CHAPTER 16 



FUNDAMENTALS OF OCEANOGRAPHY 



In previous chapters of this training 

 manual information has been presented on a 

 few of the oceanographic instruments which 

 may be encountered by the Aerographer's 

 Mate, including the rules to be followed when 

 disseminating and recording the data after it 

 was obtained. Tiis chapter will discuss, briefly, 

 some of the surface and subsurface properties 

 of the oceans. 



It should be remembered that just as a 

 study of the entire surrounding atmosphere is 

 necessary in meteorological forecasting, any 

 serious study of the sea must also include 

 ALL of the surface and subsurface elements 

 of the environment. This is normally true even 

 though only one or two of the many elements 

 involved may be of use to the particular 

 operation. The surrounding environment is 

 going to have an effect on the elements being 

 observed. 



AMBIENT NOISE. — Noise produced in the 

 sea by waves, marine animals, ship and 

 industrial activity, terrestrial movements, 

 precipitation, and other underwater or surface 

 activity. 



ANGLE OF INCIDENCE. — The angle at which 

 a ray of energy intersects a surface, measured 

 between the direction of propagation of the 

 energy (or object) and a perpendicular to the 

 surface at the point of intersection, or incidence. 



ARC. — The curved area of a ridge which 

 rises above sea level. 



ATTENUATION. — A general term applied to 

 sound, referring to the loss of energy due to 

 absorption and scattering. 



BASIN. — A large depression in the ocean 

 bottom of more or less circular or oval form. 



OCEANOGRAPHIC TERMINOLOGY 



As with any scientific field of study, there 

 are many oceanographic terms which the trainee 

 will be unfamiliar with. Only a very few are 

 included in the following paragraphs, since it 

 is desired to confine the material to the basic 

 fundamentals. Some of the terms which will 

 be encountered in various sections of this 

 chapter are as follows: 



ABSORPTION. — When a sound wave travels 

 outward from a source into the sea, some of 

 the sound energy is converted into heat by 

 friction due to molecular resistance of the 

 water, thereby decreasing the intensity of the 

 sound wave. This process is called absorption. 



AIR-SEA INTERFACE. — The boundary be- 

 tween the atmosphere and the surface of the 

 ocean. 



BOTTOM SEDIMENTS. — Unconsolidated bot- 

 tom materials; all naturally occurring uncon- 

 solidated matter which comprises the sea bottom 

 and which consists of discrete particles of any 

 size or origin. 



BOTTOM WATER. — The water mass at the 

 deepest part of the water column. It is the 

 densest water that is permitted to occupy that 

 position by the regional topography. 



DEEP. — A depression 

 exceeding 6,000 meters. 



in the ocean bottom 



DEEP WAT3R. — The water mass normally 

 found above bottom water. Deep water normally 

 begins at the base of the main thermocline. 



ISOHALINE. — Having no change in salinity 

 along a given reference plane. (Equal salinity.) 



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