An improved estimate of the isotopic air-sea disequilibrium of CO2: Implications for the oceanic uptake of anthropogenic CO2

We reevaluate the isotopic air‐sea disequilibrium of CO2 on the basis of a new high‐quality global data set of surface observations of the reduced isotopic ratio (δ13C) of dissolved inorganic carbon (DIC). We find a global mean isotopic air‐sea disequilibrium of 0.62±0.10 permil for 1990. Inserting...

Full description

Saved in:
Bibliographic Details
Published in:Geophysical research letters 2001-02, Vol.28 (3), p.555-558
Main Authors: Gruber, Nicolas, Keeling, Charles D.
Format: Article
Language:English
Subjects:
Earth, ocean, space
Exact sciences and technology
External geophysics
Physics of the oceans
Sea-air exchange processes
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:We reevaluate the isotopic air‐sea disequilibrium of CO2 on the basis of a new high‐quality global data set of surface observations of the reduced isotopic ratio (δ13C) of dissolved inorganic carbon (DIC). We find a global mean isotopic air‐sea disequilibrium of 0.62±0.10 permil for 1990. Inserting our estimate into an anthropogenic 13C budget for the period from 1985 to 1995 yields an oceanic uptake of 1.5±0.9 Pg C yr−1, within the range of most other estimates. The large uncertainty of this estimate could be reduced with (i) better characterization of the surface ocean variability in δ13C, (ii) improved knowledge of the air‐sea gas exchange coefficient, and (iii) a significant reduction in the uncertainty associated with the air‐land biosphere disequilibrium.
ISSN:0094-8276
1944-8007
DOI:10.1029/2000GL011853