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| Titel |
Role of mesoscale eddies in cross-frontal transport of carbon and nutrients in the Southern Ocean |
| VerfasserIn |
Carolina O. Dufour, Stephen M. Griffies, Jaime B. Palter, Gregory F. de Souza, Jorge L. Sarmiento, Eric D. Galbraith |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250098216
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| Publikation (Nr.) |
 EGU/EGU2014-13871.pdf |
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| Zusammenfassung |
| The Southern Ocean plays a key role in oceanic carbon storage and global nutrient
distributions. Here, carbon and nutrients are transferred into the ocean interior by the
formation and subduction of mode and intermediate water masses. Much of the
subducted carbon and nutrients in these water masses derive from waters upwelled
at the Antarctic Divergence that must cross the numerous fronts of the Antarctic
Circumpolar Current (ACC) to reach the sites of water mass formation. These energetic
frontal jets are natural barriers to tracer exchange but allow some crossings via
specific mechanisms. While northward Ekman transport has been elucidated as the
major mechanism for cross-frontal transport of tracers at intra-annual scale, little is
known about the role of mesoscale eddies in mediating tracer exchange across
fronts.
This study aims to address the role of mesoscale eddies in cross-frontal transport of
carbon and nutrients in the Southern Ocean while (i) quantifying the net transport of tracers
across the various fronts of the ACC, (ii) describing the hot spots of tracer exchange, (iii)
investigating the time-scales of this exchange and its response to climate change. To
this purpose, we use a 1/10° configuration of the GFDL climate model (CM2.6)
coupled to a simplified version of the biogeochemistry model BLING where dissolved
inorganic carbon (DIC), phosphate and oxygen are simulated. The model is started
from observations with DIC corrected to preindustrial conditions, and run for a 120
year spin-up from which two 80 year simulations are performed: a preindustrial
control with constant radiative forcing and a sensitivity with a 1%/year increase
in atmospheric CO2 concentration. We focus our analyses on the last 20 years of
both simulations sampled at monthly frequency. Online tendency terms are used to
compute the total transport of DIC, phosphate and oxygen across the main fronts of
the ACC, and to single out the mesoscale eddy component of the transport. The
contribution of mesoscale eddies to the total cross-frontal transport is presented for each
biogeochemical tracer along with its spatial and temporal variabilities. The response
of the various components of the transport to climate change is also investigated. |
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