Deep Sea Research , 51, 1475-1491, 2004.

Transport Times and Anthropogenic Carbon in the Subpolar North Atlantic Ocean.

Darryn W. Waugh1, Thomas W.N. Haine1, and Timothy M. Hall2
1Department of Earth and Planetary Science, Johns Hopkins University, Baltimore, Maryland.

2 NASA Goddard Institute for Space Studies, New York



Abstract

Simultaneous measurements of chlorofluorocarbons, tritium, and helium-3 are used to estimate the distribution of surface-to-interior transit times within the subpolar North Atlantic ocean. The observed relationships among the different tracers implies that the transit-time distributions are broad, indicating that mixing plays an important role in transport over decadal timescales. Broad transit-time distributions are further shown to be consistent with the observed time variations of mid-depth tritium in Newfoundland Basin and Northeastern Atlantic between 1972 and 1997. We use the transit-time distributions inferred from the tracers to estimate the distribution, and change over the last two decades, of anthropogenic carbon in the subpolar North Atlantic. The values obtained are smaller than previous estimates using methods that have assumed weak mixing, with largest differences occurring in the Newfoundland Basin and Northeastern Atlantic.

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