起伏条件下重力碰并造成的暖性薄云降水
ON THE FORMATION OF THE PRECIPITATION ELEMENT IN A SHALLOW WARM-CLOUD
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摘要: 本文中考虑了云中垂直气流的湍流起伏,来計算云滴的碰并增长.发現在这种上升气流有起伏的环境下,同样大小的云滴在云中可以长成不同大小的較大云滴,包括降水胚滴和降水微元(雨滴),从而对暖性薄云如何形成降水給出一个此較合理的解释.Abstract: Taking consideration of the fluctuation in the vertical current, it is pointed out that the precipitation element will form more easily in a shallow warm-cloud. Under the assumption that the frequency distribution of the vertical current is Gaussian, the growth rate of the cloud droplet is calculated for a simplified cloud model. The result shows that even in a cloud with 1 km thickness the precipitation elements of radius greater than 100μ could be formed under average condition.