SAND HORN 



sand horn — A pointed sand deposit extending 

 from shore into shallow water. See also sand 

 lobe. (2) 



sand lobe — A rounded sand deposit extending 

 from shore into shallow water. See also sand 

 horn. (2) 



sand reef — See bar. 



sandstone — (also called arenite, arenyte, psam- 

 mite, psammyte). Rock composed of cemented 

 sand sized grains, predominantly quartz. 



sand wave — See megaripple. 



saprolith — See regolith. 



sapropel — An aquatic ooze or sludge that is rich 

 in organic matter. ( 2 ) 



saprophytic nutrition — That process by which an 

 organism absorbs organic food from its sur- 

 roundings, usually after digesting it externally. 

 See heterotrophic nutrition. 



sargasso — 1. S&e Sargassum. 



2. Loosely, a large floating mass of seaweed. 

 (68) 



Sargasso Sea — The region of the North Atlantic 

 Ocean to the east and south of the Gulf Stream 

 system. This is a region of convergence of the 

 surface waters and is characterized by clear, 

 warm water, a deep blue color, and large quan- 

 tities of floating Sargassum or gulf weed. (5) 



sargasso weed — See Sargassum. 



Sargassum — ( or gulf weed, sargasso weed) . 1. A 

 genus of brown algae. 



2. The common name of a plant of this genus, 

 characterized by a bushy form, a substantial 

 holdfast when attached, and a yellowish brown, 

 greenish yellow, or orange color. Species of 

 the group have a large variety of forms and are 

 widely distributed in warm seas as attached and 

 free-floating plants. Two species {S. fluitans 

 and S. Tiatans) make up 99 percent of the macro- 

 scopic vegetation in the Sargasso Sea. 



sastrugi — Wavelike ridges of hard snow formed 

 on a level surface by the action of the wind. 

 (65) 



satin ice — See acicular ice. 



saturation — The condition in which the partial 

 pressure of any fluid constituent is equal to its 

 maximum possible partial pressure under the 

 existing environmental conditions, such that any 

 increase in the amount of that constituent will 

 initiate within it a change to a more condensed 

 state. In molecular-kinetic terms, saturation is 

 attained when the rate of return of molecules of 

 a substance form the dissolved liquid or vapor 

 phase to the more condensed parent phase is 

 exactly equal to the rate of escape of molecules 

 from the parent phase. (5) 



saturation vapor pressure — 1. The vapor pres- 

 sure of a system, at a given temperature, where- 

 in the vapor of a substance is in equilibrium with 

 a plane surface of that substance's pure liquid or 

 solid phase ; that is, the vapor pressure of a sys- 

 tem that has attained saturation but not super- 

 saturation. The saturation vapor pressure of 



any pure substance, with respect to a specified 

 parent phase, is an intrinsic property of that 

 substance, and is a function of temperature 

 alone. 



2. See equilibrium vapor pressure. 



(5) 



Savonius rotor current meter — A low-thresh- 

 hold current speed sensor composed of two 

 semicyUndrical vanes disposed to form an S- 

 shaped rotor responsive to a wide spectrum of 

 horoizontal flow components. Present instru- 

 ments generally utilize paired Savonius rotors 

 with axes displaced by 90 degrees for a more 

 nearly uniform omnidirectional torque distribu- 

 tion. (19) 



scalar irradiance — A quantitative measure of the 

 total radiant flux arriving at a point for all 

 directions about a point. It is the measure of 

 the amount of radiant energy per unit volume 

 of space at a given point. 



scalar mean — See mean current. 



scale — The ratio between the linear dijnensions of 

 a chart, drawing, etc., and the actual dimensions 

 of the <jbject represented, expressed as a propor- 

 tion. Chart or map scales are conventionally 

 classed as large (larger than 1 : 1,000,000), me- 

 dium (1:600,000 to 1:1,000,000), or small 

 (smaller than 1 : 600,000} . 



scale error — See calibration error. 



scaler — ^An electronic device which registers cur- 

 rent pulses received over a given time interval. 

 (70) 



scaphopod — See tooth shell. 



scarp — See escarpment. 



scatterance — The ratio of the radiant flux scat- 

 tered from a beam, to the incident flux. (8) 



scatterance meter — An assembly of a coUimated 

 light source and a radiance meter which di- 

 rectly measures the scatterance values of an 

 optical medium. Scatterance meters fall into 

 three main classes : free- angle, fixed-angle, and 

 integrating scatterance meters. The first type 

 is designed to determine in principle all values 

 of the volume scattering function at a given 

 point; the second is designed to determine the 

 fimction for a fixed angle; and the third type 

 is designed to integrate directly the function 

 over all angles so as to record the total scatter- 

 ing coefficient. (8) 



scattered ice — (also called sailing ice). Sea ice 

 that covers from 1- to 5-tenths of the sea surface. 



(65) 

 Note: This term is being superseded by the 



WMO term "very open pack ice". 



scattering — 1. The random dispersal of sound 



energy after it is reflected from the sea surface 



or sea bottom and/or off the surface of solid, 



liquid, or gaseous particles suspended in the 



water. 



2. The dispersion of light when a beam strikes 



very small particles suspended in air or water. 



140 



