Troposphere

n. lower layer of atmosphere in which weather phenomena are seen

The troposphere is the lowest portion of Earth's atmosphere. It contains approximately 75% of the atmosphere's mass and almost all of its water vapor and aerosols. The average depth of the troposphere is about 11 km in the middle latitudes. It is deeper in the tropical regions (up to 20 km) and shallower near the poles (about 7 km in summer, indistinct in winter). The lowest part of the troposphere, where friction with the Earth's surface influences air flow, is the planetary boundary layer. This layer is typically a few hundred meters to 2 km deep depending on the landform and time of day. The border between the troposphere and stratosphere, called the tropopause, is a temperature inversion.
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Noun
1. the lowest atmospheric layer; from 4 to 11 miles high (depending on latitude)
(hypernym) layer
(part-holonym) atmosphere
(part-meronym) tropopause

n. troposphere, lower layer of atmosphere in which weather phenomena are seen

1. The lower layers of atmosphere, in which the change of temperature with height is relatively large. It is the region where clouds form, convection is active, and mixing is continuous and more or less complete. [JP1] 2. The layer of the Earth's atmosphere, between the surface and the stratosphere, in which temperature decreases with altitude and which contains approximately 80% of the total air mass. (188 ) Note: The thickness of the troposphere varies with season and latitude. It is usually 16 km to 18 km thick over tropical regions, and less than 10 km thick over the poles.