FMIB 36792 Coup de Vent d'Ouest, au Sud de l'Australie (4 September 1895)

The Roaring Forties are strong westerly winds found in the Southern Hemisphere, generally between the

latitude In geography, latitude is a coordinate that specifies the north– south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from –90° at the south pole to 90° at the north pol ...

s of 40°S and 50°S. The strong west-to-east air currents are caused by the combination of air being displaced from the

Equator The equator is a circle of latitude, about in circumference, that divides Earth into the Northern and Southern hemispheres. It is an imaginary line located at 0 degrees latitude, halfway between the North and South poles. The term can als ...

towards the

South Pole The South Pole, also known as the Geographic South Pole, Terrestrial South Pole or 90th Parallel South, is one of the two points where Earth's axis of rotation intersects its surface. It is the southernmost point on Earth and lies antipod ...

, the Earth's rotation, and the scarcity of landmasses to serve as windbreaks at those latitudes. The Roaring Forties were a major aid to ships sailing the

Brouwer Route The Brouwer Route was a 17th-century route used by ships sailing from the Cape of Good Hope to the Dutch East Indies, as the eastern leg of the Cape Route. The route took ships south from the Cape (which is at 34° latitude south) into the Roar ...

from

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

to the

East Indies The East Indies (or simply the Indies), is a term used in historical narratives of the Age of Discovery. The Indies refers to various lands in the East or the Eastern hemisphere, particularly the islands and mainlands found in and around t ...

Australasia Australasia is a region that comprises Australia, New Zealand and some neighbouring islands in the Pacific Ocean. The term is used in a number of different contexts, including geopolitically, physiogeographically, philologically, and ecologica ...

during the

Age of Sail The Age of Sail is a period that lasted at the latest from the mid-16th (or mid- 15th) to the mid- 19th centuries, in which the dominance of sailing ships in global trade and warfare culminated, particularly marked by the introduction of naval ...

, 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 Wind power or wind energy is mostly the use of wind turbines to electricity generation, generate electricity. Wind power is a popular, sustainable energy, sustainable, renewable energy source that has a much smaller Environmental impact of wi ...

such as in New Zealand and Tasmania. Similar but even stronger conditions that occur at more southerly latitudes are called the Furious Fifties and the Shrieking or Screaming Sixties.

Dynamics

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 The Hadley cell, named after George Hadley, is a global-scale tropical atmospheric circulation that features air rising near the equator, flowing poleward at a height of 10 to 15 kilometers above the earth's surface, descending in the subtropics, ...

). At about 30°S, the outward-travelling air sinks to lower altitudes, and continues toward the poles closer to the ground (the

Ferrel Cell Atmospheric circulation is the large-scale movement of air and together with ocean circulation is the means by which thermal energy is redistributed on the surface of the Earth. The Earth's atmospheric circulation varies from year to year, but t ...

), then rises up again from about 60°S as the air joins the

Polar vortex A circumpolar vortex, or simply polar vortex, is a large region of cold, rotating air that encircles both of Earth's polar regions. Polar vortices also exist on other rotating, low-obliquity planetary bodies. The term polar vortex can be used to ...

. 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. 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 ) , nickname = , image_map = Tasmania in Australia.svg , map_caption = Location of Tasmania in AustraliaCoordinates: , subdivision_type = Country , subdi ...

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

, and the southern part of

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...

. 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 Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Japanese archipelago a ...

and

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

) impede the flow of circum-planetary westerly winds. Similar but stronger wind conditions prevalent closer to the

are referred to as the "Furious Fifties" ( 50°S to 60°S), and the "Shrieking" or "Screaming Sixties" (below 60°S). 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.

Wellington Wellington ( mi, Te Whanganui-a-Tara or ) is the capital city of New Zealand. It is located at the south-western tip of the North Island, between Cook Strait and the Remutaka Range. Wellington is the second-largest city in New Zealand by me ...

, the capital of New Zealand, is known as "Windy Welly" because it is one of the few cities situated in these gusty latitudes.

Use for sailing

During the

, ships travelling from Europe to the

would sail down the west coast of Africa and round the

Cape of Good Hope The Cape of Good Hope ( af, Kaap die Goeie Hoop ) ;''Kaap'' in isolation: pt, Cabo da Boa Esperança is a rocky headland on the Atlantic coast of the Cape Peninsula in South Africa. A common misconception is that the Cape of Good Hope is t ...

to use the Roaring Forties to speed their passage across the Indian Ocean, then on the return leg, continue eastwards across the Pacific Ocean and south of

Cape Horn Cape Horn ( es, Cabo de Hornos, ) is the southernmost headland of the Tierra del Fuego archipelago of southern Chile, and is located on the small Hornos Island. Although not the most southerly point of South America (which are the Diego Ramírez ...

before sailing up the east coast of the

Americas The Americas, which are sometimes collectively called America, are a landmass comprising the totality of North and South America. The Americas make up most of the land in Earth's Western Hemisphere and comprise the New World. Along with th ...

to home. It was first used by Dutch explorer

Hendrik Brouwer Hendrik Brouwer (; 1581 – 7 August 1643) was a Dutch explorer and governor of the Dutch East Indies. East Indies Brouwer is thought to first have sailed to the Dutch East Indies for the Dutch East India Company (VOC) in 1606. In 1610, ...

in his

, discovered in 1611, which effectively halved the duration of the trip from Europe to

Java Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's List ...

. "To run the easting down" was the phrase used to describe the fast passages achieved in the Roaring Forties. The story ''Easting Down'' by ''

Shalimar Shalimar or Shalamar refers to three historic royal gardens (or Baghs) of the Mughal Empire in South Asia: * Shalimar Bagh, Srinagar, Jammu and Kashmir, India; built in 1619 * Shalimar Gardens, Lahore, Pakistan; a UNESCO World Heritage Site built i ...

'' describes the events that befall a

steamship A steamship, often referred to as a steamer, is a type of steam-powered vessel, typically ocean-faring and seaworthy, that is propelled by one or more steam engines that typically move (turn) propellers or paddlewheels. The first steamships ...

unwisely venturing into these latitudes to achieve a faster passage. 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. An old sailor's expression goes, "below 40 degrees south, there is no law; below 50 degrees, there is no God."What are the Roaring Forties?
Surfer Today.

Impact of pollution

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 Ozone depletion consists of two related events observed since the late 1970s: a steady lowering of about four percent in the total amount of ozone in Earth's atmosphere, and a much larger springtime decrease in stratospheric ozone (the ozone l ...

and

greenhouse gas A greenhouse gas (GHG or GhG) is a gas that Absorption (electromagnetic radiation), absorbs and Emission (electromagnetic radiation), emits radiant energy within the thermal infrared range, causing the greenhouse effect. The primary greenhouse ...

emissions. This has caused faster warming in Antarctica and less rainfall in Australia, especially Western Australia.

Popular culture

In 1982, French filmmaker

Christian de Chalonge Christian de Chalonge (born 21 January 1937) is a French film director and screenwriter. He directed the 1971 film '' The Wedding Ring'', which starred Anna Karina. Selected filmography * '' The Wedding Ring'' (1971) * ''L'Argent des autres'' (1 ...

directed '' The Roaring Forties'', a drama movie inspired by the death of

Donald Crowhurst Donald Charles Alfred Crowhurst (1932 – July 1969) was a British businessman and amateur sailor who disappeared while competing in the ''Sunday Times'' Golden Globe Race, a single-handed, round-the-world yacht race. Soon after he started th ...

, a British sailor who perished in the 1969 Sunday Times Golden Globe Race.BFI_.html" ;"title="Antarctic Circumpolar Current">BFI "> Film & TV Database , Les 40e RUGISSANTS (1982)

References

External links

* {{cite web , editor=dbasha1 (UMBC user-id) , title=Clipper ships in heavy weather , publisher=

University of Maryland, Baltimore County The University of Maryland, Baltimore County (UMBC) is a public research university in Baltimore County, Maryland. It has a fall 2022 enrollment of 13,991 students, 61 undergraduate majors, over 92 graduate programs (38 master, 25 doctoral, ...