Surface temperature in the western North Atlantic. North America is black and dark blue (cold), the Gulf Stream red (warm). Source: NASA

The Gulf Stream, together with its northern extension towards Europe, the North Atlantic Drift, is a powerful, warm, and swift Atlantic ocean current that originates at the tip of Florida, and follows the eastern coastlines of the United States and Newfoundland before crossing the Atlantic Ocean. The process of western intensification causes the Gulf Stream to be a northward accelerating current off the east coast of North America. At about 40°0′N 30°0′W / 40°N 30°W / 40; -30, it splits in two, with the northern stream crossing to northern Europe and the southern stream recirculating off West Africa. The Gulf Stream influences the climate of the east coast of North America from Florida to Newfoundland, and the west coast of Europe. Although there has been recent debate, there is consensus that the climate of Western Europe and Northern Europe is warmer than it would otherwise be due to the North Atlantic drift, one of the branches from the tail of the Gulf Stream. It is part of the North Atlantic Gyre. Its presence has led to the development of strong cyclones of all types, both within the atmosphere and within the ocean. The Gulf Stream is also a significant potential source of renewable power generation.

History[link]

Benjamin Franklin's map of the Gulf Stream

European discovery of the Gulf Stream dates to the 1513 expedition of Juan Ponce de León, after which it became widely used by Spanish ships sailing from the Caribbean to Spain.^[1] A summary of Ponce de León's voyage log, on April 22, 1513, noted, "A current such that, although they had great wind, they could not proceed forward, but backward and it seems that they were proceeding well; at the end it was known that the current was more powerful than the wind."^[2] Its existence was also known to Peter Martyr d'Anghiera, and to Sir Humphrey Gilbert at that time.^[3]

As deputy postmaster of the British American colonies, Benjamin Franklin became interested in the North Atlantic Ocean circulation patterns. In 1768, while in England, Franklin heard a curious complaint from the Colonial Board of Customs: why did it take British packets several weeks longer to reach New York from England than it took an average American merchant ship to reach Newport, Rhode Island, despite the merchant ships leaving from London and having to sail down the River Thames and then the length of the English Channel before they sailed across the Atlantic, while the packets left from Falmouth in Cornwall?^[4]

Franklin asked his cousin Timothy Folger, a Nantucket whaling captain, for an answer and Folger explained that merchant ships routinely crossed the then-unnamed Gulf Stream – identifying it by whale behavior, measurement of the water's temperature and the speed of bubbles on its surface, and changes in the water's color – while the mail packet captains ran against it.^[4] Franklin worked with Folger and other experienced ship captains, learning enough to chart the Gulf Stream and giving it the name by which it is still known today. He offered this information to Anthony Todd, secretary of the British Post Office, but it was ignored by British sea captains.^[4]

Franklin's Gulf Stream chart was published in 1770 in England, where it was mostly ignored.^[5] Subsequent versions were printed in France in 1778 and the U.S. in 1786.^[6] It took many years for the British to follow Franklin's advice on navigating the current but once they did, they were able to gain two weeks in sailing time.^[6]

Properties[link]

The Gulf Stream proper is a western-intensified current, driven largely by wind stress.^[7] The North Atlantic Drift, in contrast, is largely thermohaline circulation-driven. By carrying warm water northeast across the Atlantic, it makes Western and especially Northern Europe warmer than it otherwise would be.^[8] However, the extent of its contribution to the actual temperature differential between North America and Europe is a matter of dispute as there is a recent minority opinion within the science community that this temperature difference is mainly due to the Atlantic Ocean being upwind of western Europe (producing an oceanic climate) and a landmass being upwind of the east coast of North America.^[9]

Formation and behavior[link]

Evolution of the Gulf Stream to the west of Ireland continuing as the North Atlantic Current

A river of sea water, called the Atlantic North Equatorial Current, flows westward off the coast of northern Africa. When this current interacts with the northeastern coast of South America, the current forks into two branches. One passes into the Caribbean Sea, while a second, the Antilles Current, flows north and east of the West Indies.^[10] These two branches rejoin north of the Straits of Florida, as shown on the accompanying map.

The trade winds blow westward in the tropics,^[11] and the westerlies blow eastward at mid-latitudes.^[12] This wind pattern applies a stress to the subtropical ocean surface with negative curl across the north Atlantic ocean.^[13] The resulting Sverdrup transport is equatorward.^[14] Because of conservation of potential vorticity caused by the northward-moving winds on the subtropical ridge's western periphery and the increased relative vorticity of northward moving water, transport is balanced by a narrow, accelerating poleward current, which flows along the western boundary of the ocean basin, outweighing the effects of friction with the western boundary current known as the Labrador current.^[15] The conservation of potential vorticity also causes bends along the Gulf Stream, which occasionally break off due to a shift in the Gulf Stream's position, forming separate warm and cold eddies.^[16] This overall process, known as western intensification, causes currents on the western boundary of an ocean basin, such as the Gulf Stream, to be stronger than those on the eastern boundary.^[17]

As a consequence, the resulting Gulf Stream is a strong ocean current. It transports water at a rate of 30 million cubic metres per second (30 sverdrups) through the Florida Straits. As it passes south of Newfoundland, this rate increases to 150 million cubic metres per second.^[18] The volume of the Gulf Stream dwarfs all rivers that empty into the Atlantic combined, which barely total 0.6 million cubic metres per second. It is weaker, however, than the Antarctic Circumpolar Current.^[19]

The Gulf Stream is typically 100 kilometres (62 mi) wide and 800 metres (2,600 ft) to 1,200 metres (3,900 ft) deep. The current velocity is fastest near the surface, with the maximum speed typically about 2.5 metres per second (5.6 mph).^[20] As it travels north, the warm water transported by the Gulf Stream undergoes evaporative cooling. The cooling is wind-driven: Wind moving over the water cools it and also causes evaporation, leaving a saltier brine. In this process, the water increases in salinity and density, and decreases in temperature. Once sea ice forms, salts are left out of the ice, a process known as brine exclusion.^[21] These two processes produce water that is denser and colder (or, more precisely, water that is still liquid at a lower temperature). In the North Atlantic Ocean, the water becomes so dense that it begins to sink down through less salty and less dense water. (The convective action is not unlike that of a lava lamp.) This downdraft of heavy, cold and dense water becomes a part of the North Atlantic Deep Water, a southgoing stream.^[22] Very little seaweed lies within the current, although seaweed lies in clusters to its east.^[23]

Localized effects[link]

The Gulf Stream is influential on the climate of the Florida peninsula. The portion off the Florida coast, referred to as the Florida current, maintains an average water temperature at or above 25 °C (77 °F) during the winter.^[24] East winds moving over this warm water move warm air from over the Gulf Stream inland,^[25] helping to keep temperatures milder across the state than elsewhere across the Southeast during the winter. The Gulf Stream's proximity to Nantucket adds to its biodiversity, as it is the northern limit for southern varieties of plant life, and the southern limit for northern plant species.^[26]

The North Atlantic Current of the Gulf Stream, along with similar warm air currents, helps keep Ireland and the western coast of Great Britain a couple of degrees warmer than the east.^[27] However, the difference is most dramatic in the western coastal islands of Scotland.^[28] A noticeable effect of the Gulf Stream and the strong westerly winds (driven by the warm water of the Gulf Stream) on Europe occurs along the Norwegian coast.^[8] Northern parts of Norway lie close to the Arctic zone, most of which is covered with ice and snow in winter. However, almost all of Norway's coast remains free of ice and snow throughout the year.^[29] Weather systems warmed by the Gulf Stream drift into Northern Europe, also warming the climate behind the Scandinavian mountains.

Hurricane Alex formed and moved along the axis of the Gulf Stream in 2004.

Effect on cyclone formation[link]

The warm water and temperature contrast along the edge of the Gulf Stream often increase the intensity of cyclones, tropical or otherwise. Tropical cyclone generation normally requires water temperatures in excess of 26.5 °C (79.7 °F).^[30] Tropical cyclone formation is common over the Gulf Stream, especially in the month of July. Storms travel westward through the Caribbean and then either move in a northward direction and curve toward the eastern coast of the United States or stay on a north-westward track and enter the Gulf of Mexico.^[31] Such storms have the potential to create strong winds and extensive damage to the United States' Southeast Coastal Areas. Strong extratropical cyclones have been shown to deepen significantly along a shallow frontal zone, forced by the Gulf Stream itself during the cold season.^[32] Subtropical cyclones also tend to generate near the Gulf Stream. 75 percent of such systems documented between 1951 and 2000 formed near this warm water current, with two annual peaks of activity occurring during the months of May and October.^[33] Cyclones within the ocean form under the Gulf Stream, extending as deep as 3,500 metres (11,500 ft) beneath the ocean's surface.^[34]

Possible renewable power source[link]

The Gulf Stream transports about 1.4 petawatts of heat, equivalent to 100 times the world energy demand,^[35] and research into different ways to tap this power is being undertaken. One idea, which would supply the equivalent power of several nuclear power plants, would deploy a field of underwater turbines placed 300 meters (980 ft) under the center of the core of the Gulf Stream.^[36] Ocean thermal energy could also be harnessed to produce electricity utilizing the temperature difference between cold deep water and warm surface water.^[37]

See also[link]

• Arctic dipole anomaly
• Humboldt Current           
• North Atlantic Oscillation
• Shutdown of thermohaline circulation
• Western boundary current
• Latitude of the Gulf Stream and the Gulf Stream north wall index

References[link]

Bibliography

Notes

External links[link]

Wikimedia Commons has media related to: Gulf stream

• Ocean Motion - Description of the Gulf Stream as a western boundary current

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This biographical article needs additional citations for verification. Please help by adding reliable sources. Contentious material about living persons that is unsourced or poorly sourced must be removed immediately, especially if potentially libelous or harmful. (December 2007)

Piers Richard Corbyn (born 10 March 1947)^[1] is the owner of the business Weather Action which makes weather forecasts up to a year in advance, and which he also bets on.^[2]

Personal life[link]

Corbyn was born in Chippenham, Wiltshire and began recording weather and climate patterns at age 15, constructing his own observation equipment. He obtained a first class honours degree in physics at Imperial College London, where he was a contemporary of Brian May. In 1969 he became the first President of the Imperial College Students' Union to be directly elected by the student body. Following some years of activism, he studied astrophysics in 1979 at Queen Mary College, London, later examining the relationship between the Earth's weather and climate and solar activity. Following some years of weather prediction as an occupation, he formed Weather Action, a business, in 1995.^[1] He is the brother of Jeremy Corbyn.

Weather Action[link]

Weather Action is the business through which Corbyn sells his predictions. He has in the past bet on these predictions. His betting attracted much interest in 1990, when his predictions of bad weather were met by a year of the "worst extremes".^[3]

Weather Action was formerly listed on the Alternative Investment Market (AIM) as 'Weather Action Holdings plc' in 1997,^[4] and was transferred back to private ownership in 1999, primarily because of increasing losses sustained and the impact of costs related to public status (around £70,000 annually) compared to annual revenues of £250,000.^[5] Corbyn acquired back the weather prediction business; the listed shell was taken over by investors and changed its name to 'InternetAction.com', with the intent of researching potential net-based takeover targets.^[6]

Weather Action exited the alternative investment market in 1999 after reported losses during its time as a public company of £480,000 and its share price dropped from 79p a share to 24p .^[5]

Predictions[link]

Corbyn's predictions are based on what is called "The Solar Weather Technique."^[7] The technique "combines statistical analysis of over a century of historical weather patterns with clues derived from solar observations."^[1] He considers past weather patterns and solar observations and sun-earth magnetic connectivity. Conventional meteorology claims that such influences cause minimal impact on the Earth's atmosphere.^[8] Corbyn has declined to publish the details of his method.

Corbyn is also skeptical of the theory of Anthropogenic Global Warming, and a dissenter in reports about the storms in Europe in 2000^[9] and in Martin Durkin's documentary The Great Global Warming Swindle. Corbyn has stated that the anthropogenic contribution to global warming is minimal with any increase in temperature due to increased solar activity. In 2008 Corbyn went even further than being skeptical, and took an absolutist, certain position by stating, ... "CO₂ has never driven, does not drive and never will drive weather or climate. Global warming is over and it never was anything to do with CO₂. CO₂ is still rising but the world is now cooling and will continue to do so."^[10]

Evaluation of predictions[link]

The only peer reviewed work conducted involving Corbyn's work was published in the Journal of Atmospheric and Solar-Terrestrial Physics (2001). Its investigation was limited to Corbyn's 'likely damaging gale periods' predictions for the island of Britain for October 1995 to September 1997. Corbyn's enlisted work (carried out for a consortium of insurance companies) was only for the most likely periods of the strongest winds and specifically not a full forecast to include lesser winds:^[11]

"Forecasts prepared by Weather Action would repay further attention. The results provide little evidence to dismiss the observed success rates as being attributable to mere chance or good fortune. Indeed the balance of evidence indicates that the system performs better than chance although it is recognized that the margin of success differs greatly between the seasons and is lowest in winter when gales are most frequent."

"This analysis has been wholly empirical in nature, seeking only to establish the success levels of the gale forecasts. Other aspects of the forecasts have not been considered in this evaluation. Inevitably however these results draw into the debate questions surrounding the methodology by which the forecasts are prepared. This is not, however, the arena in which such issues should be taken up."

Researchers also stated of Corbyn's predictions that:^[12]

"It is unusual for most of the detail to be completely correct, but equally it is rare for nearly everything to be wrong ... Some forecasts are clearly very good, and a few are very poor, but the majority fall in the gray area in between, where an optimistic assessor would find merit, but a critical assessor would find fault."

In accordance with this view, critics point to inaccurate predictions, such as a white Easter in 1989,^[13] and "raging weather" in September 1997.^[14]

Reliability of forecasts in 2007[link]

Corbyn predicted, from 11 months ahead,^{[citation needed]} two major storm periods for parts of the British Isles and much of Europe for November 2007.^[15] Specifically, on 17 October, Corbyn predicted “ferocious” weather and that hurricane force winds – gusting up to 130 mph as weather fronts gain in intensity – could wreak havoc across the country; and that the most severe weather event would take place during the last week of November, causing chaos. In the event, much of the weather was not exceptional for the time of year, and little or no damage was reported on the UK mainland in November.^[16]

Corbyn's 17 October predictions also included this: "From November 8 to 13 another system will batter the nation with winds of between 90mph to 110mph. While the worst affected areas will be Scotland and Northern Ireland it will still pack a hefty punch elsewhere". This prediction proved true and there were several emergency situations on both sides of the North Sea. ^{[17] [18] [19]}

Forecasts for 2008[link]

At the end of 2007, WeatherAction predicted that temperatures in January could plummet to -17 °C in the Midlands, and that the average temperature for January would be close to freezing. This prediction was dismissed by the Met Office in a Guardian article on 2 January.^[20] After the January prediction proved false, Mr. Corbyn blamed the incorrect forecast on an undefined 'procedural error,' but insisted that the second half of the month, specifically the period of 21–27 January, would be very cold, stating on his website:

""The period and forecast maps for the very cold ‘dipole’ patterns 15-21st Jan will probably be shifted later to 21st- 23rd Jan. Some exceptionally strong blizzard conditiuons (sic) and very strong cold winds are likely in this period. An ongoing similar situation with widespread heavy snow, strong winds and blizzards will continue 24th- 27th Jan."^[21]

The period 21–23 January continued very mild for the country as a whole, but with a brief colder interlude for Scotland and the far north of England, with some snow in the Highland and Pennine Mountain regions, not out of the ordinary for January.^[22] The Met Office run Hadley Observation Centre had the CET from the 1–22 January running at 6.4 °C, or 2.8 °C above normal for the time of year. This made it highly unlikely that Corbyn's very cold January forecast would come to fruition.

The final CET for January 2008 ended up over 3 °C above the standard reference average making the predictions for a cold Jan very poor. In fact it ended up being one of the warmest Januarys since records began.

Earthquakes[link]

Corbyn asserts that earthquakes can be triggered by solar activity, and hence that he can to some extent be predict them.^[23]

In an article in Wired science magazine entitled "The Fraudulent Business of Earthquake and Eruption Prediction" ^[24] Erik Klemetti, an assistant professor of Geosciences at Denison University, accused Corbyn of "cherry picking" and said people who claimed to be able to forecast earthquakes were "faith healers of the geologic community and should be seen as such".

Response to media criticism[link]

Following criticism of Weather Action's forecasts in The Times and The Guardian, in particular from journalist Paul Simons, Piers Corbyn banned the use of any extracts of them in any articles unless they were approved by Corbyn. In addition the above newspapers and any publication which carried articles by Paul Simons were also explicitly forbidden from quoting them.^[25]

Political activism[link]

Corbyn was a member of the Labour Party and a campaigns organiser, but has since left it. His brother, Jeremy Corbyn, has been Labour MP for Islington North since 1983.

Housing rights[link]

Corbyn was a housing and squatters' rights activist in the North Paddington area of Westminster in the mid-1970s. In 1974 he fought for a seat on the council as a "Squatters and Tenants" candidate; in 1978 he and a colleague fought as 'Decent Housing' candidates.^[26] In the 1977 GLC election he was the International Marxist Group candidate for Lambeth Central.^[27] He and all the squatters in Elgin Avenue were - as a result of their campaign which included the building of barricades against eviction - rehoused to Southwark, South London, by the GLC in 1975. He later moved from that rehousing in Rust Square to the Alvey Estate in Southwark where he became a leader of the Tenants Association.

Global Warming Debate[link]

Corbyn is well-known for his opposition to the idea of anthropogenic global warming. He writes about it on his website ^[28] and appears on talk shows to discuss his views of the weaknesses of the argument for manmade global warming.^[29]

Student representation[link]

As president of Imperial College Union (ICU) between 1969 and 1970 Corbyn was successful in establishing a sabbatical union president, enabling the elected student leader to be registered at the college without having to study or pay fees (in fact they received a grant from the college and union).^[30]

As well as laying the foundations for the future, Corbyn negotiated a retrospective sabbatical for himself, although he appears to have served as union president after completing his studies.

Corbyn set up a short-lived Imperial College Representative Council, seats on which were distributed between members of the college on the basis of their numbers, a system that almost gave students a majority. The ICAUT, a staff union, refused to cooperate with this student-led initiative. Although this particular council did not survive, increased student representation on college boards and committees became, like the sabbatical president, a lasting success of Corbyn's time as ICU president.

Corbyn's dress has been viewed as being a statement against upper-class formality. Corbyn, together with the rector at the time, Lord Penney, received the Queen, when she opened a new administrative building in 1969, wearing a cravat, long hair and a beard for the occasion. During the visit Corbyn petitioned the Queen in front of 900 people, asking for students to be given greater say in the governance of the college.^[31]

Scientific papers[link]

His first papers were published as an undergraduate in the Royal Meteorological Society's magazine Weather discussing his brine-filled barometer;^[1] in the Journal of the British Astronomical Association for his home-based measurements of the eccentricity of the earth's orbit; and in the Geographical Journal (of the Royal Geographical Society) for a study on the size of pebbles along Chesil Beach.

References[link]

• Some of these results were reported in an edition of the science documentary series, "QED", entitled "Sunshine and Scattered Showers". This was broadcast on BBC1 on July 4th 1996 and featured Piers, WeatherAction and Julian Hunt (who was Chief Executive of the UK's Meteorological Office at the time.)

External links[link]

• [3] The man who repeatedly beats the Met Office at its own game
• Weather Action