The gyre index constructed here from satellite altimetry is related to core aspects of the North Atlantic subpolar gyre, meridional overturning circulation, hydrographic properties in the Atlantic inflows toward the Arctic, and in marine ecosystems in the northeast Atlantic Ocean. The data series spans the period January 1993 to September 2018. Data description: Monthly gyre index from January 1993 until September 2018. The data is provided in one comma separated value (csv) file with the following entries on each row: year, month, index value. The index is normalized, i.e. it has a zero mean and unit standard deviation. Positive (negative) gyre index reflects stronger (weaker) than average surface circulation of the North Atlantic subpolar gyre.

The Joint WMO-IOC Technical Commission for Oceanography and Marine Meteorology Observing Programmes Support Centre, provides technical coordination at international level for the sustained elements of the Global Ocean Observing System. The Centre monitors in real-time the status of the observing networks and provides a toolbox to evaluate their performance and optimize their implementation and data flow. Currently JCOMMOPS monitors the Argo profiling floats, the DBCP surface drifters, coastal and tropical moorings, ice buoys, tsunami buoys, the OceanSITES moorings time-series, the GO-SHIP hydrographic reference lines, the SOT mat/ocean ship based observations and the GLOSS sea level tide gauges. A number of other observing systems are being added gradually, including ocean gliders, polar systems, marine mammals and potentially HF radars.

NASA's Physical Oceanography Distributed Active Archive Center (PO.DAAC) is located at NASA's Jet Propulsion Laboratory in Pasadena, California. PO.DAAC manages and provides tools and services for NASA's oceanographic and hydrologic data (satellite, airborne, and in-situ) to enable a greater understanding of the physical processes and conditions of the global ocean. Measurements include gravity, ocean winds, sea surface temperature, ocean surface topography, sea surface salinity, and circulation. The data support a wide range of applications including climate research, weather prediction, resource management, policy, and the stewardship of ocean data resources.