measured sea radiance. Besides, the model enables to establish the 
optima directions of observation in determining the zones with 
increased or reduced (compared to the surrounding sea surface) 
sea radiance for the given observation conditions ( the Sun’s 
position, wind velocity and direction, cloudiness). The above zones 
of different (increased or reduced) brightness may result from the 
oil film , variation of sea roughness under the influence of inter- 
nal waves etc. 
We have carried out the computations by the given model 
for the incident solar radiation wavelength of 0.7 microns .It 
must be marked that for the wavelengths approximately 0.7 microns 
and more the diffusely backscattered (from water) component of 
upward radiation is negligible. Hence, for these wavelengths the 
reflecting component represents practically the sea brightness. 
In the calculations the relationship between the sea 
brightness and the observation conditions (the observation direc- 
tion, the solar zenith angle and azimuth, the wind velocity and 
direction) is considered. 
Since we had no initial data of total and direct solar 
radiation for all cases under consideration and no data at all to 
determine the Bs as a function of e and &  ,we used 
the averaged data for the values of the relationship between 
the direct and total solar radiation as well as for the values 
of the angular distribution of sky brightness taken from handbooks 
(see Kondratiev (1954) ,Ivanoff (1978) ,Avaste et al4,(1962)3.. Bv 
means of these materials the relative values of Bs and. Eg 
were determined and also the parameters of the ellipsoid des- 
cribing the angular distribution of Bs( e, 9  .AsTaeresult, 
we have by now the values of Br only in relative. units. 
Some examples of our results are demonstrated below. 
Fig.l and 2 represent the variability of sea brightness accor- 
ding to the change of the solar zenith angle ( So ) and the wind 
velocity (.4-..) (both for pure: and for_oil slick covered water). 
A significant difference in results of Be is observed. One 
can see that in certain conditions anomalous contrasts may 
appear - brightness of clear water exceeds the corresponding 
values of the system "oil film-water". Fig.3 enables to estimate 
the contribution of sun glitter to the sea brightness. As seen, 
the maximum values of glitter occur for solar azimuth angles being 
approximately 1800 and apparently the opposite direction is 
more recommended for measurements where the influence of sun 
glitter must be minimized. It is established too that for 
avoiding the influence of sun glitter, the nadir direction of 
measurements is not suitable, but the directions of Sm being 
about 40 — 50° must be preferred (the same conclusion is 
presented in the "papers. of Plass et al.(1977)). 4 
In Fig.4 we can see the scanning curves of B, (zenith 
angle Sm changing, ..from . 20°. to. 509 ) with the assumption 
that in the zone of Sn from 26°to 34° the water is covered 
with oil slick. We _ found that the shapes Of the brightness 
curves as well as the contrasts between the values of B,, 
with and without oil film on water depend significanly.  on- the 
solar azimuth angle. - 
Our results show likewise the dependence of Br on 
the wind direction. It means that in spite of the stochastic 
character of the sea roughness the certain slopes of waves 
dominate. This dependence is not so strong for oil-covered sea: 
hence, the waves are more symmetrical under these conditions. 
  
IE 
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Fig.l. 
zenith 
angle c 
microns 
microns 
angles 
Ww V