Chemistry Reference
In-Depth Information
lick et al. (1992) who used repeated airborne SAR observations of turbu-
lent ship wakes to detect perturbations caused by surface currents. The
magnitude of a wake's displacement and information about its age allowed
them to estimate differential currents. The measured displacements were
always co-located with natural filamentary slicks and not with the narrow
light lines, as in Figures 1a and 4. This fact probably reflects differences in
both the mechanisms of surface current formation and natural film concen-
tration.
Fig. 5.
Enlarged fragment (40 km x 50 km) of the ERS-1 SAR image obtained on
May 20, 1994, at 14:20 UTC covering the area of the mesoscale cyclonic circula-
tion east of Kuroshio boundary (copyright European Space Agency). The labels
correspond to the labels in Figure 1b
Case 2
The same approach was used to estimate the surface current component
normal to the spill in Figure 4. The maximum westward component of the
surface current was observed in area
C
at a distance of 30 km behind the
ship, where the shift was
y
= 2.2 km. This corresponds to an average cur-
rent velocity of
V
c
| 0.5 ms
-1
, assuming, as in the first case, that the
ship's velocity was equal to 25 km h
-1
. The maximum eastward component
of current velocity in area
E
was about 0.43 ms
-1
(a 4-km shift for 2 h 35
min).
An enlarged fragment of the SAR image, covering vortex
9
in area
D
, is
shown in Figure 6. The velocities of the eastward (positive) and westward
(negative) components of the vortex circulation were equal to r 0.3 ms
-1
(a
r 2.3 km shift for about 2 h 10 min).
