Physical Oceanography, Vol. 16, No. 5, 2006
THERMOHYDRODYNAMICS OF THE OCEAN
ONE-DIMENSIONAL NONSTATIONARY MODEL OF VERTICAL EXCHANGE
IN THE BLACK SEA WITH REGARD FOR THE MECHANISM OF WINTER
CONVECTION IN THE SURFACE LAYER
V. N. Eremeev, A. S. Samodurov, and O. E. Kul’sha
We construct a one-dimensional nonstationary isopycnic model of vertical exchange in the Black
Sea with regard for the processes of draining and transformation of waters of the Sea of Marmara
(or “plume”), vertical diffusion, and the action of winter convection in the upper layer. It is as-
sumed that mixing in the basin is local in space and time and that the winter wind action remains
constant from year to year in the analyzed version of the model. The temperature of the upper
mixed layer introduced to simulate the winter conditions is regarded as the principal external
variable factor. Within the framework of the accepted restrictions, the model enables us to study
the annual and interannual variability of the thermohaline characteristics and hydrochemical par-
ameters in the water column of the sea. As an example, we perform the numerical analysis of the
periodic action of external thermal conditions on the characteristics of the system with a period
of six years.
The present work continues the investigations originated in [1–3], where a version of the solution of the in-
verse problem is obtained within the framework of a one-dimensional stationary model. The parameters of the
heat and salt sources and sinks in the water column of the sea are reconstructed according to the known mean
distributions of the thermohaline characteristics T
) and S
. In particular, the distributions of vertical vel-
) formed as a result of propagation and transformation of waters of the Sea of Marmara and the co-
efficient of vertical turbulent diffusion k
are determined. The schematic diagram of this process is pre-
sented in Fig.
At the same time, the analysis of the results of measurements carried out in the active layer of the sea shows
that, in this case, the processes of vertical exchange include the mechanisms that could not be adequately de-
scribed within the framework of the nonstationary problem by introducing the diffusion coefficient. This prob-
lem is discussed in what follows. It is convenient to define the active layer of the Black Sea as a layer where the
action of the surface and subsurface factors stabilizing the position of upper boundary of the main thermohalo-
cline and suppressing its upward motion under the influence of the flow of waters from the Sea of Marmara,
manifests itself directly or indirectly. Among these factors, one can mention wind mixing, atmospheric precipi-
tation, river discharge, and the seasonal course of temperature.
Marine Hydrophysical Institute, Ukrainian Academy of Sciences, Sevastopol.
Translated from Morskoi Gidrofizicheskii Zhurnal, No.
3–21, September–October, 2006. Original article submitted May 12,
0928-5105/06/1605–0257 © 2006 Springer Science+Business Media, Inc. 257