1. Moisture Moisture = Water Vapor (gas) Gets into the atmosphere by: 1.Evaporation = liquid to gas (opposite of condensation) 2.Transpiration = plants release water

2. Factors Affecting Moisture Amount of insolation or temp. Amount of water vapor in air (humidity). Surface area – spread out evaporates faster. Wind speed – wind increases evaporation

3. Relative Humidity Relative humidity = ratio of water vapor in air to amount of water vapor possible. Dew Point = condensation temp. - always lower than air temp. - equal to 100% relative humidity.

4. Psychrometer Instrument that measures humidity. Dry-bulb = regular thermometer Wet-bulb = wet thermometer Use ESRT charts and differences in these temperatures to get DP and RH.