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| Titel |
Mixing in the Black Sea detected from the temporal and spatial variability of oxygen and sulfide – Argo float observations and numerical modelling |
| VerfasserIn |
E. V. Stanev, Y. He, J. Staneva, E. Yakushev |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 11, no. 20 ; Nr. 11, no. 20 (2014-10-16), S.5707-5732 |
| Datensatznummer |
250117644
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| Publikation (Nr.) |
 copernicus.org/bg-11-5707-2014.pdf |
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| Zusammenfassung |
| The temporal and spatial variability of the upper ocean hydrochemistry in
the Black Sea is analysed using data originating from profiling floats with
oxygen sensors and carried out with a coupled
three-dimensional circulation-biogeochemical model including 24 biochemical
state variables. Major focus is on the dynamics of suboxic zone which is the
interface separating oxygenated and anoxic waters. The scatter of
oxygen data seen when plotted in density coordinates is larger than those
for temperature, salinity and passive tracers. This scatter is indicative of
vigorous biogeochemical reactions in the suboxic zone, which acts as a
boundary layer or internal sink for oxygen. This internal sink affects the
mixing patterns of oxygen compared to the ones of conservative tracers. Two
different regimes of ventilation of pycnocline were clearly identified: a
gyre-dominated (cyclonic) regime in winter and a coastal boundary layer
(anticyclonic eddy)-dominated regime in summer. These contrasting states are
characterized by very different pathways of oxygen intrusions along the
isopycnals and vertical oxygen conveyor belt organized in multiple-layered
cells formed in each gyre. The contribution of the three-dimensional
modelling to the understanding of the Black Sea hydro-chemistry, and in
particular the coast-to-open-sea mixing, is also demonstrated. Evidence is
given that the formation of oxic waters and of cold intermediate waters,
although triggered by the same physical process, each follow a different
evolution. The difference in the depths of the temperature minimum and the
oxygen maximum indicates that the variability of oxygen is not only just a
response to physical forcing and changes in the surface conditions, but
undergoes its own evolution. |
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