Spatio-Temporal Variability in CO<sub>2</sub> Fluxes in the Atlantic Sector of the Southern Ocean

The Southern Ocean (SO) plays a fundamental role in the planet’s climate system, due to its ability to absorb and redistribute heat and CO<sub>2</sub> (an important greenhouse gas). In addition, the SO connects three large oceanic basins the Pacific, the Atlantic, and the Indian Oceans,...

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Bibliographic Details
Main Authors: Gabrielle Tavares de Carvalho, Luciano Ponzi Pezzi, Nathalie Lefèvre, Celina Cândida Ferreira Rodrigues, Marcelo Freitas Santini, Carlos Mejia
Format: Article
Language:English
Published: MDPI AG 2025-03-01
Series:Atmosphere
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Online Access:https://www.mdpi.com/2073-4433/16/3/319
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Summary:The Southern Ocean (SO) plays a fundamental role in the planet’s climate system, due to its ability to absorb and redistribute heat and CO<sub>2</sub> (an important greenhouse gas). In addition, the SO connects three large oceanic basins the Pacific, the Atlantic, and the Indian Oceans, and it has an important role in the nutrient distribution in these oceans. However, the SO is poorly sampled, with most measurements made in austral spring and summer. The variability in the air–sea CO<sub>2</sub> flux is estimated, as well as the role of atmospheric and oceanic variables in this variability. The CO<sub>2</sub> fluxes are calculated using the bulk parameterization method, in the Atlantic sector of the Southern Ocean, from 2003 to 2022, using in situ measurements, satellites, and a reanalysis data set. A neural network model is built to produce maps of the partial pressure of CO<sub>2</sub> in seawater (pCO<sub>2sea</sub>). The CO<sub>2</sub> flux varies from −0.05 to 0.05 gC m<sup>−2</sup> month<sup>−1</sup>. The Atlantic sector of the SO is a sink of CO<sub>2</sub> in summer and spring and becomes a source in austral winter and autumn. The CO<sub>2</sub> absorption intensifies from 2003 to 2022 by 7.6 mmol m<sup>−2</sup> month<sup>−1</sup>, due to stronger westerly winds, related to the trend in the positive phase of the Antarctic Oscillation and the extreme El Niño Southern Ocean (ENSO) events (e.g., El Niño and La Niña).
ISSN:2073-4433