Lecture 12: Atmospheric Humidity Flashcards
Where is water in Earth’s systems?
Ice and crops in clouds, water vapor in air, snow and ice on land and in water, water in streams/lakes etc, water in rain and falling snow, water in plants and soil
How and why does water move from vapor to liquid in earth’s atmosphere?
Condensation, ocean currents, runoff and precipitation
What are some properties of water due to polarity and hydrogen bonds?
water is a good solvent and strong surface tension that form drops from hydrogen bond
Absolute humidity
amount of water vapor per cubic meter
Vapor pressure
amount of pressure contributed by water vapor
Relative humidity
amount of water vapor relative to capacity
Dew point
temperature at which air becomes saturated
Why is relative humidity temperature dependent? What happens to RH as temperature changes?
As temperature goes up, saturated vapor pressure goes up as well and RH will go down if absolute humidity remains the same. It is temperature dependent because temperature determines how much water vapor can be in the air at saturation
What are two ways air may reach its dew point?
- By adding water vapor
- By cooling the air so that it reaches its dew point
What are the general patterns of dew points in the U.S?
Southeast has high dew point and low dew point depression = humid
Western has low dew point and high dew point depression = dry heat
Hydrogen bond
attraction between polarity of two adjacent molecules
Evaporation
add energy
Condensation
remove energy
Saturation
at capacity water vapor
Dew point depression
difference between air temperature and dew point
