Chapter 18• Characteristics
of water…• Frozen water = ice• Liquid water =
water• Water as a gas =
water vapor
• Melting• Evaporation• Condensation• Sublimation• Deposition• Freezing
• Ice to water• Water to water
vapor• Water vapor to
water• Ice to water vapor• Water vapor to ice• Water to ice
• Humidity• Specific
humidity
• Relative humidity
• Water vapor in the air
• The grams of water in the air (not really used)
• The % of water vapor in the air
• If the humidity is 50%………
• Warm air holds MORE moisture than cold air
• Then the air is “holding” 50% of what it can possibly hold
• What happens at 100% humidity?
• Psychrometer
• Condensation (NOT RAIN!!!)
• Measures the humidity in the air
• Dew
• Dew Point
• Water vapor that has condensated on the ground
• The temperature at which the air can no longer “hold” the water vapor and it condenses on the ground
• Condensation nuclei
• Dust or small particles floating in the air that water vapor will condense on …helps to form fog
• Frost • When the dew point is below freezing, water vapor DEPOSITS on the ground as frost………..it is not frozen dew
• Sublimation……… • When there is frost on the ground and the temperature rises above freezing, the frost SUBLMATES straight to water vapor
• Fog • Radiation fog
• Advection Fog
• A low cloud• Clear night, warm
ground loses heat to the cool air……especially over a body of water
• Moist, warm air blows over a cool surface (like a fog over snow)
• Stratus• Cumulus• Nimbus• cirrus
• Sheets/layers• Puffy• Rain• Wispy/horse tails
(very high and mostly ice)
• Formation of clouds occurs at the condensation level….
• Air is cool enough for the water vapor to condense and begin to form clouds
18.3 Precipitation
• Rain• Hail
• Freezing Rain
• Sleet • Snow
• Water• Only from t-storm
clouds (Ice)• Rain that freezes when
it contacts the earth’s surface
• Ice • Crystallized water