Constraining ventilation during deepwater formation using deep ocean measurements of the dissolved gas ratios Ar-40/Ar-36, N-2/Ar, and Kr/Ar
| Type | : | ACL |
|---|---|---|
| Nature | : | Production scientifique |
| Au bénéfice du Laboratoire | : | Non |
| Statut de publication | : | Publié |
| Année de publication | : | 2010 |
| Auteurs (5) | : | NICHOLSON David EMERSON S,r CAILLON N JOUZEL J HAMME Roberta,c |
| Revue scientifique | : | Journal of Geophysical Research-Oceans |
| Volume | : | 115 |
| Fascicule | : | |
| Pages | : | |
| DOI | : | 10.1029/2010JC006152 |
| URL | : | - |
| Abstract | : | The concentration of inert gases and their isotopes in the deep ocean are useful as tracers of air-sea gas exchange during deepwater formation. Delta Kr/Ar, Delta N-2/Ar, and delta Ar-40 were measured in deep profiles of samples collected in the northwest Pacific, subtropical North Pacific and tropical Atlantic oceans. For the ocean below 2000 m, we determined a mean Delta Kr/Ar composition of -0.96% +/- 0.16%, a mean Delta N-2/Ar of 1.29% +/- 0.21% relative to equilibrium saturation, and for delta Ar-40 a value of 1.188% +/- 0.055% relative to air. These data are used to constrain high-latitude ventilation processes in the framework of three-box and seven-box ocean models. For the three-box model tracer data, we constrain the appropriate surface area of the high-latitude region in both models to be 3.6% (+2.5%, -1.7%) of ocean surface area and the bubble air injection rate to be 22.7 (+8.8, -7.3) mol air m(-2) yr(-1). Results for the seven-box model were similar, with a high-latitude area of 3.3% (+2.2%, -1.3%). Our results provide geochemical support for suggestions that the effective area of high-latitude ventilation is much smaller than the region of elevated preformed nutrients and demonstrate that noble gases strongly constrain the ocean solubility pump. Reducing high-latitude surface area weakens the CO2 solubility pump in the box models and limits communication between the atmosphere and deep ocean. These tracers should be useful constraints on high-latitude ventilation and the strength of the solubility pump in more complex ocean general circulation models. |
| Mots-clés | : | AIR; ANTARCTIC SEA-ICE; ATMOSPHERIC CO2; BOX MODELS; CARBON-DIOXIDE; CLIMATE; EXCHANGE; NEON; PUMP; SOLUBILITY |
| Commentaire | : | Times Cited in Web of Science Core Collection: 18 |
| Tags | : | - |
| Fichier attaché | : | - |
| Citation | : |
Nicholson D, Emerson SR, Caillon N, Jouzel J, Hamme RC (2010) Constraining ventilation during deepwater formation using deep ocean measurements of the dissolved gas ratios Ar-40/Ar-36, N-2/Ar, and Kr/Ar. J Geophys Res-Oceans 115 | doi: 10.1029/2010JC006152
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