Physical Oceanography, Vol. 17, No. 3, 2007
EXPERIMENTAL AND FIELD RESEARCH
PRELIMINARY RESULTS OF MEASUREMENTS OF ATMOSPHERIC
TURBULENCE OVER THE SEA
Yu. P. Solov’ev and V. A. Ivanov
We perform the experimental verification of the applicability of the theory of similarity to the
wave boundary layer and the assessment of wave-induced perturbations of the air flow depend-
ing on various conditions of stratification of the atmosphere and the state of the sea. The mea-
surements were carried out from a stationary platform located in the coastal part of the Black
Sea. The experimental procedure is based on the simultaneous measurements of the profile and
fluctuations of the wind speed at
levels in the
layer, the elevations of the sea sur-
face, the directions of waves and winds, and the mean gradients of temperature and humidity of
air. The structure of the boundary layer in the region of measurements depends on the direction
of the wind. For weak and moderate onshore winds
the approximate balance is pre-
served between the production and dissipation of turbulent energy in the cases of unstable and
neutral stratification. On the average, the estimates of friction velocity according to the profiles
are higher than the dissipative estimates by
mainly due to the deficiency of dissipation near
the surface. For the offshore wind, the structure of the boundary layer abruptly changes and is
determined not by the local parameters but by strong turbulent eddies formed over the dry land.
The intensity of low–frequency turbulent fluctuations and the gradient of wind velocity near the
surface in the coastal zone are
times higher than for the open sea.
As one of the main purposes of investigation of the boundary layer of the atmosphere, one can mention the
parametrization of turbulent vertical fluxes of momentum, heat, and substance by the easily measured mean val-
ues of meteorological parameters with an aim of development of the models of climate, formation of the struc-
ture of the upper layer of the ocean, and wind waves and solution of various applied problems. Among the most
important problems of this sort, we can distinguish the problems devoted to the investigation of the processes of
transport of pollutants and gas exchange in the coastal regions subjected to the anthropogenic loads whose inten-
sity strongly increases as a result of the active development of the shelf zone. As a result of the theoretical and
experimental studies of the processes running over the dry land, the problem of parametrization was, in principle,
solved in the 1960–1970s on the basis of the similarity theory developed by Monin and Obukhov . The re-
sults of parallel investigations carried out over the sea surface were much less successful. The scatter of the data
obtained in different experiments was as large
which could only partially be explained by the extre-
mely difficult conditions of measurements over the sea and the difference between the applied experimental pro-
cedures . The principal difference between the sea surface and the surface of the land is connected with the
possibility of transfer of momentum to the currents and wind waves. Together with the variations of the charac-
Marine Hydrophysical Institute, Ukrainian Academy of Sciences, Sevastopol.
Translated from Morskoi Gidrofizicheskii Zhurnal, No.
42–61, May–June, 2007. Original article submitted December 6, 2005;
revision submitted January 11, 2006.
154 0928-5105/07/1703–0154 © 2007 Springer Science+Business Media, Inc.