World Ocean Atlas
Encyclopedia
The World Ocean Atlas 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 and 2009.
-analysed global
grids at 1°
spatial resolution. The fields are three-dimensional
, and data are typically interpolated
onto 33 standardised vertical intervals from the surface (0 m) to the seafloor
(5500 m). In terms of temporal
resolution, averaged fields are produced for annual, season
al and month
ly time-scales. The WOA fields include ocean temperature
, salinity
, dissolved oxygen, apparent oxygen utilisation
(AOU), percent oxygen saturation
, phosphate
, silicic acid
, and nitrate
. Early editions of the WOA additionally included fields such as mixed layer depth
and sea surface height
.
In addition to the averaged fields of ocean properties, the WOA also contains fields of statistical
information concerning the constituent data that the averages were produced from. These include fields such as the number of data points the average is derived from, their standard deviation
and standard error
. A lower horizontal resolution (5°) version of the WOA is also available. The WOA dataset is primarily available as compressed
ASCII
, but since WOA 2005 a netCDF
version has also been produced.
Data
The term data refers to qualitative or quantitative attributes of a variable or set of variables. Data are typically the results of measurements and can be the basis of graphs, images, or observations of a set of variables. Data are often viewed as the lowest level of abstraction from which...
product of the Ocean Climate Laboratory of the National Oceanographic Data Center
National Oceanographic Data Center
The National Oceanographic Data Center is one of the national environmental data centers operated by the National Oceanic and Atmospheric Administration of the U.S. Department of Commerce. The main NODC facility is located in Silver Spring, Maryland and is made up of five divisions...
(U.S.
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
). The WOA consists of a climatology
Climatology
Climatology is the study of climate, scientifically defined as weather conditions averaged over a period of time, and is a branch of the atmospheric sciences...
of fields
Field (geography)
In the context of Spatial Analysis, Geographic Information Systems, and Geographic Information Science, the term field has been adopted from physics, in which it denotes a quantity that can be theoretically assigned to any point of space, such as temperature or density...
of in situ ocean
Ocean
An ocean is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas.More than half of this area is over 3,000...
properties for the World Ocean
World Ocean
The World Ocean, world ocean, or global ocean, is the interconnected system of the Earth's oceanic waters, and comprises the bulk of the hydrosphere, covering almost 71% of the Earth's surface, with a total volume of 1.332 billion cubic kilometres.The unity and continuity of the World Ocean, with...
. 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 and 2009.
Dataset
The fields that make up the WOA dataset consist of objectivelyObjectivity (science)
Objectivity in science is a value that informs how science is practiced and how scientific truths are created. It is the idea that scientists, in attempting to uncover truths about the natural world, must aspire to eliminate personal biases, a priori commitments, emotional involvement, etc...
-analysed global
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
grids at 1°
Degree (angle)
A degree , usually denoted by ° , is a measurement of plane angle, representing 1⁄360 of a full rotation; one degree is equivalent to π/180 radians...
spatial resolution. The fields are three-dimensional
Three-dimensional space
Three-dimensional space is a geometric 3-parameters model of the physical universe in which we live. These three dimensions are commonly called length, width, and depth , although any three directions can be chosen, provided that they do not lie in the same plane.In physics and mathematics, a...
, and data are typically interpolated
Interpolation
In the mathematical field of numerical analysis, interpolation is a method of constructing new data points within the range of a discrete set of known data points....
onto 33 standardised vertical intervals from the surface (0 m) to the seafloor
Seabed
The seabed is the bottom of the ocean.- Ocean structure :Most of the oceans have a common structure, created by common physical phenomena, mainly from tectonic movement, and sediment from various sources...
(5500 m). In terms of temporal
Time
Time is a part of the measuring system used to sequence events, to compare the durations of events and the intervals between them, and to quantify rates of change such as the motions of objects....
resolution, averaged fields are produced for annual, season
Season
A season is a division of the year, marked by changes in weather, ecology, and hours of daylight.Seasons result from the yearly revolution of the Earth around the Sun and the tilt of the Earth's axis relative to the plane of revolution...
al and month
Month
A month is a unit of time, used with calendars, which was first used and invented in Mesopotamia, as a natural period related to the motion of the Moon; month and Moon are cognates. The traditional concept arose with the cycle of moon phases; such months are synodic months and last approximately...
ly time-scales. The WOA fields include ocean temperature
Temperature
Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
, salinity
Salinity
Salinity is the saltiness or dissolved salt content of a body of water. It is a general term used to describe the levels of different salts such as sodium chloride, magnesium and calcium sulfates, and bicarbonates...
, dissolved oxygen, apparent oxygen utilisation
Apparent oxygen utilisation
In freshwater or marine systems apparent oxygen utilisation is the difference between the measured dissolved oxygen concentration and its equilibrium saturation concentration in water with the same physical and chemical properties. Such differences typically occur when biological activity acts to...
(AOU), percent oxygen saturation
Oxygen saturation
Oxygen saturation or dissolved oxygen is a relative measure of the amount of oxygen that is dissolved or carried in a given medium. It can be measured with a dissolved oxygen probe such as an oxygen sensor or an optode in liquid media, usually water.It has particular significance in medicine and...
, phosphate
Phosphate
A phosphate, an inorganic chemical, is a salt of phosphoric acid. In organic chemistry, a phosphate, or organophosphate, is an ester of phosphoric acid. Organic phosphates are important in biochemistry and biogeochemistry or ecology. Inorganic phosphates are mined to obtain phosphorus for use in...
, silicic acid
Silicic acid
Silicic acid is a general name for a family of chemical compounds of the element silicon, hydrogen, and oxygen, with the general formula [SiOx4-2x]n...
, and nitrate
Nitrate
The nitrate ion is a polyatomic ion with the molecular formula NO and a molecular mass of 62.0049 g/mol. It is the conjugate base of nitric acid, consisting of one central nitrogen atom surrounded by three identically-bonded oxygen atoms in a trigonal planar arrangement. The nitrate ion carries a...
. Early editions of the WOA additionally included fields such as mixed layer depth
Mixed layer
The oceanic or limnological mixed layer is a layer in which active turbulence has homogenized some range of depths. The surface mixed layer is a layer where this turbulence is generated by winds, cooling, or processes such as evaporation or sea ice formation which result in an increase in salinity...
and sea surface height
Sea surface height
Sea surface height is the height of the ocean's surface. On a daily basis, SSH is most obviously affected by the tidal forces of the Moon and the Sun acting on the Earth. Over longer timescales, SSH is influenced by ocean circulation. Typically, SSH anomalies resulting from these forces differ...
.
In addition to the averaged fields of ocean properties, the WOA also contains fields of statistical
Statistics
Statistics is the study of the collection, organization, analysis, and interpretation of data. It deals with all aspects of this, including the planning of data collection in terms of the design of surveys and experiments....
information concerning the constituent data that the averages were produced from. These include fields such as the number of data points the average is derived from, their standard deviation
Standard deviation
Standard deviation is a widely used measure of variability or diversity used in statistics and probability theory. It shows how much variation or "dispersion" there is from the average...
and standard error
Standard error
Standard error can refer to:* Standard error , the estimated standard deviation or error of a series of measurements* Standard error stream, one of the standard streams in Unix-like operating systems...
. A lower horizontal resolution (5°) version of the WOA is also available. The WOA dataset is primarily available as compressed
Data compression
In computer science and information theory, data compression, source coding or bit-rate reduction is the process of encoding information using fewer bits than the original representation would use....
ASCII
ASCII
The American Standard Code for Information Interchange is a character-encoding scheme based on the ordering of the English alphabet. ASCII codes represent text in computers, communications equipment, and other devices that use text...
, but since WOA 2005 a netCDF
NetCDF
NetCDF is a set of software libraries and self-describing, machine-independent data formats that support the creation, access, and sharing of array-oriented scientific data. The project homepage is hosted by the Unidata program at the University Corporation for Atmospheric Research...
version has also been produced.
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See also
- Global Ocean Data Analysis ProjectGlobal Ocean Data Analysis ProjectThe Global Ocean Data Analysis Project is a synthesis project bringing together oceanographic 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...
- OceanOceanAn ocean is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas.More than half of this area is over 3,000...
- Seven seasSeven SeasThe phrase "Seven Seas" can refer either to a particular set of seven seas or to a great expanse of water in general. Today in modern times, this also includes the four oceans, and three large seas...
- World Ocean Circulation ExperimentWorld Ocean Circulation ExperimentThe World Ocean Circulation Experiment 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...
- European Atlas of the SeasEuropean Atlas of the SeasThe European Atlas of the Seas is an interactive electronic atlas on the coasts and seas within and around Europe. The atlas is freely accessible on the internet and is available in English, French and German...