The most intense EM radiation that reaches Earth’s surface is short wavelengths of EM radiation from our Sun. This includes some ultraviolet bands all of the visible bands and the reflected infrared bands [both NIR—near infrared and SWIR—short wave infrared ]. The most intense solar radiation is the green visible band.Some solar EM radiation is absorbed by Earth materials or transmitted through them. What is not absorbed or transmitted is reflected back into space, where it is detected by satellite instruments that are remotely sensing the reflected bands of EM radiation. This is done during the day, when the reflections occur.