SOCIB performed a drifter release exercise in the Ibiza Channel

Last 30th of September an intensive drifter release exercise was performed in the Ibiza Channel inside the SOCIB Radar HF coverage area. The two main objectives of the experiment were to increase the reliability of the HF Radar surface currents measurements by comparing with drifter-derived velocities, and assess the effective measurement depths of HF Radar by using different drifters and different drogues (flexible and rigid, at different depths). Thirteen drifters were launched at four different locations, with the objective of maximizing the residence time of the drifters in the area covered by the HF Radar radial coverage.

The three kinds of drifters launched differ in shape (i.e. wind exposure effect), drogue-shape, and depth (i.e. ocean current exposure effect). All the drifters were in the HF Radar coverage during more than six days, following first a southern current, and then a northern current that drives some of them outside the radial HF Radar coverage, towards the north of Ibiza. The drifter’s tracks can be followed and in continuously updated using SOCIB Data Centre Deployment Application: http://apps.socib.es/dapp/

This experiment with the 13 drifters represents the largest number of drifters ever used in an exercise of these characteristics in the Ibiza Channel. The Ibiza Channel is a hot-spot in terms of biodiversity and choke point of circulation in the Mediterranean Sea, as well as an area with intense shipping traffic. This kind of exercise is useful to validate the current HF Radar measurements and to improve the surface currents forecast in the area.