Ghy 104 1nd Edition Lecture 16Current LectureClouds and Fog- Clouds – aggregation of tiny moisture droplets and ice crystals suspended in air, great enough in volume and concentration to be seen- Fog – a cloud that is in contact with the ground2 principal processes- Collision coalescence process- Bergeron process- Occurs in the higher parts of the troposphere- Decreased pressure means both liquid water and solid water (ice) can co-exist- Liquid water can be super-cooled below freezing- Liquid water sheds water molecules which are absorbed by growing ice crystals- Eventually snow falls, or melts during descent into rainCloud Types and Identification- Altitude and shape – key to cloud classification- Clouds occur in 3 basic forms: flat, puffy, and wispy; in 4 altitude classes: low, middle, high, and vertically developed; and 10 basic cloud types- Stratiform: horizontally developed, flat and layered- Cumuliform vertically developed, puffy- Cirroform: wispy, high in altitude, made of ice crystalsType of clouds- CirrusThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- Cirrostratus- Cirrocumulus- Altocumulus- Altostratus- Stratus- Nimbostratus- Stratocumulus- Cumulus- CumulonimbusFog- Fog formation is essentially “cloud” formation at or near the Earth’s surface- Fog can form almost the same way as clouds, but two main differences exist.- Air cools, and once Ta cools down to the Tdp, condensation occurs. Fog does not usually form from upward motion- Moisture source – higher amounts of water vapor in cooling areas. Note that clouds generally do not form this way.- Visibility restricted to >1km- Fog tells us that the Ta and Tdp at ground level are nearly _____, indicating saturated conditions- Advection fog (air in one place migrates to another where conditions are right for saturation)- When warm, moist air moves over cooler body of water- Evaporation fog – cold air lies over warmer body of water, and evaporation from water surface causes saturation and fog.- Upslope fog – air cools as it moves upslope… as in our Great Smoky Mountains- Valley fog – air in valleys is denser and colder that surrounding air, causing fog- Radiation fog (radiative cooling of a surface chills air layer directly above that surface to Tdp creating saturated conditions)- Loss of longwave radiation at night over moist surface causes saturation.The Fog BowlType of fog that impacted the “Fog Bowl” between the Philadelphia Eagles and Chicago Bears on December 31, 1988- High daytime temperatures around the Chicago area (upper 30s Fahrenheit)- Cold water in Lake Michigan (32 degrees