The first GlobCurrent global products are global maps (except the Mediterranean Sea) of the tidal currents, the Stokes drift, the geostrophic currents, and the Ekman-component currents at two distinct depths, the significant wave height (z=hs) and z=15m. A combined current is also provided for those two depths. At each depth, it is computed as the sum of the geostrophic and the Ekman currents (1).
(1)
The calculation of the geostrophic and Ekman current components are fully described in the following paper:
Rio, M.-H., S. Mulet, and N. Picot (2014), Beyond GOCE for the ocean circulation estimate: Synergetic use of altimetry, gravimetry, and in situ data provides new insight into geostrophic and Ekman currents, Geophys. Res. Lett., 41, doi:10.1002/2014GL061773.
The stokes drift is calculated using the third moment of wave spectra from the global WAVEWATCHIII model:
Rascle, N. and F. Ardhuin (2013), A global wave parameter database for geophysical applications. Part 2: model validation with improved source parameterization. Ocean Modelling 70 (2013) 174-188
The tidal current component of Globcurrent is based on the FES2012 model:
Stammer, D., et al. (2014), Accuracy assessment of global barotropic ocean tide models, Rev. Geophys., 52, 243-282, doi:10.1002/2014RG000450
Three years of data are available, spanning the period from the beginning of 2010 to the end of 2012.
The temporal resolution of the map series is daily for the geostrophic current and 3-hourly for the Ekman, tidal, Stokes currents as well as for the combined current.
Each current component is provided on a 1/10° grid.
Warning
Despite the high temporal (3-hourly) and spatial (1/10°) resolution of the GlobCurrent products grids, it should be noted that, by construction, the effective resolution of the geostrophic and Ekman currents is of the order of 5-10 days / 50-100 km. These resolutions will be improved in the future versions of the GlobCurrent products.