Air–Sea CO2 Exchange Over the Mediterranean Sea, the Red Sea and the Arabian Sea

• Published in: International Journal of Environmental Research Vol. 18; no. 3
• Main Authors: Zarghamipour, Mona, Malakooti, Hossein, Bordbar, Mohammad Hadi
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01-06-2024; Springer Nature B.V
• Subjects: Air; Air-sea flux; Anthropogenic factors; Bayesian analysis; Bayesian theory; Carbon dioxide; Carbon dioxide exchange; Carbon dioxide flux; Climate change; Climate change causes; Climate models; Climate prediction; Coastal processes; Coastal upwelling; Earth and Environmental Science; Emissions; Environment; Environmental Engineering/Biotechnology; Environmental Management; Exchanging; Fluctuations; Geoecology/Natural Processes; Global warming; Greenhouse effect; Greenhouse gases; Human influences; Landscape/Regional and Urban Planning; Marine ecosystems; Mathematical models; Natural Hazards; Nonthermal effects; Ocean circulation; Partial pressure; Probability theory; Representations; Research Paper; Sea surface; Summer monsoon; Surface wind; Temperature effects; Temporal variations; Upwelling; Water temperature; Water velocity; Wind; Wind variability; Wind-driven upwelling; Red Sea; Mediterranean Sea; Arabian Sea; Air–sea CO; exchange; Climate indices; Bayesian Model Averaging; ESM; Teleconnection patterns
• ISSN: 1735-6865; 2008-2304
• DOI: 10.1007/s41742-024-00586-6

Anthropogenic greenhouse gas emissions are reshaping oceanic CO
2
uptake patterns. This study focuses on the crucial regions of the Arabian Sea, Red Sea, and Mediterranean Sea which are highly affected by human-caused climate change, aiming to unravel the complexities of air–sea CO
2
exchange dynamics. Understanding these processes is essential for predicting climate changes and assessing the health of marine ecosystems. In this context, a combination of observation-based data (Oc_v2020), and a multi-model ensemble of climate model simulations, were employed to explore the spatial and temporal variations in air–sea CO
2
flux (FCO
2
) over these areas from 1982 to 2019. We implemented the Bayesian Model Averaging approach on the model outputs, resulting in a better representation of simulated CO
2
flux. Overall, climate models seem to underestimate the FCO
2
over the western Arabian Sea. We speculate that this model failure is attributed to the negative biased in vertical water velocity and the unrealistically representation of carbon release during coastal upwelling processes in the model. Our findings suggest that CO
2
source across the Red Sea, the Arabian Sea, and the central region of the Mediterranean Sea has been reduced with a trend of − 0.494 ± 0.009, − 1.350 ± 0.001, and − 0.329 ± 0.074 gCm
−2
 year
−1
 decade
−1
, respectively. In contrast, the CO
2
sink across the Western Mediterranean has been enhanced with a trend of − 0.793 ± 0.086 gCm
−2
 year
−1
 decade
−1
. In general, change in the water temperature was recognized as the major contributor to the sea surface partial pressure of CO
2
(pCO
2
). The exception was found in the Arabian Sea, where non-thermal effects play the major role. Our results show that the CO
2
flux variation is accompanied by regional changes in the sea surface pCO
2
. Across the North Arabian Sea, FCO
2
is also correlated with the surface wind variability, which is likely due to the changes in wind-driven upwelling. In conclusion, our study advances the understanding of regional air–sea CO
2
exchange dynamics, emphasizing the need for improved model representation in areas with intense seasonal upwelling. The prominent changes in the Arabian Sea, underscore the immediate necessity for science-based management in this region to mitigate the impacts of human-induced global warming.
Article Highlights
We implement the Bayesian Model Averaging approach on the ESM climate model
The CO
2
sources in most of the seas have been reduced.
The most prominent changes were observed in the Arabian Sea
Our results support the weakening of the summer monsoon in the western Arabian Sea