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54-521: The Modular Ocean Model ( MOM ) is a three-dimensional ocean circulation model designed primarily for studying the ocean climate system. The model is developed and supported primarily by researchers at the National Oceanic and Atmospheric Administration 's Geophysical Fluid Dynamics Laboratory (NOAA/GFDL) in Princeton, NJ, USA. MOM has traditionally been a level-coordinate ocean model, in which

108-665: A challenge. MOM3, MOM4, and MOM5 are used as a code base for the ocean component of the GFDL coupled models used in the IPCC assessment reports, including the GFDL CM2.X physical climate model series and the ESM2M Earth System Model. Versions of MOM have been used in hundreds of scientific papers by authors around the world. MOM4 is used as the basis for the El Nino prediction system employed by

162-399: A decisive role in influencing the climates of regions through which they flow. Ocean currents are important in the study of marine debris . Upwellings and cold ocean water currents flowing from polar and sub-polar regions bring in nutrients that support plankton growth, which are crucial prey items for several key species in marine ecosystems . Ocean currents are also important in

216-609: A decrease in ventilation within the system. This lack of ventilation is the primary driver of an intense oxygen minimum zone (OMZ) which is formed in the sub-surface to intermediate depths. In the north, the EUC ventilates the OMZ, and in the south the PCU advects low oxygen waters southward towards northern Chile. This OMZ is the fourth largest permanent hypoxic zone in the world's oceans. It occupies an area about 2.18 ± 0.66 × 10 km . The core of this zone

270-467: A major sardine fishery. Other common stocks include: a second anchoveta stock, jack mackerel , tuna , and swordfish . Anchoveta, jack mackerel, and sardines are the primary commercial stocks in central Chile. Anchoveta are found in more recently upwelled waters, close to the coast. Sardines, on the other hand, are typically found farther offshore. Seasonal upwelling plays a major role in the spawning behaviors of both sardines and anchoveta. By spawning at

324-562: A much colder northern Europe and greater sea-level rise along the U.S. East Coast." In addition to water surface temperatures, the wind systems are a crucial determinant of ocean currents. Wind wave systems influence oceanic heat exchange, the condition of the sea surface, and can alter ocean currents. In the North Atlantic, equatorial Pacific, and Southern Ocean, increased wind speeds as well as significant wave heights have been attributed to climate change and natural processes combined. In

378-453: A result, influence the biological composition of oceans. Due to the patchiness of the natural ecological world, dispersal is a species survival mechanism for various organisms. With strengthened boundary currents moving toward the poles, it is expected that some marine species will be redirected to the poles and greater depths. The strengthening or weakening of typical dispersal pathways by increased temperatures are expected to not only impact

432-415: A scientific community of hundreds of users, resulted in significant evolution of the code released as v4.0 (MOM4) in 2003. An update, v4.1 (MOM4p1) was released by Griffies in 2009, as was the latest version v5.0 (MOM5), which was released in 2012. Ocean circulation Ocean currents flow for great distances and together they create the global conveyor belt , which plays a dominant role in determining

486-418: A significant role in influencing climate, and shifts in climate in turn impact ocean currents. Over the last century, reconstructed sea surface temperature data reveal that western boundary currents are heating at double the rate of the global average. These observations indicate that the western boundary currents are likely intensifying due to this change in temperature, and may continue to grow stronger in

540-488: A wide range of organisms including multiple species of plankton , mollusks , sea urchins , crustaceans , fish, and marine mammals. The food web starts with the phytoplankton . The conditions of the Humboldt current are prime for these organisms to thrive. This causes a cascade effect in which larger and larger organisms are drawn to the area. The Humboldt current produces some of the most successful commercial fisheries in

594-409: Is a highly productive ecosystem . It is the most productive eastern boundary current system. It accounts for roughly 18-20% of the total worldwide marine fish catch. The species are mostly pelagic : sardines , anchovies and jack mackerel . The system's high productivity supports other important fishery resources as well as marine mammals ( eared seals and cetaceans ) and seabirds . Periodically,

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648-425: Is also known as the ocean's conveyor belt. Where significant vertical movement of ocean currents is observed, this is known as upwelling and downwelling . The adjective thermohaline derives from thermo- referring to temperature and -haline referring to salt content , factors which together determine the density of seawater. The thermohaline circulation is a part of the large-scale ocean circulation that

702-619: Is an eastern boundary current flowing in the direction of the equator , and extends 500–1,000 km (310–620 mi) offshore. The Humboldt Current is named after the German naturalist Alexander von Humboldt even though it was discovered by José de Acosta 250 years before Humboldt. In 1846, von Humboldt reported measurements of the cold-water current in his book Cosmos . The current extends from southern Chile (~ 45th parallel south ) to northern Peru (~ 4th parallel south ) where cold, upwelled, waters intersect warm tropical waters to form

756-428: Is centered off Peru, creating a shallow upper boundary that reaches from about 100 m (330 ft) down to 600 m (2,000 ft). Another factor contributing to the OMZ is sinking and decay of primary productive resources. Consequently, the OMZ forces many organisms to stay near the surface where nutrients and oxygen are obtainable. The presence of a shallow OMZ restricts the migration of zooplankton within

810-625: Is cooled by the current and thus is not conducive to generating precipitation (although clouds and fog are produced). The trade winds are the primary drivers of the Humboldt Current circulation. Variability in this system is driven by latitudinal shifts between the Intertropical Convergent Zone and the trade winds in the north. Shifts within the South Pacific High at mid-latitudes, as well as cyclonic storms and movement of

864-524: Is driven by global density gradients created by surface heat and freshwater fluxes . Wind -driven surface currents (such as the Gulf Stream ) travel polewards from the equatorial Atlantic Ocean , cooling en route, and eventually sinking at high latitudes (forming North Atlantic Deep Water ). This dense water then flows into the ocean basins . While the bulk of it upwells in the Southern Ocean ,

918-408: Is found both within and outside of the 200-mile economic exclusive zone. Jurel became an important fishery in the 1970s to alleviate the pressure put on the anchoveta stock. During the 1980s, however, the jurel decreased in population size due to poor recruitment and overfishing . Restrictions of jurel fishing were imposed in 1998 which led to regrowth of the population. Since 2002, the jurel population

972-558: Is now under full exploitation. Between 1993 and 2008, the hake fishery in Peru declined significantly. This was due to overfishing, environmental stress, and decreased reproductive capacity. The Chilean hake population in central-south Chile catch exceeded 100,000 tons, and dropped to 40,000 tons in 2007. The productivity of the Humboldt Current System is strongly affected by El Niño and La Niña events. During an El Niño event,

1026-477: The Atlantic meridional overturning circulation (AMOC) is in danger of collapsing due to climate change, which would have extreme impacts on the climate of northern Europe and more widely, although this topic is controversial and remains an active area of research. The "State of the cryosphere" report, dedicates significant space to AMOC, saying it may be enroute to collapse because of ice melt and water warming. In

1080-496: The East Australian Current , global warming has also been accredited to increased wind stress curl , which intensifies these currents, and may even indirectly increase sea levels, due to the additional warming created by stronger currents. As ocean circulation changes due to climate, typical distribution patterns are also changing. The dispersal patterns of marine organisms depend on oceanographic conditions, which as

1134-493: The Equatorial Front . Sea surface temperatures off the coast of Peru, around 5th parallel south , reach temperatures as low as 16 °C (61 °F). This is highly uncharacteristic of tropical waters, as most other regions have temperatures measuring above 25 °C (77 °F). Upwelling brings nutrients to the surface, which support phytoplankton and ultimately increase biological productivity. The Humboldt Current

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1188-465: The National Centers for Environmental Prediction . MOM owes its genesis to work at GFDL in the late 1960s by Kirk Bryan and Michael Cox . This code, along with a version generated at GFDL and UCLA/NCAR by Bert Semtner , is the ancestor of many of the level-coordinate ocean model codes run around the world today. In the late 1980s, Ron Pacanowski , Keith Dixon , and Tony Rosati at GFDL rewrote

1242-473: The Peru-Chile undercurrent (PCU) that moves poleward. Off the coast of central Chile, there is a coastal transition zone (CTZ), which is characterized by high eddy kinetic energy. This energy forms mesoscale eddies which extend 600–800 km (370–500 mi) offshore. The CTZ has three distinct regions within its boundaries: The limb of the Humboldt Current System that veers off the coast of Peru creates

1296-563: The climate of many of Earth's regions. More specifically, ocean currents influence the temperature of the regions through which they travel. For example, warm currents traveling along more temperate coasts increase the temperature of the area by warming the sea breezes that blow over them. Perhaps the most striking example is the Gulf Stream , which, together with its extension the North Atlantic Drift , makes northwest Europe much more temperate for its high latitude than other areas at

1350-533: The southern hemisphere . In addition, the areas of surface ocean currents move somewhat with the seasons ; this is most notable in equatorial currents. Deep ocean basins generally have a non-symmetric surface current, in that the eastern equator-ward flowing branch is broad and diffuse whereas the pole-ward flowing western boundary current is relatively narrow. Large scale currents are driven by gradients in water density , which in turn depend on variations in temperature and salinity. This thermohaline circulation

1404-721: The thermocline and upper region of the OMZ deepen to greater than 600 m. This causes a loss of nitrogen and decrease in export of carbon. El Niño also causes poleward currents to increase in velocity. During non-El Niño years, productivity is very high due to the high nutrient contents, nitrogen recycling through processes such as denitrification, increased carbon export, and remineralization. During El Niño events, fish abundance and distribution are significantly affected, often leading to stock crashes and cascading social and economic impacts. These events have led to sequential changes, where sardines and anchovies have replaced each other periodically as

1458-621: The Bryan-Cox-Semtner code in a modular form, enabling different options and configurations to be more easily generated and new physical parameterizations to be more easily included. This version, released on December 5, 1990, became known as Modular Ocean Model v1.0 (MOM1). Further development by Pacanowski, aided by Charles Goldberg and encouraged by community feedback, led to the release of v2.0 (MOM2) in 1995. Pacanowski and Stephen Griffies released v3.0 (MOM3) in 1999. Griffies, Matthew Harrison, Rosati and Pacanowski, with considerable input from

1512-522: The Southern Westerlies southward also contribute to system changes. Atmospheric variability off central Chile is enhanced by the aggravation of coastal low pressure systems trapped between the marine boundary layer and the coastal mountains. This is prominent poleward from 27th parallel south to 42nd parallel south . The Humboldt current, occupying the upper ocean, flows equatorward carrying fresh, cold Sub-Antarctic surface water northward, along

1566-477: The atmosphere and the deep ocean due to the way water upwells and downwells on either side of it. Ocean currents are patterns of water movement that influence climate zones and weather patterns around the world. They are primarily driven by winds and by seawater density, although many other factors influence them – including the shape and configuration of the ocean basin they flow through. The two basic types of currents – surface and deep-water currents – help define

1620-414: The character and flow of ocean waters across the planet. Ocean currents are driven by the wind, by the gravitational pull of the moon in the form of tides , and by the effects of variations in water density. Ocean dynamics define and describe the motion of water within the oceans. Ocean temperature and motion fields can be separated into three distinct layers: mixed (surface) layer, upper ocean (above

1674-455: The circulation has a large impact on the climate of the Earth. The thermohaline circulation is sometimes called the ocean conveyor belt, the great ocean conveyor, or the global conveyor belt. On occasion, it is imprecisely used to refer to the meridional overturning circulation , (MOC). Since the 2000s an international program called Argo has been mapping the temperature and salinity structure of

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1728-544: The cost and emissions of shipping vessels. Ocean currents can also impact the fishing industry , examples of this include the Tsugaru , Oyashio and Kuroshio currents all of which influence the western North Pacific temperature, which has been shown to be a habitat predictor for the Skipjack tuna . It has also been shown that it is not just local currents that can affect a country's economy, but neighboring currents can influence

1782-402: The diets of marine mammals, seabirds, and larger fish. Shifts in these populations ultimately cause a shift in the energy processing within the Humboldt Current System. Jack mackerel (jurel) is the second largest fishery in the Humboldt Current System. As with the anchoveta in Peru, this species is believed to be composed of a single stock. Jurel are a straddling species. This means the species

1836-564: The dispersal and distribution of many organisms, inclusing those with pelagic egg or larval stages. An example is the life-cycle of the European Eel . Terrestrial species, for example tortoises and lizards, can be carried on floating debris by currents to colonise new terrestrial areas and islands . The continued rise of atmospheric temperatures is anticipated to have various effects on the strength of surface ocean currents, wind-driven circulation and dispersal patterns. Ocean currents play

1890-468: The dominant species in the ecosystem. These species changes can have negative consequences for the fishing industry and the economies of the countries that fish the system. The anchoveta fishery in Peru was booming during the 1960s. In 1970, catches were reported to exceed 12 million tons per year. This accounted for 20% of the world's catches. An El Niño event occurred during 1972 and caused the anchoveta population to collapse. However, sardine populations saw

1944-403: The end of winter, egg and larval survival is greatly enhanced. This is due to the moderate upwelling, which causes lower turbulence, as well as a weakened Ekman drift offshore. These two species experience population shifts related to climate changes and environmental events such as El Niño . This is due to changes in the availability of each species habitat. Anchoveta are an important component in

1998-403: The high biological productivity of the Humboldt current. Upwelling within the current is not uniform across the entire system. Three notable upwelling subsystems are produced by this current: Due to the upwelling zones within the Humboldt current, biological diversity is extremely high. The Humboldt Current is considered a Class I, highly productive (>300 gC/m /yr) ecosystem. The current hosts

2052-504: The large scale prevailing winds drive major persistent ocean currents, and seasonal or occasional winds drive currents of similar persistence to the winds that drive them, and the Coriolis effect plays a major role in their development. The Ekman spiral velocity distribution results in the currents flowing at an angle to the driving winds, and they develop typical clockwise spirals in the northern hemisphere and counter-clockwise rotation in

2106-462: The near future. There is evidence that surface warming due to anthropogenic climate change has accelerated upper ocean currents in 77% of the global ocean. Specifically, increased vertical stratification due to surface warming intensifies upper ocean currents, while changes in horizontal density gradients caused by differential warming across different ocean regions results in the acceleration of surface zonal currents . There are suggestions that

2160-423: The ocean interior is largely along lines of constant potential density rather than along lines of constant depth, mixing must be rotated relative to the coordinate grid- a process that can be computationally expensive. By contrast, in codes which represent the ocean in terms of constant-density layers (which represent the flow in the ocean interior much more faithfully)- representation of the ocean mixed layer becomes

2214-433: The ocean is divided into boxes whose bottoms are located at fixed depths. Such a representation makes it easy to solve the momentum equations and the well-mixed, weakly stratified layer known as the ocean mixed layer near the ocean surface. However, level coordinate models have problems when it comes to the representation of thin bottom boundary layers (Winton et al., 1998) and thick sea ice. Additionally, because mixing in

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2268-515: The ocean with a fleet of automated platforms that float with the ocean currents. The information gathered will help explain the role the oceans play in the earth's climate. Ocean currents affect temperatures throughout the world. For example, the ocean current that brings warm water up the north Atlantic to northwest Europe also cumulatively and slowly blocks ice from forming along the seashores, which would also block ships from entering and exiting inland waterways and seaports, hence ocean currents play

2322-464: The oldest waters (with a transit time of around 1000 years) upwell in the North Pacific. Extensive mixing therefore takes place between the ocean basins, reducing differences between them and making the Earth's oceans a global system. On their journey, the water masses transport both energy (in the form of heat) and matter (solids, dissolved substances and gases) around the globe. As such, the state of

2376-416: The outskirts of the subtropical gyre . The main flow of the current veers offshore in southern Peru, as a weaker limb continues to flow equatorward. Around 18th parallel south the fresh, cold waters begin to mix with the warm, high salinity Subtropical Surface waters. This collision causes partial subductions . Within this region, the equatorial undercurrent (EUC) flows eastward along the equator, feeding

2430-575: The same latitude North America's weather was colder. A good example of this is the Agulhas Current (down along eastern Africa), which long prevented sailors from reaching India. In recent times, around-the-world sailing competitors make good use of surface currents to build and maintain speed. Ocean currents can also be used for marine power generation , with areas of Japan, Florida and Hawaii being considered for test projects. The utilization of currents today can still impact global trade, it can reduce

2484-541: The same latitude. Another example is Lima, Peru , whose cooler subtropical climate contrasts with that of its surrounding tropical latitudes because of the Humboldt Current . The largest ocean current is the Antarctic Circumpolar Current (ACC), a wind-driven current which flows clockwise uninterrupted around Antarctica. The ACC connects all the ocean basins together, and also provides a link between

2538-450: The same time, the Antarctic Circumpolar Current (ACC) is also slowing down and is expected to lose 20% of it power by the year 2050, "with widespread impacts on ocean circulation and climate". UNESCO mentions that the report in the first time "notes a growing scientific consensus that melting Greenland and Antarctic ice sheets, among other factors, may be slowing important ocean currents at both poles, with potentially dire consequences for

2592-413: The survival of native marine species due to inability to replenish their meta populations but also may increase the prevalence of invasive species . In Japanese corals and macroalgae, the unusual dispersal pattern of organisms toward the poles may destabilize native species. Knowledge of surface ocean currents is essential in reducing costs of shipping, since traveling with them reduces fuel costs. In

2646-518: The thermocline), and deep ocean. Ocean currents are measured in units of sverdrup (Sv) , where 1 Sv is equivalent to a volume flow rate of 1,000,000 m (35,000,000 cu ft) per second. There are two main types of currents, surface currents and deep water currents. Generally surface currents are driven by wind systems and deep water currents are driven by differences in water density due to variations in water temperature and salinity . Surface oceanic currents are driven by wind currents,

2700-562: The upwelling that drives the system's productivity is disrupted by the El Niño-Southern Oscillation (ENSO) event, often with large social and economic impacts. The Humboldt has a considerable cooling influence on the climate of Chile , Peru and Ecuador . It is also largely responsible for the aridity of the Atacama Desert in northern Chile and coastal areas of Peru and also of the aridity of southern Ecuador. Marine air

2754-807: The viability of local fishing industries. Currents of the Arctic Ocean Currents of the Atlantic Ocean Currents of the Indian Ocean Currents of the Pacific Ocean Currents of the Southern Ocean Oceanic gyres Humboldt Current 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 . It

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2808-418: The water column. Between 0 and 600 m (0–1,969 ft), many species of zooplankton occupy this space within the OMZ. This allows for a substantial exchange of carbon between the euphotic layer and the OMZ. 75% of the total zooplankton biomass move in and out of the OMZ. The OMZ also serves as a refuge for organisms that can live in hypoxic conditions. Coastal upwelling is the main factor contributing to

2862-523: The wind powered sailing-ship era, knowledge of wind patterns and ocean currents was even more essential. Using ocean currents to help their ships into harbor and using currents such as the gulf stream to get back home. The lack of understanding of ocean currents during that time period is hypothesized to be one of the contributing factors to exploration failure. The Gulf Stream and the Canary current keep western European countries warmer and less variable, while at

2916-417: The world. The major catches include: sardines , anchovies , mackerel , hake , and squid . Three major stocks of anchoveta are distributed between 4°S and 42°S within the Humboldt Current System. North-central Peru's fishery is primarily composed of one stock of anchoveta. Sardines, chub mackerel , and bonito are also common catches, but not as prominent, in Peru. Southern Peru and Northern Chile host

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