The relationship between vertical air velocity at cloud base and primary ice formation has been measured for shallow mixed-phase cloud layers (thickness <380 m) by means of ground-based cloud radar and Doppler lidar. For layers with a cloud-top temperature below −12 °C, an increase of vertical-velocity standard deviation from 0.1 to 1.0 m s⁻¹ leads to an increase in the mass flux of ice water by two orders of magnitude. The cloud layers under study were selected in such a way that secondary ice-formation processes played a minor role, and primary ice formation was the dominant source of ice formation. Phenomenological parameterizations of the ice mass and the ice mass flux as functions of standard deviation of vertical air velocity are given.

利用地面云雷达和多普勒激光雷达测量了浅层混合相云层（厚度<380 m）的云底垂直空气速度与初次冰层之间的关系。对于云顶温度低于-12°C的层，垂直速度标准偏差从0.1到1.0 ms ^-1的增加导致冰水的质量通量增加两个数量级。选择要研究的云层的方式使得次要的冰形成过程起着较小的作用，而主要的冰形成是主要的冰形成来源。给出了冰质和冰质通量的物象学参数化，作为垂直空气速度的标准偏差的函数。