Layers of the Atmosphere

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Layers of the Atmosphere
The envelope of gas surrounding the Earth changes from the ground up. Five distinct layers have been identified using... •thermal characteristics (temperature changes),
chemical composition,
movement, and
density.
Each of the layers are bounded by "pauses" where the greatest changes in thermal characteristics, chemical composition, movement, and density occur. Troposphere
The troposphere begins at the Earth's surface and extends from 4 to 12 miles (6 to 20 km) high. This is the layer of the atmosphere in which we live.

The height of the troposphere varies from the equator to the poles. At the equator it is around 11-12 miles (18-20 km) high, at 50°N and 50°S, 5½ miles and at the poles just under four miles high.

As the density of the gases in this layer decrease with height, the air becomes thinner. Therefore, the temperature in the troposphere also decreases with height in response. As one climbs higher, the temperature drops from an average around 62°F (17°C) to -60°F (-51°C) at the top of the troposphere. Almost all weather occurs in this region.

The transition boundary between the troposphere and the layer above is called the tropopause. Together the tropopause and the troposphere are known as the lower atmosphere.

Stratosphere
The Stratosphere extends from the top of the troposphere up to around 31 miles (50 km) above the Earth's surface. This layer holds 19 percent of the atmosphere's gases but very little water vapor.

In this region the temperature increases with height. Heat is produced in the process of the formation of Ozone and this heat is responsible for temperature increases from an average -60°F (-51°C) at tropopause to a maximum of about 5°F (-15°C) at the top of the stratosphere.

This increase in temperature with height means warmer air is located above cooler air. This prevents "convection" since there is no upward vertical movement of the gases and is the reason for the 'anvil-shaped'...
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