EESB03H3 Lecture Notes - Lecture 4: Cloud Condensation Nuclei, Freezing Rain, Ice Pellets
27 Feb 2020
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Stable : air that rises will be pushed down. Unstable : air that rises will continue to rise. Water molecules connect together but then get blown apart by other particles. Some sort of urface is required to condense on and lower the surface area. Rain: liquid precipitation greater than 0. 5mm droplet size. Drizzle: liquid less than 0. 5mm droplet size. Ice pellets(sleet): air below freezing,originates as snow, but freezes. Freezing rain or drizzle: supercooled water-freezes with impact to ground. Hail: small spheres or chunks of ice, 5-50mm- updrafts cause successive accretion of water droplets around ice core. Strong updrafts allows for very large stnes. Curvature effects and cloud condensation nuclei (ccn) required. Ccn is a hygroscopic material that clouds droplets form on. Supersaturation occurs if no ccn are avaibale. Supersaturation means the rh can exceed 100% What factors affect the production of raindrops-(not all precipitation turns into rain)
