Gulf Stream(redirected from Gulf-stream)
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Gulf Stream,warm ocean current of the N Atlantic Ocean, off E North America. It was first described (1513) by Spanish explorer Ponce de LeónPonce de León, Juan
, c.1460–1521, Spanish explorer, first Westerner to reach Florida. He served against the Moors of Granada, and in 1493 he accompanied Columbus on his second voyage to America.
..... Click the link for more information. . The Gulf Stream originates in the Gulf of Mexico and, as the Florida Current, passes through the Straits of Florida and along the coast of SE United States with a breadth of c.50 mi (80 km). North of Cape Hatteras, it is separated from the coast by a narrow southern extension of the cold Labrador Current and flows NE into the Atlantic Ocean. Where the warm surface waters of the Gulf Stream meet the cold winds accompanying the Labrador Current, one of the densest concentrations of fog in the world occurs. Parts of the Gulf Stream current are diverted SE, forming the Canary Currents, which carry cooler waters to the Iberian peninsula and NW Africa. An ensuing current, known as the North Atlantic DriftNorth Atlantic Drift,
warm ocean current in the northern part of the Atlantic Ocean. It is a continuation of the Gulf Stream, the merging point being at lat. 40°N and long. 60°W.
..... Click the link for more information. , flows NW and provides temperate, relatively warm waters to W Europe. The Gulf Stream has an average speed of 4 mi (6.4 km) per hr but slows down as it widens to the north. At the beginning of the Gulf Stream the water temperature is 80°F; (27°C;); the temperature decreases as the current moves north.
See H. Stommel, The Gulf Stream (1977).
a warm current in the North Atlantic Ocean. In a broad sense, the term “Gulf Stream” refers to the large system of warm currents that extend for 10,000 km from the shores of the Florida peninsula to the islands of Spitsbergen and Novaia Zemlia. The Gulf Stream itself begins in the southern part of the Straits of Florida as the outflow current of the Gulf of Mexico. It joins the Antilles Current and continues to the Grand Banks of Newfoundland.
The Gulf Stream is caused by the trade winds, which drive water across the Yucatán Channel into the Gulf of Mexico and by the resulting significant difference in the levels of the Gulf of Mexico and the adjacent portion of the Atlantic. On entering the ocean the rate of the current is 25 million cu m per sec (2,160 cu km per day)—20 times the discharge of all the world’s rivers. In the ocean the Gulf Stream joins the Antilles Current, and its rate increases, reaching 82 million eu m per sec at 38° N lat. In contrast to the general pattern of movement in the northern hemisphere, when it enters the ocean, the Gulf Stream does not turn to the right under the influence of the earth’s rotation but rather turns to the left. This is caused by the increased level of the ocean in the anticyclonic region of the subtropical portion of the Atlantic, as well as by the raising of the level of the waters entering from the south, from the Gulf of Mexico, by the Antilles Current.
In the ocean the Gulf Stream flows north at a speed of 6 km/hr (sometimes up to 10 km/hr) along the edge of the continental shelf of North America. At Cape Hatteras the current turns to the northeast toward the Grand Banks, and its speed decreases to 3–4 km/hr. In the south the Gulf Stream is 75 km wide, and at Cape Hatteras it is 110–120 km wide. The depth of the flow is 700–800 m. As the Gulf Stream moves, it forms numerous meanders, and whirlpools develop in the current itself.
The Gulf Stream carries a great deal of warmth and salt. The average annual surface water temperature is 25°-26° C, and the salinity is 36.2–36.4 parts per thousand (‰). At a depth of 400 m, the temperature is 10°-12°C. Maximum salinity (36.5‰) has been recorded at a depth of 200 m.
Changes in the water temperature of the Gulf Stream depend to a great extent on fluctuations in the force of the trade winds, which drive warm tropical waters into the Gulf of Mexico. An increase in the velocity of the northeast trade wind is reflected in a rise in the temperature of the Gulf Stream after three to six months, and the effect of increased velocity of the southeast trade wind is felt after six to nine months. After the rise in temperature there are periods of cooling, which are due to the fact that the increased velocity of the trade winds simultaneously causes the cooling of the ocean’s surface off the African coast by the rise of cold waters from the bottom of the ocean. The temperature of the Gulf Stream decreases nine to 11 months after an increase in the velocity of the northeast trade wind and ten to 12 months after an increase in the velocity of the southeast trade wind.
Off the southern edge of the Grand Banks, the Gulf Stream is approached from the north by the cold Labrador Current, on whose boundary the surface waters mix and subside. After passing the Grand Banks, at approximately 40° W long., the Gulf Stream becomes the North Atlantic Drift, which, under the influence of westerly and southwesterly winds, crosses the ocean from west to east, gradually changing to a northeasterly direction off the European coast. As the North Atlantic Drift approaches the port of Thomson, a branch splits off—the warm Irminger Current, part of which flows into the Greenland Sea, skirting the west coast of Iceland. However, the basic mass of the Irminger Current moves west, skirting southern Greenland and following its western coast under the name of the West Greenland Current into Baffin Bay. The basic flow of the North Atlantic Current continues into the Norwegian Sea and moves north along the western coast of the Scandinavian Peninsula, where it is called the Norwegian Current. At the northern extremity of the Scandinavian Peninsula a branch separates from the Norwegian Current—the Nordkapp Current, which flows east through the southern part of the Barents Sea. The basic flow of the Norwegian Current continues north, and under the name of the Spitsbergen Current it flows along the western shores of Spitsbergen. North of Spitsbergen, this current submerges, and it can be traced in the Arctic Ocean beneath the cold and freshened surface waters as a warm and salty intermediate current.
The system of the warm Gulf Stream currents has a great effect on the hydrologic and biological characteristics of the seas and the Arctic Ocean as well as on the climate of the European nations bordering the Atlantic Ocean. The masses of warm water heat the air passing over it, and this air is carried by the westerly winds over Europe. The deviations in air temperature from the mean latitudinal values in January reach 15°-20° C in Norway and more than 11° C in Murmansk.
REFERENCESGershman, I. G. “Gol’fstrim i ego vliianie na klimat.” Meteorologiia i gidrologiia, 1939, nos. 7–8.
Shuleikin, V. V. Fizika moria, 3rd ed. Moscow, 1953.
A. M. MUROMTSEV