Physical Oceanography, Vol. 17, No. 6, 2007
THERMOHYDRODYNAMICS OF THE OCEAN
GENERATION OF SEICHES BY MOVING BARIC FORMATIONS
S. F. Dotsenko and N. A. Miklashevskaya
We consider a plane problem of generation of barotropic seiches in the case of motion of a regi-
on of disturbances of atmospheric pressure over a bounded basin. The nonlinear system of equa-
tions of long waves with regard for the quadratic dependence of bottom friction is solved by the
finite-difference method. The calculations are carried out for three basins of variable depth cor-
responding to rectangular sections of the Black Sea and Sea of Azov. It is shown that the pas-
sage of the baric anomaly over the basin is accompanied by the generation of the lowest seiches.
The oscillations of fluid are especially intense in the shallow-water zones of the basins. Seiches
exhibit a trend to intensification as the velocity of motion of the atmospheric disturbance in-
creases. The dependence on the width of the baric anomaly is not monotonic. In the shelf zone,
the amplitude of oscillations of the level can be several times higher that the pure hydrostatic re-
sponse of the sea surface. In the analyzed basins, the influence of nonlinearity on the seiches is
The variations of atmospheric pressure can be regarded as one of the main causes of the space-time vari-
ability of hydrophysical fields in the World Ocean . The oscillations of the oceanic fields on synoptic scales
are largely determined by the wind stresses, whereas the energy transfer from the atmosphere into the ocean
caused by the action of baric fields and buoyancy flows on the sea surface is weak [2, 3]. The relative contribu-
tion of the variations of the baric field to the oscillations of the sea level depends on the scale of the process. The
analysis of the data of measurements and the results of numerical simulations shows that the contribution of the
baric field to the nontidal oscillations of the ocean level is predominant on periods from ten hours to ten days and
space scales of
[4–7]. Therefore, the analysis of the response of the ocean to the variations of the
baric field is in no case of less significance for the comprehension of the dynamics of the World Ocean than the
analysis of the action of fluctuations of the wind field upon the marine media. In recent years, the investigations
of the mechanisms of formation of the variations of sea level have become much more intense due to the deve-
lopment of the altimetric methods of recording the level of the sea surface for the solution the fundamental and
applied problems of oceanology, including the development of satellite methods of early notification about cata-
strophic tsunami waves .
Note that that about
cyclones participate in the cyclogenesis over the World Ocean for one year .
The process of passage of intense meteorological formations is accompanied by the variations of the sea level
whose amplitudes are
times greater than the equilibrium values .
Marine Hydrophysical Institute, Ukrainian Academy of Sciences, Sevastopol.
Translated from Morskoi Gidrofizicheskii Zhurnal, No.
3–15, November–December, 2007. Original article submitted May 31,
0928-5105/07/1706–0313 © 2007 Springer Science+Business Media, Inc. 313