Excess radiocarbon constraints on air-sea gas exchange and the uptake of CO2 by the oceans
Article first published online: 1 JUN 2006
Copyright 2006 by the American Geophysical Union.
Geophysical Research Letters
Volume 33, Issue 11, June 2006
How to Cite
2006), Excess radiocarbon constraints on air-sea gas exchange and the uptake of CO2 by the oceans, Geophys. Res. Lett., 33, L11802, doi:10.1029/2005GL025408., , , and (
- Issue published online: 1 JUN 2006
- Article first published online: 1 JUN 2006
- Manuscript Accepted: 18 APR 2006
- Manuscript Revised: 3 APR 2006
- Manuscript Received: 2 DEC 2005
 We re-assess the constraints that estimates of the global ocean excess radiocarbon inventory (IE) place on air-sea gas exchange. We find that the gas exchange scaling parameter aq cannot be constrained by IE alone. Non-negligible biases in different global wind speed data sets require a careful adaptation of aq to the wind field chosen. Furthermore, aq depends on the spatial and temporal resolution of the wind fields. We develop a new wind speed- and inventory-normalized gas exchange parameter aqN which takes into account these biases and which is easily adaptable to any new estimate of IE. Our study yields an average estimate of aq of 0.32 ± 0.05 for monthly mean winds, lower than the previous estimate (0.39) from Wanninkhof (1992). We calculate a global annual average piston velocity for CO2 of 16.7 ± 2.9 cm/hr and a gross CO2 flux between atmosphere and ocean of 73 ± 10 PgC/yr, significantly lower than results from previous studies.