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The Atmosphere
| Term | Definition |
|---|---|
| Atmosphere | an invisible layer of gases that envelops Earth. it performs several ecologically important functions. it protects the Earth's surface from most of the sun's ultraviolet radiation and X-rays. |
| Troposphere | the layer of the atmosphere closest to Earth's surface. it extends to a height of 12 km. weather, including turbulent wind, storms, and most clouds, occurs in this area. |
| Stratosphere | the layer of the atmosphere found directly above the troposphere. it extends from 12 km to 50 km. steady wind, but no turbulence. it contains a layer of ozone, which is critical to life, because it absorbs much of the sun's damaging ultraviolet radiation. |
| Mesosphere | the layer of atmosphere directly above the stratosphere. it extends from 50 km to 80 km above the earth's surface. temperatures drop steadily to the lowest in the atmosphere. |
| Thermosphere | the layer of atmosphere is the outermost one. it extends from 80 km to 480 km. gases in the thin air of this area absorb x-rays and short-wave ultraviolet radiation. it also reflects outgoing radio waves back to earth without the aid of satellites. |
| Winds | complex horizontal movements. |
| Coriolis Effect | the influence of Earth's rotation, which tends to turn fluids (air and water) toward the right in the Northern Hemisphere and toward the left in the Southern Hemisphere. |
| Prevailing Winds | major surface winds that blow more or less continually. |
| Polar Easterlies | prevailing winds that generally blow from the northeast near the North Pole or from the southeast near the South Pole. |
| Westerlies | winds that generally blow in the mid-latitudes from the southwest in the Northern Hemisphere or from the northwest in the Southern Hemisphere. |
| Trade Winds | tropical winds that generally blow from the northeast in the Northern Hemisphere or from the southeast in the Southern Hemisphere. |