A new constraint on global air‐sea CO2 fluxes using bottle carbon data. Issue 8 (30th April 2013)

• Record Type: Journal Article
• Authors: Sasse, Tristan P.; McNeil, Ben I.; Abramowitz, Gab
• Is Part Of: Geophysical research letters. Volume 40:Issue 8(2013:Apr.)
• Page Start: 1594
• Page End: 1599
• Publication Date: 2013-04-30
• Subjects: Biogeochemistry -- Oceanography -- Ocean carbon uptake; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/grl.50342
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract : [1] We develop a new observationally derived monthly ocean surface climatology for the partial pressure of CO2 ( p CO2 ) that allows an independent data‐based constraint on contemporary air‐sea CO2 fluxes. Our approach uses a neural network, trained on ~17, 800 bottle‐derived measurements of p CO2, to diagnose monthly p CO2 levels from standard ocean hydrographic data. Although the pattern of contemporary air‐sea CO2 fluxes is generally consistent with the independent underway p CO2 data network, we find a strong shift in the magnitude of oceanic sources and sinks of CO2 . In particular, we find a contemporary Southern Hemisphere oceanic CO2 uptake of 0.93 PgC/year, driven by a prominent CO2 sink in the subpolar region (25°S–60°S), that is five times the magnitude of the Northern Hemisphere oceanic sink (0.18 PgC/year). Globally, our results suggest a net open‐ocean CO2 sink of 1.55 ± 0.32 PgC/year for the nominal year of 2000. Key Points: New data‐based approach to diagnose monthly surface ocean p CO2 distributions Independent constraint on global air‐sea CO2 flux distribution and magnitude Southern Hemisphere carbon uptake is five times the magnitude of the Northern Hemisphere