A

David

Darling

troposphere

The troposphere is the lowest level of a planetary atmosphere where convection keeps the gas mixed. In the case of Earth's atmosphere, the troposphere extends up to a height of 10 to 16 kilometers, where it meets the tropopause. Its temperature decreases steadily with altitude from about 290 K to 240 K at a rate of about 6.5 K per kilometer. Almost all the atmospheric water vapor and weather systems occur here.