ENVIRSC 1A03 Lecture Notes - Lecture 7: Nimbostratus Cloud, Cirrocumulus Cloud, Advection
8 Nov 2015
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Document Summary
How do cloud droplets form: form by collision and bonding of water vapour molecules. Condensation nuclei: given their small size, formation of droplets only occur under supersaturation, therefore the small size requires a catalyst called the condensation nuclei, sea salt is a condensation nuclei. Assumptions to simplify formation of clouds: no mixing takes place between rising air and its surroundings, only a single thermal produces the cloud, cloud forms when relative humidity is 100, rising air in the cloud remains saturated. Orographic uplift: when a mass of air is deflected over or around terrain like a hill or mountain, produces adiabatic cooling and the development of clouds, does not require tall mountains to happen. Straight clouds: blanket like and cover most of the sky. Nimbus clouds: associated to rainfall and other forms of precipitation. Cirrus: high clouds composed of ice crystals; wispy appearance is due to low water content and cold temperatures.
