WMO CODE 



white water — 1. Frothy water as in whitecaps or 

 breakers. 



2. Light-colored water over a shoal. 

 (68) 



Wien's law — One of tlie radiation laws which 

 states that the wavelength of maximnm radia 

 tion intensity for a black body is inversely pro- 

 portional to the absolute temperature of the 

 radiating black body. (5) 



wind chill — That part of the total cooling of a 

 body caused by air motion. (5) 



wind-chill factor — See wind-chill index. 



wind-chill index — (also called w'md-chUl factor) . 

 The cooling effect of any combination of tem- 

 perature and wind, expressed as the loss of body 

 heat in kilogram calories per hour per square 

 meter of skin surface. The wind-chiU index is 

 based on the cooling rate of a nude body in the 

 shade; it is only an approximation because of 

 individual body variations in shape, size, and 

 metabolic rate. (5) 



wind chop — See chop. 



wind direction — The direction from which the 

 wind blows. (68) 



wind drift — 1. See drift current, wind-driven 

 current. 



2. That portion of the total vector drift of sea 

 ice from which the effects of the current have 

 been subtracted. 



wind-driven current — (sometimes called lolnd 

 driftj drift current). A current formed by the 

 fore* of the wind. Theoretically, currents pro- 

 duced by the wind will set to the right of the 

 direction of the wind in the Northern Hemi- 

 sphere and to the left in tlie Southern Hemi- 

 sphere. See Ekman spiral. 



wind mixing — Mechanical stirring of water due 

 to motion, induced by the surface wind. Simi- 

 lar to mechanical mixing. 



window — An unfrozen portion of a river, which 

 remains unfrozen all or part of the winter be- 

 cause of a strong current or a local inflow of 

 warm water. (59) 



wind rose — 1. A diagram showing the relative 

 frequency of winds blowing from different di- 

 rections. It may also show average speed or 

 frequency of occurrence of various speeds from 

 different directions. 



2. A diagram showing the average relation be- 

 tween winds from different directions and the 

 occurrence of other meteorological phenomena, 

 such as rain. (68) 



wind set-up — 1. The vertical rise in the still water 

 level on the leeward side of a body of water 

 caused by wind stresses on the surface of the 

 water. 



2. The difference in still water levels on the 

 windward and the leeward sides of a body 

 of water caused by wind stresses on the surface 

 of the water. 



3. Synonymous with wind tide. Wind tide is 

 usually reserved for use on the ocean and large 



bodies of water. Wind set-up is usually reserved 

 for use on reservoirs and smaller bodies of water. 

 See meteorological tide. 

 (61) 



wind stress — The force, per unit area, of the wind 

 acting on the water surface to produce waves and 

 currents; its magnitude depends on the wind 

 speed, air density, and roughness of the water 

 surface. 



wind tide — See wind set-up, meteorological tide. 



windward — The direction from which the wind is 

 blowing. (61) 



wind wave — A wave resulting from the action of 

 wind on a water surface. While tlie wind is 

 acting on it, it is a sea, thereafter, a swell. See 

 fetch. (5) 



winged headland — A seacliff with two bays or 

 spits, one on either side. (2) 



Winkler method — A chemical method for esti- 

 mating the dissolved oxygen in sea water. In 

 this method manganous hydroxide is allowed to 

 react with the oxygen of the sample to i^roduce a 

 manganese compound which in the presence of 

 acid potassium iodide liberates an equivalent 

 quantity of iodine that can be titrated with 

 standard sodium thiosulphate. 



winnow — In regard to current action, to sort se- 

 lectively and carry oiT fine sediment grains from 

 a heterogeneous sediment deposit, leaving the 

 coarse grains. 



winter drift ice — Drift ice composed exclusively 

 of winter ice. 



winter fast ice — 1. Fast ice in fiords, gulfs, and 



straits, mainly formed by growth from the shore, 



but also by cementing of pack ice. AVinter fast 



ice rises and falls according to the tide. (74) 



2. Fast ice made up of winter ice. 



winter ice — 1. Generally unbroken level ice of less 

 than one winter's growth. It is between 15 

 centimeters and 2 meters (6.0 inches to 6.6 feet) 

 thick. See medium winter ice, thick winter 

 ice. 



2. Sea ice more than eight inches thick and 

 less than one year old; the stage which follows 

 young ice. 



winter solstice — For either hemisphere, the sol- 

 stice at which the sun is above the opposite 

 hemisphere. In northern latitudes, the time of 

 this occurrence is approximately 22 December. 

 (5) iS'ee solstice. 



wiping — See flashing. 



wire angle — The angle measured between the 

 oceanographic wire and the vertical. 



wire angle indicator — A device used to measure 

 the angle of the oceanographic wire from the 

 vertical. It consists of a protractor with a 

 weighted plumb arm. The indicator is sus- 

 pended from the wire at two jwints and the 

 plumb arm points to the wire angle. 



WMO Code — An international nomenclature 

 adopted by the World Meteorological Organiza- 

 tion for use by all reporting nations. 



183 



