The Global Ocean Data Analysis Project (GLODAP) is a synthesis project bringing together

oceanographic Oceanography (), also known as oceanology and ocean science, is the scientific study of the oceans. It is an Earth science, which covers a wide range of topics, including ecosystem dynamics; ocean currents, waves, and geophysical fluid dynamics ...

data, featuring two major releases as of 2018. The central goal of GLODAP is to generate a global

climatology Climatology (from Ancient Greek, Greek , ''klima'', "place, zone"; and , ''wiktionary:-logia, -logia'') or climate science is the scientific study of Earth's climate, typically defined as weather conditions averaged over a period of at least 30 ...

of the

World Ocean The ocean (also the sea or the world ocean) is the body of salt water that covers approximately 70.8% of the surface of Earth and contains 97% of Earth's water. An ocean can also refer to any of the large bodies of water into which the wor ...

carbon cycle The carbon cycle is the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of the Earth. Carbon is the main component of biological compounds as well as a major componen ...

for use in studies of both its natural and anthropogenically forced states. GLODAP is funded by the

National Oceanic and Atmospheric Administration The National Oceanic and Atmospheric Administration (abbreviated as NOAA ) is an United States scientific and regulatory agency within the United States Department of Commerce that forecasts weather, monitors oceanic and atmospheric conditi ...

, the

U.S. Department of Energy The United States Department of Energy (DOE) is an executive department of the U.S. federal government that oversees U.S. national energy policy and manages the research and development of nuclear power and nuclear weapons in the United States. ...

, and the

National Science Foundation The National Science Foundation (NSF) is an independent agency of the United States government that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National ...

. 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 to 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 Dissolved inorganic carbon (DIC) is the sum of the aqueous species of inorganic carbon in a solution. Carbon compounds can be distinguished as either organic or inorganic, and as dissolved or particulate, depending on their composition. Organic ...

(DIC),

alkalinity Alkalinity (from ar, القلوي, al-qaly, lit=ashes of the saltwort) is the capacity of water to resist acidification. It should not be confused with basicity, which is an absolute measurement on the pH scale. Alkalinity is the strengt ...

, carbon-14 (¹⁴C),

CFC-11 Trichlorofluoromethane, also called freon-11, CFC-11, or R-11, is a chlorofluorocarbon (CFC). It is a colorless, faintly ethereal, and sweetish-smelling liquid that boils around room temperature. CFC-11 is a Class 1 ozone-depleting substance ...

and CFC-12. The fields consist of

three-dimensional Three-dimensional space (also: 3D space, 3-space or, rarely, tri-dimensional space) is a geometric setting in which three values (called ''parameters'') are required to determine the position of an element (i.e., point). This is the informal ...

, objectively-analysed global grids at 1°

horizontal resolution Dots per inch (DPI, or dpiThe acronym appears in sources as either "DPI" or lowercase "dpi". See "Print Resolution Understanding 4-bit depth – Xerox" (PDF). Xerox.com. September 2012.) is a measure of spatial printing, video or image scanner ...

, interpolated onto 33 standardised vertical intervals from the surface (0 m) to the

abyssal The abyssal zone or abyssopelagic zone is a layer of the pelagic zone of the ocean. "Abyss" derives from the Greek word , meaning bottomless. At depths of , this zone remains in perpetual darkness. It covers 83% of the total area of the ocean an ...

seafloor The seabed (also known as the seafloor, sea floor, ocean floor, and ocean bottom) is the bottom of the ocean. All floors of the ocean are known as 'seabeds'. The structure of the seabed of the global ocean is governed by plate tectonics. Most of ...

(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 Arctic Ocean is the smallest and shallowest of the world's five major oceans. It spans an area of approximately and is known as the coldest of all the oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, ...

, the

Caribbean Sea The Caribbean Sea ( es, Mar Caribe; french: Mer des Caraïbes; ht, Lanmè Karayib; jam, Kiaribiyan Sii; nl, Caraïbische Zee; pap, Laman Karibe) is a sea of the Atlantic Ocean in the tropics of the Western Hemisphere. It is bounded by Mexico ...

, the

Mediterranean Sea The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ...

and

Maritime Southeast Asia Maritime Southeast Asia comprises the countries of Brunei, Indonesia, Malaysia, the Philippines, Singapore, and East Timor. Maritime Southeast Asia is sometimes also referred to as Island Southeast Asia, Insular Southeast Asia or Oceanic Sout ...

. Additionally, analysis has attempted to separate natural from anthropogenic DIC, to produce fields of pre- industrial (18th century) DIC and "present day" anthropogenic . This separation allows estimation of the magnitude of the ocean

sink A sink is a bowl-shaped plumbing fixture for washing hands, dishwashing, and other purposes. Sinks have a tap (faucet) that supply hot and cold water and may include a spray feature to be used for faster rinsing. They also include a drain ...

for anthropogenic , and is important for studies of phenomena such as

ocean acidification Ocean acidification is the reduction in the pH value of the Earth’s ocean. Between 1751 and 2021, the average pH value of the ocean surface has decreased from approximately 8.25 to 8.14. The root cause of ocean acidification is carbon dioxi ...

.Orr, J. C. ''et al.'' (2005)
Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms.
''Nature'' 437, 681–686Raven, J. A. ''et al.'' (2005)
Ocean acidification due to increasing atmospheric carbon dioxide.
Royal Society, London, UK 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) to deconvolute anthropogenic from natural DIC (there are a number of alternative methods). This uses information about ocean

biogeochemistry Biogeochemistry is the scientific discipline that involves the study of the chemical, physical, geological, and biological processes and reactions that govern the composition of the natural environment (including the biosphere, the cryospher ...

and 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 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. 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). 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 In mathematics, a Green's function is the impulse response of an inhomogeneous linear differential operator defined on a domain with specified initial conditions or boundary conditions. This means that if \operatorname is the linear differenti ...

). 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 A carbonate is a salt of carbonic acid (H2CO3), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word ''carbonate'' may also refer to a carbonate ester, an organic compound containing the carbonat ...

ion concentration by the ambient saturation concentration for calcium carbonate (for the biomineral polymorphs

calcite Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on the Mohs scale of mineral hardness, based on scra ...

and

aragonite Aragonite is a carbonate mineral, one of the three most common naturally occurring crystal forms of calcium carbonate, (the other forms being the minerals calcite and vaterite). It is formed by biological and physical processes, including pre ...

), and relates to an oceanographic property, the

carbonate compensation depth Carbonate compensation depth (CCD) is the depth in the oceans below which the rate of supply of calcite ( calcium carbonate) lags behind the rate of solvation, such that no calcite is preserved. Shells of animals therefore dissolve and carbonate ...

. Values of this below 1 indicate

undersaturation Undersaturation is a state of a solution that contains less of a dissolved material than could be dissolved by that quantity of solvent under normal circumstances. It can also refer to a vapor of a compound that has a lower (partial) pressure than ...

, and potential dissolution, while values above 1 indicate

supersaturation In physical chemistry, supersaturation occurs with a solution when the concentration of a solute exceeds the concentration specified by the value of solubility at equilibrium. Most commonly the term is applied to a solution of a solid in a liq ...

, 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. 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 Mass is an intrinsic property of a body. It was traditionally believed to be related to the quantity of matter in a physical body, until the discovery of the atom and particle physics. It was found that different atoms and different element ...

units (per kilogram of seawater) rather than the

volume Volume is a measure of occupied three-dimensional space. It is often quantified numerically using SI derived units (such as the cubic metre and litre) or by various imperial or US customary units (such as the gallon, quart, cubic inch). Th ...

units (per cubic metre of seawater) used in the GLODAPv1.1 panels.

References

External links

GLODAP website
Bjerknes Climate Data Centre
GLODAP v1.1 website

GLODAP v2 website
National Oceanic and Atmospheric Administration {{physical oceanography Biological oceanography Carbon Chemical oceanography Chlorofluorocarbons Oceanography Physical oceanography

Dataset

Gallery

See also

References

External links