SOLAR ACTIVITY
SOLAR IRRADIANCE
Solar irradiance at the top of the atmosphere on a plane normal to the incident¿radiation, and at the mean distance of the Earth from the Sun. Solar irradiance¿is also referred to as the solar constant. In satellite remote sensing, the¿solar irradiance is used as an onboard calibration of visible band sensors.¿Some climate studies suggest that small variations in the solar irradiance¿associated with solar activity over days to decades may have an effect the¿Earth's climate.¿ The intensity of the sun's radiation at different wavelengths. The radiation is generally given in terms of solar constant \\ S, defined in terms of flux of total radiation received outside the earth's atmosphere per unit area at mean sun earth distance., and has the value S = 1.34 X 10*6 ergs cm*-2 sec*-1.