DYNE 



a function of the state of the science rather than 

 of the subject matter itself. 



dynamic prediction — Methods of predicting the 

 future state of the environments by using physi- 

 cal models — as opposed to empirical or statistical 

 methods. 



dynamic theory — A theory considering the hori- 

 zontal tide-producing forces to be the most im- 

 portant factor in causing movement of water. 

 The vertical tide-producnig forces are simply 

 considered small periodical variations in the 

 acceleration of gravity. 



dynamic topography — The configuration formed 

 by the geopotential difference or dynamic 

 height (measured in dynamic meters) be- 

 tween a given isobaric surface and a reference 

 surface (for example, in the ocean the 2,000- 

 decibar surface). A topographic chart formed 

 may be used in determining geostrophic cur- 

 rents within the oceans. The current along the 

 isopleths of dynamic height must be considered 



to move relative to the motion of the water at 

 the reference surface. If the water at the refer- 

 ence surface has no motion, the current direction 

 along the isobaric surface is considered 

 absolute. 



dynamometer — (sometimes called strain gauge). 

 An instrument used in bottom sampling or other 

 oceanographic operations to indicate that bot- 

 tom has been reached. The instrument meas- 

 ures variations on wire tension and is only 

 effective to depths where the tension due to the 

 weight of the sampling device is somewhat 

 greater than the tension caused by the weight 

 of the lowering cable and the variable loads 

 produced by ship motion. 



dyne — A force which, acting on a mass of one 

 gram, imparts to that mass an acceleration of 

 one centimeter per second per second. See gal. 

 The dyne is the unit of force of the cgs sys- 

 tem. Since 1930, gravity has been reported in 

 terms of the gal, rather than the dyne. ( 37 ) 



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