The Roaring Forties are strong westerly winds found in the Southern Hemisphere, generally between the latitudes of 40°S and 50°S.[2] The strong west-to-east air currents are caused by the combination of air being displaced from the Equator towards the South Pole, the Earth's rotation, and the scarcity of landmasses to serve as windbreaks at those latitudes.
Roaring Forties as they contract towards southern Australia (observed in September 1895).[1]
The Roaring Forties were a major aid to ships sailing the Brouwer Route from Europe to the East Indies or Australasia during the Age of Sail, and in modern times are favoured by yachtsmen on round-the-world voyages and competitions. The boundaries of the Roaring Forties are not consistent: The wind-stream shifts north or south depending on the season. The strong and continuous winds in the Roaring Forties make this zone highly prospective for wind power such as in New Zealand and Tasmania.[3]
Similar but even stronger conditions that occur at more southerly latitudes are called the Furious Fifties and the Shrieking or Screaming Sixties.
Hot air rises at the Equator and is pushed towards the poles by cooler air travelling towards the Equator (an atmospheric circulation feature known as the Hadley Cell).[2] At about 30°S, the outward-travelling air sinks to lower altitudes, and continues toward the poles closer to the ground (the Ferrel Cell), then rises up again from about 60°S as the air joins the Polar vortex.[2] This travel in the 30°–60°S zone combines with the rotation of the earth to move the air currents from west to east, creating westerly winds.[2]
Unlike in the northern hemisphere, which features huge landmasses (North America, Europe, and Asia) thereby obstructing air currents, the large tracts of open ocean south of 40°S are interrupted only by Tasmania, New Zealand, and the southern part of South America. These relatively small obstructions, which are themselves bordered by large tracts of open water along their southern shores, allow high wind speeds to develop – much higher than near 40°N, where two large continents (Eurasia and North America) impede the flow of circum-planetary westerly winds.[2] Similar but stronger wind conditions prevalent closer to the South Pole are referred to as the "Furious Fifties" (50°S to 60°S), and the "Shrieking" or "Screaming Sixties" (below 60°S).[4]
The latitude ranges for the Roaring Forties and similar winds are not consistent: All shift towards the South Pole in the southern summer, and towards the Equator in the southern winter.[2]Wellington, the capital of New Zealand, is known as "Windy Welly" because it is one of the few cities situated in these gusty latitudes.[5]
Use for sailing
The Clipper Route, taken by ships sailing from Europe to Australia in order to take advantage of the Roaring Forties
During the Age of Sail, ships travelling from Europe to the East Indies or Australasia would sail down the west coast of Africa and round the Cape of Good Hope to use the Roaring Forties to speed their passage across the Indian Ocean,[6] then on the return leg, continue eastwards across the Pacific Ocean and south of Cape Horn before sailing up the east coast of the Americas to home.
It was first used by Dutch explorer Hendrik Brouwer in his Brouwer Route, discovered in 1611, which effectively halved the duration of the trip from Europe to Java.[citation needed] "To run the easting down" was the phrase used to describe the fast passages achieved in the Roaring Forties.[6] The story Easting Down by Shalimar describes the events that befall a steamship unwisely venturing into these latitudes to achieve a faster passage.[7]
Modern round-the-world sailors also take advantage of the Roaring Forties to speed travel times, in particular those involved in record attempts or races.[6] An old sailor's expression goes, "below 40 degrees south, there is no law; below 50 degrees, there is no God."[5]
Impact of pollution
A ship sailing through the Roaring Forties
The peak band of winds has moved approximately 2.5 degrees south in the late 20th century, from a combination of human-induced ozone depletion and greenhouse gas emissions. This has caused faster warming in Antarctica and less rainfall in Australia, especially Western Australia.[8]
^ abcDear, I.C.B.; Kemp, Peter, eds. (2007). "Roaring Forties". The Oxford Companion to Ships and the Sea. Oxford Reference Online. Oxford University Press. ISBN978-0-19-860616-1. OCLC 60793921. Retrieved 14 April 2011.
^Tanner, Tony, ed. (2002) [1994]. The Oxford book of sea stories. Oxford University Press. ISBN0192803700. OCLC 1200552340.
^Helen Davidson (11 May 2014). "Roaring Forties' shift south means more droughts for southern Australia". TheGuardian.com.
^[ BFI | Film & TV Database | Les 40e RUGISSANTS (1982)
External links
Look up roaring forties in Wiktionary, the free dictionary.
roaring, forties, electric, company, roaring, confused, with, roaring, twenties, strong, westerly, winds, found, southern, hemisphere, generally, between, latitudes, strong, west, east, currents, caused, combination, being, displaced, from, equator, towards, s. For the electric company see Roaring 40s Not to be confused with Roaring Twenties The Roaring Forties are strong westerly winds found in the Southern Hemisphere generally between the latitudes of 40 S and 50 S 2 The strong west to east air currents are caused by the combination of air being displaced from the Equator towards the South Pole the Earth s rotation and the scarcity of landmasses to serve as windbreaks at those latitudes Roaring Forties as they contract towards southern Australia observed in September 1895 1 The Roaring Forties were a major aid to ships sailing the Brouwer Route from Europe to the East Indies or Australasia during the Age of Sail and in modern times are favoured by yachtsmen on round the world voyages and competitions The boundaries of the Roaring Forties are not consistent The wind stream shifts north or south depending on the season The strong and continuous winds in the Roaring Forties make this zone highly prospective for wind power such as in New Zealand and Tasmania 3 Similar but even stronger conditions that occur at more southerly latitudes are called the Furious Fifties and the Shrieking or Screaming Sixties Contents 1 Dynamics 2 Use for sailing 3 Impact of pollution 4 Popular culture 5 See also 6 References 7 External linksDynamics Edit The Roaring Forties in the Cook Strait of New Zealand produce high waves and they erode the shore as shown in this image See also Prevailing winds and Atmospheric circulation Hot air rises at the Equator and is pushed towards the poles by cooler air travelling towards the Equator an atmospheric circulation feature known as the Hadley Cell 2 At about 30 S the outward travelling air sinks to lower altitudes and continues toward the poles closer to the ground the Ferrel Cell then rises up again from about 60 S as the air joins the Polar vortex 2 This travel in the 30 60 S zone combines with the rotation of the earth to move the air currents from west to east creating westerly winds 2 Unlike in the northern hemisphere which features huge landmasses North America Europe and Asia thereby obstructing air currents the large tracts of open ocean south of 40 S are interrupted only by Tasmania New Zealand and the southern part of South America These relatively small obstructions which are themselves bordered by large tracts of open water along their southern shores allow high wind speeds to develop much higher than near 40 N where two large continents Eurasia and North America impede the flow of circum planetary westerly winds 2 Similar but stronger wind conditions prevalent closer to the South Pole are referred to as the Furious Fifties 50 S to 60 S and the Shrieking or Screaming Sixties below 60 S 4 The latitude ranges for the Roaring Forties and similar winds are not consistent All shift towards the South Pole in the southern summer and towards the Equator in the southern winter 2 Wellington the capital of New Zealand is known as Windy Welly because it is one of the few cities situated in these gusty latitudes 5 Use for sailing Edit The Clipper Route taken by ships sailing from Europe to Australia in order to take advantage of the Roaring Forties During the Age of Sail ships travelling from Europe to the East Indies or Australasia would sail down the west coast of Africa and round the Cape of Good Hope to use the Roaring Forties to speed their passage across the Indian Ocean 6 then on the return leg continue eastwards across the Pacific Ocean and south of Cape Horn before sailing up the east coast of the Americas to home It was first used by Dutch explorer Hendrik Brouwer in his Brouwer Route discovered in 1611 which effectively halved the duration of the trip from Europe to Java citation needed To run the easting down was the phrase used to describe the fast passages achieved in the Roaring Forties 6 The story Easting Down by Shalimar describes the events that befall a steamship unwisely venturing into these latitudes to achieve a faster passage 7 Modern round the world sailors also take advantage of the Roaring Forties to speed travel times in particular those involved in record attempts or races 6 An old sailor s expression goes below 40 degrees south there is no law below 50 degrees there is no God 5 Impact of pollution Edit A ship sailing through the Roaring Forties The peak band of winds has moved approximately 2 5 degrees south in the late 20th century from a combination of human induced ozone depletion and greenhouse gas emissions This has caused faster warming in Antarctica and less rainfall in Australia especially Western Australia 8 Popular culture EditIn 1982 French filmmaker Christian de Chalonge directed The Roaring Forties a drama movie inspired by the death of Donald Crowhurst a British sailor who perished in the 1969 Sunday Times Golden Globe Race 9 See also EditAntarctic Circumpolar Current Clipper route Doldrums Antarctic oscillation Southerly buster Subtropical ridge Winds in the Age of SailReferences Edit Roaring Forties shift south means more droughts for southern Australia by Helen Davidson from The Guardian 12 May 2014 Retrieved 3 September 2022 a b c d e f Catchpole Heather 20 September 2007 Roaring forties ABC Science In Depth Australian Broadcasting Corporation Retrieved 7 April 2011 Wind turbine Exploring the Southern Ocean Eco Photo Explorers 21 December 2009 Retrieved 7 April 2011 a b What are the Roaring Forties Surfer Today a b c Dear I C B Kemp Peter eds 2007 Roaring Forties The Oxford Companion to Ships and the Sea Oxford Reference Online Oxford University Press ISBN 978 0 19 860616 1 OCLC 60793921 Retrieved 14 April 2011 Tanner Tony ed 2002 1994 The Oxford book of sea stories Oxford University Press ISBN 0192803700 OCLC 1200552340 Helen Davidson 11 May 2014 Roaring Forties shift south means more droughts for southern Australia TheGuardian com https web archive org web 20090207074123 http ftvdb bfi org uk sift title 324109 BFI Film amp TV Database Les 40e RUGISSANTS 1982 External links Edit Look up roaring forties in Wiktionary the free dictionary dbasha1 UMBC user id ed Clipper ships in heavy weather Catonsville MD University of Maryland Baltimore County Retrieved 14 May 2021 a href Template Cite web html title Template Cite web cite web a editor has generic name help CS1 maint url status link Retrieved from https en wikipedia org w index php title Roaring Forties amp oldid 1125924475, wikipedia, wiki, book, books, library,
