An equatorial current is an oceanic current which is flowing towards the west near the equator region. Point 4: This is the main reason behind counter equatorial current (the backward movement of equatorial waters). The conditions of the Humboldt current are prime for these organisms to thrive. The SE turns south and behaves the opposite of the gyres in the Northern Hemisphere. They. The interactions between the ocean and atmosphere alters weather around the world and can result in severe storms or mild weather, drought or flooding. The SECC seems to cross the entire South Atlantic at about 7S to 9S to at least the Greenwich Meridian but part of the water might get . Antarctic bottom water has a very narrow range of both salinity and temperature; this water is nearly homogeneous. Pacific Ocean Currents | Phytoplankton and Fishing - PMF IAS The local effects on weather caused by La Nia ("little girl" in Spanish) are generally the opposite of those associated with El Nio ("little boy" in Spanish). This helps explain why productivity is often high in the water over seamounts. La Nia is considered to be the counterpart to El Nio, which is characterized by unusually warm ocean temperatures in the equatorial region of the Pacific Ocean.. In the oceans the zone where density of water changes rapidly with depth is called a pycnocline. Marine Region (Region 7) Currents generally diminish in intensity with increasing depth. As water current flows over the blocks, they dissolve. With the fish gone, sea birds that depend on them may die or go elsewhere. A strong El Nio is often associated with flooding rains and warm weather in Peru, drought in Indonesia, Africa, and Australia, torrential downpours and mudslides in southern California, a mild winter in the northeast, and fewer hurricanes in the southeast. National Geographic Headquarters 1145 17th Street NW Washington, DC 20036. La Niadelivers drier, warmer, and sunnier weather along the southern tier of the United States, from California to Florida. Upwelling and Climate Nutrients include plankton eaten by fish and crustaceans. The main part of the South Equatorial Current divides into three large branches as it flows westward. Historically, some of the most productive commercial fishing grounds have been associated with coastal upwelling. El Nio is an oceanic and atmospheric system that moves across the central Pacific from Asia toward Peru. If the seafloor is shallower than this depth the net direction of water movement is not as deflected compared to the air current. The system's high productivity supports other important fishery resources as well as marine mammals (eared seals and cetaceans) and seabirds. When multiple meters are used at once, current velocity maps can be generated. [1] Upwelling within the current is not uniform across the entire system. The two westernmost branches, on reaching the east coast of Australia, swing south to form the East Australian Current, which, becoming the Tasman Current, turns back to the northeast and dissipates west of New Zealand. Even these complex models, however, cannot predict the exact intensity or duration of an El Nio, nor can they predict how areas will be affected. Ballast water control legislation requires vessels coming into U.S. ports to: The ecology of San Francisco Bay is being disrupted by: Estuary areas and associated wetlands are generally increasing in the United States today. Coastal upwelling is the main factor contributing to the high biological productivity of the Humboldt current. It is estimated that roughly _____ or more of all material dumped at sea is dredged material from ports and waterways. For example, as deep water currents encounter seamounts or other raised features, the water is forced upwards, bringing nutrient-rich water to the surface. Water movement in surface currents is called Ekman transport. HS-ESS2-2 Analyze geoscience data to make the claim that one change to Earth's surface can create feedbacks that cause changes to other Earth systems. It is a significant Pacific and Atlantic Ocean current that flows from east to west. Upwelling brings cold, nutrient-rich waters to the surface. The Coriolis effect influences the surface ocean as well as deeper ocean water layers, which are created by slight differences in temperature and salinity. If extremely cold fresh water is added on top of seawater.. These low-pressure zones contribute to increased rainfall.Rainfall associated with the summer monsoon in Southeast Asia tends to be greater than normal, especially in northwest India and Bangladesh. This can produce hazardous shipping conditions, for it can carry icebergs into an area of the Atlantic where they are not usually found. Strong currents and eddies also influence shipping routes and have been known to . Stellar sea lion populations in the Gulf of Alaska are thought to be declining because the animals are: High concentrations of toxic heavy metals in estuaries are most likely to be found in: The final discharge location of Boston Harbor's sewage effluent will be the: How much oil is usually recovered after a spill? Which current flows south along the west coast of the U.S.? La Nia, the "cool phase" of ENSO, is a pattern that describes the unusual cooling of the region's surface waters. These currents, as deep as 1 km, generally remain in deeper water beyond the continental shelf. Labrador Current - Wikipedia Gulf Stream, warm ocean current flowing in the North Atlantic northeastward off the North American coast between Cape Hatteras, N.C., U.S., and the Grand Banks of Newfoundland, Can. University of Hawaii, 2011. outgoing and incoming tides and the direction of the tidal current flow (b and c), The center of mass of the earth-moon system, lies beneath Earth's surface on a line that joins the centers of Earth and the moon and describes the true orbit of the Earth-moon system about the sun (a b and c), ____ tides occur at the first quarter moon. The Ekman spiral causes current speed to increase with depth. Three major stocks of anchoveta are distributed between 4S and 42S within the Humboldt Current System. The movement of surface currents also plays a role in the vertical movements of deeper water, mixing the upper water column. The Ekman spiral describes the motion or Ekman transport of water influenced by wind and the Coriolis effect. Once the payment is made, you need to log in to the Downloads Page to download the files (check your email for the login details). In the Indian Ocean the place of a north equatorial current is taken by the Monsoon Current. Explain how a convention current transports energy around the globe. The Humboldt Current, also called the Peru Current, is a cold, low-salinity ocean current that flows north along the western coast of South America. El Nio is the "warm phase" of a larger phenomenon called the El Nio-Southern Oscillation (ENSO). Gyres in the Northern Hemisphere travel in clockwise directions while gyres in the Southern Hemisphere travel in counter-clockwise directions. Using buoy data in conjunction with visual information they receive from satellites, scientists are able to more accurately predict ENSO and visualize its development and impact around the globe. Winds are described by the direction from which they blow, whereas water currents are described by the direction toward which they flow. The equatorial currents have similar climatic effects upon continental shores they touch, bringing warmth and higher humidity to the east coasts and dry conditions to the west. Subtropical gyres are formed by an intricate process . It takes about 54 months for water to travel the circuit of the North Pacific gyre, while only 14 months in the North Atlantic gyre. Current Affairs of 2021 & earlier are available for free on PMF IAS Google Drive Folder. However, sardine populations saw a dramatic increase in the next 1520 years. Canary Current, also called Canaries Current, part of a clockwise-setting ocean-current system in the North Atlantic Ocean. El Nio and La Nia | National Oceanic and Atmospheric Administration The clockwise gyre of the Arctic Ocean is driven by the polar easterlies. Downwelling occurs where surface currents converge. Convergence of the two equatorial currents, Occurrence of the belt of calm near the equator, The north equatorial current turns northward off the Philippines to form the. Gyres form in both the northern and southern hemispheres. Characteristically, equatorial-current systems consist of two westward-flowing currents approximately 600 miles (1,000 km) wide (North and South equatorial currents) separated by an eastward-flowing countercurrent only 300 miles (480 km) wide. A halocline is a region where ______________ changes rapidly with depth. La Nia is characterized by lower-than-normal air pressure over the western Pacific. Pacific Wind and Current Changes Bring Warm, Wild Weather The Pacific South Equatorial Current, flowing approximately between latitude 5 N and 1520 S, is propelled westward by the Southeast Trade Winds to about longitude 180 E. There it splits, part turning north to blend with the countercurrent and the rest veering south to become the East Australian Current and a flow passing east of New Zealand. At the Cape of Good Hope this feeds east into the South Indian Current, which supplies the West Australian Current. It takes its name from the Angolan port of Benguela, which was founded by the Portuguese in 1617. Speed can be calculated by measuring the time it takes a drifter to travel a known distance. The Peru Current flows north as a source of the Pacific South Equatorial Current. Dumping the muds from dredged harbors offshore does not affect the coastal sediments. The movement of the Indian South Equatorial Current is particularly strong off the Somali coast and southeastern Arabia, where upwelling lowers the surface temperature of the water near shore. In the perfect gas law, pressure is ______ proportional to volume. The ocean warming off South America is just one of these events. OTEC plants require a difference in water temperature of about 20 degrees C over a depth of 1000 m or less in order to operate effectively. The North Equatorial Current (NE) and the South Equatorial Current (SE) flow in the same direction. These gyres are driven by the combination of trade winds in the tropics and westerly winds that are found south of about 30 degrees south, through a rather complicated process that includes western boundary current intensification. Currents range in size from relatively small longshore currents near a beach, to currents that span ocean basins. Weakening of the east-to-west wind during a phase of the Southern Oscillation allows warm water in the western margin to slip back to the east by increasing the flow of the . A gyre is a circular ocean current formed by a combination of the prevailing winds, the rotation of the Earth, and landmasses. A current meter is used to measure water flow speed and direction from a drifting oceanographic vessel. The deep water masses of the Pacific Ocean have uniform salinity. Any interactives on this page can only be played while you are visiting our website. An Ekman spiral is the result of drag created from increasing ocean depth, when ocean water encounters wind at the surface (Fig. The Labrador Current has a tendency to sometimes go farther south and/or east than normal. 3.13. The South Equatorial current of the Pacific Ocean moves surface water from the Southern Hemisphere to the Northern Hemisphere. 75% of the total zooplankton biomass move in and out of the OMZ. In both oceans, it is separated from the equatorial circulation by the equatorial countercurrent, which flows eastward. The rotational motion of the earth influences ocean currents. Modern methods also rely on this principle. It deflects off the South American eastern border. La Nia events are also associated with rainier-than-normal conditions are over southeastern Africa and northern Brazil.La Nia is also characterized by higher-than-normal pressure over the central and eastern Pacific. Fig. Upon reaching the Philippines, the current divides, with the lesser part turning south and then east to start the Pacific Equatorial Countercurrent, and the greater part flowing north. The National Oceanic and Atmospheric Administration (NOAA), for instance, operates a network of buoys which measure sea-surface temperature, air temperature, currents, winds, and humidity. Sardines, on the other hand, are typically found farther offshore. Please refer to the appropriate style manual or other sources if you have any questions. Effect on Global Climate. It then meets the South pacific current near Tasmania which flows from west to east. Why are tropical waters highly unproductive? In the Indian Ocean, the westward-flowing South Equatorial Current is well-developed only south of the equator. It is a cold current, which finally feeds the south equatorial current, thus completing the great circuit. Marine mammals, such as seals and sea lions, that feed on fish may be affected. Wind waves in the open sea have wavelengths and speeds that are defined by the wave period. Point 3: Salinity greatly influences vertical currents and its influence on horizontal movement is less significant. La Nia is considered to be the counterpart to El Nio, which is characterized by unusually warm ocean temperatures in the equatorial region of the Pacific Ocean. However, the direction and speed of water currents do not match those of the wind currents above them. Ocean current in the Pacific, Atlantic, and Indian Ocean, Learn how and when to remove this template message, https://en.wikipedia.org/w/index.php?title=South_Equatorial_Current&oldid=1093325008, Short description is different from Wikidata, Articles lacking sources from December 2009, Creative Commons Attribution-ShareAlike License 3.0, This page was last edited on 15 June 2022, at 21:54. Res., 110, C10021, Last edited on 22 February 2023, at 12:34, introducing citations to additional sources, "Two Unusual Tropical Cyclones in the Southeast Pacific", 10.1175/1520-0493(1991)119<0218:TUTCIT>2.0.CO;2, https://en.wikipedia.org/w/index.php?title=Humboldt_Current&oldid=1140919900. The South Equatorial Current are ocean currents in the Pacific, Atlantic, and Indian Ocean that flow east-to-west between the equator and about 20 degrees south. Drifters, buoys, Argo floats and more help scientists monitor the global ocean, including areas that are difficult to travel to via research ship. South equatorial current, south Atlantic drift, Brazilian current, and Benguela current make up this Gyre. Three notable upwelling subsystems are produced by this current: Due to the upwelling zones within the Humboldt current, biological diversity is extremely high. These instruments bounce sound off wind induced surface currents. As current moves down the water column, some water flows in a direction opposite to the surface current (Fig.
