Physical Oceanography, Vol. 18, No. 2, 2008
THERMOHYDRODYNAMICS OF THE OCEAN
GENERATION OF SEICHES BY MOVING BARIC FRONTS IN BOUNDED BASINS
S. F. Dotsenko and N. A. Miklashevskaya
We consider a plane problem of barotropic seiches generated by a front of atmospheric pressure
moving over a bounded basin. A system of nonlinear equations of long waves is solved by the
finite-difference method with regard for the bottom friction and Earth’s rotation. The numerical
analyses are performed for two basins with distributions of depths typical of the Black Sea. It is
shown that the passage of a baric front over the basin leads to the generation of lower seiches.
The oscillations of level and the corresponding currents are especially intense in the shallow-wa-
ter zones of the basins. The seiches become more intense as the velocity of transfer of the atmo-
spheric front increases and the width of the front decreases. Earth’s rotation leads to the genera-
tion of longshore currents and promotes the process of weakening of residual oscillations of the
fluid following the passage of the front. The influence of nonlinearity on seiches is small for the
The process of interaction with the atmosphere is one of the causes of the space variability of hydrophysical
fields in the World Ocean . On the synoptic scales of motion, the predominant contribution to the energy
transfer from the atmosphere into the ocean is made by the wind stresses . The relative contribution of the
variations of atmospheric pressure to the oscillations of the sea level depends on the scales of the process. The
analyses of the in-situ data and the results of numerical simulations reveal the predominant role of the baric
field in the generation of nontidal oscillations of sea level with periods from ten hours to ten days on space scales
km [3, 4]. For this reason, the investigation of the response of marine media to the variations of
atmospheric pressure is necessary to understand the dynamics of the World Ocean.
During a year, about
cyclones and anticyclones participate in cyclogenesis over the World Ocean .
The passage of intense meteorological formations can be accompanied by displacements of the sea level 3–4
times larger than the equilibrium values . As follows both from the data of in-situ observations [5–9] and
from the results of numerical simulations for the Black Sea and Sea of Azov [10, 11] the process of motion of
baric formations over closed basins can lead to the generation of seiches. At the same time, the general physical
regularities of the process of generation of seiches in closed basins of variable depth by moving baric fronts are
now studied insufficiently well.
In what follows, we study the plane problem of generation of barotropic seiches by a front of atmospheric
pressure moving over a bounded basin. We analyze the dependence of the efficiency of generation of nonlinear
seiches on the velocity of motion and width of the front. Unlike our previous work , the analysis of the dy-
namics of water in the basin is performed for a moving front with regard for Earth’s rotation.
Marine Hydrophysical Institute, Ukrainian Academy of Sciences, Sevastopol, Ukraine.
Translated from Morskoi Gidrofizicheskii Zhurnal, No.
3–18, March–April, 2008. Original article submitted November 10,
0928-5105/08/1802–0063 © 2008 Springer Science+Business Media, Inc. 63