Global Ocean Currents Database (GOCD)
The Global Ocean Current Database (GOCD) integrates ocean current data from a wide variety of capture methods, resolutions, and formats into a single format (NetCDF) archive. The GOCD is a valuable resource that gives scientists and researchers a comprehensive depiction of global current activity and structure. It also allows ocean modelers, ocean resource managers, and the shipping industry quantify the impact of currents on their operations.
- Ocean Currents
The GOCD data access portal includes search interfaces for moored current meter, acoustic doppler profiler, drifting platform, high frequency radar, and ocean glider data. The portal also includes a suite of the originators datasets that make up the GOCD product.
Sun, Charles; US DOC/NOAA/NESDIS > National Centers for Environmental Information (2018). NCEI Standard Product: Global Ocean Currents Database (GOCD) (NCEI Accession 0171666). Version 3.0. NOAA National Centers for Environmental Information. Dataset. [access date]
- Acoustic Doppler Current Profiler (ADCP)
- An instrument used to measure current speed. Different forms of ADCP are used to measure current from specific angles and directions:
- Data variables can contain a collection of timeSeriesProfile features, one feature per station
- A timeSeriesProfile instance dimension, also called a station dimension
- Instance variables, which have only this dimension, including latitude and longitude for example, are also referred to as station variables and contain information describing the stations
- Ocean Glider
- An ocean glider is an unpiloted, autonomous underwater vehicle used to collect oceanographic data, often equipped with sensors to monitor temperature, salinity, currents, and other ocean conditions
- Sea Glider (Developed by the University of Washington/iRobot Corp.)
- Slocum Glider (Developed by Teledyne Webb Research)
- Spray Glider (Developed by scientists from Scripps Institution of Oceanography and Woods Hole Oceanographic Institution)
- Wave Glider (Developed by Liquid Robotics Oil & Gas)
Current Capture Methods
- Underwater gliders use a hydrodynamic model to navigate in still water based on speed and direction. This model determines depth-averaged currents by comparing the predicted surfacing location of the vehicle with the actual surfacing position according to the GPS. Depth average current estimates have an accuracy of 0.01 cm/s and are assumed to act over the whole profile uniformly.
- High Frequency (HF)
HF Radar is used to measure surface current velocity fields near the coast. Radar antennas can measure surface currents (the top 1-2 m of the water column) up to 200 km away with resolutions ranging from 500 m to 6 km depending on the radar frequency. HF Radar data is generally accurate to 10 cm/s of current speed and 10 degrees of current direction.
Note: Presented values are spatial and time averages and may not be representative of the currents of a specific point within a grid cell (particularly near shore) or of an instant in time during the observed hourly period.
- Drifter Derived
- Indirect determinations of ocean surface currents based on the ship drift method. The difference between a ship's dead-reckoned position (determined from its previous position, speed, and heading) and actual position determined from a navigational fix is ascribed solely to the effect of surface currents.