@article{fdi:010082743,
  title = {{A}n atmospheric constraint on the seasonal air-sea exchange of oxygen and heat in the extratropics},
  author = {{M}organ, {E}. {J}. and {M}anizza, {M}. and {K}eeling, {R}. {F}. and {R}esplandy, {L}. and {M}ikaloff-{F}letcher, {S}. {E}. and {N}evison, {C}. {D}. and {J}in, {Y}. {M}. and {B}ent, {J}. {D}. and {A}umont, {O}livier and {D}oney, {S}. {C}. and {D}unne, {J}. {P}. and {J}ohn, {J}. and {L}ima, {I}. {D}. and {L}ong, {M}. {C}. and {R}odgers, {K}. {B}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he air-sea exchange of oxygen ({O}-2) is driven by changes in solubility, biological activity, and circulation. {T}he total air-sea exchange of {O}-2 has been shown to be closely related to the air-sea exchange of heat on seasonal timescales, with the ratio of the seasonal flux of {O}-2 to heat varying with latitude, being higher in the extratropics and lower in the subtropics. {T}his {O}-2/heat ratio is both a fundamental biogeochemical property of air-sea exchange and a convenient metric for testing earth system models. {C}urrent estimates of the {O}-2/heat flux ratio rely on sparse observations of dissolved {O}-2, leaving it fairly unconstrained. {F}rom a model ensemble we show that the ratio of the seasonal amplitude of two atmospheric tracers, atmospheric potential oxygen ({APO}) and the argon-to-nitrogen ratio ({A}r/{O}-2), exhibits a close relationship to the {O}-2/heat ratio of the extratropics (40-70 degrees). {T}he amplitude ratio, {A}({APO})/{A}({A}r{N}2), is relatively constant within the extratropics of each hemisphere due to the zonal mixing of the atmosphere. {A}({APO})/{A}({A}r{N}2) is not sensitive to atmospheric transport, as most of the observed spatial variability in the seasonal amplitude of delta {APO} is compensated by similar variations in delta({A}r/{N}-2). {F}rom the relationship between {O}-2/heat and {A}({APO})/{A}({A}r{N}2) in the model ensemble, we determine that the atmospheric observations suggest hemispherically distinct {O}-2/heat flux ratios of 3.3 +/- 0.3 and 4.7 +/- 0.8 nmol {J}(-1) between 40 and 70 degrees in the {N}orthern and {S}outhern {H}emispheres respectively, providing a useful constraint for {O}-2 and heat air-sea fluxes in earth system models and observation-based data products. {P}lain {L}anguage {S}ummary {T}ypically, the surface of the ocean releases oxygen to the atmosphere during summer and takes it up during winter. {T}his cycle is driven by circulation, biology (photosynthesis and respiration), and the seasonal cycle in water temperature, which changes the solubility of oxygen in surface water. {W}e have used measurements of two atmospheric tracers, one which tracks oxygen and one which tracks heat, to estimate the amount of oxygen taken up or released by a change in ocean heat content. {B}y looking at ocean models and atmospheric observations of the two atmospheric tracers, we find that the oxygen exchange between the ocean and atmosphere in the {S}outhern {H}emisphere is more responsive to changes in heat content than in the {N}orthern {H}emisphere. {T}hese hemispheric metrics are useful tests of how ocean models simulate some biological and physical processes.},
  keywords = {},
  booktitle = {},
  journal = {{J}ournal of {G}eophysical {R}esearch : {O}ceans},
  volume = {126},
  numero = {8},
  pages = {e2021{JC}017510 [20 p.]},
  ISSN = {2169-9275},
  year = {2021},
  DOI = {10.1029/2021jc017510},
  URL = {https://www.documentation.ird.fr/hor/fdi:010082743},
}