characterized by a spatial or temporal distribution 

 of amplitude of some specified characteristic dif- 

 fering from that of the individual superposed waves. 

 (2) 



WAVE LENGTH . 1. The wave length of a periodic 

 wave in an isotropic medium is the perpendicular 

 distance between two wave fronts in which the 

 displacements have a difference in phase of one 

 complete period. (2) 



2, The horizontal distance between 

 successive ocean wave crests or the distance in 

 meters traveled by a wave during the time interval 

 of one complete cycle. It is equal to the velocity 

 divided by the frequency. (36) 



WAVE NUMBER . The reciprocal of wave length; the 

 number of waves per unit distance in the direc- 

 tion of propagation; or, frequently, 2v times 

 this quantity. Thus, in the simple harmonic com- 

 ponent sin k(x - ct) , the wave number is am- 

 biguously k or k/2T . (12) 



WAVE OF TRANSLATION . A wave in which the indivi- 

 dual particles of the medium are shifted in the 

 direction of wave travel, as ocean waves in shoal 

 waters; in contrast with an OSCILLATORY WAVE, in 

 which only the form advances, the individual par- 

 ticles moving in closed orbits, as ocean waves in 

 deep water. (17) 



WAVE PERIOD . In a train of identical waves the 

 period Is the time elapsed between the passage of 

 a given phase on one wave and the arrival of the 

 same phase on the next succeeding wave, as observed 

 from a fixed station. 



WAVE PROPAGATION . The radiation, as from an an- 

 tenna of r-f energy into space, or of sound energy 

 into a conducting medium. (10) 



WAVE SPECTRUM . In oc»an wave studies, a graph 

 showing the distribution of wave heights with 

 respect to frequency in a wave record. (12) 



WAVE SPEED . See PHASE SPEED. 



WAVE STEEPNESS . Of a water-surface wave, the 

 ratio of wave height to wave length. (12) 



WAVE SYSTEM . In ocean wave studies, a group of 

 waves having the same height, direction, and length. 

 Ocean surface waves are generally composed of a 

 number of superimposed wave systems. (12) 



WAVE VELOCITY . Wave velocity is a vector quantity 

 that specifies the speed and direction with which a 

 sound wave travels through a medium. (2) 



WB . U. S. Weather Bureau. 



W/D . Weight-displacement ratio. 



WDC . World Data Center. 



WEATHER PATROL SHIP . See OCEAN STATION VESSEL. 



WEATHER SHIP . See OCEAN STATION VESSEL. 



WEDGE . See RIDGE. 



WEST AUSTRALIA CURRENT . A seasonal Indian Ocean 

 current flowing along the west coast of Australia. 

 In the northern hemisphere winter it flows north- 

 ward from off Cape Leeuwin to Northwest Cape, where 

 it curves northwestward to continue as part of the 

 SOUTH EQUATORIAL CURRENT. The west Australia cur- 

 rent is formed from the northern part of the west 

 wind drift current and a current setting westerly 

 along the south coast of Australia, and is the 

 eastern part of the general counterclockwise 



oceanic circulation of the southern part of the 

 Indian Ocean. In the northern hemisphere summer, 

 this northward flowing current is replaced by a 

 southwesterly and southerly flow from the Arafura 

 Sea to the vicinity of Cape Leeuwin, where it 

 merges with the WEST WIND DRIFT CURRENT. (17) 



WESTERLIES . 



Specifically: the dominant west- 



to-east motion of the atmosphere, centered over 

 the middle latitudes of both hemispheres. At the 

 earth's surface, the westerly belt extends, on the 

 average, from about 35° to 65° latitude. At upper 

 levels, the westerlies extend farther equatorward 

 and poleward . The equatorward boundary is fairly 

 well defined by the SUBTROPICAL HIGH-PRESSURE BELT; 

 the poleward boundary is quite diffuse and variable. 



2. Generally, any winds with components from 

 the west. (14) 



WEST GREENLAND CURRENT . An Atlantic Ocean current 

 flowing northwestward and northward along the south- 

 west and west coast of Greenland from off Cape 

 Farewell, the southern tip of Greenland, through 

 Davis Strait and into Baffin Bay. The west Green- 

 land current is the continuation, along the west 

 coast of Greenland, of the EAST GREENLAND CURRENT, 

 (17) 



WESTON PHOTRONIC CELL . See BARRIER LAYER CELL. 



WEST WIND DRIFT CURRENT . A circumpolar ocean cur- 

 rent flowing eastward around Antarctica, and hav- 

 ing its northern limits determined by the southern 

 limits of Australia, New Zealand, South America, 

 and Africa, and by the general oceanic circulation 

 of the South Pacific, South Atlantic, and Indian 

 Oceans. The west wind drift current is fed by 

 several southward flowing currents, and in turn, 

 it augments certain northward flowing currents, 

 notably the PERU CURRENT of the South Pacific 

 Ocean and the BENGUELA CURRENT of the South Atlan- 

 tic Ocean. That part of the west wind drift cur- 

 rent flowing eastward in the immediate vicinity of 

 Cape Horn is called CAPE HORN CURRENT. (17) 



WEST WIND DRIFT . 

 CURRENT) 



(see ANTARCTIC CIRCUMPOLAR 



WET-BULB TEMPERATURE . 1. Isobaric wet -bulb temper- 

 ature: The temperature an air parcel would have if 

 cooled adiabatically to saturation at constant pres- 

 sure by evaporation of water into it, all latent 

 heat being supplied by the parcel. 



2. Adiabatic wet-bulb temperature (or pseudo 

 wet-bulb temperature): The temperature an air 

 parcel would have if cooled adiabatically to satu- 

 ration and then compressed adiabatically to the 

 original pressure in a saturation-adiabatic process. 

 This is the wet-bulb temperature as read off the 

 thermodynamic diagram and is always less than the 

 isobaric wet-bulb temperature, usually by a frac- 

 tion of a degree centigrade. 



3. The temperature read from the wet-bulb 

 thermometer (See PSYCHROMETER) . The thermodynamics 

 of this thermometer is still under discussion, but 

 for practical purposes the temperature so obtained 

 is identified with the Isobaric wet-bulb tempera- 

 ture. (14) 



WET DENSITY . Of a bottom sediment sample is the 

 ratio of the weight of the sample to its volume. 

 (15) 



WET DOCK . See DOCK. 



WET SUIT. See RUBBER SUIT. 



WHARF . A structure serving as a berthing place 

 for vessels . A wharf approximately parallel to 

 the shore line, accommodating ships on one side 

 only, and usually of solid construction, as dis- 

 tinguished from open pile construction, is called 



xa8 



