Temporal Variability of Currents
in the Ross Sea (Antarctica)
P. Picco1, L. Amici2, R. Meloni2, L. Langone3 and M. Ravaioli3
1 ENEA CRAM, P.O. Box 316,19100 La Spezia, Italy
2 CNR Istituto di Oceanografia Fisica, P.O. Box 316,19100 La Spezia, Italy
3 CNR Istituto di Geologia Marina, Via Gobetti 110,40129 Bologna, Italy
Abstract
Some results from the analysis of about one year long time sériés of currents, température and salinity data collected in the central-western part of the Ross Sea
during 1995 are here presented. Temporal évolution and seasonal variability of
currents at intermediate and deep layers in different locations are described. The
rôle of surface seasonal processes and of the advection of different water masses
on température and salinity variations is investigated. Spectral analysis, focusing
on low frequency oscillations, évidences that kinetic energy is mainly concentrated on mesoscale phenomena time scale at which barotropic movements prevail.
At higher frequencies, the tidal component strongly dominâtes, while the inertial
oscillation, whose frequency is the same band, is less important. The ice formation and melting processes affect also the intermediate level as evidenced in température and salinity time sériés, but do not seem to modify significantly the circulation in this layer. Apart from a weakeness in kinetic energy observed in most
of the locations from late April to early June, the general circulation does not présent an important seasonal variability, suggesting that the open océan Antarctic
Circumpolar Current acts as a prevailing forcing with respect to the thermoaline
forcings.
1 The Experiment and Data Treatment
Six moorings composed of current meters, température and conductivity sensors,
sédiment traps and turbidimeters were deployed in the central-western part of
the Ross Sea Shelf by the end of December 1994 during the océanographie expédition of N/O “Italica”, in the framework of the Italian National Programme for
Antarctic Research [1]. Three of the moorings (D, F, H) were deployed in the
framework of CLIMA (Climatic Long-term Interaction for the Mass balance in
Antarctic) Project; the others (A, B, C) were managed by the CNR Istituto di
Geologia Marina of Bologna to support the studies of biogeochemical processes
in the Ross Sea (ROSSMIZE Project) involved in the seasonal retreat of the sea-ice
margin. Ail the moorings were recovered, maintenanced, and deployed again the
following year, during the 1995/1996 expédition [2].
Mooring F was located 2 miles in front of the edge of the Ross Sea Ice Shelf, at
the latitude of 177°W. H was located 2° north of mooring F, at about the same Ion-
in the Ross Sea (Antarctica)
P. Picco1, L. Amici2, R. Meloni2, L. Langone3 and M. Ravaioli3
1 ENEA CRAM, P.O. Box 316,19100 La Spezia, Italy
2 CNR Istituto di Oceanografia Fisica, P.O. Box 316,19100 La Spezia, Italy
3 CNR Istituto di Geologia Marina, Via Gobetti 110,40129 Bologna, Italy
Abstract
Some results from the analysis of about one year long time sériés of currents, température and salinity data collected in the central-western part of the Ross Sea
during 1995 are here presented. Temporal évolution and seasonal variability of
currents at intermediate and deep layers in different locations are described. The
rôle of surface seasonal processes and of the advection of different water masses
on température and salinity variations is investigated. Spectral analysis, focusing
on low frequency oscillations, évidences that kinetic energy is mainly concentrated on mesoscale phenomena time scale at which barotropic movements prevail.
At higher frequencies, the tidal component strongly dominâtes, while the inertial
oscillation, whose frequency is the same band, is less important. The ice formation and melting processes affect also the intermediate level as evidenced in température and salinity time sériés, but do not seem to modify significantly the circulation in this layer. Apart from a weakeness in kinetic energy observed in most
of the locations from late April to early June, the general circulation does not présent an important seasonal variability, suggesting that the open océan Antarctic
Circumpolar Current acts as a prevailing forcing with respect to the thermoaline
forcings.
1 The Experiment and Data Treatment
Six moorings composed of current meters, température and conductivity sensors,
sédiment traps and turbidimeters were deployed in the central-western part of
the Ross Sea Shelf by the end of December 1994 during the océanographie expédition of N/O “Italica”, in the framework of the Italian National Programme for
Antarctic Research [1]. Three of the moorings (D, F, H) were deployed in the
framework of CLIMA (Climatic Long-term Interaction for the Mass balance in
Antarctic) Project; the others (A, B, C) were managed by the CNR Istituto di
Geologia Marina of Bologna to support the studies of biogeochemical processes
in the Ross Sea (ROSSMIZE Project) involved in the seasonal retreat of the sea-ice
margin. Ail the moorings were recovered, maintenanced, and deployed again the
following year, during the 1995/1996 expédition [2].
Mooring F was located 2 miles in front of the edge of the Ross Sea Ice Shelf, at
the latitude of 177°W. H was located 2° north of mooring F, at about the same Ion-