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• Main Authors: Ute Schuster, Andrew J. Watson
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: North Atlantic; North Atlantic oscillation
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.371.6737; http://lgmacweb.env.uea.ac.uk/ajw/Reprints/Schuster_Watson_JGR_in_press.pdf

6 [1] A time series of observations from merchant ships between the U.K. and the 7 Caribbean is used to establish the variability of sea surface pCO2 and air-to-sea flux from 8 the mid-1990s to early 2000s. We show that the sink for atmospheric CO2 exhibits 9 important interannual variability, which is in phase across large regions from year to year. 10 Additionally, there has been an interdecadal decline, evident throughout the study 11 region but especially significant in the northeast of the area covered, with the sink 12 reducing>50 % from the mid-1990s to the period 2002–2005. A review of available 13 observations suggests a large region of decrease covering much of the North Atlantic but 14 excluding the western subtropical areas. We estimate that the uptake of the region between 15 20°N and 65°N declined by 0.24 Pg C a 1 from 1994/1995 to 2002–2005. Declining 16 rates of wintertime mixing and ventilation between surface and subsurface waters due to 17 increasing stratification, linked to variation in the North Atlantic Oscillation, are suggested 18 as the main cause of the change. These are exacerbated by a contribution from the changing 19 buffer capacity of the ocean water, as the carbon content of surface waters increases.