CORA (standing for Coriolis Ocean database ReAnalysis) is a global oceanographic temperature and salinity dataset produced and maintained by the French institute IFREMER. Most of those data are real-time data coming from different types of platforms such as research vessels, profilers, underwater gliders, drifting buoys, moored buoys, sea mammals and ships of opportunity.
This in-situ dataset produced by the French institute Ifremer in the framework of the European project MyOcean and French project CORIOLIS is a picture of the content of the operational oceanographic database CORIOLIS. This database is the main tool of Coriolis project which is a global data assembly center of in situ data: such as US-GODAE centre of Monterey in California. The latest version of CORA product is v5.0, it covers the years 1950 up to 2015 and has been released in April 2017. Observations are profiles distributed on measured levels (pressure or depth) and organized by dates of measurement and type of platform. Main users of CORA dataset are ocean modelers who needs to constraint and initialize their model. CORA [1] is free of access and can be download via CORIOLIS website [2] in netCDF file format. The main different of CORA dataset with other available datasets is that CORA provides data at depth levels where measurements were made rather than at standard levels such as in World Ocean Atlas or ENACT3. In addition data in CORA are retrieved from Coriolis database where each profile is visually checked by specialist operators if suspicious.
The CORA dataset is designed for operational oceanography, so most global real time monitoring networks are plugged into this database. The data sources are the following:
| Date of release | Time span | Comments | |
|---|---|---|---|
| CORA1.0 | 2007 | 2002-2006 | Beta version of the dataset, full years extracted |
| CORA2.2 | 2009 | 1990-2008 | Add of validation procedures (climatological checks) and gridding of the data |
| CORA3.1 | 2010 | 1990-2009 | Full years updated + 2009 added |
| CORA3.2 | 2011 | 1990-2010 | Add of validation procedures (duplicate check, XBT depth correction) integration of sea mammals data, automatisation of the update procedure |
| CORA3.3 | 2012 | 1990-2011 | Article [6] submitted to Ocean Science review, add of year 2011, completion of anomalies feedback from objective analysis towards CORA dataset and Coriolis database. |
| CORA3.4 | 2013 | 1990-2011 | New ICES CTD data added |
| CORA4.0 | 2014 | 1990-2012 | Update of profiles and addition of Time series from drifters, ferrybox, profilers. |
| CORA4.1 | 2015 | 1950-1989 (Extraction from EN4), 1990-2013 | Addition of TSG data, delayed mode sea mammals and surface drifters + Integration of XBT and CTD from EN4 |
| CORA4.2 | 2016 | 1950-1989 (Extraction from EN4), 1990-2014 | Inclusion of 2,4 million profiles from the SHOM (Service Hydrographique de la Marine), mostly of XBTs CTDs and MBTs from 1950 to 2009 |
| CORA5.0 | 2017 | 1950-2015 |
A buoy is a floating device that can have many purposes. It can be anchored (stationary) or allowed to drift with ocean currents.
A weather station is a facility, either on land or sea, with instruments and equipment for measuring atmospheric conditions to provide information for weather forecasts and to study the weather and climate. The measurements taken include temperature, atmospheric pressure, humidity, wind speed, wind direction, and precipitation amounts. Wind measurements are taken with as few other obstructions as possible, while temperature and humidity measurements are kept free from direct solar radiation, or insolation. Manual observations are taken at least once daily, while automated measurements are taken at least once an hour. Weather conditions out at sea are taken by ships and buoys, which measure slightly different meteorological quantities such as sea surface temperature (SST), wave height, and wave period. Drifting weather buoys outnumber their moored versions by a significant amount.
Sea surface temperature (SST), or ocean surface temperature, is the ocean temperature close to the surface. The exact meaning of surface varies according to how we measure it. It is between 1 millimetre (0.04 in) and 20 metres (70 ft) below the sea surface. Sea surface temperatures greatly modify air masses in the Earth's atmosphere within a short distance of the shore. Local areas of heavy snow can form in bands downwind of warm water bodies within an otherwise cold air mass. Warm sea surface temperatures can develop and strengthen cyclones over the Ocean. Experts call this process tropical cyclogenesis. Tropical cyclones can also cause a cool wake. This is due to turbulent mixing of the upper 30 metres (100 ft) of the ocean. Sea surface temperature changes during the day. This is like the air above it, but to a lesser degree. There is less variation in sea surface temperature on breezy days than on calm days. Ocean currents, such as the Atlantic Multidecadal Oscillation, can affect sea surface temperatures over several decades. Thermohaline circulation has a major impact on average sea surface temperature throughout most of the world's oceans.
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, 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.
Argo is an international programme for researching the ocean. It uses profiling floats to observe temperature, salinity andcurrents. Recently it has observed bio-optical properties in the Earth's oceans. It has been operating since the early 2000s. The real-time data it provides support climate and oceanographic research. A special research interest is to quantify the ocean heat content (OHC). The Argo fleet consists of almost 4000 drifting "Argo floats" deployed worldwide. Each float weighs 20–30 kg. In most cases probes drift at a depth of 1000 metres. Experts call this the parking depth. Every 10 days, by changing their buoyancy, they dive to a depth of 2000 metres and then move to the sea-surface. As they move they measure conductivity and temperature profiles as well as pressure. Scientists calculate salinity and density from these measurements. Seawater density is important in determining large-scale motions in the ocean.
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."
Weather buoys are instruments which collect weather and ocean data within the world's oceans, as well as aid during emergency response to chemical spills, legal proceedings, and engineering design. Moored buoys have been in use since 1951, while drifting buoys have been used since 1979. Moored buoys are connected with the ocean bottom using either chains, nylon, or buoyant polypropylene. With the decline of the weather ship, they have taken a more primary role in measuring conditions over the open seas since the 1970s. During the 1980s and 1990s, a network of buoys in the central and eastern tropical Pacific Ocean helped study the El Niño-Southern Oscillation. Moored weather buoys range from 1.5–12 metres (5–40 ft) in diameter, while drifting buoys are smaller, with diameters of 30–40 centimetres (12–16 in). Drifting buoys are the dominant form of weather buoy in sheer number, with 1250 located worldwide. Wind data from buoys has smaller error than that from ships. There are differences in the values of sea surface temperature measurements between the two platforms as well, relating to the depth of the measurement and whether or not the water is heated by the ship which measures the quantity.
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, with later editions at roughly four year intervals in 1998, 2001, 2005, 2009, 2013, 2018, and 2023.
The Ocean Observatories Initiative (OOI) is a National Science Foundation (NSF) Major Research Facility composed of a network of science-driven ocean observing platforms and sensors in the Atlantic and Pacific Oceans. This networked infrastructure measures physical, chemical, geological, and biological variables from the seafloor to the sea surface and overlying atmosphere, providing an integrated data collection system on coastal, regional and global scales. OOI's goal is to deliver data and data products for a 25-year-plus time period, enabling a better understanding of ocean environments and critical ocean issues.
MyOcean is a series of projects granted by the European Commission within the GMES Program, whose objective is to define and to set up a concerted and integrated pan-European capacity for ocean monitoring and forecasting. The activities benefit several specified areas of use: Maritime security, oil spill prevention, marine resources management, climate change, seasonal forecasting, coastal activities, ice sheet surveys, water quality and pollution. The series of MyOcean projects ended in 2015, and their services are now continued by the Copernicus Programme.
The following are considered ocean essential climate variables (ECVs) by the Ocean Observations Panel for Climate (OOPC) that are currently feasible with current observational systems.
The Hawaii Ocean Time-series (HOT) program is a long-term oceanographic study based at the University of Hawaii at Manoa. In 2015, the American Society for Microbiology designated the HOT Program's field site Station ALOHA a "Milestone in Microbiology", for playing "a key role in defining the discipline of microbial oceanography and educating the public about the vital role of marine microbes in global ecosystems."
RAFOS floats are submersible devices used to map ocean currents well below the surface. They drift with these deep currents and listen for acoustic "pongs" emitted at designated times from multiple moored sound sources. By analyzing the time required for each pong to reach a float, researchers can pinpoint its position by triangulation. The floats are able to detect the pongs at ranges of hundreds of kilometers because they generally target a range of depths known as the SOFAR channel, which acts as a waveguide for sound. The name "RAFOS" derives from the earlier SOFAR floats, which emitted sounds that moored receivers picked up, allowing real-time underwater tracking. When the transmit and receive roles were reversed, so was the name: RAFOS is SOFAR spelled backward. Listening for sound requires far less energy than transmitting it, so RAFOS floats are cheaper and longer lasting than their predecessors, but they do not provide information in real-time: instead they store it on board, and upon completing their mission, drop a weight, rise to the surface, and transmit the data to shore by satellite.
The International Comprehensive Ocean-Atmosphere Data Set (ICOADS) is a digital database of 261 million weather observations made by ships, weather ships, and weather buoys spanning the years 1662 to 2007. The database was initially constructed in 1985 and continues to be expanded upon and updated on a regular basis. From the original data, gridded datasets were created. ICOADS information has been useful in determining the reliability of ship and buoy wind measurements, helping to determine temperature trends in the sea surface temperature field, and updating the Atlantic hurricane database.
The ocean temperature varies by depth, geographical location and season. Both the temperature and salinity of ocean water differs. Warm surface water is generally saltier than the cooler deep or polar waters; in polar regions, the upper layers of ocean water are cold and fresh. Deep ocean water is cold, salty water found deep below the surface of Earth's oceans. This water has a very uniform temperature, around 0-3 °C. The ocean temperature also depends on the amount of solar radiation falling on its surface. In the tropics, with the Sun nearly overhead, the temperature of the surface layers can rise to over 30 °C (86 °F) while near the poles the temperature in equilibrium with the sea ice is about −2 °C (28 °F). There is a continuous circulation of water in the oceans. Thermohaline circulation (THC) is a part of the large-scale ocean circulation that is driven by global density gradients created by surface heat and freshwater fluxes. Warm surface currents cool as they move away from the tropics, and the water becomes denser and sinks. The cold water moves back towards the equator as a deep sea current, driven by changes in the temperature and density of the water, before eventually welling up again towards the surface.
Coriolis involves 7 institutes in operational oceanography in France decided in 2001 to joint their efforts within Coriolis in order to:
The Tropical Atmosphere Ocean (TAO) project is a major international effort that instrumented the entire tropical Pacific Ocean with approximately 70 deep ocean moorings. The development of the TAO array in 1985 was motivated by the 1982-1983 El Niño event and ultimately designed for the study of year-to-year climate variations related to El Niño and the Southern Oscillation (ENSO). Led by the TAO Project Office of the Pacific Marine Environmental Laboratory (PMEL), the full array of 70 moorings was completed in 1994.
The Research Moored Array for African-Asian-Australian Monsoon Analysis and Prediction (RAMA) is a system of moored observation buoys in the Indian Ocean that collects meteorological and oceanographic data. The data collected by RAMA will greatly enhance the ability of scientists to understand climatic events and predict monsoon events. Climatic and oceanic events in the Indian Ocean affect weather and climate throughout the rest of the world, so RAMA will support weather forecasting and climate research worldwide. Although widely supported internationally, the system has only been partially implemented due to pirate activity off the coast of Somalia.
The Global Drifter Program (GDP) was conceived by Prof. Peter Niiler, with the objective of collecting measurements of surface ocean currents, sea surface temperature and sea-level atmospheric pressure using drifters. It is the principal component of the Global Surface Drifting Buoy Array, a branch of NOAA's Global Ocean Observations and a scientific project of the Data Buoy Cooperation Panel (DBCP). The project originated in February 1979 as part of the TOGA/Equatorial Pacific Ocean Circulation Experiment (EPOCS) and the first large-scale deployment of drifters was in 1988 with the goal of mapping the tropical Pacific Ocean's surface circulation. The current goal of the project is to use 1250 satellite-tracked surface drifting buoys to make accurate and globally dense in-situ observations of mixed layer currents, sea surface temperature, atmospheric pressure, winds and salinity, and to create a system to process the data. Horizontal transports in the oceanic mixed layer measured by the GDP are relevant to biological and chemical processes as well as physical ones.
The Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) project is a large scale National Science Foundation funded research project based at Princeton University that started in September 2014. The project aims to increase the understanding of the Southern Ocean and the role it plays in factors such as climate, as well as educate new scientists with oceanic observation.
