The objective of this subtask is to demonstrate the value of the in-situ surface currents observing system by ensuring the link with the ESA GlobCurrent project. GlobCurrent is an ESA Data User Element started in October 2013 (running until June 2017) whose objective is “to advance the quantitative estimation of ocean surface currents from satellite sensor synergy and demonstrate impact in user-led scientific, operational and commercial applications that, in turn, will increase the uptake of satellite measurements”.

In the framework of Globcurrent, several surface and near-surface current products have been calculated: global, ¼ ° maps of ocean surface geostrophic currents (from altimetry), Ekman currents at two distinct depths (surface and 15m) and combined Geostrophic+Ekman currents at 0 and 15m depth have been calculated for the period January 1993 - May 2016

In this document, we will calculate merged SSH/SST velocity maps over the AtlantOS region for a period with a satisfying drifting buoy coverage and compare them to the AtlantOS drifting buoy velocities. The merged SSH/SST currents could finally be combined to the AtlantOS drifter velocities through a multivariate analysis approach to further improve the ocean surface current retrieval. This method is currently developed in the framework of the CNES DUACS-MR project.

In a second chapter, we explore the SISMER SADCP (Shipboard Acoustic Doppler Current Profiler, IFREMER /IDM/SISMER) database to assess the possibility to extract a wind driven component from the measured velocity to compare with an Ekman model and the use of these in-situ data for model validation.