Sarmiento,
J. L., P. Monfray, E. Maier-Reimer, O. Aumont, R. J. Murnane, and J.
C. Orr, 2000: Sea-air CO2 fluxes and
carbon transport: A comparison of three ocean general circulation models.
Global Biogeochemical Cycles, 14(4), 1267-1281. |
Abstract: Many estimates of the atmospheric
carbon budget suggest that most of the sink for CO2
produced by fossil fuel burning and cement production must be in the
Northern Hemisphere. Keeling et al. [1989] hypothesized
that this asymmetry could be explained instead by a northward
preindustrial transport of ~1 Pg C y-1
in the atmosphere balanced by an equal and opposite southward transport
in the ocean. We explore this hypothesis by examining the
processes that determine the magnitude of the preindustrial
interhemispheric flux of carbon in three ocean carbon models. This
study is part of the first stage of the Ocean Carbon Model
Intercomparison Project organized by International Geosphere Biosphere
Programme Global Analysis, Interpretation, and Modelling Task
Force. We find that the combination of interhemispheric heat
transport (with its associated carbon transport), a finite gas exchange,
and the biological pump, yield a carbon flux of only -0.12 to +0.04 Pg C
y-1 across the equator (positive to the
north). An important reason for the low carbon transport is the
decoupling of the carbon flux from the interhemispheric heat transport
due to the long sea-air equilibration time for surface CO2.
A possible additional influence on the interhemispheric exchange is
oceanic transport of carbon from rivers. |