CROSSWIND 



COTIDAL CHART 



A. Nodal point; B. Cotidol line; C. Cotidol hour; 



D. Amphidromic region; E. Degenerate omphidromic system 



The lines show the lapse of time, usually in 

 lunar-hour intervals, between the moon's transit 

 over a reference meridian (usually Greenwich) 

 and tlie occurrence of liigli water for any point 

 lying along the line. {See figure for cotidal 

 chart.) 



count — In radiation measurements, the external 

 indication of a device designed to enumerate 

 ionizing events. It may refer to a single de- 

 tected event or to the total registered in a 

 given period of time. The term often is errone- 

 ously used to designate a disintegration, ioniz- 

 ing event, or voltage pulse. (70) 



counter — A special gear box that indicates the 

 amount of oceanographic wire passed over the 

 sheave of the meter wheel. The comiter may be 

 mounted directly on the meter wheel or con- 

 nected by a flexible cable. 



counter current — A current flowing adjacent to 

 tlie main current but in the opposite direction. 



counterradiation — (also called hack radiation). 

 The downward flux of atmospheric radiation 

 passing through a given level surface, usually 

 taken as the earth's surface and, more specifi- 

 cally in oceanography, the sea surface. (5) 



counter resolving time — The minimum time in- 

 terval between two distinct events which will 

 permit both to be counted. It may refer to an 

 electronic circuit, to a mechanical indicating 

 device, or to a counter tube. (70) 



countertrades — See antitrades. 



cove — A small bay or baylike recess in the coast, 

 usually affording anchorage and shelter to small 

 craft. 



crack — Any fracture or rift in sea ice not suffi- 

 ciently wide to be described as a lead (lane). 

 (74) 



cream ice — See sludge. 



creek — A small, narrow bay which extends 

 farther inland than a cove and is longer than 

 it is wide. (68) 



crest — 1. The highest part of a wave. 



2. A narrow rise of more or less irregular 

 longitudinal profile which constitutes the top of 

 an elevation of the sea bottom. (30) 



crest length — See crest width. 



crest of berm — The seaward margin of the berm. 

 {See figure for shore profile.) 



crest of wave — See wave crest. 



crest width — (or crest length). The length of a 

 wave along its crest. (61) 



crinoid — (or sea lily., feather star., sea feather). 

 One of a class (Crinoidea) of echinoderms most 

 of which eitlier permanently or when immature 

 are attached by a long stalk to the bottom ; spe- 

 cies without stalks either creep slowly about or 

 swim. Crinoids occur in shallow water as well 

 as at great depths. About 2,000 fossil species 

 are known. 



crinoidal limestone— /S'ee limestone. 



criquina — See limestone. 



critical damping — The minimum viscous damp- 

 ing that will allow a displaced system to return 

 to its initial position without oscillation. (6) 



critical point — The thermodynamic state in 

 which liquid and gas phases of a substance 

 coexist in equilibrium at the highest possible 

 temperature. At higher temperatures than the 

 critical no liquid phase can exist. (5) 



critical velocity — The speed at which a current 

 can scour the bottom enough to maintain the 

 required deptli in a channel. 



Cro3iwell Current — See Cromwell Under- 

 current. 



Cromwell Undercurrent — (or Cromwell Cur- 

 rent) . An eastward-setting subsurface current 

 that extends about Xy^ degrees north and south 

 of the Equator, and from about 150°E to 

 92 °W. It is 300-kilometers wide and 0.2-kil- 

 ometer thick ; at its core the speed is 100 to 150 

 centimeters per second. 



cross sea — The confused, irregular state of the 

 sea which occurs where waves from two or more 

 different storms have arrived at a point of ob- 

 servation. Sometimes the waves appear to be 

 moving in the same direction as one of the 

 original waves; sometimes in between. (46) 



cross spectrum — Tlie complex vector sum of the 

 cospectrum and quadrature spectrum. 



cross swell — (or intersecting waves). See cross 

 sea. 



cross tide — See beam tide. 



crosswind — Tliat wind vector component which is 

 perpendicular to the course of an exposed 

 moving object. 



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