Tides in the Mediterranean and Adjacent Seas 



449 



Table 69. Tidal data at spring tide for points at the North Siberian Shelf 



(according to Sverdrup) 



stations on the open shelf, but are quite different for stations in the vicinity 

 of the coast, where the currents become almost alternating and parallel to 

 the coast. 



(2) The currents are not uniform in the layers between the surface and 

 the bottom of the ocean and show a definite correlation with the vertical 

 density distribution (see p. 451). The time of the greatest velocity does not 

 correspond exactly to the high water, but it occurs about 1 or 2 h earlier. 



(3) The velocity of propagation of the wave differs considerably from the 

 value | gh; when the current is rotating in a circle, the velocity is too large 

 in comparison with the velocity of the formula, and too small when the cur- 

 rent is more alternating. 



(4) The tidal range varies from 210 cm (7 ft) directly north of the New 

 Siberian Islands to only 3 cm (1 in.) at Bear Island. The amplitudes of the 

 waves decrease along the co-tidal lines from right to left (taken in their 

 direction of propagation) and also in the direction of propagation of the 

 wave itself. The amplitude drops from 210 cm (7 ft) at the New Siberian 

 Islands to 14 cm (1 ft) near Point Barrow, and in the direction of propagation 

 they drop from 18 cm (1-5 ft) at a point 400 nm off the coast to 5 cm (2 in.) 

 near the Aion Island and to 3 cm (If in.) near Bear Islands. 



All these characteristics can be explained theoretically, if one considers the 

 tide wave as a progressive wave affected by gravity, and takes into account the 

 friction at the boundary and caused by turbulence. In connection therewith 



29 



