Based on a detailed investigation of the distribution and sea-to-air fluxes of N2O in the eastern equatorial Atlantic (EEA), we show that the onset and seasonal development of the ACT can be clearly observed in surface N2O concentrations, which increase progressively as the cooling in the equatorial region proceeds during spring-summer. We observed a strong influence of the surface currents of the EEA on the N2O distribution, which allowed identifying “high” and “low” concentration regimes that were, in turn, spatially delimited by the extent of the warm eastward-flowing North Equatorial Countercurrent and the cold westward-flowing South Equatorial Current.

Continuous Surface Ocean and related atmospheric N2O measurements from MSM18/2 and MSM18/3 cruise measured with LGR OA-ICOS N2O Analyzer DLT 100 coupled to Weiss-type showerhead equilibrator.

Supplement to: Arévalo-Martínez, Damian L; Kock, Annette; Steinhoff, T; Brandt, Peter; Dengler, Marcus; Fischer, Tim; Körtzinger, Arne; Bange, Hermann Werner (2017): Nitrous oxide during the onset of the Atlantic cold tongue. Journal of Geophysical Research: Oceans, 122(1), 171-184