Journal Highlights

Impacts of ENSO on air-sea oxygen exchange: observations and mechanisms

Editors’ Highlights­­—

The exchange of oxygen between the air and sea reflects the physical and biogeochemical processes of the ocean and their interactions. Our understanding of the responses of the above-ocean processes to climate change could be improved with insights into the inter-annual variability in ocean O2 flux with respect to climate variations. This paper examines the responses of the air-sea O2 exchange to the El Niño-Southern Oscillation (ENSO) cycle and their mechanisms based on the atmospheric inverse estimates and ocean model simulations. The authors found that the O2 flux in the western equatorial Pacific responds to ENSO in the opposite way to those in the eastern and central Pacific. The simulated meridional atmospheric potential oxygen (APO) profiles in the western equatorial Pacific show similar contrasting features, which is reinforced by the ENSO-related variation in the atmospheric mixing. These results explain the apparently conflicting results of Rödenbeck et al. (2008) and Tohjima et al. (2015).