South Atlantic High

Short description: Semipermanent anticyclone over the Atlantic Ocean

South Atlantic High on the right.

South Atlantic High is a semipermanent pressure high centered at about 25°S, 15°W, in the Atlantic Ocean. It is also called the St. Helena High, Saint Helena island being the only land in the area. It can stretch thousands of miles across the South Atlantic.[1][2] This does not mean that the position and the intensity of this anticyclone are permanent, but just that there is an anticyclone on the maps describing the average monthly pressure. This area of high pressure is part of the great subtropical belt of anticyclones called the subtropical ridge. The centre of the high pressure region tends to follow the seasonal variation in position of the sun, moving south in the southern summer and north in the southern winter. This affects the climate of the adjacent continental areas, bringing seasonal changes to the climate and weather as the position of the high oscillates.

## Contents

* 1 Formation
* 2 Associated weather
* 3 Climatic influence on economy
* 4 References
* 5 External links

## Formation

Hadley cell transporting heat and humidity from the Tropics toward the mid-latitudes.

In the Horse latitudes, generally in the region between 30 and 35 degrees of north and south latitude, there are more or less permanent highs. This is the subsiding part of Hadley cells. Indeed, near the equator, where the Coriolis force is quite weak, a direct circulation of air is established. In the lower levels of the atmosphere, the difference in temperature between the equator and the northerly warmer regions gives rise to the intertropical convergence zone where the warmer air rises because of convergence and relatively lower density. Subsequently, this air spreads north and south and cools at higher altitude and descends further north and south.[1]

## Associated weather

This system greatly affects sailing because the associated winds are generally not strong and sailing vessels have to go far north or south of the centre of the high pressure region depending on the direction of travel to find winds that are favourable in strength and direction.[3]

## Climatic influence on economy

The anticyclonic circulation produces a dry climate, contributing to the aridity of the Namib and Kalahari deserts, but its influence does not stop there: the South Atlantic High brings warm weather from the east coast of South America to Africa in summer as it carries tropical air to its southern flank.[1] On its northern flank, where the winds are easterly trade winds, there is the intertropical convergence zone that controls the African monsoon and the rainy season in the Guianas.[4]

## References

1. ↑ 1.0 1.1 1.2 Leduc, Richard; Gervais, Raymond (1985) (in fr). Connaître la météorologie. Montréal: Presses de l'Université du Québec. p. 72 (section 3.6 "Les grands traits de la circulation générale"). ISBN 2-7605-0365-8. https://archive.org/details/connaitrelameteo0000ledu. Retrieved 2009-02-16. "circulation de Hadley."
2. ↑ "South Atlantic high". Glossary. American Meteorological Society. http://glossary.ametsoc.org/wiki/South_atlantic_high. Retrieved April 18, 2019.
3. ↑ "L'anticyclone de Sainte Hélène bientôt de retour" (in fr). Organisation du Vendée Globe. November 24, 2008. Archived from the original on February 20, 2009. https://web.archive.org/web/20090220010621/http://www.vendeeglobe.org/fr/meteo/resume/6120/l-anticyclone-de-sainte-helene-bientot-de-retour.html. Retrieved 2009-08-03.
4. ↑ Christine Poixblanc (April 2001). "La Zone de Convergence Intertropicale, qu'est-ce-que c'est ?" (in fr). La ZIC, responsable des saisons en Guyane. Terres de Guyane. Archived from the original on December 2, 2017. https://web.archive.org/web/20171202203213/http://www.terresdeguyane.fr/articles/climat/default.asp. Retrieved 2009-08-02.

## External links

* v
* t
* e

Cyclones and anticyclones of the world (Centers of action)

Concepts|

* Anticyclonic storm
* Storm
* High-pressure area
* Low-pressure area
* Rapid intensification
* Central dense overcast
* Annular tropical cyclone
* Bar (tropical cyclone)
* Superstorm
* Hypercane

Anticyclone|

| Northern Hemisphere|

* North Polar High
* Siberian High
* Azores High
* North American High
* North Pacific High
* Ridiculously Resilient Ridge
* Subtropical ridge

|

Southern Hemisphere|

* South Polar High
* South Atlantic High
* South Pacific High
* Kalahari High
* Subtropical ridge

Cyclone|

| Synoptic scale|

| Surface-based|

| Polar|

* North Polar low
* South Polar low

|

* v
* t
* e

Extratropical cyclones

Concepts|

* Anticyclonic storm
* Storm
* Cyclone
* Post-tropical cyclone
* Low-pressure area
* Weather bomb
* Sting jet
* List
* Rainband

Northern Hemisphere|

| North America|

| Continental|

| Lee Cyclone|

* Alberta clipper
* Colorado low
* Great basin low

|

Other|

* Panhandle hook
* Witch of November

Oceanic|

* Aleutian Low
* Hatteras low
* Nor'easter
* Gulf low
* Pacific Northwest windstorm

Europe|

* v
* t
* e

European windstorms

Historical|

* Grote Mandrenke
* Burchardi flood
* Great Storm of 1703
* Great Storm of 1824
* Night of the Big Wind
* Moray Firth fishing disaster
* Tay Bridge disaster
* Eyemouth disaster

20th century|

* Iberia 1941
* North Sea flood of 1953
* Hurricane Debbie 1961
* North Sea flood of 1962
* 1968 Scotland storm
* Quimburga 1972
* Gale of January 1976
* December 1981 windstorm
* Ex-Hurricane Charley 1986
* Great Storm of 1987
* Burns' Day storm 1990
* New Year's Day Storm 1992
* Braer Storm of January 1993
* Christmas Eve storm 1997
* Boxing Day Storm of 1998
* Anatol 1999
* Lothar and Martin 1999

2000s|

* Oratia 2000
* Jeanett 2002
* Gudrun 2005
* Per 2007
* Kyrill 2007
* Emma 2008
* Klaus 2009
* Xynthia 2010
* Berit 2011
* Friedhelm/Bawbag 2011
* Joachim 2011
* Dagmar 2011
* Andrea 2012
* St Jude 2013
* Xaver 2013
* Dirk 2013
* Tini 2014
* Elon and Felix 2015
* Niklas 2015
* Egon 2017
* Thomas (Doris) 2017
* Zeus 2017
* Xavier 2017
* Ophelia 2017
* Herwart 2017
* Eleanor (Burglind) 2018
* Friederike (David) 2018

2015–present|

* 2015–16
* 2016–17
* 2017–18
* 2018–19
* 2019–20

See also|

* List of European windstorms
* List of atmospheric pressure records in Europe

Other|

* Black Sea storms
* Icelandic Low
* Genoa low

Asia|

* Western Disturbance
* Continental North Asian storms
* East Asian-northwest Pacific storms

Other areas|

* Arctic
* Kona storm

Southern Hemisphere|

| Australia|

* Australian east coast low
* Black nor'easter

|

Other areas|

* Southern Ocean cyclone
* Sudestada

Subtropical|

* Kona storm
* Australian east coast Low
* Lake Huron cyclone
* Mediterranean tropical-like cyclone
* Thermal

Tropical
(List)|

| Northern Hemisphere|

* Atlantic hurricane
* Cape Verde hurricane
* Pacific hurricane
* Typhoon
* North Indian Ocean tropical cyclone
* Mediterranean tropical-like cyclone

|

Southern Hemisphere|

* South-West Indian Ocean tropical cyclone
* Australian region tropical cyclone
* South Pacific tropical cyclone
* South Atlantic tropical cyclone

Upper level|

* Cold-core low
* Polar vortex
* Upper tropospheric cyclonic vortex

Mesoscale|

| Mesoscale ocean eddies|

* Catalina eddy
* Haida Eddies

|

Mesoscale convective system|

* Wake Low
* Mesohigh
* Mesoscale convective vortex
* Line echo wave pattern

Whirlwind|

| Major|

* Mesocyclone
* Supercell
* Low-topped supercell
* Wall cloud
* Funnel cloud
* Tornado
* Multiple-vortex tornado
* Satellite tornado
* Anticyclonic tornado
* Landspout
* Waterspout

|

Minor|

* Gustnado
* Dust devil
* Steam devil
* Fire whirl

[ ⚑ ]  25°00′S 15°00′W﻿ / ﻿25°S 15°W﻿ / -25; -15

0.00

(0 votes)

Original source: https://en.wikipedia.org/wiki/South Atlantic High. Read more

|

Retrieved from "https://handwiki.org/wiki/index.php?title=Earth:South_Atlantic_High&oldid=758840"
*[v]: View this template
*[t]: Discuss this template
*[e]: Edit this template