Lower atmosphere

Lower atmosphere is a collective term sometimes used to refer to various layers of the atmosphere of the Earth and corresponding regions of the atmospheres of other planets, and includes:


 * The troposphere, which on Earth extends from the surface to an altitude of about 12 km
 * The stratosphere, which on Earth lies between the altitudes of about 12 km and 50 km, sometimes considered part of the "middle atmosphere" rather than the lower atmosphere