potentially can be affected anthropogenically), we can draw 

 conclusions about the extent of pollution and to monitor its 

 dynamics. 



The paper presents the results of complex hydrooptical 

 studies in the waters of the Bering and Chukchi Seas, The main 

 objective pursued was to study spatial and time variability of 

 hydrooptical characteristics and their correlation with biological 

 and microphysical parameters of particulates. 



Hydrooptical Quantities — Definitions 



Distribution of light in the ocean water is a function of its 

 absorption and scattering. These phenomena can (neglecting 

 polarization) be fully described by three primary hydrooptical 

 quantities; 1. indices of absorption k; 2. scattering cr, and 

 3. the angular dependence of scattering, x(Y) indicatrix. 



If a collimated monochromatic beam of light is incident 

 along an axis (1) traveling through a small volume dV=dSdl in 

 the medium, this beam passes in solid angle, dw and creates 

 illumination E„(dS ) on an area normal to the beam. The amount 

 of flux absorbed by the volume will be proportional to 



dF=KE„dSdl 



(1) 



Proportionally factor k is known as the coefficient of absorption, 

 its dimension is M ' ". The scattering index cr. 



dF =aE„dSdl . 



(2) 



so that the full value of flux, scattered and absorbed on its path 

 dl, will equal equations ( 1 ) and (2): 



dF=dF,+dF =(K+o)E„dSdl^E„dSdl . 



(3) 



The sum of absorption k and scattering o indices is known as 

 attenuation index 8 , and the relationship A=5/e is the probability 

 01 photon survival. The dimension of attenuation index is 

 e[M ']. T=e' defines the transmissivity of a water layer 1-m 

 thick, also referred to as transparency of water. 



Expression (3) is a differential fonn of Bouguer's Law, 

 according to which any flux that has travelled in a scattering 

 and absorbing medium, is attenuated (hereinafter we shall 

 consider the values of relevant indices determined to the In 

 base): 



F(l)=F(o)exp(£l). 



(4) 



Scattering of light varies with direction. A flux of light, 

 scattered in a single solid angle (or intensity of light dl) in a 

 direction, making up angle y with axis 1, will be proportional to 

 the value of volume dV of flux; 



dI(Y)-C(Y)E„dV. 



(5) 



Proportionality factor cs(y ) is ternied as the index of directed 

 scattering and has the direction [ M ' ster ' ] ■ Scattered ( radiation 

 diffused) is known as the indicatrix of scattering: 



X(Y)= 0(Y) ■ <6) 



o 

 SinceJ /(y) dw= I, it can be treated as three-dimensional density 

 of probability of photon scattering at some angle (y ) with 

 respect to the direction of light propagation. 



Often used in hydrooptics are the so-called integral 

 quantities — indices of scattering in front (6) and back ((i) 

 hemispheres: 



5=27tl C3(7)sinYdY, 



P = 2rtj cXyJsiuYdY 



kI2 



(7) 



(8) 



and their ratio K=5/p, called the asymmetry factor. The extent 

 of isotropy of scattering is defined by the mean cosine of 

 scattering: 



c5sY = 2jrI x(Y)sinYCOSYdY 



(9) 



Parameters K and cosy characterize indicatrix "stretching," 

 which increases with the increase of particle sizes. The 

 anisotropy of scattering will also be characterized by 



R(YJ = 27i1 x(Y)sin(Y)dY. 



(10) 



determining a part of radiation scattered into solid angle with 

 angular opening from to y,,- Let us take 2° for Yo- 



Hydrooptic Instruments 



Critical for making complex hydrooptical measurements 

 //( situ is their synchronism. The apparatus complex, used by 

 us, made it possible to realize this principle with the help of 

 rather simple technical means. The complex included an 

 immersible transmittance meter with a bathometer and a board 

 meter of angular light scattering indicatrix-meter. First, a 

 vertical profile attenuation index e of water was measured, and 

 second, the angular characteristics of light scattering (C5( y ) ) of 

 samples were taken from different horizons. 



The photometer/transmittance meter used was a 

 '■Kvant-3." The optical-mechanical and electronic units of the 

 instrument are accommodated inside a hermetic case, which, 

 via traction and electric connectors, is connected with a double 

 cable-line, type KF 7-90-180. The meter measures and 

 compares the intensity of light flux before and after its passing 

 through a layer of certain thicknesses 1 ( defined by the instrument 

 measurement base). This principle of measurement is realized 

 as follows: formed by corresponding elements of the optical- 

 mechanical unit, a probing beam of light is emitted through a 



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