Geoscience Reference
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10 −5
10 −6
10 −7
10 −8
observations
Andreas (1998)
Gong (2003)
10 −9
0
20
40
60
80
U 10 (m/s)
Figure 9.4 Sea-spray volume as a function of U 10 wind speed. Dots - laboratory observations of
Toffol i et al. ( 2010b ); lines - parameterisations of Andreas ( 1998 ) (dashed) and Gong ( 2003 ) (solid)
1800
1600
1400
1200
1000
0
20
40
60
80
U 10 (m/s)
Figure 9.5 Average intensity of the laser signal as a function of the reference wind speed U 10
speeds, the field dependences and laboratory data are not expected to agree, as discussed
above. These wind speeds were simply employed to generate larger spray concentrations
in order to extend the laser calibration.
The attenuation of the laser intensity due to the droplet concentration is shown in
Figure 9.5 . Here, the average intensity is presented as a function of the wind speed U 10 .
With an increase of wind speed, and hence of sea-spray concentration (see Figure 9.4 ), the
laser beam clearly decays more strongly. This confirms that there is a well-defined relation-
ship between the magnitude of the returned laser radiation and the concentration of spume
droplets.
Dependence between the laser intensity and the sea-spray volume is shown in Figure 9.6 .
Here, a regression model for an estimate of the amount of spray volume that remains in
 
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