On which timescales do gas transfer velocities control North Atlantic CO2 flux variability?.

Couldrey, Matthew P., Oliver, Kevin I. C., Yool, Andrew, Halloran, Paul R. and Achterberg, Eric P. (2016) On which timescales do gas transfer velocities control North Atlantic CO2 flux variability?. Global Biogeochemical Cycles, 30 (5). pp. 787-802. DOI 10.1002/2015GB005267.

[img] Text
Couldrey.pdf - Published Version
Restricted to Registered users only

Download (2388Kb) | Contact

Supplementary data:

Abstract

The North Atlantic is an important basin for the global ocean's uptake of anthropogenic and natural carbon dioxide (CO2), but the mechanisms controlling this carbon flux are not fully understood. The air-sea flux of CO2, F, is the product of a gas transfer velocity, k, the air-sea CO2 concentration gradient, ΔpCO2, and the temperature- and salinity-dependent solubility coefficient, α. k is difficult to constrain, representing the dominant uncertainty in F on short (instantaneous to interannual) timescales. Previous work shows that in the North Atlantic, ΔpCO2 and k both contribute significantly to interannual F variability but that k is unimportant for multidecadal variability. On some timescale between interannual and multidecadal, gas transfer velocity variability and its associated uncertainty become negligible. Here we quantify this critical timescale for the first time. Using an ocean model, we determine the importance of k, ΔpCO2, and α on a range of timescales. On interannual and shorter timescales, both ΔpCO2 and k are important controls on F. In contrast, pentadal to multidecadal North Atlantic flux variability is driven almost entirely by ΔpCO2; k contributes less than 25%. Finally, we explore how accurately one can estimate North Atlantic F without a knowledge of nonseasonal k variability, finding it possible for interannual and longer timescales. These findings suggest that continued efforts to better constrain gas transfer velocities are necessary to quantify interannual variability in the North Atlantic carbon sink. However, uncertainty in k variability is unlikely to limit the accuracy of estimates of longer-term flux variability.

Document Type: Article
Additional Information: WOS:000379949100011
Keywords: carbon flux; gas transfer velocity; carbon cycle; ocean model; climate dynamics; variability
Research affiliation: OceanRep > The Future Ocean - Cluster of Excellence
OceanRep > GEOMAR > FB2 Marine Biogeochemistry > FB2-CH Chemical Oceanography
Kiel University
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1002/2015GB005267
ISSN: 0886-6236
Projects: Future Ocean
Date Deposited: 27 Jun 2016 09:13
Last Modified: 01 Feb 2019 15:07
URI: http://oceanrep.geomar.de/id/eprint/33261

Actions (login required)

View Item View Item

Document Downloads

More statistics for this item...