Beschreibung:
<jats:title>Abstract</jats:title><jats:p>The North Atlantic is a substantial sink for anthropogenic CO<jats:sub>2</jats:sub>. 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 CO<jats:sub>2</jats:sub> difference (Δ<jats:italic>p</jats:italic>CO<jats:sub>2</jats:sub>) on seasonal and interannual time scales. We demonstrate that on seasonal time scales, the subpolar North Atlantic Δ<jats:italic>p</jats:italic>CO<jats:sub>2</jats:sub> signal is predominantly correlated with biological processes, whereas seawater temperature dominates in the subtropics. However, the same factors do not necessarily control Δ<jats:italic>p</jats:italic>CO<jats:sub>2</jats:sub> on interannual time scales. Our results imply that the mechanisms driving seasonal variability in Δ<jats:italic>p</jats:italic>CO<jats:sub>2</jats:sub> cannot necessarily be extrapolated to predict how Δ<jats:italic>p</jats:italic>CO<jats:sub>2</jats:sub>, and thus the North Atlantic CO<jats:sub>2</jats:sub> sink, may respond to increases in anthropogenic CO<jats:sub>2</jats:sub> over longer time scales.</jats:p>