1. Atmospheric Moisture

2. What is Atmospheric Moisture Changing forms of water Changing forms of water Energy absorbed and lostEnergy absorbed and lost Latent Energy

3. Sublimation – solid (ice) turns to water vapor. Ex: dry ice, add to clouds & make bigger (dry and cold) make bigger (dry and cold) Deposition – water vapor changes directly to ice. Ex: snow formation in clouds in clouds

4. Humidity Humidity – Amount of water vapor in the atmosphere. Humidity – Amount of water vapor in the atmosphere. Controlled by rates of condensation and evaporationControlled by rates of condensation and evaporation As the temperature of the air increases, the more water vapor the air can holdAs the temperature of the air increases, the more water vapor the air can hold Relative Humidity – ratio of the amount of water vapor in the air to the amount of water vapor it can hold. (saturated  at equilibrium) Relative Humidity – ratio of the amount of water vapor in the air to the amount of water vapor it can hold. (saturated  at equilibrium)

5. Absolute Humidity Absolute Humidity Mass or actual amount of water vapor in the airMass or actual amount of water vapor in the air Calculating Absolute Humidity Calculating Absolute Humidity Absolute humidity = mass of water vapor (grams) volume of air (cubic meters) volume of air (cubic meters) It’s hard to measure due to the changing/shifting of the air!!! Probably result of the temperature and pressure

6. Dew Point Dew point – The temperature to which air must be cooled to reach saturation. Dew point – The temperature to which air must be cooled to reach saturation. Below 32º F, dew is frozen = frost Dew- moisture that forms at dew point

7. Measuring Humidity Psychrometer – instrument used to measure relative humidity. Psychrometer – instrument used to measure relative humidity. Try to better predict weather conditions Try to better predict weather conditions Consists of two thermometers Consists of two thermometers One damp and one dryOne damp and one dry Absorption and Evaporation ofAbsorption and Evaporation of Moister Moister Compare the temperatureCompare the temperature readings readings Calculate Relative HumidityCalculate Relative Humidity If no difference then If no difference then atmosphere is saturated