ISSN 0001-4370, Oceanology, 2015, Vol. 55, No. 1, pp. 56–67. © Pleiades Publishing, Inc., 2015.
Original Russian Text © A.A. Kubryakov, S.V. Stanichny, 2015, published in Okeanologiya, 2015, Vol. 55, No. 1, pp. 65–77.
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INTRODUCTION
Mesoscale eddies are essential elements of the
dynamic structure of the Black Sea basin [1–7, 15, 16,
25, 27, 28, 30, etc.]. A large number of works have
been devoted to studies of the structure and dynamics
of individual eddies using hydrological measurements
[1, 3, 6, 7, 8, 21, 30, etc.], as well as to the study of the
characteristics of eddies, their movement trajectories,
and the manifestations of eddy structures in the fields
of temperature and optical contrasts using satellite
imagery in the infrared (IR) and optical bands [1, 2, 5,
15, 16, 28, etc.].
Contact methods have a number of indisputable
advantages: they provide information about the three-
dimensional structure of eddies in fields of different
parameters. A lack of contact methods consists in the
irregularity of the measurements and the inability to
carry out quasi-synchronous measurements over a vast
water area; ship observations can at best give informa-
tion on the evolution of 2–3 eddies over a short period
of time. Satellite images in the infrared and optical
bands are characterized by higher spatial and temporal
resolution. However, cloudiness prevents receiving
regular satellite information on eddy formation using
such measurements. Moreover, not all eddies can be
detected in fields of the temperature or optical bands.
In these conditions, for the systematic study of
eddies, satellite altimetry measurements have signifi-
cant advantages. Since 1992, satellite altimeters have
carried out high-precision (up to 2 cm) measurements
of the sea surface topography [14]. These data are
available on a regular basis and cover the entire surface
of the Black Sea basin, because clouds are transparent
for the signal in the microwave range. Furthermore,
altimetry measurements allow to directly determine
the dynamic structure of the eddy, in contrast to mea-
surements in the optical and IR channels, which allow
obtaining only a picture of the eddy in the field of trac-
ers. The combining of along-track measurements
obtained from several altimeters using the methods
developed in [19, 23] allows reconstruction of maps of
sea level anomalies.
The mesoscale eddies in the Black Sea using satellite
altimetry data have been studied earlier in [18, 27, 30].
However, in these studies, the authors analyzed eddies
by detecting them visually; as a result, mostly qualitative
results were obtained.
After the appearance of the array of mapped altim-
etry measurements, there has been rapid development
of methods for automatic identification of eddies [10,
17]. These methods allow automatically identify each
individual eddy manifesting in altimetry data during
the studied period and to further explore both the indi-
vidual features of the evolution of single eddy struc-
tures and the statistical properties of the entire ensem-
ble of eddies in the region as a whole. This paper ana-
lyzes the eddy characteristics for the period of 1992–
2011: their number, spatial distribution and life dura-
tion, kinematic and geometric properties, trajectories,
and speeds of movement. It also analyzes the evolution
of different characteristics of the eddies depending on
the time of their existence.
DATA
Satellite altimetry. This paper uses a regional array
of mapped sea level anomalies from Archivage Valida-
tion Interprétation des données des Satellites Océano-
graphiques (AVISO) for the Black Sea
(http://www.aviso.oceanobs.com/) from 1992 to 2011.
The regional array was created by the Collection and
Location by Satellite agency (CLS). The spatial resolu-
tion of the maps is 1/8° (~12.5 km), which is two times
higher than for the global dataset (1/4°); the temporal
Mesoscale Eddies in the Black Sea from Satellite Altimetry Data
A. A. Kubryakov and S. V. Stanichny
Marine Hydrophysical Institute, National Academy of Sciences of Ukraine, Sevastopol
e-mail: arskubr@gmail.com
Received July 10, 2013; in final form, November 8, 2013
Abstract—The mesoscale eddy dynamics in the Black Sea is investigated using the method of automated
eddy identification based on the determination of closed streamlines in the altimetry-derived velocity fields.
In total, more than 800 eddies of different signs with a lifetime of more than four weeks and more than
40 kilometers in diameter were identified over the period from 1992 to 2011. Using the obtained array of data,
this paper investigates the quantity, life span, geometrical and kinematic characteristic of eddies, character-
istic trajectories and velocities of their movement; specifies areas of their primary formation and collapse; and
analyzes evolution of different characteristics of the eddies depending on the time of their existence.
DOI: 10.1134/S0001437015010105
MARINE PHYSICS