The study of clouds, their location and characteristics, plays a key role in the understanding of climate change. Low, thick clouds primarily reflect solar radiation and cool the surface of the Earth. High, thin clouds primarily transmit incoming solar radiation, but at the same time they trap some of the outgoing infrared radiation emitted by the Earth and radiate it back downward, thereby warming the surface. Parameters include temperature and moisture profiles, fractional cloud cover, cloud top height, cloud top pressure, surface temperature and surface emissivity.