Gulf Stream

Introduction

The Gulf Stream is a strong, fast-running, and clockwise-rotating system of warm ocean currents that begins in the Gulf of Mexico; proceeds through the Straits of Florida; follows the eastern coast of the United States and the Grand Banks of Newfoundland, Canada, in a general northeasterly direction; and then crosses easterly the North Atlantic Ocean. During its travels along the North American coast, the Gulf Stream appears much bluer in color when compared to other waters and has a high salt content. On its way east across the Atlantic Ocean, it splits into the northern stream (the North Atlantic Drift [NAD]), which flows to the coast of Western Europe and the islands of the Arctic Ocean, and the southern stream (the Canary Current), which veers off toward northwestern Africa.

Based on past and current meteorological studies, global climate change may affect the Gulf Stream. Whether this is the case or not is very important to the world's climate, especially with regard to Western Europe and other land masses adjacent to the Gulf Stream.

Historical Background and Scientific Foundations

The two equatorial sources of the Gulf Stream are the North Equatorial Current (NEC), which flows generally westward along the Tropic of Cancer, and the South Equatorial Current (SEC), which flows westward from southwestern Africa to South America and then northward to

the Caribbean Sea. Together, these two warm currents, along with waters from the Gulf of Mexico, form the Gulf Stream.

At the Florida Straits, the Gulf Stream transports its waters at a rate of about 39 million cubic yd (30 million cubic m) per second at a depth of about 1 mi (1.6 km) and a width of less than 50 mi (80 km). At this location, its temperature averages about 80°F (27°C). Further north, off of North Carolina, the flow rate of water increases to about 105 million cubic yd (80 million cubicm) per second. It averages a depth of up to 0.75 mi (1.2 km) and a width of about 50 to 93 mi (80 to 150 km). The Gulf Stream surface waters have a maximum speed of around 6.5 ft (2 m) per second at its northern boundary but overall average about 4 ft (1.2 m) per second. At Cape Hatteras, North Carolina, the cold NEC meets the warm SEC, resulting in some of the world's largest and most severe storms.

Impacts and Issues

The steady increase in the average temperature of Earth, what is commonly called global warming, could affect the Gulf Stream. Scientists studying this association speculate that global warming could decrease the circulation of the North Atlantic Drift if the pattern remains in effect over the next several decades. If such a decrease in circulation happens, the North Atlantic Ocean could become cooler, which could likely cause colder climates along coastal areas of Europe. However, diminished circulation of the Gulf Stream in recent years could just be a natural cycle that will eventually reverse itself.

The Gulf Stream is extremely important to the global climate because it provides moderating temperatures on neighboring land areas of the east coast of North America, the coasts of Western Europe and northwestern Africa, and other coastal areas along its path. In the United States, for instance, it allows the southeastern coast of Florida to maintain warmer temperatures during the winter months than neighboring off-coastal states. Further north, the waters off the Grand Banks contain some of the best commercial fishing areas in the world due to the Gulf Stream. The adjacent Gulf Stream along the coastal areas of Western Europe, especially the southwestern United Kingdom, provides for much milder winters when compared to other areas on similar northern latitudes.

The Gulf Stream is also a primary ingredient in moderating temperature differences between equatorial regions and areas about the north and south poles. It releases its heat into the atmosphere of the colder northern latitudes. Then, the cooler Gulf Stream waters begin to sink under colder water because of its heavier density (caused by its high salt content) when compared to other waters. In a process called thermohaline circulation, this downward movement helps to bring in warmer tropical waters to these colder waters.

However, geological and meteorological studies of ice-sheet cores and deep-sea sediments have described past eras where these moderating effects associated with thermohaline circulation have been reduced in intensity. This activity caused much cooler conditions throughout the northern climates. If today's thermohaline circulation were slowed or halted, the global climate patterns could likewise be changed. Computer models have shown that if this condition becomes reality, then northern latitude winters, such as those in the northeastern United States, would be much colder than normal as the ocean waters of the North Atlantic cool down.

WORDS TO KNOW

LATITUDE: The angular distance north or south of Earth's equator measured in degrees.

THERMOHALINE CIRCULATION: Large-scale circulation of the world ocean that exchanges warm, low-density surface waters with cooler, higher-density deep waters. Driven by differences in temperature and saltiness (halinity) as well as, to a lesser degree, winds and tides. Also termed meridional overturning circulation.

TROPIC OF CANCER: In geography, a tropic is one of the two lines of latitude (lines of equal distance from the equator on Earth's surface) at 23° 26′ north and 23° 26′ south. The northern tropic is the Tropic of Cancer and the southern tropic is the Tropic of Capricorn. The belt of Earth's surface between these lines is the tropic.

According to the Woods Hole Oceanographic Institution, the cooling of the North Atlantic Ocean could be in a range of 5-9°F (3-5°C) if thermohaline circulation were completely stopped. With global trends showing warming temperatures around the planet, more regional trends within the areas of the Gulf Stream could be just the opposite, growing colder over the next several decades or longer.

See Also Africa: Climate Change Impacts; Global Warming; Meteorology; Ocean Circulation and Currents; Oceans and Seas; Sea Temperatures and Storm Intensity.

BIBLIOGRAPHY

Books

Permetta, John. Guide to the Oceans. Richmond Hill, Ontario, Canada: Firefly Books, 2003.

Voituriez, Bruno. The Changing Ocean: Its Effects on Climate and Living Resources. Paris, France: UNESCO, 2003.

Voituriez, Bruno. The Gulf Stream. Paris, France: UNESCO, 2006.

Wang, Chunzia, Shang-Ping Xie, and James A. Carton, eds. Earth's Climate: The Ocean-Atmosphere Interaction. Washington, DC: American Geophysical Union, 2004.

Web Sites

“Abrupt Climate Change: Should We Be Worried?” Woods Hole Oceanographic Institution, January 27, 2003. <http://www.whoi.edu/page.do?pid=12455&tid=282&cid=9986> (accessed November 4, 2007).

GULF STREAM

GULF STREAM. A powerful, warm, surface current in the North Atlantic Ocean, east of North America, the Gulf Stream is one of the strongest known currents. It originates in the Gulf of Mexico as the Florida Current, with an approximate temperature of 80 degrees Fahrenheit, a breadth of no more than fifty miles and a depth of a mile or more. It passes through the Straits of Florida and up along the eastern coast of the United States to the Grand Banks of Newfoundland, Canada, driven northward by southwest winds.

As the Gulf Stream reaches Cape Hatteras, North Carolina, the cold Labrador Current that flows from the north separates it from the coast. At this confluence, the warm Gulf Stream waters combine with the cold winds accompanying the Labrador Current, forming one of the densest concentrations of fog in the world. Because of this immense heat transfer, atmospheric storms tend to intensify in this region. Also at this location, the Gulf Stream is split into two currents: the Canary Currents, which are diverted southeast and carry cooler waters to the Iberian Peninsula and northwestern Africa; and the North Atlantic Drift, which flows northwest toward western Europe, providing temperate waters to the western coastal areas of Europe. The water temperature decreases with the northward flow and the breadth of the current spans several hundred miles at its widest. The average speed of the Gulf Stream is four miles per hour, slowing to one mile per hour as the current widens to the north. The Gulf Stream transports as much as 3.99 billion cubic feet of water per second, an amount greater than that carried by all of the world's rivers combined. The current's core, or jet, follows the contours of the continental rise.

The Spanish explorer Juan Ponce de León was the first to describe the Gulf Stream in 1513 as he searched for the fountain of youth in what is now Florida. The Gulf Stream played a major role in the settling of southeastern regions of the United States. North America's oldest city, St. Augustine, sits on the coast of eastern Florida where the Gulf Stream flows. It was founded during the Spanish period, fifty years or so after De León's trek. When the United States acquired Florida, land speculators quickly moved in and formed large plantations. Tourism in the region escalated soon after, and continued to thrive in the early 2000s, especially along Florida's Treasure Coast. The Gulf Stream was also popularized in art, as evidenced in Winslow Homer's 1899 painting The Gulf Stream.

Another major contribution of the Gulf Stream is its warming effect on the climates of adjacent land areas that it passes, especially in northern latitudes, where the coastal weather is quite temperate, even in winter. The Gulf Stream is known as a western-boundary current, a current that is located on the western side of every ocean basin. It is part of a clockwise-rotating system of currents in the North Atlantic. The Gulf Stream is the most extensively studied ocean current in the world, but many questions about it remain unanswered.

BIBLIOGRAPHY

Groves, Donald G., and Lee M. Hunt. The Ocean World Encyclopedia. New York: McGraw-Hill, 1980.

Mary AnneHansen

See alsoClimate ; Grand Banks ; Oceanography .

Gulf Stream

The Gulf Stream is a well-known, fast, intense, and warm ocean current in the North Atlantic Ocean. Its path goes from the Gulf of Mexico and the Caribbean Sea, along the eastern coast of the United States, heading to the northeast Atlantic Ocean, to the British Isles, and the Norway coasts. This western boundary current is responsible for the mild climate of western Europe , which is located at a much higher latitude than most of New England, but experiences much milder weather .

The origin of the Gulf Stream goes back to the broad, slow, and warm North Equatorial Current under the trade winds, which moves to the west, and when it reaches the Caribbean Sea, its water moves through the Yucatan Channel. Here, it becomes not only narrower, but also gains strength, meandering around the Gulf of Mexico (here it is often referred to as the Loop Current), then exiting the Gulf at the Straits of Florida (here, it is called the Florida Current). Along the east coast of Florida, the current meets the Antilles Current, and the flow, now called the Gulf Stream, runs parallel to the coast until reaching Cape Hatteras, North Carolina, where it moves away from the coast. Around 50 degrees West, it splits into different currents, the largest of which is the North Atlantic Current, which also feeds the northbound Norwegian Current. The Canary Current flows towards the equator on the eastern side of the Atlantic Ocean.

The Gulf Stream also has mesoscale eddies or rings, large, concentric cylinders, reaching deep down in the water, which are usually about 62–186 mi (100–300 km) in diameter. They appear on both sides of the Gulf Stream, forming as a meandering loop cut off from the current, and can contain both a warm or a cold core. These rings help to maintain the termohaline (temperature and salinity) balance in the ocean basin.

The Gulf Stream not only helps to redistribute heat by carrying warm waters towards the North Pole, but also has a large impact on the climate on land by bringing humid, mild air to the British Isles and Northwest Europe, causing significantly milder winters than at the same latitudes in the West.

See also Ocean circulation and currents

Gulf Stream The most important ocean-current system in the northern hemisphere, which stretches from Florida to north-western Europe. It incorporates several currents: the Florida Current; the Gulf Stream itself; and an eastern extension, the North Atlantic Drift. The Florida Current is fast, deep, and narrow, but after passing Cape Hatteras the Gulf Stream becomes less effective at depth and develops a series of large meanders which form, detach, and reform in a complicated manner. After passing the Grand Banks (off Newfoundland) the flow forms the diffuse, shallow, slower-moving North Atlantic Drift. The temperature (18–20°C) and salinity (36 parts per thousand) tend to be seasonally constant, unlike neighbouring coastal water masses.

Gulf Stream The most important ocean-current system in the northern hemisphere, which stretches from Florida to north-western Europe. It incorporates several currents: the Florida Current, the Gulf Stream itself, and an eastern extension, the North Atlantic Drift. The Florida Current is fast, deep, and narrow, but after passing Cape Hatteras the Gulf Stream becomes less effective at depth and develops a series of large meanders which form, detach, and reform in a complicated manner. After passing the Grand Banks (off Newfoundland), the flow forms the diffuse, shallow, slower-moving N. Atlantic Drift. The temperature (18–20 °C) and salinity (36 parts per thousand) tend to be seasonally constant, unlike neighbouring coastal water masses.