Temporal variability of the anthropogenic CO2 storage in the Irminger Sea

• Main Authors: Perez, F. F., Vazquez-rodriguez, M., Louarn, E., Padin, X. A., Mercier, Herle, Rios, A. F.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus publications 2008
• Subjects: Irminger Basin; Irminger Sea; Labrador Sea; North Atlantic; North Atlantic oscillation
• Online Access: https://archimer.ifremer.fr/doc/2008/publication-5925.pdf; https://archimer.ifremer.fr/doc/00000/5925/

The anthropogenic CO2 (C-ant) estimates from cruises spanning more than two decades (1981-2006) in the Irminger Sea area of the North Atlantic Subpolar Gyre reveal a large variability in the C-ant storage rates. During the early 1990's, the C-ant storage rates (2.3 +/- 0.6 mol C m(-2) yr(-1)) doubled the average rate for 1981-2006 (1.1 +/- 0.1 mol C m(-2) yr(-1)), whilst a remarkable drop to almost half that average followed from 1997 onwards. The C-ant storage evolution runs parallel to chlorofluorocarbon-12 inventories and is in good agreement with C-ant uptake rates of increase calculated from sea surface pCO(2) measurements. The contribution of the Labrador Seawater to the total inventory of C-ant in the Irminger basin dropped from 66% in the early 1990s to 49% in the early 2000s. The North Atlantic Oscillation shift from a positive to a negative phase in 1996 led to a reduction of air-sea heat loss in the Labrador Sea. The consequent convection weakening accompanied by an increase in stratification has lowered the efficiency of the northern North Atlantic CO2 sink.