Preprints
https://doi.org/10.5194/egusphere-2025-4651
https://doi.org/10.5194/egusphere-2025-4651
06 Oct 2025
 | 06 Oct 2025
Status: this preprint is open for discussion and under review for Ocean Science (OS).

Eddy Kinetic Energy Variability From 30 Years of Altimetry in the Mediterranean Sea

Paul Hargous, Vincent Combes, Bàrbara Barceló-Llull, and Ananda Pascual

Abstract. Mesoscale activity plays a central role in ocean variability, substantially influencing the mixing of biogeophysical tracers, such as heat and carbon, and driving changes in ecosystems. Eddy Kinetic Energy (EKE), a metric used for studying the intensity of mesoscale processes, has recently been shown to increase in regions of intense EKE worldwide. Strong EKE positive trends are observed, for example, in the principal western boundary current regions, such as the Gulf Stream, Kuroshio Extension, and the Brazil/Malvinas Confluence. In this study, we assess whether the Mediterranean Sea, known to be a hotspot for climate change impacts, also exhibits such intensification. Despite the high number of observational data and modeling experiments, there is a gap in understanding the long-term evolution of mesoscale dynamics and EKE trends in the Mediterranean Sea. This study investigates EKE trends in the Mediterranean Sea using daily geostrophic currents derived from satellite altimetric data. To test the robustness of the results, we compare EKE trends computed from three different gridded altimetric products: a global product derived from a stable two-satellite constellation (two-sat) and two other products (global and European) incorporating all available satellites (all-sat). While all products reveal a general increase in EKE in the Mediterranean Sea over the last three decades, the trends calculated from the two-sat product are significantly smaller than those computed from the all-sat products. We show that this discrepancy is strongly linked to the increasing number of satellites over time used to construct the all-sat data sets, which enhances both spatial and temporal coverage, and hence, their capacity to detect higher energy levels. To evaluate the fidelity of these gridded products in capturing EKE trends, we compare them with along-track data in high-energy regions of the Mediterranean Sea: the Alboran Sea and the Ierapetra area. These regions exhibit contrasting EKE trends: positive in the Alboran Sea and negative in the Ierapetra area. These findings highlight the importance of using altimetric products with a stable number of satellites constructed for climate applications when addressing long-term ocean variability analysis.

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this paper. While Copernicus Publications makes every effort to include appropriate place names, the final responsibility lies with the authors. Views expressed in the text are those of the authors and do not necessarily reflect the views of the publisher.
Share
Paul Hargous, Vincent Combes, Bàrbara Barceló-Llull, and Ananda Pascual

Status: open (until 01 Dec 2025)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
Paul Hargous, Vincent Combes, Bàrbara Barceló-Llull, and Ananda Pascual
Paul Hargous, Vincent Combes, Bàrbara Barceló-Llull, and Ananda Pascual
Metrics will be available soon.
Latest update: 06 Oct 2025
Download
Short summary
Over the last three decades, satellites have revealed rising activity of swirling ocean currents in the Mediterranean Sea. We show that the strength of this increase depends strongly on how satellite data are combined. Products that merge many satellites may give the impression of stronger changes simply because coverage improved over time. This work underlines the importance of using stable and consistent datasets to track long-term changes in ocean variability.
Share