GEOG 1290 Lecture Notes - Lecture 21: Altostratus Cloud, Stratocumulus Cloud, Cirrocumulus Cloud
29 Nov 2014
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Document Summary
Little water vapor and low temp clouds are thin and composed of ice crystals. Low bases with heights up to 15 km. Process that produce precipitation: collision and coalescence. Precipitation in tropics and midlatitudes (warm clouds where temperatures are above 0 degrees c) Merging of water droplets until they are large enough to fall. Ice crystals and supercooled droplets coexist in cold clouds. Ice crystals attract vapor, supercooled drops evaporate to replenish the vapor. Common outside of tropical regions: unequal heating of surface causes air to expand and parcel to rise, pressure of unstable air decreases as it rises (and cools adiabatically- condensation at lcl, spontaneous (no external force) Orographic: air mass travels upslope and precipitation is produced if air is cooled to the dew point (lcl) Unstable air: precipitation continues as it rises. Stable air: air descends, adiabatic warming occurs and precipitation stops. Radiation: formed when temperature of air at ground level falls below dew point.
