Difference between revisions of "AY Honors/Weather/Answer Key"
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| − | + | [[Image:Wave cloud.jpg|thumb|320 px|This wave cloud pattern formed off of the [[Île Amsterdam]] in the far southern [[Indian Ocean]], due to orthographic lift of an airmass with alternating bands of high and low humidity over the island.]] | |
| − | Orographic | + | '''Orographic lift''' occurs when an [[air mass]] is forced from a low [[elevation]] to a higher elevation as it moves over rising terrain. As the air mass gains [[altitude]] it expands and cools [[Adiabatic cooling|adiabatically]]. This cooler air cannot hold the moisture as well as warm air and this effectively raises the [[relative humidity]] to 100%, creating [[cloud]]s and frequently [[precipitation (meteorology)|precipitation]]. |
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| + | Orographic lift is demonstrated in many places in the world, but few examples are as clear as those in the [[Northwestern United States]]. In the states of [[Washington]] and [[Oregon]], places on the sea-facing side of coastal mountains see over 100 inches (over 2.5 m) of [[precipitation (meteorology)|precipitation]] per year. These locales are on the side of the [[mountain]]s which are in the path of [[storm]] systems, and therefore receive the moisture which is effectively squeezed from the clouds. However, on the other side of the [[mountain]]s, sometimes as little as 15 miles (25 km) away, annual [[precipitation (meteorology)|precipitation]] can be as low as 8 inches (200 mm) per year. | ||
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| + | Also it happens on the [[Hawaii]]an [[island]] of [[Kauai]] | ||
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| + | Orthographic lift can create [[lenticular cloud]]s and [[wave cloud]]s on the leeward side of mountains. | ||
==See also== | ==See also== | ||
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[[Category:Climate forcing]] | [[Category:Climate forcing]] | ||
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| + | [[fr : Onde orographique]] | ||
Revision as of 01:18, 14 February 2006
Orographic lift occurs when an air mass is forced from a low elevation to a higher elevation as it moves over rising terrain. As the air mass gains altitude it expands and cools adiabatically. This cooler air cannot hold the moisture as well as warm air and this effectively raises the relative humidity to 100%, creating clouds and frequently precipitation.
Orographic lift is demonstrated in many places in the world, but few examples are as clear as those in the Northwestern United States. In the states of Washington and Oregon, places on the sea-facing side of coastal mountains see over 100 inches (over 2.5 m) of precipitation per year. These locales are on the side of the mountains which are in the path of storm systems, and therefore receive the moisture which is effectively squeezed from the clouds. However, on the other side of the mountains, sometimes as little as 15 miles (25 km) away, annual precipitation can be as low as 8 inches (200 mm) per year.
Also it happens on the Hawaiian island of Kauai
Orthographic lift can create lenticular clouds and wave clouds on the leeward side of mountains.
