Chemistry Reference
In-Depth Information
between a few meters and about 100 m, depending on incidence angle and
radar band), while time differences and state of evolution of the slick in
our opinion play a minor role. Additional systematic investigations are re-
quired in order to answer these questions.
The analysis of a large number of ERS SAR data revealed improved sta-
tistical information on the oil pollution of European marginal waters. The
results show that the consideration of local environmental conditions
(namely the local wind speed) improves the statistical results significantly:
the Baltic Sea seems to be only slightly less polluted than the northwestern
Mediterranean, which is not in accordance with results from earlier studies
where local wind speeds had not been taken into account.
The results from the wind-wave tank measurements show that at X- and
Ka-band the radar backscattering from a slick-free water surface is caused
by bound as well as by free propagating ripples. In the presence of a
monomolecular surface film at certain wind speeds only bound or only free
propagating ripples are responsible for the backscattering at X-band, which
can explain higher measured damping ratios.
Fig. 9. C
omparison of the radar contrast caused by the deployed OLA slicks dur-
ing both shuttle missions in April (
left panel
) and October (
right panel
), 1994.
The solid circles denote results obtained by HELISCAT, the open circles denote
results obtained from SIR-C/X-SAR data. Note that in both cases, SIR-C/X-SAR
measured lower damping ratios than HELISCAT
