Physical Oceanography, Vol. 15, No. 5, 2005
AUTOMATION OF SCIENTIFIC RESEARCH IN SEAS AND OCEANS
“SIGMA-1” MEASURING COMPLEX FOR THE INVESTIGATION OF
SMALL-SCALE CHARACTERISTICS OF HYDROPHYSICAL FIELDS
IN THE UPPER LAYER OF THE SEA
A. S. Samodurov, V. Z. Dykman, V. A. Barabash, O. I. Efremov,
A. G. Zubov, O. I. Pavlenko, and A. M. Chukharev
We describe a new measuring complex aimed at the investigation of small-scale processes in the
upper active layer of the sea. The necessity of creation of a complex of this sort is justified and a
circle of problems that can be solved with the help of this complex is described. The scales of
resolution of horizontal and vertical inhomogeneities in measuring in the mode of vertical prob-
ing are theoretically estimated. The basic technical characteristics of the complex are presented.
We also present the results of laboratory and field tests, which confirm the agreement between
the calculated and actual technical possibilities of the complex. The structural features of various
versions of the “Sigma-1” measuring complex (the “Sigma-1P” point-to-point-operation version
and the “Sigma-1Z” probing version) are described.
The investigation of small-scale processes is one of the main directions of oceanology, which received a
powerful impetus for its development in the middle of the last century with the introduction of field measure-
ments performed with the help of high-resolution CTD-probes into general practice. The initial period of obser-
vations was characterized by the active assimilation and accumulation of new data. In this period, a hypothesis
was proposed that the obtained results of measurements are explained by the imperfections of the applied equip-
ment. Thus, the extensive application of Nansen bottles in the practice of measurements led to the formation of a
common opinion concerning the smoothness of the vertical structure of hydrophysical fields of the ocean. How-
ever, later, it became clear that the observed phenomena indeed exist and can be regarded as a consequence of
the action of a broad spectrum of processes of different physical nature and different space-and-time scales. To
reflect the result of action of these processes in the formation of “nonsmoothness” of the vertical profiles of hy-
drophysical characteristics on scales from several tens of meters to about a meter, it is now customary to speak
about the “fine structure” of hydrophysical fields.
Among the physical mechanisms affecting the formation of the fine structure of the ocean, one can mention
the kinematic effect of internal waves, the intrusion exchange through the frontal zones, the specific features of
the bottom topography and bottom friction, the density convection and breaking of the surface waves, various
manifestations of the mechanism of differential diffusion convection, local mixing as a result of shear instability
and breaking of internal waves, coastal discharge, exchange through the channels, underwater volcanic activity
and bottom geothermal heat flows, melting of sea ice, etc.
Marine Hydrophysical Institute, Ukrainian Academy of Sciences, Sevastopol.
Translated from Morskoi Gidrofizicheskii Zhurnal, No.
60–71, September–October, 2005. Original article submitted June 1,
2004; revision submitted August 12, 2004.
0928-5105/05/1505–0311 © 2005 Springer Science+Business Media, Inc. 311