Gulf Stream

The Gulf Stream is an ocean current in the Atlantic Ocean that begins off the coast of Florida in the United States and then moves eastward across the Atlantic. It has a large impact on the climate of the regions along its path.

The Gulf Stream is a global phenomenon that affects the climate of the entire planet and is particularly important for mitigating the climate of Western European countries, particularly the British Isles and the northern coasts of the Scandinavian Peninsula.

The image from space clearly shows the boundary between the fast warm Gulf Stream (lower part) and calmer coastal waters near the eastern part of the USA.

History

The Gulf Stream was discovered in the early 16th century by Spanish navigators, and at first they called it the Florida Current. In the era of the sailing fleet the routes between Europe and the New World were built with the help of trade winds, west winds and related currents, whose location on the map was not in doubt. At first, the Gulf Stream was something of a maritime legend: it was known to those who constantly came across it. Many experienced captains learned to use its power by moving with the current, or to cross the stream in time when they had to go in the opposite direction. But they were in no hurry to share their knowledge with competitors, considering the secret of the Gulf Stream as their “intellectual property” which gave them an advantage at sea.

The outstanding American scientist and public figure Benjamin Franklin (1706-1790) was the first to explore this current, in 1769 to map it (using the advice of his cousin – the captain of a whaling ship) and give it the “popular” name of the Gulf Stream (English “golf” – gulf, “stream” – current).

Franklin, having the widest range of interests, was convinced that there must necessarily be benefits from science. In particular, the purpose of the study of the current was to draw the best route for mail ships.

Before the twentieth century, people had the most general ideas about the nature of ocean currents. In the days of sailing, it was believed that surface currents formed only winds: for example, tropical trade winds, blowing steadily from the east, drove waves westward, forming trade wind currents. In the temperate latitudes of the Southern Hemisphere and in the circumpolar “Roaring Forties” in the north, westerly winds blow. But why do the southern trade winds deflect to the west and the northern trade winds deflect to the east? Later, physicists will add a theory to the intuitive observations of sailors: tropical trade winds (winds) are accelerated by the rotation of the Earth, the winds create surface currents in the upper 45 m of the ocean, but under the action of physical laws, the currents move at an angle to the wind direction. Because of this, the system of currents of the Atlantic Ocean in the Northern Hemisphere generally resembles a grandiose spiral, moving clockwise (and the Gulf Stream is one of the key links in this chain), and in the Southern Hemisphere a similar spiral winds the ring of currents counterclockwise (there are five major ocean cycles in the world). In this case, locally, the contours of the continents also have a great influence on the trajectory of the surface jet currents. But this is not all: the emergence of currents is now explained by the combined effect of Coriolis forces (rotational acceleration that deflects an object moving on a rotating disk along the radius in the opposite direction from the rotation), differences in temperature and salinity of water, atmospheric pressure variations and interaction with the moving atmosphere; currents are divided into drift (caused by winds), gradient and tidal (in addition, the ocean has a habit of forming synoptic eddies, seiche and tsunami)…

In general, a complex multi-layered circulation of a closed system of ocean currents, warm surface currents and cold deep currents, whose general scheme under the conventional name of the “Global Ocean Conveyor” was proposed in the 1980s by the American oceanographer Wallace Brocker, is constantly going on in the World Ocean. But the circulation of the atmosphere and waters of the World Ocean is still not fully understood.

Warm Atlantic Current

In a narrow sense, the “Gulf Current” is that stretch of broad, powerful current carrying its warm waters from south to north along the east coast of North America that begins at the Straits of Florida and ends at Newfoundland Bank.

It is this current that is marked on geographical maps as the Gulf Stream. It then divides into branches, and one branch turns back into the tropics, while the other changes curvature and goes into the North Atlantic (the North Atlantic Current).

Ocean currents of such magnitude as the trade winds, the West Winds, the Gulf Stream, and the Kuroshiro, determine in many ways not only the conditions of navigation and fishing, but also the climate of the continents, so they are often compared to the pulse of the planet. But even more often they are compared to rivers.

If you imagine the Gulf Stream as a river and use the appropriate terms, this “river” is formed near the Bahamas by the merger of two “tributaries”: the Florida Current (an extension of the Yucatan Current, flowing from the Caribbean Sea into the Gulf of Mexico between Cuba and Yucatan), a powerful stream exiting through the narrow strait between Cuba and Florida, and the Antilles Current. The excess water in the Caribbean Sea is pushed by the North Passage Current. The Gulf Stream gathers most of its heat by warming up in the Gulf of Mexico, one of the warmest bodies of water on Earth.

The current then follows a narrow band along the coast to the level of North Carolina and there leaves the coastal zone, heading into the open ocean in a northeasterly direction.

Along its course, the current forms eddies along its edges, occasionally breaking away from the main stream and forming offshoots – “sleeves”. Having reached the shoal of the Grand Banks of Newfoundland, the Gulf Stream deviates further to the east and rushes across the North Atlantic towards Europe, having changed its name to the North Atlantic Current. But before that, a part of the flow has time to separate, turning northward, to Iceland (the Irminger Current) and Greenland, to the Labrador Basin; then they are picked up by the Labrador Current, closing the ring. The other “arm” deviates from the main stream to the south, reaching along the Portuguese coast to the Mediterranean Sea, where it is picked up and closed in a ring by the Canary Current.

Meanwhile, the North Atlantic Current (central continuation of the Gulf Stream), reaching the British Isles and Scandinavia, significantly softens the climate there: average temperatures differ from latitudinal norms by 5-6 and 10-15 degrees respectively.

On the northern coast of the Scandinavian Peninsula the current has local names – Norwegian and Nordkapp. Traces of the Gulf Stream can be found even in the Arctic Ocean: its residual heat “warms up” the port of Murmansk on the Kola Peninsula, making shipping possible there year-round, even when located to the south of Arkhangelsk on the White Sea is blocked by ice.

What and where does the Gulf Stream carry? Water (although one of the modern theories claims that the currents have a cyclic nature of wave dynamics and do not carry matter). Heat, which significantly softens the climate of Western and Northern Europe.

Kinetic energy, which has recently begun to be captured by devices like wind turbines and used for household purposes. Sea turtles and eels, helping them in their grand migration. The current in a particular area has an important navigational value, speeding up the movement of ships. In general, the current picks up and carries everything in its path, and it is not always good: it drags with it masses of algae, oil, hazardous waste (chemical fertilizers from plantations), and so on.

The Gulf Stream can deviate from its route, but the stopping of this powerful current, which appeared after the closure of the Isthmus of Panama about 3 million years ago, is impossible in principle. But this cannot be said about the North Atlantic Current: it depends on many “variables”, and its strong weakening, known as the Dunsgaard-Esger oscillations, has been observed 17 times over the past 60 thousand years. If the weakened North Atlantic Current were to turn entirely southward toward Africa, this could be a real disaster for Western and Northern Europe.

General Information

• The outflowing current of the Gulf of Mexico, which has a moderating effect on the climate of Northern and Western Europe.
• Location: North Atlantic, runs along the east coast of North America from the Strait of Florida to Newfoundland Island.
• Catchment countries: United States.
• Time of discovery: 16th century (Spanish sailors).
• First explorer and cartographer: Benjamin Franklin in 1768-1770 and later.
• Predecessor currents: Florida and Antilles.
• Branch currents: the Irminger, West Greenland, North Atlantic, and its branches.

The Gulf Stream at the exit to the ocean from the Florida Strait

• Stream width: about 75 km.
• Stream thickness: 700-800 m.
• Average water flow: 25 million m3/s (this is 20 times the flow of all rivers).
• Average current velocity: 9-10 km/h.
• Water temperature at the surface: +24-28°C.
• Salinity: 36.0-36.9%o (at the surface).
• Maximum flow rate: up to 85 million m3 /s (after joining the Antilles Current).

In the Greater Newfoundland Bank area

• Stream width: up to 200 km.
• Average flow velocity: 3-4 km/h.
• Water temperature at the surface: +10-20°C.
• Salinity: about 35%o (at the surface).
• Maximum length (from Spitsbergen): up to 10,000 km.

Climate and weather

• The Gulf Stream has an enormous influence on the climate of the northern Atlantic and the adjacent Arctic Ocean as well as on the climate of Europe, creating very mild conditions for northern latitudes.
• The average temperatures in January: due to the warm currents, they deviate from the average latitudinal norms in Norway by 15-20°C.

Economy

• The Gulf Stream is important for shipping and fishing; its kinetic energy can be used to generate electricity; its decisive influence on the world climate and the chemical-biological composition of the World Ocean is undeniable.

Fun facts

• The Gulf Stream at the very beginning of its journey passes through the Bermuda Triangle (between Florida, Bermuda and Puerto Rico), an area in the Sargasso Sea notorious for its anomalous zone where ships and planes disappear without a trace.
• Coming out of the Gulf of Mexico, the Gulf Stream carries large accumulations of floating sargassum algae and various species of thermophilic fish (including flying fish) into the Sargasso Sea, a stretch of ocean that flows nowhere, but is swirled clockwise by currents, most notably the Gulf Stream. Despite the huge amount of algae, which has become a real disaster for sailors, the water in the Sargasso Sea is amazingly clear: a white disk can be seen at a depth of 65.5 meters.
• Water color in the Gulf Stream area is soft blue, in coastal areas there are greenish shades; the boundary between the current and ocean waters – dark blue and less transparent – can be clearly seen. Water transparency decreases from south to north.
• Where the warm Gulf Stream meets the colder Labrador Current and comes in contact with colder air, fogs are observed almost constantly.
• After the emergence of the Isthmus of Panama, the North Atlantic warmed by 6-7 degrees, and in the Southern Hemisphere, on the contrary, it got colder. The Gulf Stream was formed. Thus, favorable climate for the person in Europe has arisen thanks to an isthmus which has generated global interoceanic circulation.
• The Gulf Stream has not disappeared since, as the Isthmus of Panama was formed, that is about 3 million years, and hardly will disappear, owing to the nature, but it can change latitudes on which it crosses Atlantic. Depending on whether it passes to the south or north, different moisture and heat flows will form, because the contrast with the air will be different. If the current goes south, the warm air will contain more moisture and more powerful cyclones will form.
• The island of Tresco in the southwest of Great Britain, was washed by the Gulf Stream in the 19th century and was famous for its gardens, where a wide variety of crops, including subtropical ones, were grown.