Once a year and for the fifth year in a raw, the Mercator Ocean Forecasting Center in Toulouse and the Coriolis Infrastructure in Brest publish a common newsletter. Some papers are dedicated to observations only, when others display collaborations between the 2 aspects: Observations and Modelling/Data assimilation.
The fi rst paper by Cabanes et al. introducing this issue is presenting a new methodology aiming at correcting Argo fl oat salinity measurements in delayed time when Argo fl oats conductivity sensors are subject to drift and offset due to bio-fouling or other technical problems.
Then, Cravatte et al. are using the Argo arrays in order to compile Argo fl oats’ drifts and show that they are a very valuable tool allowing determining the absolute velocity. They apply this to study zonal jets at 1000 meters depth in the Tropics.
In the next paper, Maes and O’Kane provide with some results indicating the impact of a sustained ocean observing Argo network on the ability to resolve the seasonal cycle of salinity stratifi cation by contrasting periods pre- and post-Argo. They take into account the respective thermal and saline dependencies in the Brunt-Väisälä frequency (N2) in order to isolate the specifi c role of the salinity stratifi cation in the layers above the main pycnocline.
Picheral et al. are telling us about the Tara Oceans voyage that took place on the schooner “Tara” from 2009 to 2013 and visited all oceans. The ship was adapted for modern oceanography. Scientifi c instruments were mounted on a dedicated CTD frame and installed on an underway fl ow-through system. Data were sent daily to Coriolis. Post cruise calibrations were performed leading to a high quality dataset.
Then, Roquet et al. demonstrate the importance of the contribution of hydrographic and biogeochemical data collected by Antarctic marine mammals, and in particular elephant seals, equipped with a new generation of oceanographic tags, for the environmental monitoring of the Southern Ocean.The last paper of the present issue is displaying the collaboration between the Ocean Observations and Ocean Modelling communities: Turpin et al. perform several Observing System Experiments in order to assess the impact of Argo observations on the Mercator Océan global analysis and forecasting system at ¼ degree resolution.

• DELAYED MODE ANALYSIS OF ARGO FLOATS: IMPROVEMENTS OF THE METHOD IN THE NORTH ATLANTIC AND SOUTHERN OCEAN
• ZONAL JETS AT 1000M IN THE TROPICS OBSERVED FROM ARGO FLOATS’ DRIFTS
• UPPER OCEAN SALINITY STRATIFICATION IN THE TROPICS AS DERIVED FROM N2, THE BUOYANCY FREQUENCY
• MONITORING THE OCEAN WITH TARA – A CORIOLIS PERSPECTIVE
• ELEPHANT SEALS HELP US TO BETTER OBSERVE THE SOUTHERN OCEAN
• OBSERVING SYSTEM EXPERIMENT: A SIMPLE TOOL TO ASSESS THE MULTIPLE ROLES PLAYED BY ARGO OBSERVATIONS ON THE OPERATIONAL FORECASTING SYSTEM OF MERCATOR OCÉAN