standard station— Same as reference station. Use of this term is discouraged. 



standard time— A kind of time based on the transit of the Sun over a certain specified 

 meridian, called the time meridian, and adopted for use over a considerable area. With a 

 few exceptions, standard time is based on some meridian which differs by a multiple of 

 15° from the meridian of Greenwich. The United States first adopted standard time in 

 1883 on the initiative of the American Railway Association, and at noon on November 

 18 of that year the telegraphic time signals from the Naval Observatory at Washington 

 were changed to tliis system. 



storm surge— A departure from a normal elevation of tlie sea due to the pUing up of water 

 against (or withdrawal from) a coast by strong winds such as tliose accompanying a 

 hurricane or other intense storm. Reduced atmospheric pressure often contributes to the 

 departure in height during hurricanes. It is potentially catastrophic, especially in deltaic 

 regions with onshore winds at the time of high water and extreme wind wave heights. 



subordinate current station— (1) A current station from which a relatively short series of 

 observations is reduced by comparison with simultaneous observations from a control 

 current station. (2) A station Usted in tidal current tables for which predictions are 

 obtained by means of differences and ratios apphed to the fuU predictions at a reference 

 station. 



subordinate tide station— (1) A tide station from which a relatively short series of 

 observations is reduced by comparison with simultaneous observations from a tide 

 station with a relatively long series of observations. (2) A station listed in tide tables for 

 which predictions are obtained by means of differences and ratios apphed to the fuU . 

 predictions at a reference station. See primary control tide station, secondary control 

 tide station, tertiary tide station, and reference station. 



summer time— British term for dayhght saving time. 



synodical month— The average period of the revolution of the Moon around the Earth with 

 respect to the Sun, or the average interval between corresponding phases of tlie Moon. 

 The synodical month is approximately 29.530588 days in lengtli. 



syzygy— Position of the Moon when it is new or fuU. 



Si -Solar diurnal constituent. 



Sa —Principal solar semidiurnal constituent. This constituent represents the rotation of the 

 Earth with respect to the Sun. 



S4, S^ —Shallow- water overtides of the principal solar constituent. 



