| Aerosol | Fine solid or liquid particles in the atmosphere, such as smoke, fog, dust or mist. |
| Albedo | The fraction of solar radiation that is reflected by a surface (such as the earth). |
| Atmospheric Profile | A description of the atmosphere, including the pressure, temperature, water content, and ozone at every altitude. |
| Filter Function | The response function of an instrument at each wavelength. |
| Irradiance | Radiant flux density incident on a surface. Watts per square meter. (W/m2). |
| Optical Depth | A measure of the number of scattering events that occur between a source of light and the observer. |
| Radiance | The flux density of radiant energy per unit solid angle and per unit area. Watts per square meter per steradian. (W/m2/str). |
| Radiant Energy | The energy of electromagnetic waves (light). Joules. symbol Q. |
| Radiant Flux | The rate at which radiant energy is transmitted in waves. Watts. (dQ/dt). |
| Solar Constant | The quantity of solar energy normally received at the outer layer of the earth's atmosphere. |
| Spectral Irradiance | The radiant flux density incident on a surface, resolved spectrally. (W/m2/um). |
| Spectral Radiance | The radiant flux density per unit solid angle, resolved spectrally. (W/m2/um/str). |
W = Watts, m2 = meters squared, um = micrometer, str = steradian