Global Ocean Data Analysis Project

The Global Ocean Data Analysis Project (GLODAP) is a synthesis project bringing together oceanographic data, featuring two major releases as of 2018. The central goal of GLODAP is to generate a global climatology of the World Ocean's carbon cycle for use in studies of both its natural and anthropogenically-forced states. GLODAP is funded by the National Oceanic and Atmospheric Administration, the U.S. Department of Energy, and the National Science Foundation.

The first GLODAP release (v1.1) was produced from data collected during the 1990s by research cruises on the World Ocean Circulation Experiment, Joint Global Ocean Flux Study and Ocean-Atmosphere Exchange Study programmes. The second GLODAP release (v2) extended the first using data from cruises from 2000—2013. The data are available both as individual "bottle data" from sample sites, and as interpolated fields on a standard longitude, latitude, depth grid.

Dataset

The GLODAPv1.1 climatology contains analysed fields of "present day" (1990s) dissolved inorganic carbon (DIC), alkalinity, carbon-14 (14C), CFC-11 and CFC-12.[1] The fields consist of three-dimensional, objectively-analysed global grids at 1° horizontal resolution, interpolated onto 33 standardised vertical intervals[2] from the surface (0 m) to the abyssal seafloor (5500 m). In terms of temporal resolution, the relative scarcity of the source data mean that, unlike the World Ocean Atlas, averaged fields are only produced for the annual time-scale. The GLODAP climatology is missing data in certain oceanic provinces including the Arctic Ocean, the Caribbean Sea, the Mediterranean Sea and Maritime Southeast Asia.

Additionally, analysis has attempted to separate natural from anthropogenic DIC, to produce fields of pre-industrial (18th century) DIC and "present day" anthropogenic CO2. This separation allows estimation of the magnitude of the ocean sink for anthropogenic CO2, and is important for studies of phenomena such as ocean acidification.[3][4] However, as anthropogenic DIC is chemically and physically identical to natural DIC, this separation is difficult. GLODAP used a mathematical technique known as C* (C-star)[5] to deconvolute anthropogenic from natural DIC (there are a number of alternative methods). This uses information about ocean biogeochemistry and CO2 surface disequilibrium together with other ocean tracers including carbon-14, CFC-11 and CFC-12 (which indicate water mass age) to try to separate out natural CO2 from that added during the ongoing anthropogenic transient. The technique is not straightforward and has associated errors, although it is gradually being refined to improve it. Its findings are generally supported by independent predictions made by dynamic models.[3][6]

The GLODAPv2 climatology largely repeats the earlier format, but makes use of the large number of observations of the ocean's carbon cycle made over the intervening period (2000—2013).[7][8] The analysed "present-day" fields in the resulting dataset are normalised to year 2002. Anthropogenic carbon was estimated in GLODAPv2 using a "transit-time distribution" (TTD) method (an approach using a Green's function).[9][8] In addition to updated fields of DIC (total and anthropogenic) and alkalinity, GLODAPv2 includes fields of seawater pH and calcium carbonate saturation state (Ω; omega). The latter is a non-dimensional number calculated by dividing the local carbonate ion concentration by the ambient saturation concentration for calcium carbonate (for the biomineral polymorphs calcite and aragonite), and relates to an oceanographic property, the carbonate compensation depth. Values of this below 1 indicate undersaturation, and potential dissolution, while values above 1 indicate supersaturation, and relative stability.

Gallery

The following panels show sea surface concentrations of fields prepared by GLODAPv1.1. The "pre-industrial" is the 18th century, while "present-day" is approximately the 1990s.

WOA05 GLODAP pi DIC AYool
Pre-industrial DIC
WOA05 GLODAP pd DIC AYool
"Present day" DIC
WOA05 GLODAP pd aco2 AYool
"Present day" anthropogenic CO2
WOA05 GLODAP pd ALK AYool
"Present day" alkalinity
GLODAP sea-surf CFC11 AYool
"Present day" CFC-11
GLODAP sea-surf CFC12 AYool
"Present day" CFC-12

The following panels show sea surface concentrations of fields prepared by GLODAPv2. The "pre-industrial" is the 18th century, while "present-day" is normalised to 2002. Note that these properties are shown in mass units (per kilogram of seawater) rather than the volume units (per cubic metre of seawater) used in the GLODAPv1.1 panels.

Surface ocean pre-industrial DIC concentration, GLODAPv2
Surface ocean pre-industrial DIC concentration, GLODAPv2
Surface ocean present-day DIC concentration, GLODAPv2
Surface ocean present-day DIC concentration, GLODAPv2
Surface ocean anthropogenic CO2 concentration, GLODAPv2
Surface ocean anthropogenic CO2 concentration, GLODAPv2
Surface ocean present-day total alkalinity, GLODAPv2
Surface ocean present-day total alkalinity, GLODAPv2
Surface ocean present-day pH, GLODAPv2
Surface ocean present-day pH, GLODAPv2
Surface ocean present-day omega calcite, GLODAPv2
Surface ocean present-day omega calcite, GLODAPv2

See also

References

  1. ^ Key, R.M., Kozyr, A., Sabine, C.L., Lee, K., Wanninkhof, R., Bullister, J., Feely, R.A., Millero, F., Mordy, C. and Peng, T.-H. (2004). A global ocean carbon climatology: Results from GLODAP. Global Biogeochemical Cycles 18, GB4031
  2. ^ Standardised intervals are at 0, 10, 20, 30, 50, 75, 100, 125, 150, 200, 250, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1750, 2000, 2500, 3000, 3500, 4000, 4500, 5000, 5500 m
  3. ^ a b Orr, J. C. et al. (2005). Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms. Archived June 25, 2008, at the Wayback Machine Nature 437, 681-686
  4. ^ Raven, J. A. et al. (2005). Ocean acidification due to increasing atmospheric carbon dioxide. Royal Society, London, UK
  5. ^ Gruber, N., Sarmiento, J.L. and Stocker, T.F. (1996). An improved method for detecting anthropogenic CO2 in the oceans, Global Biogeochemical Cycles 10:809– 837
  6. ^ Matsumoto, K.; Gruber, N. (2005). "How accurate is the estimation of anthropogenic carbon in the ocean? An evaluation of the DC* method". Global Biogeochem. Cycles. 19. Bibcode:2005GBioC..19.3014M. doi:10.1029/2004GB002397.
  7. ^ Olsen, A.; Key, R.M.; van Heuven, S.; Lauvset, S.K.; Velo, A.; Lin, X.; Schirnick, C.; Kozyr, A.; Tanhua, T.; Hoppema, M.; Jutterström, S.; Steinfeldt, R.; Jeansson, E.; Ishii, M.; Pérez, F.F.; Suzuki, T. (2016). "The Global Ocean Data Analysis Project version 2 (GLODAPv2) – an internally consistent data product for the world ocean". Earth System Science Data. 8: 297–323. Bibcode:2016ESSD....8..297O. doi:10.5194/essd-8-297-2016. Retrieved 2018-07-02.
  8. ^ a b Lauvset, S.K.; Key, R.M.; Olsen, A.; van Heuven, S.; Velo, A.; Lin, X.; Schirnick, C.; Kozyr, A.; Tanhua, T.; Hoppema, M.; Jutterström, S.; Steinfeldt, R.; Jeansson, E.; Ishii, M.; Pérez, F.F.; Suzuki, T.; Watelet, S. (2016). "A new global interior ocean mapped climatology: the 1° ×  1° GLODAP version 2". Earth System Science Data. 8: 325–340. Bibcode:2016ESSD....8..325L. doi:10.5194/essd-8-325-2016. Retrieved 2018-07-02.
  9. ^ Waugh, D.W.; Hall, T.M.; McNeil, B.I.; Key, R.; Matear, R.J. (2006). "Anthropogenic CO2 in the oceans estimated using transit-time distributions". Tellus. 58B: 376–390. Bibcode:2006TellB..58..376W. doi:10.1111/j.1600-0889.2006.00222.x. Retrieved 2018-07-02.

External links

Alkalinity

Alkalinity (from Arabic "al-qalī") is the capacity of water to resist changes in pH that would make the water more acidic. (It should not be confused with basicity which is an absolute measurement on the pH scale.) Alkalinity is the strength of a buffer solution composed of weak acids and their conjugate bases. It is measured by titrating the solution with a monoprotic acid such as HCl until its pH changes abruptly, or it reaches a known endpoint where that happens. Alkalinity is expressed in units of meq/L (milliequivalents per liter), which corresponds to the amount of monoprotic acid added as a titrant in millimoles per liter.

Although alkalinity is primarily a term invented by oceanographers, it is also used by hydrologists to describe temporary hardness. Moreover, measuring alkalinity is important in determining a stream's ability to neutralize acidic pollution from rainfall or wastewater. It is one of the best measures of the sensitivity of the stream to acid inputs. There can be long-term changes in the alkalinity of streams and rivers in response to human disturbances.

Bahama Banks

The Bahama Banks are the submerged carbonate platforms that make up much of the Bahama Archipelago. The term is usually applied in referring to either the Great Bahama Bank around Andros Island, or the Little Bahama Bank of Grand Bahama Island and Great Abaco, which are the largest of the platforms, and the Cay Sal Bank north of Cuba. The islands of these banks are politically part of the Bahamas. Other banks are the three banks of the Turks and Caicos Islands, namely the Caicos Bank of the Caicos Islands, the bank of the Turks Islands, and wholly submerged Mouchoir Bank. Further southeast are the equally wholly submerged Silver Bank and Navidad Bank north of the Dominican Republic.

Carbonate platform

A carbonate platform is a sedimentary body which possesses topographic relief, and is composed of autochthonous calcareous deposits. Platform growth is mediated by sessile organisms whose skeletons build up the reef or by organisms (usually microbes) which induce carbonate precipitation through their metabolism. Therefore, carbonate platforms can not grow up everywhere: they are not present in places where limiting factors to the life of reef-building organisms exist. Such limiting factors are, among others: light, water temperature, transparency and pH-Value. For example, carbonate sedimentation along the Atlantic South American coasts takes place everywhere but at the mouth of the Amazon River, because of the intense turbidity of the water there. Spectacular examples of present-day carbonate platforms are the Bahama Banks under which the platform is roughly 8 km thick, the Yucatan Peninsula which is up to 2 km thick, the Florida platform, the platform on which the Great Barrier Reef is growing, and the Maldive atolls. All these carbonate platforms and their associated reefs are confined to tropical latitudes. Today’s reefs are built mainly by scleractinian corals, but in the distant past other organisms, like archaeocyatha (during the Cambrian) or extinct cnidaria (tabulata and rugosa) were important reef builders.

Chemical oceanography

Chemical oceanography is the study of ocean chemistry: the behavior of the chemical elements within the Earth's oceans. The ocean is unique in that it contains - in greater or lesser quantities - nearly every naturally occurring element in the periodic table.

Much of chemical oceanography describes the cycling of these elements both within the ocean and with the other spheres of the Earth system (see biogeochemical cycle). These cycles are usually characterized as quantitative fluxes between constituent reservoirs defined within the ocean system and as residence times within the ocean. Of particular global and climatic significance are the cycles of the biologically active elements such as carbon, nitrogen, and phosphorus as well as those of some important trace elements such as iron.

Another important area of study in chemical oceanography is the behaviour of isotopes (see isotope geochemistry) and how they can be used as tracers of past and present oceanographic and climatic processes. For example, the incidence of 18O (the heavy isotope of oxygen) can be used as an indicator of polar ice sheet extent, and boron isotopes are key indicators of the pH and CO2 content of oceans in the geologic past.

Geochemical Ocean Sections Study

The Geochemical Ocean Sections Study (GEOSECS) was a global survey of the three-dimensional distributions of chemical, isotopic, and radiochemical tracers in the ocean. A key objective was to investigate the deep thermohaline circulation of the ocean, using chemical tracers, including radiotracers, to establish the pathways taken by this.Expeditions undertaken during GEOSECS took place in the Atlantic Ocean from July 1972 to May 1973, in the Pacific Ocean from August 1973 to June 1974, and in the Indian Ocean from December 1977 to March 1978.Measurements included those of physical oceanographic quantities such as temperature, salinity, pressure and density, chemical / biological quantities such as total inorganic carbon, alkalinity, nitrate, phosphate, silicic acid, oxygen and apparent oxygen utilisation (AOU), and radiochemical / isotopic quantities such as carbon-13, carbon-14 and tritium.

Global Ocean Ecosystem Dynamics

Global Ocean Ecosystem Dynamics (GLOBEC) is the International Geosphere-Biosphere Programme (IGBP) core project responsible for understanding how global change will affect the abundance, diversity and productivity of marine populations. The programme was initiated by SCOR and the IOC of UNESCO in 1991, to understand how global change will affect the abundance, diversity and productivity of marine populations comprising a major component of oceanic ecosystems.

The aim of GLOBEC is to advance our understanding of the structure and functioning of the global ocean ecosystem, its major subsystems, and its response to physical forcing so that a capability can be developed to forecast the responses of the marine ecosystem to global change.

Joint Global Ocean Flux Study

The Joint Global Ocean Flux Study (JGOFS) was an international research programme on the fluxes of carbon between the atmosphere and ocean, and within the ocean interior. Initiated by the Scientific Committee of Oceanic Research (SCOR), the programme ran from 1987 through to 2003, and became one of the early core projects of the International Geosphere-Biosphere Programme (IGBP).

The overarching goal of JGOFS was to advance the understanding of, as well as improve the measurement of, the biogeochemical processes underlying the exchange of carbon across the air—sea interface and within the ocean. The programme aimed to study these processes from regional to global spatial scales, and from seasonal to interannual temporal scales, and to establish their sensitivity to external drivers such as climate change.Early in the programme in 1988, two long-term time-series projects were established in the Atlantic and Pacific basins. These — Bermuda Atlantic Time-series Study (BATS) and Hawaii Ocean Time-series (HOT) — continue to make observations of ocean hydrography, chemistry and biology to the present-day. In 1989, JGOFS undertook the multinational North Atlantic Bloom Experiment (NABE) to investigate and characterise the annual spring bloom of phytoplankton, a key feature in the carbon cycle of the open ocean.An important aspect of JGOFS lay in its objective to develop an increased network of observations, made using routine procedures, and curated such that they were easily available to researchers. JGOFS also oversaw the development of models of the marine system based on understanding gained from its observational programme.

List of submarine volcanoes

A list of active and extinct submarine volcanoes and seamounts located under the world's oceans. There are estimated to be 40,000 to 55,000 seamounts in the global oceans. Almost all are not well-mapped and many may not have been identified at all. Most are unnamed and unexplored. This list is therefore confined to seamounts that are notable enough to have been named and/or explored.

Mollweide projection

The Mollweide projection is an equal-area, pseudocylindrical map projection generally used for global maps of the world or night sky. It is also known as the Babinet projection, homalographic projection, homolographic projection, and elliptical projection. The projection trades accuracy of angle and shape for accuracy of proportions in area, and as such is used where that property is needed, such as maps depicting global distributions.

The projection was first published by mathematician and astronomer Karl (or Carl) Brandan Mollweide (1774–1825) of Leipzig in 1805. It was reinvented and popularized in 1857 by Jacques Babinet, who gave it the name homalographic projection. The variation homolographic arose from frequent nineteenth-century usage in star atlases.

Ocean acidification

Ocean acidification is the ongoing decrease in the pH of the Earth's oceans, caused by the uptake of carbon dioxide (CO2) from the atmosphere. Seawater is slightly basic (meaning pH > 7), and ocean acidification involves a shift towards pH-neutral conditions rather than a transition to acidic conditions (pH < 7). An estimated 30–40% of the carbon dioxide from human activity released into the atmosphere dissolves into oceans, rivers and lakes. To achieve chemical equilibrium, some of it reacts with the water to form carbonic acid. Some of the resulting carbonic acid molecules dissociate into a bicarbonate ion and a hydrogen ion, thus increasing ocean acidity (H+ ion concentration). Between 1751 and 1996, surface ocean pH is estimated to have decreased from approximately 8.25 to 8.14, representing an increase of almost 30% in H+ ion concentration in the world's oceans. Earth System Models project that, within the last decade, ocean acidity exceeded historical analogues and, in combination with other ocean biogeochemical changes, could undermine the functioning of marine ecosystems and disrupt the provision of many goods and services associated with the ocean beginning as early as 2100.Increasing acidity is thought to have a range of potentially harmful consequences for marine organisms, such as depressing metabolic rates and immune responses in some organisms, and causing coral bleaching. By increasing the presence of free hydrogen ions, the additional carbonic acid that forms in the oceans ultimately results in the conversion of carbonate ions into bicarbonate ions. Ocean alkalinity (roughly equal to [HCO3−] + 2[CO32−]) is not changed by the process, or may increase over long time periods due to carbonate dissolution. This net decrease in the amount of carbonate ions available may make it more difficult for marine calcifying organisms, such as coral and some plankton, to form biogenic calcium carbonate, and such structures become vulnerable to dissolution. Ongoing acidification of the oceans may threaten future food chains linked with the oceans. As members of the InterAcademy Panel, 105 science academies have issued a statement on ocean acidification recommending that by 2050, global CO2 emissions be reduced by at least 50% compared to the 1990 level.While ongoing ocean acidification is at least partially anthropogenic in origin, it has occurred previously in Earth's history. The most notable example is the Paleocene-Eocene Thermal Maximum (PETM), which occurred approximately 56 million years ago when massive amounts of carbon entered the ocean and atmosphere, and led to the dissolution of carbonate sediments in all ocean basins.

Ocean acidification has been compared to anthropogenic climate change and called the "evil twin of global warming" and "the other CO2 problem". Freshwater bodies also appear to be acidifying, although this is a more complex and less obvious phenomenon.

Oceanic plateau

An oceanic or submarine plateau is a large, relatively flat elevation that is higher than the surrounding relief with one or more relatively steep sides.There are 184 oceanic plateaus covering an area of 18,486,600 km2 (7,137,700 sq mi), or about 5.11% of the oceans. The South Pacific region around Australia and New Zealand contains the greatest number of oceanic plateaus (see map).

Oceanic plateaus produced by large igneous provinces are often associated with hotspots, mantle plumes, and volcanic islands — such as Iceland, Hawaii, Cape Verde, and Kerguelen. The three largest plateaus, the Caribbean, Ontong Java, and Mid-Pacific Mountains, are located on thermal swells. Other oceanic plateaus, however, are made of rifted continental crust, for example Falkland Plateau, Lord Howe Rise, and parts of Kerguelen, Seychelles, and Arctic ridges.

Plateaus formed by large igneous provinces were formed by the equivalent of continental flood basalts such as the Deccan Traps in India and the Snake River Plain in the United States.

In contrast to continental flood basalts, most igneous oceanic plateaus erupt through young and thin (6–7 km (3.7–4.3 mi)) mafic or ultra-mafic crust and are therefore uncontaminated by felsic crust and representative for their mantle sources.

These plateaus often rise 2–3 km (1.2–1.9 mi) above the surrounding ocean floor and are more buoyant than oceanic crust. They therefore tend to withstand subduction, more-so when thick and when reaching subduction zones shortly after their formations. As a consequence, they tend to "dock" to continental margins and be preserved as accreted terranes. Such terranes are often better preserved than the exposed parts of continental flood basalts and are therefore a better record of large-scale volcanic eruptions throughout Earth's history. This "docking" also means that oceanic plateaus are important contributors to the growth of continental crust. Their formations often had a dramatic impact on global climate, such as the most recent plateaus formed, the three, large, Cretaceous oceanic plateaus in the Pacific and Indian Ocean: Ontong Java, Kerguelen, and Caribbean.

Outline of oceanography

The following outline is provided as an overview of and introduction to Oceanography.

Physical oceanography

Physical oceanography is the study of physical conditions and physical processes within the ocean, especially the motions and physical properties of ocean waters.

Physical oceanography is one of several sub-domains into which oceanography is divided. Others include biological, chemical and geological oceanography.

Physical oceanography may be subdivided into descriptive and dynamical physical oceanography.Descriptive physical oceanography seeks to research the ocean through observations and complex numerical models, which describe the fluid motions as precisely as possible.

Dynamical physical oceanography focuses primarily upon the processes that govern the motion of fluids with emphasis upon theoretical research and numerical models. These are part of the large field of Geophysical Fluid Dynamics (GFD) that is shared together with meteorology. GFD is a sub field of Fluid dynamics describing flows occurring on spatial and temporal scales that are greatly influenced by the Coriolis force.

Undersea mountain range

Undersea mountain ranges are mountain ranges that are mostly or entirely underwater, and specifically under the surface of an ocean. If originated from current tectonic forces, they are often referred to as a mid-ocean ridge. In contrast, if formed by past above-water volcanism, they are known as a seamount chain. The largest and best known undersea mountain range is a mid-ocean ridge, the Mid-Atlantic Ridge. It has been observed that, "similar to those on land, the undersea mountain ranges are the loci of frequent volcanic and earthquake activity".

Wave base

The wave base, in physical oceanography, is the maximum depth at which a water wave's passage causes significant water motion. For water depths deeper than the wave base, bottom sediments and the seafloor are no longer stirred by the wave motion above.

World Ocean Atlas

The World Ocean Atlas (WOA) is a data product of the Ocean Climate Laboratory of the National Oceanographic Data Center (U.S.). The WOA consists of a climatology of fields of in situ ocean properties for the World Ocean. It was first produced in 1994 (based on the earlier Climatological Atlas of the World Ocean), with later editions at roughly four year intervals in 1998, 2001, 2005, 2009, and 2013.

World Ocean Circulation Experiment

The World Ocean Circulation Experiment (WOCE) was a component of the international World Climate Research Program, and aimed to establish the role of the World Ocean in the Earth's climate system. WOCE's field phase ran between 1990 and 1998, and was followed by an analysis and modeling phase that ran until 2002. When the WOCE was conceived, there were three main motivations for its creation. The first of these is the inadequate coverage of the World Ocean, specifically in the Southern Hemisphere. Data was also much more sparse during the winter months than the summer months, and there was—and still to some extent—a critical need for data covering all seasons. Secondly, the data that did exist was not initially collected for studying ocean circulation and was not well suited for model comparison. Lastly, there were concerns involving the accuracy and reliability of some measurements. The WOCE was meant to address these problems by providing new data collected in ways designed to “meet the needs of global circulation models for climate prediction.”

World Ocean Database Project

The World Ocean Database Project, or WOD, is a project established by the Intergovernmental Oceanographic Commission (IOC). The project leader is Sydney Levitus who is director of the International Council for Science (ICSU) World Data Center (WDC) for Oceanography, Silver Spring. In recognition of the success of the IOC Global Oceanographic Data Archaeological and Rescue Project (GODAR project), a proposal was presented at the 16th Session of the Committee on International Oceanographic Data and Information Exchange (IODE), which was held in Lisbon, Portugal, in October–November 2000, to establish the World Ocean Database Project. This project is intended to stimulate international exchange of modern oceanographic data and encourage the development of regional oceanographic databases as well as the implementation of regional quality control procedures. This new Project was endorsed by the IODE at the conclusion of the Portugal meeting, and the IOC subsequently approved this project in June 2001.

The World Ocean Database represents the world’s largest collection of ocean profile-plankton data available internationally without restriction. Data comes from the: (a) Sixty-five National Oceanographic Data Centers and nine Designated National Agencies (DNAs) (in Croatia, Finland, Georgia, Malaysia, Romania, Senegal, Sweden, Tanzania, and Ukraine), (b) International Ocean Observing Projects such as the completed World Ocean Circulation Experiment (WOCE) and Joint Global Ocean Flux Study (JGOFS), as well as currently active programs such as CLIVAR and Argo, (c) International Ocean Data Management Projects such as the IOC/IODE Global Oceanographic Data Archaeology and Rescue Project (GODAR), and (d) Real-time Ocean Observing Systems such as the IOC/IODE Global Temperature-Salinity Profile Project (GTSPP). All ocean data acquired by WDC Silver Spring – USA are considered as part of the WDC archive and are freely available as public domain data.

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