32
V. Cardin and L. Ursella
a
30
29
28
o
10
20
b
30
29
28
o
10
20
27
11'):
<"i :
26
30
di stance (krn)
27
26
o
o
30
40
distance (krn)
25
24
23
first group
- : 25 '.. - - - ....
: : ~2
:
: .s -{----- __
second group
third group
25
24
23
first group
second group
third group
50
60
Fig.8a,b. a Steady and b residual across section current field at transect C. Positive values indicate southward flow, while negative ones mean northward flow. Water masses individuated by the cluster analysis are superimposed
mesoscale eddies. The difference in the coastal
current intensities at various transects is probably due to the different distance from the coast of
each section.
In the surface layer, where water of fluvial
origin is present, the residual field seems to fit the
water mass pattern obtained from the cluster
analysis better than the steady one. On the contrary, in the bottom layer, the water mass pattern
is similar to the steady field. As the residual field
presents a variability on the order of a few days,
the correlation found at the surface may suggest
a strong temporal variability of the field of mass
as well. Also, as the residual currents reflect very
closely the mass distribution, their behaviour
seems to be geostrophic in a first approximation.
Comparing at the surface, for the period during
which the CTD data were collected, the distribution of the residual field of different transects
with the spatial pattern obtained from the cluster
analysis, it can be established that in most cases
where water of fluvial origin is present, the residual current field indicates southward flow. The
spatial correspondence of these structures is only
qualitative and sometimes is not perfect; this is
probably because the resolution of the residual
field is half a kilometre, while the one of the field
of mass is about 10 km and does not permit to
resolve smaller structures. The similarity has
been observed almost over the entire area. In
general, the alternance of the inflows and outflows in the residual current field broadly agrees
V. Cardin and L. Ursella
a
30
29
28
o
10
20
b
30
29
28
o
10
20
27
11'):
<"i :
26
30
di stance (krn)
27
26
o
o
30
40
distance (krn)
25
24
23
first group
- : 25 '.. - - - ....
: : ~2
:
: .s -{----- __
second group
third group
25
24
23
first group
second group
third group
50
60
Fig.8a,b. a Steady and b residual across section current field at transect C. Positive values indicate southward flow, while negative ones mean northward flow. Water masses individuated by the cluster analysis are superimposed
mesoscale eddies. The difference in the coastal
current intensities at various transects is probably due to the different distance from the coast of
each section.
In the surface layer, where water of fluvial
origin is present, the residual field seems to fit the
water mass pattern obtained from the cluster
analysis better than the steady one. On the contrary, in the bottom layer, the water mass pattern
is similar to the steady field. As the residual field
presents a variability on the order of a few days,
the correlation found at the surface may suggest
a strong temporal variability of the field of mass
as well. Also, as the residual currents reflect very
closely the mass distribution, their behaviour
seems to be geostrophic in a first approximation.
Comparing at the surface, for the period during
which the CTD data were collected, the distribution of the residual field of different transects
with the spatial pattern obtained from the cluster
analysis, it can be established that in most cases
where water of fluvial origin is present, the residual current field indicates southward flow. The
spatial correspondence of these structures is only
qualitative and sometimes is not perfect; this is
probably because the resolution of the residual
field is half a kilometre, while the one of the field
of mass is about 10 km and does not permit to
resolve smaller structures. The similarity has
been observed almost over the entire area. In
general, the alternance of the inflows and outflows in the residual current field broadly agrees