Uncoupled transport of chlorofluorocarbons and anthropogenic carbon in the subpolar North Atlantic

• Published in: Deep Sea Research Part I: Oceanographic Research Papers
• Main Authors: Alvarez, Marta, Gourcuff, Claire
• Format: Article in Journal/Newspaper
• Language: English
• Published: Pergamon-elsevier Science Ltd 2010
• Subjects: Anthropogenic carbon; CFC; Advective transports; Subpolar North Atlantic; Greenland; Irminger Sea; East Greenland; east greenland current; Labrador Sea; North Atlantic
• Online Access: https://archimer.ifremer.fr/doc/00009/11994/9039.pdf; https://doi.org/10.1016/j.dsr.2010.03.009; https://archimer.ifremer.fr/doc/00009/11994/

Chlorofluorocarbon (CFC) 11 and 12 transports across the transoceanic World Ocean Circulation Experiment (WOCE) A25 section in the subpolar North Atlantic are derived from an inverse model using hydrographic and ADCP data (Lherminier et al., 2007). CFC and anthropogenic carbon (C-ANT) advective transports contrary to expected are uncoupled: C-ANT is transported northeastwards (82 +/- 39 kmol s(-1)) mainly within the overturning circulation, while CFC-11 and CFC-12 are transported southwestwards (-24 +/- 4 and -11 +/- 2 mol s(-1), respectively) as part of the large-scale horizontal circulation. The main reason for this uncoupled behaviour is the complex CFC vs. C-ANT relation in the ocean, which stems from the contrasting temperature relation for both tracers: more C-ANT dissolves in warmer waters with a low Revel le factor, while CFC's solubility is higher in cold waters. These results point to C-ANT and CFC having different routes of uptake, accumulation and transport within the ocean, and hence: C-ANT transport would be more sensitive to changes in the overturning circulation strength, while CFC to changes in the East Greenland Current and Labrador Sea Water formation in the Irminger Sea. Additionally, C-ANT and CFCs would have different sensitivities to circulation and climate changes derived from global warming as the slowdown of the overturning circulation, increase stratification due to warming and changes in wind stress.