The REP14-MED experiment was conducted by the Centre of Maritime Research and Experimentation (CMRE, La Spezia, Italy), and supported by 20 partners from six different nations, offshore from Sardinia. In a limited area of about 110x110 km², dense oceanographic observations were collected in the period 7–24 June 2014 by two research vessels, eleven underwater gliders from three different manufacturers, various oceanographic and meteorological moorings, surface drifters, and a profiling float.

The main objective of the experiment was the collection of adequate data sets in order to pursue several objectives, including (i) finding the best sampling strategy for ocean forecasting, (ii) model validation, (iii) evaluation of forecast skill, (iv) exploring ocean variability, (v) performing a cost–benefit analysis of glider data collection, and (vi) analysis of mesoscale and submesoscale structures.

This special issue includes invited papers, but it is also open for additional contributions if coherent (to be evaluated by the editors) with the objectives as specified.