1. absolute humidity = mass of water per volume of air
   (grams per meter cubed)
2. specific humidity = mass of water per mass of air
   (grams per kilogram)
3. mixing ratio = mass of water per mass of dry air
   (grams per kilogram)
4. vapor pressure / actual vapor pressure
   --- high actual vapor pressure = large # of H₂O molecules
5. saturation vapor pressure
   --- H₂O vapor necc. to saturate the air
6. relative humidity = amount of water vapor realtive to amount if air were saturated
   • temperature dependent
   • diurnal and seasonal cycle
   • unit = %
7. dew point temperature ... interactive chart
8. "90 degrees and 90% humidity"
   • human perception
9. instruments for measuring humidity
   • hygrometer
   • psychrometer

MOISTURE/PRECIP CHAPTERS ----->

Humidity

Clouds

Stability

Precipitation