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Ann. Geophys., 21, 89-102, 2003
www.ann-geophys.net/21/89/2003/
© European Geosciences Union 2003
Sub-inertial variability in the Cretan Sea from the M3A buoy
V. Cardin1, M. Gačić1, K. Nittis2, V. Kovačević1, and L. Perini1
1Istituto Nazionale di Oceanografia e di Geofisica Sperimentale OGS, Italy
2National Centre for Marine Research, Institute of Oceanography, Athens, Greece
Abstract. One year of continuous
records of temperature, salinity data at various depths, and currents obtained
from by an upward looking acoustic Doppler current profiler (ADCP) moored at a
site in the Cretan Sea were analyzed. Temperature and salinity data revealed
the influence of a multi-scale circulation pattern prevailing in this area.
This pattern consists of mesoscale cyclonic and anticyclonic vortices moving
together as a dipole, and inducing downwelling and upwelling in the water
column. The dipole movements, which control the circulation in the area, have
been evidenced from horizontal current variability in the upper 250 m. The
basin-scale circulation also shows a prominent seasonal variability. The
Empirical Orthogonal Function analysis applied to either zonal or meridional
components of the currents, confirmed the prevalence of a depth-independent
mode over the baroclinic-like one for the whole period of measurements and for
both current components. Nevertheless, the depth-dependent structure indicated
the out-of-phase behaviour of the upper 250 m layer with respect to the deeper
one. The first mode of the temperature EOF analysis, which accounts for most of
the variance, represents the seasonal heating of the water column being
principally associated with the surface mixed layer at the level of the
seasonal thermocline.
Key words. Oceanography: physical
(currents, eddies and mesoscale processes, general circulation)
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