1. Temperature
   • Temperature - the measure of average kinetic energy (KE) of a gas, liquid, or solid. KE is energy of motion.
   • For air and other gases (in the troposphere only), it is common to consider the KE to be proportional to the number of molecular collisions. More collisions means higher temps while less collisions means lower temps.
   • The three temperature scales must be known for the quiz.
   • Kelvin scale is called the absolute temperature scale because it is the only scale that directly measures energy. There are negative temps on the other two scales and it is impossible to have a negative energy.

2. Temperature Profile of the Atmosphere
   • The atmosphere may be divided into four distinct temperature layers:
     • Troposphere: contains most of the atmosphere even though it is very shallow. Gravity causes the air to be concentrated in this layer. The normal environmental lapse rate (ELR) is negative (cooling with increasing height) because the ground is the heat source, but a temperature inversion may exist which results in a positive ELR (warming with height).
     • Stratosphere: above the tropopause, a layer of air that has a positive ELR due to absorption of UV rays from the sun by the ozone.
     • Mesosphere: above the stratopause, a layer of air that has a negative ELR since there is no ozone present and this layer is at an extremely high altitude.
     • Thermosphere: above the mesopause, this layer of air has so few air molecules that the KE is extremely high due to the very high velocities of these few air molecules. By definition that implies a very high temperature so the ELR is positive. In reality, the air is not "hot to the touch" since there is so little air present one would not feel anything.

3. Methods of Heat Transfer
   • Conduction - heat that is transferred via molecule to molecule contact. Ex. surface air is heated by touching the warmer surface of the earth.
   • Radiation - heat that is transferred by wave-like energy (ex. photons) without any molecular contact and with no air movement involved. Ex. earth is warmed by the sun via radiation.
   • Convection - heat that is transferred by moving air or water. Ex. warm air rising into the atmosphere transfers heat from the lowest levels to above.

4. Adiabatic Process (See the mathematical argument)
   • The process which involves a rising or sinking air parcel and the temperature changes associated with that motion.
   • As an air parcel rises it moves into an area of lower pressure aloft. This lower pressure causes the air parcel to expand. The expansion allows more room for the air molecules inside the parcel to move about. More room means less collisions between the molecules. Fewer collisions means less average KE. Less average KE means cooler temperatures. Therefore, RISING AIR ALWAYS COOLS.
   • As an air parcel SINKS it moves into an area of higher pressure below. This higher pressure causes the air parcel to compress. The compression allows less room for the air molecules inside the parcel to move about. Less room means more collisions between the molecules. More collisions means greater average KE. Greater average KE means warmer temperatures. Therefore, SINKING AIR ALWAYS WARMS.
   • The rate of warming or cooling is constant and is known as the adiabatic lapse rate (ALR). The ALR = 5.5 ^oF/1,000 ft. or 10 ^oC/1 Km.

5. Environmental Lapse Rate
   • Refer to the Math Quiz Help.

Helpful Links:

UIUC Online Guides
Temperature Scales
How Things Work - Info on heat transfers.
Air Temperature - Another professor's notes.
Adiabatic Process
Plotting Isopleths - Please visit this link!
Plotting Isopleths - Test your skills on this interactive map.
Temperature World