STAND OF TIDE 



motion but maximum horizontal motion. At 

 the antinodes the underlying water particles 

 have no horizontal motion and maximum verti- 

 cal motion. They may be the result of two 

 equal progressive wave trains traveling 

 through each other in opposite directions. (61) 



"V ^"^^ ^-^. »■* -^ ~ 



ir^ >^. ^ 



LEGEND 



PROGRESSIVE WAVE 



REFLEaED PROGRESSIVE WAVE 



RESULTING STANDING WAVE 



ARROWS INDICATE DIRECTION OF WAVES 



FORMATION OF A STANDING WAVE BY REFLECTION OF A 

 PROGRESSIVE WAVE 



(Ana KING. 1962) 



stand of tide — (or stand, tidal stand). The in- 

 terval at high or low water when there is no 

 appreciable change in the height of the tide; 

 its duration will depend on the range of the tide, 

 being longer when the tide range is small and 

 shorter when tlie tide range is large. "Wliere a 

 double tide occurs, the stand may last for sev- 

 eral hours even with a large range of tide. 



starfish — See sea star. 



state of sea — See sea state. 



static instability — See instability. 



station — 1. In oceanography, the geographic loca- 

 tion at which any set of oceanographic observa- 

 tions was taken ; also, the observations recorded 

 at the location. The appropriate verbal phrase 

 is "occupy a station." 



2. In science generally, a permanent or tem- 

 porary location whei*e scientihc observations and 

 measurements are made. 



3. See also serial station, ocean station. 



(5) 

 stationary field — A natural field of force as a 



gravimetric or magnetic field. 

 stationary wave — See standing wave. 



stationary wave theory — A theory which assumes 

 that the basic tide motion in the open ocean con- 

 sists of a system of standing wave oscillations ; 

 progressive waves are of secondary importance 

 except where the tide advances into tributary 

 waters. 



station data — Data collected by an oceanographic 

 ship while taking a station. Station data usu- 

 ally consists of identifying information, weather 

 data, and water temperature, salinity, and chem- 

 ical composition at specified depths. 



statistical oceanography — The study of the 

 oceanic environment by use of statistical meth- 

 ods uninfluenced by physical theories. 



statistical prediction — Prediction of the future 

 state . of the ocean environment by use of ob- 

 served variables which show correlation with 

 unobserved and predictive variables. 



steadiness — See persistence. 



steam fog — (or sea srnhohe; also called arctic sea 

 smoke, arctic smoke, frost smoke, water smoke, 

 sea mist, steam, mist). Fog formed when water 

 vapor is added to air Which is much colder than 

 the vapor's source; most commonly, when very 

 cold air drifts across relatively warm water. 



No matter what the nature of the vapor source 

 (warm water, industrial combustion, exhaust, 

 exhaled breath), its equilibrium vapor pres- 

 sure is greater than that which corresponds to 

 the colder air; thus, the water vapor, upon be- 

 coming mixed with and cooled by the cold air, 

 rapidly condenses. It should be noted that al- 

 though advection of air is necessary to produce 

 steam fog, it differs greatly from an advection 

 fog, in the usual sense, which is caused by warm, 

 moist air moving over a cold surface. 



Steam fog is commonly observed over lakes 

 and streams on cold autumn mornings, as well 

 as in polar regions. It is sometimes confused 

 wdth ice fog, but its particles are entirely liquid. 

 At temperatures below — 20°F, these may freeze 

 into droxtals (ice crystals) and create a type of 

 ice fog which may be known as frost smoke. (5) 



steam mist — See steam fog. 



Stefan-Boltzmann law — (or Stefan's law). 

 One of the radiation laws which states tliat the 

 amount of energy radiated per unit time from a 

 unit surface area of an ideal black body is pro- 

 portional to the fourth power of the absolute 

 temperature of the black body. (5) 



Stefan's law — See Stefan-Boltzmann law. 



stenohaline — Capable of existence only within a 

 narrow range of salinity, as certain marine 

 organisms. 



stenothermic — Tolerant of only a very narrow 

 range of temperature. 



step — The nearly horizontal section which more 

 or less divides the beach from the shoreface. 

 {See figure for shore profile.) 



156 



