loweratmosphere

Lower atmosphere is a term used to describe the lowest portion of a planet’s atmosphere, and on Earth it is generally understood to correspond to the troposphere and the near-surface region just above it. The troposphere extends from the surface up to the tropopause, a boundary whose height varies with latitude and season. It typically lies about 8 to 12 kilometers above the poles, around 12 to 15 kilometers at mid-latitudes, and up to roughly 16 to 18 kilometers near the equator. The lower atmosphere contains the majority of the atmosphere’s mass—roughly 75 to 80 percent—and is the domain where most weather phenomena occur.

Temperature in the lower atmosphere generally decreases with height. In the troposphere the standard lapse rate is about 6.5 degrees Celsius per kilometer, though actual values vary with moisture, instability, and atmospheric conditions. The composition is predominantly nitrogen and oxygen, with smaller amounts of argon, carbon dioxide, neon, helium, and other trace gases, alongside variable amounts of water vapor that drive humidity and cloud formation.

Key processes in the lower atmosphere include convection, turbulence, cloud development, and precipitation, all of which interact with the planetary boundary layer—the portion of the lower atmosphere directly influenced by the surface. The lower atmosphere is routinely studied using weather balloons, ground-based sensors, radar and satellite observations, and numerical models to understand weather, climate, air quality, and environmental change. Above the troposphere lies the stratosphere, marking the transition to higher atmospheric layers.