Controls on open-coean North Atlantic ΔpCO2 at seasonal and interannual time scales are different

Stephanie A. Henson, Matthew P. Humphreys, Peter E. Land, Jamie D. Shutler, Lonneke Goddijn-Murphy, Mark Warren

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The North Atlantic is a substantial sink for anthropogenic CO2. Understanding the mechanisms driving the sink's variability is key to assessing its current state and predicting its potential response to global climate change. Here we apply a time series decomposition technique to satellite and in situ data to examine separately the factors (both biological and nonbiological) that affect the sea‐air CO2 difference (ΔpCO2) on seasonal and interannual time scales. We demonstrate that on seasonal time scales, the subpolar North Atlantic ΔpCO2 signal is predominantly correlated with biological processes, whereas seawater temperature dominates in the subtropics. However, the same factors do not necessarily control ΔpCO2 on interannual time scales. Our results imply that the mechanisms driving seasonal variability in ΔpCO2 cannot necessarily be extrapolated to predict how ΔpCO2, and thus the North Atlantic CO2 sink, may respond to increases in anthropogenic CO2 over longer time scales.
Original languageEnglish
Pages (from-to)9067-9076
Number of pages10
JournalGeophysical Research Letters
Issue number17
Early online date6 Aug 2018
Publication statusPublished - 16 Sep 2018

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