| Section S | S index | 301-309 of 1376 terms |
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shallow fogIn weather-observing terminology, low-lying fog that does not obstruct horizontal visibility at a level 2 m (6 ft) or more above the surface of the earth. This is, almost invariably, a form of radiation fog. Compare ground fog.
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shallow water approximationAn approximation to the equations of motion whereby it is assumed that the fluid is homogeneous and horizontal scales of interest are much larger than the depth of the fluid. See shallow water wave.
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shallow water wave(Also called long wave, Lagrangian wave.) An ocean wave with its length sufficiently large compared to the water depth (i.e., 25 or more times the depth) that the following approximation is valid:  where c is the wave velocity, g the acceleration of gravity, and H the water depth. Thus the velocity of shallow water waves is independent of wavelength L. In water depths between 0.5L and 0.04L it is necessary to use the more precise expression  See deep-water wave, gravity wave.
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shamal(Also called barih; also spelled shemaal, shimal, shumal.) The northwest wind in the lower valley of the Tigris and Euphrates and the Persian Gulf. It may set in suddenly at any time, and generally lasts from one to five days, dying down at night and freshening again by day; however, in June and early July it continues almost without cessation (the “great” or “forty-day” shamal). Although the wind rarely exceeds 13 m s−1 (30 mph), it is very hot, dry, and dusty. The sky is cloudless but the haze is often so thick as to obscure the land, making navigation dangerous.
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sharki(Also spelled sherki, shuquee, shurgee, shurkiya.) Same as kaus.
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