Extraterrestrial irradiance (E0) and Top of Atmosphere (ToA) radiation
This service provides daily values of the Extraterrestrial irradiance (E0), i.e. received by a plane normal to sun rays and outside the atmosphere, and Top of Atmosphere (ToA) radiation, i.e. received by a horizontal surface and outside the atmosphere. E0, in W/m², depends on the sun-earth distance, and thus on the date. ToA is given in irradiance (W/m²) and irradiation (J/m², Wh/m²).