Physical Oceanography, Vol. 18, No. 3, 2008
MATHEMATICAL MODELING OF MARINE SYSTEMS
MODELING OF WIND UPWELLINGS ON THE NORTHWEST SHELF OF THE
BLACK SEA NEAR LOCAL FEATURES OF THE BOTTOM TOPOGRAPHY
V. A. Ivanov, É. N. Mikhailova, and N. B. Shapiro
We discuss the results of numerical experiments aimed at the investigation of the process of for-
mation of the three-dimensional structure of the zones of upwelling on the northwest shelf of the
Black Sea depending on the direction of the wind. We perform the detailed analysis of three
zones (I, II, and III) with fairly well pronounced inhomogeneities of the bottom topography.
Zone I is located in the north part of the shelf and, in this region, we observe a narrow depression
to the southwest of the Tendrovskaya Spit. In zone II located in the near-Danube zone, we ob-
serve a height reaching the sea surface (Zmeinyi Island). Zone III is located in the east part of
the shelf and corresponds to a sharp drop of depths with specific curvature of the coastal line of
the Kalamitskii Bay and Gerakleiskii Peninsula. The performed analysis enables us to conclude
that, in the vicinity of the local features of the bottom topography and coastal line (such as un-
derwater heights, depressions, and capes), we observe the appearance of the zones of upwelling
of waters, especially pronounced in the deep-water layers of the sea.
The northwest shelf of the Black Sea attracts significant attention of researchers in various fields as a pro-
mising object of industrial and economic utilization. Hence, the problem of investigation of the circulation of
water masses in this region under the action of various external factors seems to be of high importance [1–9].
The processes running on the shelf strongly differ from the processes observed in the abyssal regions of the sea.
In the shallow-water coastal zone, the currents are, as a rule, quite strong and the role of bottom friction (insigni-
ficant in the open sea) becomes noticeable. The presence of the coastal line imposes restrictions on the motion
of waters and leads to the formation of surges. The river discharge promotes the process of freshening of seawa-
ter near the coast, i.e., decreases its salinity and, hence, density and, in this way, affects the currents. The influ-
ence of external thermal factors on the shelf is also characterized by certain specific features. Thus, for the same
heat fluxes through the sea surface, the shallow-water coastal zones suffer greater temperature variations than the
abyssal regions. On the boundary of the shelf and the abyssal part of the sea, there is a drop of depths, where the
bottom slope sharply increases. Large slopes of the bottom lead to a special character of circulation responsible
for the formation of frontal zones and intense jet currents. In turn, the process of meandering of these currents,
promotes the formation of eddies and the appearance of upwellings and downwellings.
In general, the northwest shelf can be regarded as a striking example of a region (with three-dimensional
structure of circulation and thermohaline fields) interacting with the abyssal part of the sea. The phenomenon of
upwelling observed both near the coasts and in the open sea is one of the most typical but insufficiently studied
phenomena in this region. In this region, a large part of the events of upwelling, especially near the coasts, has
mainly the wind character. This means that they are caused by the wind-induced deviations of pure drift currents
from the coast toward the open sea with subsequent elevation of the abyssal waters to the surface.
Marine Hydrophysical Institute, Ukrainian Academy of Sciences, Sevastopol, Ukraine.
Translated from Morskoi Gidrofizicheskii Zhurnal, No.
68–80, May–June, 2008. Original article submitted January 18, 2007;
revision submitted February 14, 2007.
168 0928-5105/08/1803–0168 © 2008 Springer Science+Business Media, Inc.