The amount of solar radiation reflected from land and sea surfaces, as well as the amount absorbed, depends partly on that portion of the spectral distribution of transmitted irradiant energy from the Sun that finally reaches these surfaces. That is confirmed in the plot shown below that also shows many of the principal water, carbon dioxide, and oxygen absorption bands. Heat is transferred into and out of near surface layers owing to external heating by the thermal processes of conduction, convection, and radiation. For any given material, certain characteristic internal properties play important roles in governing the temperature of a body at equilibrium with its surroundings. It is given in cgs units of calories per cubic cm.
P is a measure of the heat transfer rate across a boundary between two materials.
The interpretation of thermal data and images depicting temperature distribution over an area is not a simple matter. It may be possible to correct for the influence of some of the variable factors but this is difficult to do routinely. Measurements made at isolated individual points in a scene and extrapolated to the general scene have limited validity.