Physical Oceanography, Vol.
4, November, 2011 (Ukrainian Original No.
4, July–August, 2011)
THERMOHYDRODYNAMICS OF THE OCEAN
NUMERICAL MODELING OF THE INFLUENCE OF LAND–SEA TEMPERATURE
CONTRASTS ON THE ATMOSPHERIC CIRCULATION IN THE BLACK-SEA REGION
V. V. Ef i m o v
and A. E. Anisimov
The formation of the fields of surface winds over the Black Sea occurs under the action of numerous
physical factors. One of the most important factors is the monsoon mechanism connected with the sea-
sonal variations of buoyancy contrasts over the sea and surrounding land. To separate the effects caused
by this mechanism, we performed and described the numerical experiments aimed at the evaluation of
the sensitivity of the regional model of atmospheric circulation to the variations of land–sea temperature
contrasts. It is shown that the influence of these effects is restricted to the lower part of the atmosphere.
The presented estimates of the climatic fields of disturbances enable us to describe the monsoon mech-
anism specifying the seasonal variability of the field of vorticity of the wind velocities and, as a conse-
quence, the seasonal variability of the large-scale circulation of waters in the Black Sea.
Keywords: Black Sea, monsoon effect, climate, climate modeling.
In closed or almost closed basins of the Northern Hemisphere, such as the Black and Caspian Seas, the
character of large-scale circulation is cyclonic. As a typical example, we can mention the Rim Current exhibit-
ing a cyclonic trend in the edge regions of the sea. It is generally accepted that the seasonal variations of the
Rim Current are connected with the seasonal variations of the land–sea thermal contrasts [1, 2] and a significant
role in the annual average circulation is played by the cyclonic wind field over the sea formed mainly under the
influence of the typical coastal orography: The Caucasian and Pontic Mountains in the southeast serve as obsta-
cles for the surface winds . The seasonal variability of the surface wind is most clearly pronounced in the
west part of the sea, which is connected with the seasonal variations of the buoyancy contrasts over the sea and
surrounding land whose action can be regarded as the monsoon mechanism. In addition, the field of surface
winds suffers the influence of the intense orographic effect in the east part of the sea whose seasonal variability
is weak. In general, the vorticity of the wind velocity over the sea remains cyclonic for the whole year and its
annual average value is comparable with the range of seasonal variability.
Description of Numerical Experiments
The fields of surface winds and their seasonal variations are formed under the action of numerous physical
Marine Hydrophysical Institute, Ukrainian National Academy of Sciences, Sevastopol, Ukraine.
Corresponding author; e-mail: firstname.lastname@example.org.
Translated from Morskoi Gidrofizicheskii Zhurnal, No.
3–12, July–August, 2011. Original article submitted March 18, 2010; revi-
sion submitted April 20, 2010.
0928–5105/11/2104–0221 © 2011 Springer Science+Business Media, Inc. 221