Ch. 2 Geography

one two-billionth of the energy emitted by the Sun. Some is directly absorbed by the atmosphere and surface. It provides the energy for the movement of the atmosphere, the growth of plants, the evaporation of water, and infinately other activities.

the movement of heat through a substance without appreciable movement of molecules. An example of this is a metal rod above a campfire. The rod above the flame is warmed and the molecules there gain energy. Heat is "passed"

the transfer of heat by the mixing of fluids

only form of heat transfer that can be propagated without a transfer medium. EVERYTHING radiates electromagnetic energy.

hypothetical bodies that do not exist in nature. They emit maximum radiation at every wavelength. . Earth and sun are close to blackbodies. The factor that determines how much energy a blackbody radiates is its temperature. Hotter bodies emit more energy than cold ones do

capable of emiting maximum radiation at certain temperatures.

the percentage of energy radiated by a substance relative to that of a blackbody

wavelengths less than 4 um. Sun mostly emits shortwave radiation

electromagnetic energy with wavelengths longer than 4 um. The radiation emanating from the earth is longwave radiation.

imaginary surface that is flat on which the earth rotates.

the point at which the earth is CLOSEST to the sun. This occurs every year on or about January 4th

the point at which the earth is furthest away. This occurs on or about July 4th.

when the northern hemisphere of the earth has its maximum tilt toward the sun. This occurs on June 21

when the northern hemisphere has its minimum availability of solar radiation. Occurs on December 21st

an tntermediate between the two solstices where everywhere on earth has equal amounts of energy and recieves 12 hours of sunlight. Occurs on March 21st

• an tntermediate between the two solstices where everywhere on earth has
• equal amounts of energy and recieves 12 hours of sunlight. occurs on September 21st

at 23.5 degrees North latitude where the most northward latitude at which the subsolar point is located. The sun never passes directly overhead of this pint. This occurs in June

the southernmost pint where the sun never passes and this occurs on December 21st.