edu.ucar.opensky::articles:15461 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-26T15:08:43.667388 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d7v125tt Oceanic sources, sinks, and transport of atmospheric CO₂ 2009-02-18T00:00:00Z publication https://n2t.org/ark:/85065/d7v125tt https://doi.org/10.1029/2008GB003349 Gruber, N. author Gloor, M. author Mikaloff Fletcher, S. author Doney, S. author Dutkiewicz, S. author Follows, M. author Gerber, M. author Jacobson, A. author Joos, F. author Lindsay, Keith author Menemenlis, D. author Mouchet, A. author Müller, S. author Sarmiento, J. author Takahashi, T. author UCAR/NCAR - Library publisher We synthesize estimates of the contemporary net air-sea CO₂ flux on the basis of an inversion of interior ocean carbon observations using a suite of 10 ocean general circulation models (Mikaloff Fletcher et al., 2006, 2007) and compare them to estimates based on a new climatology of the air-sea difference of the partial pressure of CO₂ (pCO₂) (Takahashi et al., 2008). These two independent flux estimates reveal a consistent description of the regional distribution of annual mean sources and sinks of atmospheric CO₂ for the decade of the 1990s and the early 2000s with differences at the regional level of generally less than 0.1 Pg C a⁻¹. This distribution is characterized by outgassing in the tropics, uptake in midlatitudes, and comparatively small fluxes in thehigh latitudes. Both estimates point toward a small (∼ -0.3 Pg C a⁻¹) contemporary CO₂ sink in the Southern Ocean (south of 44°S), a result of the near cancellation between a substantial outgassing of natural CO₂ and a strong uptake of anthropogenic CO₂. A notable exception in the generally good agreement between the two estimates exists within the Southern Ocean: the ocean inversion suggests a relatively uniform uptake, while the pCO₂-based estimate suggests strong uptake in the region between 58°S and 44°S, and a source in the region south of 58°S. Globally and for a nominal period between 1995 and 2000, the contemporary net air-sea flux of CO₂ is estimated to be -1.7 ± 0.4 Pg C a⁻¹ (inversion) and -1.4 ± 0.7 Pg C a⁻¹ (pCO₂-climatology), respectively, consisting of an outgassing flux of river-derived carbon of ∼+0.5 Pg C a⁻¹, and an uptake flux of anthropogenic carbon of −2.2 ± 0.3 Pg C a⁻¹ (inversion) and -1.9 ± 0.7 Pg C a⁻¹ (pCO₂-climatology). The two flux estimates also imply a consistent description of the contemporary meridional transport of carbon with southward ocean transport throughout most of the Atlantic basin, and strong equatorward convergence in the Indo-Pacific basins. Both transport estimates suggest a small hemispheric asymmetry with a southward transport of between -0.2 and -0.3 Pg C a⁻¹ across the equator. While the convergence of these two independent estimates is encouraging and suggests that it is now possible to provide relatively tight constraints for the net air-sea CO₂ fluxes at the regional basis, both studies are limited by their lack of consideration of long-term changes in the ocean carbon cycle, such as the recent possible stalling in the expected growth of the Southern Ocean carbon sink. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication An edited version of this paper was published by AGU. Copyright 2009 American Geophysical Union. None eng geoscientificInformation