Section 6 



Station No. 



0-1 



10 



20- 



Q 30. 



40- 



50 



56.1 



Fig. ."i. Section 6. (Stations 82-86) Vertical stnjctureoltransmittancc. "H" and "M" letter codes above refer to Kopclevich water types; the first letter specifies 

 volumetric content of fine particles and the second letter that of coarse particles. Refer to Table 1 for numerical equivalents. 



Section 5 



. (89) 



Station No. 

 (90) 



Fig. 6. Section 5. (Stations 89-41 ) 

 (See Figure 5 legend.) 



Vertical structure of transmittance. 



Chukchi Seci 



The attenuation intdex fieltd for the Chukchi Sea is shown 

 sectionally in Figs. 1 1-14. 



The figures show that clear water (e = 0.25-0.4 m') 

 spreads in the surface layer in the northwestern region, anii it 

 gradually moves towards the Chukchi coast with decreasing 

 latitude. Areas of clear water can be traced at the northwestern 

 region and at depths of 25-40 m beneath a thick surface layer 

 of particulates (the core of this layer is shown in these sections 

 densely shaded). Occasionally such portions of clear water 

 occur in the lower interlayers. Also, deep clear water is 

 gradually ousted by the rising bottom water and forced to flow 

 towards the Chukchi coast. As a result, the ousted water 

 merges with a cloudy subsurface layer in the central and eastern 

 parts of the region explored. The angular and integral 

 characteristics of assays, taken from surface and deep clear 

 waters at Station 45, horizons 5, 19, and 28, are very close to 

 and generally compatible with those of watercontaining diatom 

 particulates. The difference lies in higher values of light 

 scattering indicatrices at small angles (x,i > s 95-105), which, 

 when studied optically, suggest bigger "effective" size of 

 coarse fraction scatterers. It should be mentioned that the areas 

 of relatively clear surface water have been recorded at Stations 

 51,52, 54, 65, and 67. At the areas of its spreading, the average 

 transmittance is somewhat higher, which can be seen in the 

 chart of zonal distribution (Fig. 1. isolines 0.8-0.9 in the 

 eastern part of the region explored). 



142 



