60 minutes. It is of low height; usually less than 

 0.3 foot. (2) in fluid flow, long interval varia- 

 tions in velocity and pressure, not necessarily 

 periodic, perhaps even transient in nature. (11) 



3. The fore and aft movement of the center 

 of gravity of a ship. 



4. Water transported up a beach by break- 

 ing waves . (12) 



SURGE. STORM . That rise above normal water level 

 on the open coast due only to the action of wind 

 stress on the water surface. Storm surge resulting 

 from a hurricane also includes that rise in level 

 due to atmospheric pressure reduction as well as 

 that due to wind stress. (11) 



SWASH MARK . The thin wavy line of fine sand, mica 

 scales, bits of seaweed, etc., left by the UPRUSH 

 when it recedes from its upward limit of movement 

 on the beach face. (11) 



SWAY . Lateral movement of the center of gravity 

 of a ship. (12) 



SWELL . A long and relatively symmetrical wave 

 having a period in the order of 10 seconds pro- 

 duced by winds and storms at some distance from 

 the point of observation. 



SWIM FINS (FLIPPERS) . Any device designed to be 

 attached to the feet of a swimmer or SCUBA diver 

 to increase the power and control of the swimmer. 



SUSPENSION CURRENT . See TURBIDITY CURRENT. SWINGIN G BUOY. 



SVTP . Sound Velocity, Temperature, and Pressure. 

 A measuring instrument which measures sound velocity 

 by a velocimeter, temperature via a Wien bridge 

 and pressure by means of a VIBRATRON. 



SWAFAC . Southwest Atlantic Fisheries Advisory 

 Commission. 



SWALLOW-TYPE NEUTRAL FLOATS . These floats are 

 objects that can be "trimmed" to make them settle 

 at any depth in the ocean. Equipped with sound 

 pingers they can be "followed" to investigate the 

 flow of deep water. The float consists of an o- 

 ring sandwiched between two commercial plpecap 

 forgings. The Instrumentation within a float is 

 designed to measure the position and acceleration 

 of the shell and to obtain the temperature of the 

 surrounding water, 



A neutrally buoyant float is stable at a 

 given depth, if it is less compressible than water 

 and has the same density as the water at that depth. 

 A settled float will follow horizontal water motion 

 because it is subjected to the same horizontal driv- 

 ing forces as an equivalent volume of water. The 

 neutrally buoyant cans will follow horizontal 

 motions fairly closely at all depths, and probably 

 can be used to measure the horizontal displacements 

 associated with deep internal waves. (30) 



SWASH CHANNEL , 1, On the open shore, a channel 

 cut by flowing water in its return to the parent 

 body (e,g, a rip channel), 



2, A secondary channel passing SYZGY , 



through or shoreward of an inlet or river bar, (11) (14) 



A buoy placed at a favorable loca- 

 tion to assist a vessel to adjust its compass or 

 swing ship. The bow of the vessel is made fast to 

 one such buoy and the vessel is swung by means of 

 lines to a tug or to additional buoys. (17) 



SYMBIOSIS . The living together of two or more or- 

 ganisms in an association which is mutually advan- 

 tageous. (18) 



SYNODICAL MONTH . The average period of the revolu- 

 tion of the moon around the earth with respect to 

 the sun, or the average interval between corres- 

 ponding phases of the moon. The synodical month 

 is approximately 29.530588 days in length. (14) 



SYNOPTIC . In general, pertaining to or affording 

 an overall view. 



In meteorology, this term has become somewhat 

 specialized in referring to the use of meteorologi- 

 cal data obtained simultaneously over a wide area 

 for the purpose of presenting a comprehensive and 

 nearly instantaneous picture of the state of the 

 atmosphere. Thus, to a meteorologist, "synoptic" 

 takes on the additional connotation of simultaneity. 

 (24) 



SYSTOPHE . The condition whereby the chromatophores , 

 usually scattered, are collected into a group when 

 exposed to strong light. Observed in some algae, 

 (X3) 



Position of the moon when it is new or full. 



T 



TABLEMOUNT , A SEAMOUNT rising more than 500 fathoms 

 from the sea floor and having a comparatively 

 smooth, flat top with minor irregularities, (26) 



TABULAR ICEBERG , A mass of ice calved from an ice 

 shelf in the Antarctic, having a flat upper sur- 

 face, and at least the upper portion being composed 

 of stratified snow or NEVE, Tabular icebergs are 

 characterized by their vast size (often measured 

 in miles), rectangular block cleavage, relatively 

 large air content, and white color and lustre. 

 When a tabular iceberg becomes unbalanced, so that 

 the flat, level top is inclined, it is called a 

 Tilted iceberg. Large tabular icebergs and some- 

 what similar formations in the arctic are called 

 Ice Islands. Also called Barrier Iceberg. (17) 



TAFFRAIL LOG . A log consisting essentially of a 

 rotator towed through the water by a braided log 

 line attached to a distance registering device 

 usually secured at the taf frail, the railing at 

 the stern. Also called patent log. (17) 



TAPE GAGE . A tide gage which consists essentially 

 of a float attached to a tape and counterpoise. 

 The float operates in a vertical box or pipe which 

 dampens out short-period wind waxes while admitting 

 the slower tidal movement. For the standard instal- 

 lation, the tape is graduated with numbers increas- 

 ing toward the float and is arranged with pulleys 

 and counterpoise to pass up and down over a fixed 

 reading mark as the tide rises and falls. (14) 



TARGET LENGTH . The distance, measured along the 

 direction of propagation, between the first point 

 and the last point, on a given target, to return 

 detectable echo signals to the source is known as 

 the target length. (4) 



TARGET STRENGTH . Measure of reflecting power of 

 the target. Ratio, in decibels, of the target echo 



U.7 



