Ocean ventilation as a driver of interannual variability in atmospheric potential oxygen

摘要: We present observations of interannual variability on 2–5 yr timescales in atmospheric potential oxygen (APO ≈ O 2 +CO ) from the Scripps Institution Oceanography global flask sampling network. Interannual variations tracer APO are expected to arise air–sea fluxes alone, because is insensitive exchanges with terrestrial biosphere. These shown be regionally coherent and robust analytical artefacts. focus explaining a feature dominant records Northern Hemisphere stations, marked by increasing late 1990s, followed an abrupt drawdown 2000–2001. The timing matches renewal deep convection North Atlantic, next year severe winter western Pacific that may have allowed ventilation denser isopycnals than usual. find weak correlation between changes interhemispheric difference El Nino indices, show no strong features 1997–98 Nino. Comparisons estimates ocean productivity heat content demonstrate these processes secondary influences at timescales. conclude evidence points as main driver APO. DOI: 10.1111/j.1600-0889.2008.00376.x