Mountain jet
Encyclopedia
Mountain jets are a type of jet stream
created by surface winds channeled through mountain passes, sometimes causing high wind speeds and drastic temperature changes.
The North Pacific east of about 120°W is strongly influenced by winds blowing through gaps in the Central American cordillera. Air flow in the region forms the Intra-Americas Low-Level Jet, a westward flow about 1 km above sea level. This flow, trade winds, and cold air flowing south from North America contribute to winds flowing through several mountain valleys.
Along Central America
are three main wind jets through breaks in the American Cordillera
, on the Pacific Ocean
side due to prevailing winds.
n continent.
The meteorological mechanism that causes Tehuano and Papagayo winds is relatively simple. In the winter, cold high-pressure weather systems move southward from North America over the Gulf of Mexico. These high pressure systems create strong pressure gradients between the atmosphere over the Gulf of Mexico and the warmer, moister atmosphere over the Pacific Ocean. Just as a river flows from high elevations to lower elevations, the air in the high pressure system will flow "downhill" toward lower pressure, but the Cordillera mountains block the flow of air, channeling it through Chivela Pass
in Mexico, the lake district of Nicaragua, and also Gaillard (Culebra) Cut in Panama. Many times, a Tehuano wind is followed by Papagayo and Panama winds a few days later as the high pressure system moves south.
The arrival of these cold surges, and their associated anticyclonic circulation, strengthens the trade winds at low latitudes, and this effect can last for several days. The wind flow over Central America is actually composed of the confluence of two air streams; one from the north, associated with cold surges, and the other from the northeast, associated with trade winds north of South America
.
and over the waters of the Gulf of Tehuantepec, sometimes extending more than 500 miles (800 km) into the Pacific Ocean. The surface waters under the Gulf of Tehuantepec wind jet can cool by as much as 10 °C in a day. In addition to the cold water that is detectable from other satellite sensors, the ocean’s response to these winds shows up in satellite estimates of chlorophyll from ocean color measurements. The cold water and high chlorophyll concentration are signatures of mixing and upwelling of cold, nutrient-rich deep water. Fish converge on this food source, which supports the highly successful fishing industry in the Gulf of Tehuantepec.
Jet stream
Jet streams are fast flowing, narrow air currents found in the atmospheres of some planets, including Earth. The main jet streams are located near the tropopause, the transition between the troposphere and the stratosphere . The major jet streams on Earth are westerly winds...
created by surface winds channeled through mountain passes, sometimes causing high wind speeds and drastic temperature changes.
Central America jets
Along Central America
Central America
Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...
are three main wind jets through breaks in the American Cordillera
American cordillera
The American Cordillera is a cordillera that consists of an essentially continuous sequence of mountain ranges that form the western "backbone" of North America, Central America, South America and Antarctica. From north to south, this sequence of overlapping and parallel ranges begins with the...
, on the Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
side due to prevailing winds.
- Tehuano windTehuano windThe Tehuano wind is a north to northeasterly wind which periodically blows across the Isthmus of Tehuantepec in southern Mexico. The wind is stronger than the trade winds which normally blow here. It is notable for causing a pronounced increase in upwelling of cooler, nutrient-rich waters in the...
blows from the Gulf of MexicoGulf of MexicoThe Gulf of Mexico is a partially landlocked ocean basin largely surrounded by the North American continent and the island of Cuba. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States, on the southwest and south by Mexico, and on the southeast by Cuba. In...
through Chivela PassChivela PassThe Chivela Pass is a narrow mountain pass in the Sierra Madre Mountains that funnels cooler drier air from the North American continent, through southern Mexico, into the Pacific...
in MexicoMexicoThe United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
's Isthmus of TehuantepecIsthmus of TehuantepecThe Isthmus of Tehuantepec is an isthmus in Mexico. It represents the shortest distance between the Gulf of Mexico and the Pacific Ocean, and prior to the opening of the Panama Canal was a major shipping route known simply as the Tehuantepec Route...
and out over the Gulf of TehuantepecGulf of TehuantepecGulf of Tehuantepec is a large body of water on the Pacific coast of the Isthmus of Tehuantepec, southeastern Mexico, at . Most of the hurricanes that form in the Eastern Pacific organize in or near this body of water...
on the Pacific coast. Chivela Pass is a gap between the Sierra Madre del SurSierra Madre del SurThe Sierra Madre del Sur is a mountain range in southern Mexico, extending from southern Michoacán east through Guerrero, to the Istmo de Tehuantepec in eastern Oaxaca.-Geography:...
and the Sierra MadreSierra MadreSierra Madre may refer to one of several mountain ranges:*In Mexico:**Sierra Madre Occidental, a mountain range in northwestern Mexico and southern Arizona...
range to the south. - Papagayo windPapagayo windThe Papagayo wind is a north to northeasterly wind which periodically blows through the gap in the mountain ranges of Central America in which Lake Nicaragua is located. It is named for the Gulf of Papagayo on the Pacific coast in this region. The wind is stronger than the trade winds which...
shrieks over the lakes of NicaraguaNicaraguaNicaragua is the largest country in the Central American American isthmus, bordered by Honduras to the north and Costa Rica to the south. The country is situated between 11 and 14 degrees north of the Equator in the Northern Hemisphere, which places it entirely within the tropics. The Pacific Ocean...
and pushes far out over the Gulf of PapagayoGulf of PapagayoThe Gulf of Papagayo is a large body of water off Guanacaste province and the northwestern coast of Costa Rica. It lies at .The Gulf and its coastline are part of a major tourism project by Costa Rica's government...
on the Pacific coast. The Cordillera Central Mountains rise to the south, gradually descending to Gatun LakeGatun LakeGatun Lake is a large artificial lake situated in the Republic of Panama; it forms a major part of the Panama Canal, carrying ships for of their transit across the Isthmus of Panama....
and the Isthmus of PanamaIsthmus of PanamaThe Isthmus of Panama, also historically known as the Isthmus of Darien, is the narrow strip of land that lies between the Caribbean Sea and the Pacific Ocean, linking North and South America. It contains the country of Panama and the Panama Canal...
. - Panama winds slice through to the Pacific through the Gaillard CutGaillard CutThe Gaillard Cut, or Culebra Cut, is an artificial valley that cuts through the continental divide in Panama. The cut forms part of the Panama Canal, linking Lake Gatún, and thereby the Atlantic Ocean, to the Gulf of Panama and hence the Pacific Ocean...
in PanamaPanamaPanama , officially the Republic of Panama , is the southernmost country of Central America. Situated on the isthmus connecting North and South America, it is bordered by Costa Rica to the northwest, Colombia to the southeast, the Caribbean Sea to the north and the Pacific Ocean to the south. The...
, which also holds the Panama CanalPanama CanalThe Panama Canal is a ship canal in Panama that joins the Atlantic Ocean and the Pacific Ocean and is a key conduit for international maritime trade. Built from 1904 to 1914, the canal has seen annual traffic rise from about 1,000 ships early on to 14,702 vessels measuring a total of 309.6...
.
Cause
The air flow is due to surges of cold dense air originating from the North AmericaNorth America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
n continent.
The meteorological mechanism that causes Tehuano and Papagayo winds is relatively simple. In the winter, cold high-pressure weather systems move southward from North America over the Gulf of Mexico. These high pressure systems create strong pressure gradients between the atmosphere over the Gulf of Mexico and the warmer, moister atmosphere over the Pacific Ocean. Just as a river flows from high elevations to lower elevations, the air in the high pressure system will flow "downhill" toward lower pressure, but the Cordillera mountains block the flow of air, channeling it through Chivela Pass
Chivela Pass
The Chivela Pass is a narrow mountain pass in the Sierra Madre Mountains that funnels cooler drier air from the North American continent, through southern Mexico, into the Pacific...
in Mexico, the lake district of Nicaragua, and also Gaillard (Culebra) Cut in Panama. Many times, a Tehuano wind is followed by Papagayo and Panama winds a few days later as the high pressure system moves south.
The arrival of these cold surges, and their associated anticyclonic circulation, strengthens the trade winds at low latitudes, and this effect can last for several days. The wind flow over Central America is actually composed of the confluence of two air streams; one from the north, associated with cold surges, and the other from the northeast, associated with trade winds north of South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
.
Local effects
The winds blow at speeds of 80 km/h or more down the hillsides from Chivela PassChivela Pass
The Chivela Pass is a narrow mountain pass in the Sierra Madre Mountains that funnels cooler drier air from the North American continent, through southern Mexico, into the Pacific...
and over the waters of the Gulf of Tehuantepec, sometimes extending more than 500 miles (800 km) into the Pacific Ocean. The surface waters under the Gulf of Tehuantepec wind jet can cool by as much as 10 °C in a day. In addition to the cold water that is detectable from other satellite sensors, the ocean’s response to these winds shows up in satellite estimates of chlorophyll from ocean color measurements. The cold water and high chlorophyll concentration are signatures of mixing and upwelling of cold, nutrient-rich deep water. Fish converge on this food source, which supports the highly successful fishing industry in the Gulf of Tehuantepec.