Geography 120 Ch.5

  1. Absolute Humidity
    measure of water vapor content or density of water vapor. Not widley used because it is dependent on temperature even though the amount of vater vapor never changes. it does this because if an air parcel expands the absolute humidity will fall.
  2. Specific Humidity
    expresses the mass of water vapor existing in a given mass of air.
  3. Relative Humidity
    most commonly used measure of water vapor content. relates amount of water vapor in the air to the maximum possible aat the current temperature.
  4. Dew Point
    moisture index free of temperature relationship. it shows the temperature at which saturation occurs.
  5. Name the three ways air can become saturated
    • 1. adding water vapor to the air
    • 2. mixing of cold air and warm air
    • 3. lowering temperature to dew point
  6. Supercooled water
    water having a temperature below the melting point of ice but nonetheless existing in a liquid state. this occurs at temperatures between 0 and -4 C.
  7. Diabatic Process
    when energy is added to or removed from a system resulting in changing temperature
  8. Adiabatic Processes
    when temperature changes but no heat is added to or removed from a substance.
  9. Dry Adiabatic Lapse Rate
    a parcel of unsaturated air cools 1 degree Celsius for every 100 meters of asent despite the fact that no heat is removed.
  10. Lifting Condensation Level (LCL)
    when a parcel of air rises high enough and cools sufficiently, expansion lowers its temperature to te dew or frost point and condensation or deposition commences.
  11. Saturated Adiabatic Lapse Rate (SALR)
    for every 100 meters a parcel of air rises it loses .5 degrees celsius.
  12. Environmental Lapse Rate
    applies to the vertical change in temperature through still air. the rate at which an ambient parcel of air decreases with height. the ELR for the troposphere is highly variable.
  13. Radiation Fog
    also known as ground fog, develop when nighttime loss of longwave radiation causes cooling to the dew point. it is likely to form ON CLOUDLESS NIGHTS WITH LIGHT WINDS. in the early moring the fog will burn off.
  14. Advection Fog
    forms when relatively warm, moist air moves horizontally over a cooler surface. (term advection refers to horizontal movement). As the air passes over the cooler surface it transfers heat downward; this causes it to cool diabatically. If sufficient cooling occurs, a fog forms. San Franciso Bay area.
  15. Upslope Fog
    formed by adiabatic cooliing., when air flows along a gently sloping surface, it expands and coolsas it moves upward. Seen a lot west of the mississippi river.
Card Set
Geography 120 Ch.5
geography ch5 terms