Light energy, passing through layers of air, water and ice, is not only absorbed but also 

 scattered. 



The coefficient of scattering for slightly turbid media is inversely proportional to the fourth 

 power of the wavelength. Hence, it follows that the longer the wave, the less it will scatter, i.e. , 

 this is the opposite of what takes place for absorption in the light part of the spectrum. With an 

 increase in the size of the particles in any medium, the exponent decreases with wavelength, and 

 when the particles are quite large and the light ray is both reflected from the surface of the parti- 

 cles and is absorbed by the particles, the exponent becomes zero, i.e. , scattering becomes inde- 

 pendent of wavelength. 



The heat, light and color regimes of the ocean and the atmosphere are determined by the 

 selectivity of the absorption process and by the combined effect of absorption and scattering. 



It is very important that the dark, loi^-wave rays in which up to 60 per cent of the thermal 

 energy is concentrated are absorbed in the uppermost layers of the ocean. At a depth of 1 cm, the 

 thermal effect of solar energy is approximately 94 times less than at the water surface, while at a 

 depth of 1 m it is 8,350 times less. Light penetrates to the ocean depths, but the heat is absorbed 

 by the surfacemost layers. This shows that the ocean would be practically unheated, if various 

 factors did not cause mixing of its upper layers. 



Since in clear or slightly turbid media, the short rays are the ones most scattered, the 

 clearer the medium, the fewer the particles, and the fewer the particles per unit volume, the bluer 

 the medium appears. This explains the blue color of the sky, water, ice, smoke, etc. On the 

 other hand, scattered light does not change color with an increase in the size of foreign inclusions. 

 This explains the white color of clouds and mists, the droplet sizes of which are considerable in 

 comparison with the size of the light waves. 



In the ocean itself, as observations have shown, the intensity of illumination decreases rap- 

 idly with depth due to selective absorption and scattering: the twilight which prevails even at moder- 

 ate depths keeps deepening, the green becomes light blue, dark blue, violet, and at great depths 

 there is complete darkness. 



Neither the transparency nor the color of the sea is connected with either temperature or 

 salinity, but is a function exclusively of the size and number of impurities of organic and inorganic 

 origin. Therefore, the sea, as a rule, is transparent and blue far from shore, and becomes less 

 transparent closer to shore, taking on a greenish-brovra hue. The water in shallows and off shore 

 becomes considerably less transparent after storms. 



Sea ice and glacier ice always contain organic and inorganic impurities. Therefore, in 

 regions where ice melts, transparency always decreases and the color of the sea becomes green. 

 This is further intensified by the vigorous growth of microscopic algae, which always accompanies 

 melting. Further, myriads of tiny air bubbles trapped in the ice enter the water when the ice 

 melts. These bubbles, remaining in a suspended state for a long time and decreasing transparency, 

 give the water a whitish tint, although preserving its basic color. When glacier ice melts, the so- 

 called glacier milk affects the color of the sea, giving it a whitish-light blue tint. On the other 

 hand, amid non-melting ices, due to the singular purification of the sea by vertical circulation, the 

 sea is very transparent in the ice-formation period and approaches a dark blue color. 



LITERATURE: 62, 73, 77. 



21 



