TONGUE OF THE OCEAN 



which tlie height of the tide at any time can 

 be read directly. (50) 



tide station — A place where tide observations are 

 obtained. It is a primary tide station when 

 continuous observations are available for a suffi- 

 cient number of years to determine the charac- 

 teristic tide features for the locality. A second- 

 ary tide station is operated during a short period 

 of time to obtain data for a sijecific purpose. 

 (50) See secondary tide station, reference 

 station. 



tide tables — Tables which give daily predictions, 

 usually a year in advance, of the times and 

 heights of the tide. These predictions are usu- 

 ally supplemented by tidal differences and con- 

 stants by means of whicli additional predictions 

 can be obtained for numerous other places. ( 50) 

 8ee tide prediction, tidal difference. 



tidewater — (or tidal ivater). Water affected by 

 tides or sometimes that part of it which covers 

 the tideland. The term is sometimes used 

 broadly to designate the seaboard. (68) 



tidewater glacier — See tidal glacier. 



tide wave — (or tide 'bulge). A long-period wave 

 associated with the tide-producing forces of 

 the moon and sun; identified with the rising 

 and falling of the tide. (50) See tide, tidal 

 movement, stand of tide. 



tideway — A channel through which a tidal cur- 

 rent flows. (68) 



tilted iceberg — A tabular iceberg that has be- 

 come unbalanced, so that the flat, level top is 

 inclmed. (68) 



time — Time is measured by the rotation of the 

 earth with respect to some point in the celestial 

 sphere and may be designated as sidereal, solar, 

 or lunar, according to whether the measurement 

 is taken in reference to the vernal equinox, the 

 sun, or the moon. Solar time may be Apparent 

 or Mean, according to whether the reference is 

 to the actual sun or the mean sun. Mean solar 

 time may be local or standard according to 

 w'hether it is based upon the transit of the sun 

 over the local meridian or a selected meridian 

 adopted as a standard over a considerable area. 

 Greenwich time is standard time based upon the 

 meridian of Greenwich, England. In Ci\al time 

 the day conunences at midnight, while in As- 

 tronomical time as used prior to 1925 the be- 

 ginning of the day was reckoned from the noon 

 of the civil day of the same date. The name 

 Universal Time is now applied to the Greenwich 

 Civil Time. On 1 January 1953, the term Green- 

 wich Mean Time replaced the term Greenwich 

 Civil Time in the United States. (73) 



time constant— (also called lag coefficient) . Gen- 

 erally, the time required for an instrument to 

 indicate a given percentage of the final reading 

 resulting from an input signal ; the relaxation 

 time of an instrument. In the case of instru- 

 ments such as thermometers, whose response to 



step changes in an applied signal is exponential 

 in character, the time constant is equal to the 

 time required for the instrument to indicate 63.2 

 percent of the total change, that is, when the 

 transient error is reduced to 1/e of the original 

 signal change. (5) 



time series — Values of a variable during a finite 

 time period. 



tintinnid — Any of a suborder (Tintinnoinea) of 

 microscopic planktonic Protozoa which possess 

 a tubular or vase-shaped outer shell. Several 

 species are luminescent. 



titration — A chemical method for determming the 

 concentration of a substance in solution. This 

 concentration is established in terms of the 

 smallest amount of the substance required to 

 bring about a given effect in reaction with an- 

 other known solution or substance. The most 

 common titration is that for chlorinity. 



tombolo — A bar or spit connecting or "tying" an 

 island to the mainland or to another island. (2) 



TOMBOLO 



(BEB; n~*. 19541 



tongue — 1. A projection of the ice edge up to sev- 

 eral kilometers in length. It is caused by winds 

 or currents. (74) 



2. A narrow peninsula formed by a glacier 

 and a ste«p, narrow cliff of ice rising high above 

 glacial neve is called an ice tongue. An exten- 

 sion of a glacier into the sea is called a glacier 

 tongue, and, if the end is afloat, an ice tongue 

 afloat. (68) 



3. An inlet. (68) 



4. A narrow, rapid current. (68) 



5. Protrusion of water into a region of differ- 

 ent temperature. A tongue is cold when it ex- 

 tends into an area of warmer water, or warm 

 when it extends into an area of colder water. 



Tongue of the Ocean— (abbreviated TOTO) . A 

 steep-sided, deepwater embayment approxi- 

 mately 100 nautical miles long, 20 nautical miles 

 wide, and one nautical mile deep, connected to the 

 Atlantic Ocean by Northeast Providence Chan- 



167 



