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| Titel |
Numerical simulation of inter-annual variations in the properties of the upper mixed layer in the Black Sea over the last 34 years |
| VerfasserIn |
Georgy I. Shapiro, Fred Wobus, Andrei G. Zatsepin, Tatiana M. Akivis, Marcus Zanacchi, Sergey Stanichny |
| 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 |
250087154
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| Publikation (Nr.) |
 EGU/EGU2014-1174.pdf |
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| Zusammenfassung |
| The Black Sea is a nearly land-locked basin where a combination of salt and heat budgets
results in a unique thermohaline water mass structure. An important feature of the Black Sea
is that oxygen is dissolved and rich sea life made possible only in the upper water levels. This
is due to a strong pycnocline which cannot be mixed even by strong winds or winter
convection (Shapiro, 2008). The upper mixed layer (UML) with a nearly uniform temperature
profile and a very sharp seasonal thermocline at its lower boundary develops during the
summer season (Sur & Ilyin, 1997). The deepening of the UML has an important effect on
the supply of nutrients into the euphotic upper layer from the underlying nutrient-rich water
mass. The temperature of the UML at any given location is dependent on the surface
heat flux, horizontal advection of heat, the depth and the rate of deepening of the
UML.
In this study we use a 3D ocean circulation model, NEMO-SHELF (O’Dea et al, 2012)
to simulate the parameters of the UML in the Black Sea over the last 34 years.
The model has horizontal resolution of 1/12x1/16 degrees and 33 layers in the
vertical. The vertical discretization uses a hybrid enveloped s-z grid developed
in Shapiro et al. (2012). The model is spun up from climatology (Suvorov et al.,
2004); it is forced by the Drakkar Forcing Set v5.2 (Brodeau et al., 2010, Meinvielle
et al., 2013) and river discharges from 8 major rivers are included. For each year
the model is run from 1st January and the data for the period April to October are
used for analysis. The sea surface temperature produced by the model is compared
with satellite data ( Modis–Aqua, 2013) to show a good agreement. The model
simulations are validated against in-situ observations (BSERP-3, 2004; Piotukh et
al., 2011). The analysis is performed for the deep basin where the depth of the
sea is greater than 1000m. It clearly shows the inter-annual variations of both the
SST and the depth of UML. The depth of UML is calculated using the method by
Thomson (1976). It is highly dependent on the meteorological forcing, in particular the
wind speed. The correlation between the variations of parameters of UML, the
weather patterns, buoyancy fluxes and the kinetic energy of the UML circulation is
analysed.
This study was supported by EU FP7 PERSEUS and EU FP7 MyOcean2 projects.
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