Chemistry Reference
In-Depth Information
the slick its -3 dB contour, the apparent size of the slick at C-band 40°
would be 65 m instead of 50 m. A further consequence is that the location
of the slick will appear to be displaced in the wind direction. All these ef-
fects become more pronounced at lower wind speeds.
Fig. 8.
Computed radar contrasts across a slick (oleic acid) that occupies 50 m <
x
< 100 m. X-band 55˚ incidence (drawn), C-band 40˚ (dashed), C-band 23˚ (dot-
ted), L-band 55˚ (dash-dot) and P-band 55˚ (drawn). Radar look direction is
downwind, VV polarisation, wind speed
U
10
= 5 m/s, neutrally stable atmosphere
5 Discussion and conclusions
The VIERS-1 wave spectral physical model, which is based on an energy
flux divergence formulation, has been extended to include the saturation
range by introducing a dissipation term proportional to wave energy
squared. This leads to a physics-based wave spectral model in which the
effects of slicks can be taken into account over the full saturation, grav-
ity/capillary transition and capillary ranges. The model is not completely
closed, however, because it needs to be supplied with a boundary energy
flux value from the spectral peak, which is not included in the physical
modelling but retains a JONSWAP parameterisation.
