Ananda Pascual (IMEDEA (CSIC-UIB), Spain); Emma Heslop (SOCIB, Spain); Krissy Reeve (SOCIB, Spain); Yannice Faugère (CLS, France); Marc Torner (SOCIB, Spain); Joaquin Tintoré (IMEDEA (CSIC-UIB), SOCIB, Spain)

Our knowledge of mesoscale structures, such as eddies, is still incomplete because of their intrinsic time and space scales and the associated sampling difficulties. Recently, the comparison of glider measurements and new generation of remotely sensed data, offered the opportunity to investigate some of the characteristics of eddies, such as radius, water masses biochemical parameters, track and rotational speed. Nevertheless, the lack of high resolution in situ data, through eddies and along their edges, still remains a main concern.

In the frame of the Copernicus Marine Environment Monitoring Service (CMEMS) Sea Level Thematic Assembly Center (SL-TAC), a glider mission was undertaken between May and June 2016 contemporaneous with and along the same track as the overpass of the Sentinel 3A satellite in the Southern Mallorca region. In addition a one-day ship mission on May 30, synchronous with the overpass of the satellite, captured two transects of moving vessel ADCP. The aim was to compare the along track altimeter products and multi-platform in-situ observations, and in particular to explore the potential of the Synthetic Aperture Radar Mode (SARM) instrumentation of Sentinel-3 mission. The ultimate goal is to contribute to a more complete understanding of physical ocean processes and biogeochemical impacts.

The analyses presented here are conducted through the comparison of Absolute Dynamic Topography (ADT) obtained from the Sentinel-3A altimetry measurements along ground-track #713 and Dynamic Heights (DH) derived from temperature and salinity profiles measured by the glider along the trajectory followed by the satellite. The high resolution glider data allows us to investigate spatial scales smaller than in previous studies at the meso-submeso scale. Moreover, geostrophic currents derived from altimetry, and in-situ glider and ADCP data are also analysed.

This mission is part of a study focused on mesoscale variability and comparison of the along-track and gridded interpolated maps altimetry products in the western Mediterranean Sea using in-situ data including Argo, ADCP, gliders, drifters, HF radar and tide gauges data. This experiment also contributes to the preparatory cal/val activities of the forthcoming wide-swath satellite altimeter (SWOT) that will provide daily high resolution sea surface height measurements during the fast phase after launch around the Balearic Islands.