448 TYLER A2SrD PREISENDOKFER [CHAP. 8 



B. Photosynthesis and Other Biological Phenomena 



The phytoplankton productivity of various areas of the ocean and the total 

 standing crop at any location are intimately associated with the amount of 

 light available for photosynthesis. It is well known that an increase in micro- 

 organisms is associated with a change in optical properties. Thus it is to be 

 expected that correlation will be found between light measurements and 

 nutrient concentration, or temperature. 



This work is reported by Clarke and Denton (page 456). 



C. Image- Recording Equipment 



In image -recording equipment like the human eye, the camera or television 

 apparatus, a prime optical requisite for useful operation, is adequate contrast 

 from the object. The theoretical work of Duntley (1952) and Preisendorfer 

 {loc. cit.) clearly shows the degenerative effect of the ocean environment on 

 object contrast as it is seen by such equipment, and provides means for com- 

 puting contrast under specified circumstances. 



The methods are discussed by Duntley (page 452). 



13. List of Symbols 



N Radiance 



Nq Inherent radiance 



Nf Apparent radiance 



N(p, 6, (f>) Field radiance at point p arriving from direction 6, cf) 



N{p, 6', (f>') Field radiance at point p arriving from direction 6' , (f)' 



Ni*{d) Field radiance for path of sight I at angle 6 from beam of light 



iV^ Path function 



iV^(^) Path function — radiance per unit length in direction 6 generated by 



scattering 



N*{p, 0, (f>) Path function at point p observed in direction 6, <f> 



H Irradiance 



H{Z, + ) Upwelling irradiance 



H{Z, — ) Downwelling irradiance 



H{Z, + ) Net upwelling irradiance 



dH(Z, + ) Net upwelling irradiance 



h Scalar irradiance 



h{p) Scalar irradiance at point p 



h{Z, + ) Upwelling scalar irradiance 



h(Z, — ) Downwelling scalar irradiance 



h(Z) Scalar irradiance at depth Z 



h/\^T, Spherical irradiance 



h^nip) Spherical irradiance at point p 



P Flux 



P{p, 6, (f)) Flux at point p observed in direction 6, cf) 



a Total attenuation coefficient 



a{Z, ± ) Total attenuation coefficient for up ( + ) and down ( — ) streams of flux 



a Absorption coefficient 



a(Z) Absorption coefficient at depth Z 



a{Z,±) Absorption coefficient for up ( + ) and down ( — ) streams of flux 



