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| Titel |
Physically driven Patchy O2 Changes in the North Atlantic Ocean simulated by the CMIP5 Earth System Models |
| VerfasserIn |
Filippos Tagklis, Annalisa Bracco, Takamitsu Ito |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250144647
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| Publikation (Nr.) |
 EGU/EGU2017-8500.pdf |
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| Zusammenfassung |
| Centennial trends of oxygen in the upper 700 m of the North Atlantic Ocean are investigated
in Earth System Models (ESMs) included in the Coupled Model Intercomparison Project
Phase 5. The focus is on the subpolar region, which is key for the oceanic uptake of oxygen
and carbon dioxide. Historical simulations covering the twentieth century and projections for
the twenty-first century under the Representative Concentration Pathway 8.5 scenario are
investigated. Although the representation of convective activity differs among the models in
space and strength, and most models have a cold bias south of Greenland resulting from a
poor representation of the pathway of the North Atlantic Current, the observed climatological
distribution of dissolved O2 averaged for the recent past period (1975-2005) is generally
well captured. By the end of the 21st century, all models predict an increase in
depth-integrated temperature of 2-3oC, a consequent solubility decrease, a weakening of the
vertical mass transport, a decrease in nutrient supply into the euphotic layer, and a
spatially variable change in apparent oxygen utilization (AOU). Despite an overall
tendency of the North Atlantic to lose oxygen by the end of twenty-first century, patchy
regions of O2 increase are observed in a subset of models. This regional resistance to
deoxygenation is explained by the weakening of the North Atlantic Current that causes a
regional solubility increase exceeding the effect of increasing stratification. Our results
imply that potential shifts in the North Atlantic Current play a crucial role in the
future projection of the regional oxygen concentration in the warming climate. |
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