒸发效应大，直径小于1.0 mm的雨滴难以落到地面，因此本次过程只产生弱的降水。

Analysis of the Microphysical Precipitation Mechanism for a Cold Vortex Process

The distribution characteristics of microphysical elements, growing mechanism of precipitation particle and evaporation effects of subcloud raindrop in a cold vortex process are analysed. The results show that the cloud system consists of two vertical lavers, lower warm stratocumulus and principal cool altostratus. The altostratus base is 2 km high, and cloud top is higher than 5 km. The supercooled water exists abundantly in the cloud, the maximum is up to 0.21 g · m – 3 at – 11.20℃, but its distribution is not homogeneous, 87% of continuous distribution width are less than 2.4 km, which is disadvantage to the rime increasing of ice crystal in the cloud. Meanwhile, the evaporation effect of subcloud raindrop is very big, the diameter of raindrops which could not arrive the ground is less than 1 mm. Therefore, the cold vortex process produces the weak precipitation.