valuesof Atoassess( e) |,,Jn those regions where no hydrooptic 

 apparatus-assisted measurements have been carried out but a 

 lot of material on white disk obsei^ation exists. 



The value of A for waters of the World Ocean varies from 

 3 to 8 (Ivanov, 1975). However, the calculations made by the 

 author (Levin, 1983) show that under certain "standard" 

 conditions of observation, the range of A depends on the actual 

 variability of optical properties so the range should be narrower. 

 Thus, if the Sun's altitude is more than 60°, and if the disk is 

 observed from the solar board side, the coefficient A for waters 

 having transmitlancy within 5-20 m and oblong indicatrix of 

 scatting (1/k < 0.02). will change almost linearly with the 

 change of probability of photon survival A from 5.1 (with 

 A = 0.06) up to 6.6 (with A == 0.9). Calculations show that the 

 most scattered ocean indicatrices known lower the A value by 

 10%. When the Sun's altitude is 30° and Ais within the same 

 range, the A value must vary from 4 to 5.5 (if observed from the 

 solar side of board) and from 5 to 8.5, when observed from the 

 shadow side. Slight heaving of the sun will lower the A value 

 to 3-5. 



From our apparatus-assisted and visual observations, we 

 can assess the value of the proportionality factor for the waters 

 of northern latitudes. 



Figure 2 shows an experimentally determined function of 

 H,^ in the waters of the Chukchi Sea (triangles), northern area of 

 the Bering Sea (clear circles), and Gulf of Anadyr (solid 

 circles). 



It is obvious that most turbid waters are in the Chukchi Sea 

 (Hf,= 4-10 m), moderately cloudy waters are in the northern 

 area of the Bering Sea ( H^ = 6- 1 6 m), and relatively clear waters 

 are in the Gulf of Anadyr (H^ = 10-24 m). 



Figure 2 illustrates two approximating curves plotted 

 according tot 13) fortwo values of factor A (4.3 and 4.8). It is 

 obvious that clear waters of the Bering Sea are more accurately 

 described by (13) when A = 4.3 and turbid waters of the 

 Chukchi Sea at A = 4.8. Discrimination, as manifested by the 

 above-given assessments from the paper (Levin, 1983), may 

 possibly be an evidence of different correlation between 

 absorbing and scattering abilities of suspended matter in different 

 areas. However, this fact can more reliably be borne out by 

 numerous apparatus-assisted and visual observations. 



Eh-I'^ 1 





 Fig. 



E,\penmentally found function of H^^ in the waters of the Chukchi Se 

 (A), northern area of the Benng Sea ( O) and Gulf of Anadyr (•). 



At this stage, the average value of A for northern areas is 

 equal to 4.5. 



As mentioned earlier, the transmittance of water in the 

 blue-green field of spectrum will depend mostly on the amount 

 of particles present in the water. In productive areas of the 

 ocean, the bulk mass of suspended matter is made up of 

 phytoplankton. Optically, the type of algae can be defined by 

 size, shape, and index of refraction. These characteristics 

 directly affect the angular structure scattered radiation. The 

 bigger size of biological particles and the higher their content 

 in the total composition of suspended matter, the more forward- 

 extended is the water scattering indicatrix and the higher the 

 values of its integral characteristics — asymmetry factor K, 

 mean cosine of scattering angle c"os"y, and portion of light R, 

 scattered in the minor "forward" angle. 



As waters are carried over by currents from the regions 

 where they formed, the conditions of suspended matter alter, 

 due to the content changes and composition transformers. It is 

 clear that since the latter of the two processes is more inertial, 

 the angular characteristics of light scattering are inore 

 conservative as compared with water transmittance. In this 

 connection, it seems reasonable to determine the totality of 

 angular and integral characteristics that are typical of water in 

 which some species of algae prevail (some peculiar features of 

 such algae being quite typical) and then to employ these 

 characteristics as an indicator for identifying this type of water 

 in the process of its propagation. The transmittance field 

 correlates over lesser areas and can be used to give details in the 

 processes of synoptic nature. 



Bearing in mind the aforesaid, let us now turn directly to 

 analyzing the experimental data. We shall begin our review 

 with considering the cross sections of transmittance field in the 

 northern waters moving from to lower to higher latitudes. 



Gulf of Anadyr 



The crosscurrent Hows northwardly through this region 

 (Sukhovey. 1986). We shall assume that waters at the starting 

 points ofthe area underconsideration are of Pacific origin. The 

 upper layer of water between 60° and 62° north latitude 

 showed clear water in all quasi-latitudinal sections. Such water 

 followed bottom relief and gradually ascended from 100 to 

 60 m. Beginning approximately from 62°N, the clear water 

 mass was split by a subsurface maximum of cloudiness, 

 propagating northward, to the Gulf of Anadyr. 



As proved by the analysisof angular and integral 



characteristics of light scattering, the waters in the area under 



investigations have high values of asymmetry factor 



(K = 80- 1 20) and mean cosine (0.95-0.96), an indication ofthe 



presence of coarse biological particles. Theirrelative volumetric 



content amounts to 88-92%. A cross section at nearly 63°N 



(Station 24) has an unusual transmittance structure of water 



(Fig. 3). In this and other figures, the solid circles show the 



horizons from which water assays were taken to assess light 



scattering data. Station numbers and depths from which assays 



have been taken are given in the figures. In the left-hand 



column are the asymmetry factor K , relative to volumetric 



content of suspended matter fine fraction: 



P= '^f ; R {Yo=2), 

 V, + V,. 



139 



