Basically because without clouds the relatively warm sensor loses (radiates) heat to space, which is very cold, clouds are much warmer. Scientifically it’s Terrestrial Radiative Cooling, see this Wikipedia article.
Basically because without clouds the relatively warm sensor loses (radiates) heat to space, which is very cold, clouds are much warmer. Scientifically it’s Terrestrial Radiative Cooling, see this Wikipedia article.