Results of the first Wave Glider experiment in the southern Tyrrhenian Sea

Abstract

<p>A wave-propelled autonomous vehicle (Wave Glider) instrumented with a variety of oceanographic and meteorological sensors was launched from Gulf of Naples on the 12<sup>th </sup>of September 2012 for a two-week mission in the Southern Tyrrhenian Sea. The main objective of the mission was a preliminary evaluation of the potential of commercial autonomous platforms to provide reliable measurements of sea surface parameters which can complement existing satellite based products moving from the local to the synoptic scale. To this aim Wave Glider measurements were compared to equivalent, or near-equivalent, satellite products achieved from MODIS (Moderate Resolution Imaging Spectroradiometer) sensors onboard the EOS (Earth Observing System) satellite platforms and from AVISO (Archiving Validation and Interpretation of Satellite Oceanographic Data). Level-3 near real time and Level-4 reprocessed sea surface foundation temperature products provided by the CMEMS (Copernicus Marine Environment Monitoring Service) were also included in this study as well as high resolution model output supplied by NEMO (Nucleus for European Modelling of the Ocean). The Wave Glider was equipped with sensors to measure temperature, salinity, currents, as well as Colored Dissolved Organic Matter (CDOM), turbidity and refined fuels fluorescence. The achieved results confirmed the emerging value of Wave Gliders in the framework of multiplatform monitoring systems of the ocean surface parameters. In particular, they showed that Wave Glider measurements captured the southern Tyrrhenian Sea major surface oceanographic features, including the coast to open sea haline gradient and the presence of a cyclone-anticyclone system in the southeastern sub-region. The Wave Glider also had the capability to monitor upper ocean currents at finer spatial and temporal scales than satellite altimetric observations and model outputs. Nonetheless, results stressed the existence of several limits in the combined use of satellite and Wave Glider observations and the necessity of further analyses concerning the monitoring of the ocean optical properties. In fact, Wave Glider and satellite-based products agree in terms of sea surface temperature and currents patterns, while bio-optical properties turned out to be less well correlated. No significant traces of refined fuels have been detected along the WG track.</p>

Permanent Thermohaline Staircases in the Tyrrhenian Sea

“…Its typical water column yields a three-layer system composed of the surface Atlantic Water, the Levantine Intermediate Water (LIW), and the Tyrrhenian Deep Water. The intensity of the cyclonic surface and intermediate circulation decreases from the boundaries to the center of the basin, while the deep circulation is very weak (Astraldi & Gasparini, 1995;Aulicino et al, 2016;Hopkins, 1988;Menna & Poulain, 2010). The Tyrrhenian basin is considered a merging collector of both the Eastern and Western signals (Astraldi & Gasparini, 1995), receiving a considerable amount of eastern waters, mainly the LIW (Sparnocchia et al, 1999) as well as Atlantic Water and Western Mediterranean Deep Water (WMDW) of western origin (Schroeder et al, 2016).…”

In Situ and Satellite Sea Surface Salinity in the Algerian Basin Observed through ABACUS Glider Measurements and BEC SMOS Regional Products

“…Several studies have assessed the advantages of multiplatform ocean monitoring over different scales, including mesoscale, and at different latitudes [31][32][33][34][35][36][37]. Recent experiments demonstrated that combining new technologies for in situ data collection, mainly autonomous underwater vehicles (AUVs), and reliable satellite data in the AB (e.g., [12,38,39]), provides useful contributions to properly address state-of-the-art scientific challenges [40][41][42]. AUVs allow the collection of high resolution physical and biochemical data along the water column from surface to 975 m depth [17], while their use in combination with remote sensing observations provides a better understanding of basin-scale processes, such as those influencing the southwestern Mediterranean Sea dynamics [38,43].…”

Glider data collected during the Algerian Basin Circulation Unmanned Survey from 2014 to 2016

“…To this aim, frequent dedicated observations at higher horizontal and vertical resolution, along the water column, are essential (Pascual et al, 2017). Multi-platform monitoring strategies, which enable the integration of data from satellites, Autonomous Underwater Vehicles (AUV) and numerical models, have already demonstrated their capabilities in the assessment of oceanographic processes in different regions of the global ocean, such as the Atlantic Ocean (Shcherbina et al, 2015) and the Mediterranean Sea (Carret et al, 2018;Troupin et al, 2018;Pascual et al, 2017;Aulicino et al, 2016). The value of these is improved when implemented along repeated monitoring lines coincident with the satellite groundtracks (Aulicino et al, 2018).…”