Clouds Identify cloud types from photos Recognize and define prefixes and suffixes for cloud types Associate general weather conditions with cloud types Describe different fog types

Clouds

Click on the image to access the Main Cloud Type image search page

Click on the image to access the NOAA Cloud Chart

Three kinds of fog Radiation fog Advection fog Evaporation fog Evaporation fog on the Kentucky River

Precipitation Explain the collision coalescence process and the Bergeron process Describe the basic role naturally occurring atmospheric aerosols play in precipitation formation Explain how supersaturated atmospheric conditions develop Describe how air pollution impacts cloud formation and precipitation Explain the logic behind weather modification

Collision coalescence process of precipitation formation –Water droplets collide and increase in size until large enough for gravity to pull them out of the cloud –Occurs in tropics and warmer midlatitudes –Precip leaves cloud as liquid water

Collision coalescence process requires presence of condensation nuclei –In clean air, RH must equal 120% for condensation to occur –Air would be considered supersaturated with water vapor –Presence of condensation nuclei allows condensation at 100% humidity

Bergeron process of precipitation formation –Occurs in midlatitudes to poles –All three states of water present –Supercooled water crystallizes upon contact with freezing nuclei –Ice crystals form around freezing nuclei and grow through deposition at the expense of water droplets –Precipitation leaves cloud as ice crystal

Precipitation types under Bergeron conditions Rain – ice crystal melts and liquid water reaches surface Sleet – warm layer melts ice but refreezes as “pellet”. Winter phenomena. Snow – ice crystal falls to ground intact Freezing rain – supercooled liquid water freezes at surface Hail – summertime thunderstorm phenomena.

Conditions for frozen precipitation in KY/Upper South/Lower OH Valley Midlatitude cyclones

Life cycle of midlatitude cyclone

Snow temperature profile Sleet profile Freezing rain profile

Where the low pressure center of the mid latitude cyclone tracks determines the atmospheric temperature profile and whether or not Lexington or another location gets snow, wintery mix (sleet or freezing rain), or rain. Draw a profile for rain

Aerosol air pollution, clouds, and precipitation

Albedo greater in polluted atmosphere Clouds last longer in polluted atmosphere