CURRENT VECTOR 



current vector — A geometric presentation show- 

 ing both current direction and speed, generally 

 by an arrow whose length is proportional to 

 the speed and whose direction is resolved into 

 points of the compass. 



current velocity — A rate of motion in which di- 

 rection as well as speed of flow is considered. 

 See current speed. 



curved path theory — A method for the analysis 

 and plotting of seismic data which allows for 

 the curvature of ray paths, resulting from in- 

 creasing velocities with depth in the earth. 

 (35) 



curve fitting — (also called graduation). The ap- 

 propriate representation of empirical data by a 

 mathematical function, typically with arbitrary 

 constants determined by least squares. (5) 



cushion ice — Fine fragmented ice found between 

 ice floes. It has the eifect of cushioning the 

 impact of floes on each other. (Rare) 



cusp — See beach cusp. 



cuspate bar — A crescent-shaped bar uniting with 

 the shore at each end. It may be formed by a 

 single spit growing from shore turning back to 

 again meet the shore, or by two spits growing 

 from shore uniting to form a bar of sharply 

 cuspate form. (61) 



cut — A notch, depression, or furrow produced by 

 erosion or excavation of a slope. Many cuts of 

 this type occur on the upper portion of a con- 

 tinental shelf. 



cutting edge — See core cutter. 



cycle — 1. One complete and consecutive set of all 

 the changes which occur in a recurrent action or 

 phenomenon, starting from any point in the 

 action and ending with all conditions as they 

 were at the start. 



2. A unit of wave frequency, actually one cycle 

 per second. 



(5) 

 cycloidal wave — A very steep, symmetrical wave 



whose crest forms an angle of 120 degrees. The 



wave form is that of a cycloid. A trochoidal 



wave of maximum steepness. (61) 



cyclone — An atmospheric cyclonic circulation, a 



closed circulation. A cyclone's direction of ro- 



tation (counterclockwise in the Northern Hem- 

 isphere) is opposite to that of an anticyclone. 



Because cyclonic circulation and relatively 

 low atmospheric pressure usually coexist, the 

 term cyclone and low are used interchangeably 

 in common practice. (5) 



cyclonic — Having a sense of rotation about the 

 local vertical the same as that of the earth's rota- 

 tion: that is, as viewed from above, counter- 

 clockwise in the Northern Hemisphere, clock- 

 wise in the Southern Hemisphere, undefined at 

 the Equator ; the opposite of anticyclonic. (5) 



cylindrical projection — A map projection in 

 which the surface of a sphere is conceived as 

 projected, in the geometrical sense, on a tangent 

 cylinder, which is then developed on the plane. 



cylindrical spreading — See spreading of sound. 



cylindrical wave — A wave in which the instan- 

 taneous free surface of the fluid takes the shape 

 of a cylindrical surface with the horizontal gen- 

 eratrices describing the profile of the wave. 



cyphonautes larva — The planktonic triangular- 

 shaped young of a bryozoan, which is enclosed 

 in a bivalve shell. 



cyprid larva — (or cypris). The stage at which 

 the young of barnacles attach. 



cypris — See cyprid larva. 



CUSPATE BAR 



(Ul, TI-4, )934| 



44 



