Monitoring the regional Ocean Heat Content change over the Atlantic Ocean with the space geodetic approach

• Main Authors: Rousseau, Victor, Fraudeau, Robin, Hammond, Matthew, Houndegnonto, Odilon Joël, Ablain, Michaël, Blazquez, Alejandro, Calafat, Fransisco Mir, Desbruyères, Damien, Foti, Giuseppe, Llovel, William, Marti, Florence, Meyssignac, Benoît, Restano, Marco, Benveniste, Jérôme
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus GmbH 2023
• Subjects: North Atlantic
• Online Access: https://archimer.ifremer.fr/doc/00848/96002/103975.pdf; https://doi.org/10.5194/essd-2023-236; https://archimer.ifremer.fr/doc/00848/96002/

The estimation of the regional Ocean Heat Content (OHC) is essential for climate analysis and future climate predictions. In this study, we propose a method to estimate and propagate uncertainties in regional OHC changes. The OHC is estimated with space geodetic steric data corrected from salinity variations estimated with in situ measurements. A variance-covariance matrix method is used to propagate uncertainties from space geodetic data to the OHC change. The integrated OHC change over the Atlantic basin is 0.17 W m-2 which represents 21 % of the global OHC trend, with significant trends observed in 52 % of the Atlantic basin. Uncertainties in OHC trends are mainly attributed to manometric sea level change uncertainties. We validate our space geodetic OHC estimates at two test sites, representing the subtropical and subpolar regions of the North Atlantic, highlighting their importance in understanding climate dynamics. Our results show good agreement between space geodetic estimates and in situ measurements in the North Atlantic region. The space geodetic OHC trends reveal a warming pattern in the southern and western parts of the North Atlantic, particularly in the Gulf Stream region, while the northeastern part exhibits cooling trends. Overall, our study provides valuable insights and a new framework to estimate regional OHC change and its uncertainties, contributing to a better understanding of the Earth's climate system and its future projections. The space geodetic OHC change product (version 1.0) is freely available at https://doi.org/10.24400/527896/a01-2022.012 (Magellium/LEGOS, 2022)