Intrabasin comparison of surface radiocarbon levels in the Indian Ocean between coral records and three-dimensional global ocean models
Article first published online: 23 APR 2005
Copyright 2005 by the American Geophysical Union.
Global Biogeochemical Cycles
Volume 19, Issue 2, June 2005
How to Cite
2005), Intrabasin comparison of surface radiocarbon levels in the Indian Ocean between coral records and three-dimensional global ocean models, Global Biogeochem. Cycles, 19, GB2010, doi:10.1029/2004GB002289., , , , and (
- Issue published online: 23 APR 2005
- Article first published online: 23 APR 2005
- Manuscript Accepted: 15 FEB 2005
- Manuscript Revised: 26 JAN 2005
- Manuscript Received: 26 APR 2004
 Oceanic uptake and transport of bomb-produced radiocarbon is used as a diagnostic in global ocean models to test parameterizations of mixing and air-sea gas exchange between the ocean and atmosphere. A model's ability to simulate bomb-produced 14C is also a good indicator of its ability to predict uptake of anthropogenic CO2. We have conducted a model-data comparison of surface radiocarbon time series from coral records from the coasts of Kenya and Sumatra and a suite of dynamical three-dimensional ocean models that were included in the second phase of the Ocean Carbon-Cycle Model Intercomparison Project. The coral records comprise the first intrabasin record of surface water Δ14C variability in the equatorial Indian Ocean and provide an independent evaluation of model performance. Differing treatments of lateral subgrid scale mixing in different models appear to be less important than other, unknown factors in explaining differences in results between the models. Those models that include a dynamic vertical mixing scheme appear to be more capable of matching observed coral radiocarbon time series. However, among models with the same parameterization of lateral subgrid scale mixing, there is a large degree of variation, suggesting that at both sites, factors such as resolution, topography, physical forcing and horizontal advection are more important than mixing parameterization in explaining intermodel differences. None of the models reproduce the time lag in the rate of bomb 14C response between the Kenya and Sumatra coral sites. Future efforts are needed to improve model simulation of radiocarbon in surface waters in the equatorial Indian Ocean.