Atmospheric Moisture and Stability Current Weather Humidity Atmospheric Stability Return and Go Over Exam I For Next Class: Read Chapter 6: pp. 167-181 No Class on Friday – Look for Assignment on AsUlearn
Humidity What are some common measures of water vapor in the atmosphere and what do they mean?
Water Vapor in the Atmosphere Relative Humidity Compares the actual amount of water vapor in the air with the amount of water vapor that would be present if that same air were saturated Expressed as a percentage When air is saturated, relative humidity is 100% Varies inversely with temperature © AMS
Relative Humidity Figure 7.8
Water Vapor in the Atmosphere Vapor Pressure Pressure produced by the gas molecules composing air depends on mass of the molecules kinetic molecular activity © AMS
Specific humidity: grams of water vapor per kilogram of air (g/kg) Absolute humidity: grams of water vapor per cubic meter of air (g/m3) Source: Wikipedia
Precipitable Water Depth of water that would be produced if all the water vapor in a vertical column of air were condensed into liquid water © AMS
Dewpoint The dewpoint is the temperature at which dew forms and is a measure of atmospheric moisture. It is the temperature to which air must be cooled at constant pressure and water content to reach saturation. Source: Wikipedia
Wet Bulb Temperature The wet-bulb temperature is the temperature a parcel of air would have if it were cooled to saturation (100% relative humidity) by the evaporation of water into it, with the latent heat being supplied by the parcel. Critical temperature for snowmaking at ski resorts Source: Wikipedia
Relative Humidity Patterns Figure 7.11
Saturation Vapor Pressure Figure 7.12
Maximum Specific Humidity Figure 7.13
Adiabatic Processes What does adiabatic mean?
Adiabatic Processes Figure 7.17
Adiabatic Cooling Figure 7.17
Adiabatic Heating Figure 7.17
Atmospheric Temperatures and Stability Figure 7.18
Stable vs. Unstable Air https://scied.ucar.edu/webweather/weather-ingredients/stable-unstable-air
Three Examples of Stability Figure 7.19