384 



Tides in the Mediterranean and Adjacent Seas 



north of the Cotentin peninsula but only increases the crowding on the 

 northern side whereas on the southern side they are more spaced. However, 

 in the Hoofden we have the picture of a well-developed amphidromy. 



The combination of the longitudinal and transverse oscillations gives 

 finally the theoretical tides, and it must be admitted that they agree very well 

 with the observations, especially if one considers that the theory bases itself 

 only on the tidal observations at the ends of the connecting channel. Figure 159 

 gives a comparison between the observations and the theory for the northern 

 coast of the channel. Figure 160 shows a comparison for four hours of the tidal 



Sections 



n 



Fjg. 160. Tidal currents in the English Channel and Hoofden (nm/h). +, direction 

 North Sea; — , direction Atlantic Ocean; , computed; ~~ '— |_l - ' observed. 



period; the same conditions prevail for the other hours. There is no doubt 

 that the tides of the English Channel and of the south-western North Sea 

 result from the impulse which their water-masses receive from the Atlantic 

 Ocean and from the North Sea. It can also be shown that the diurnal tides 

 in the Channel are small because the diurnal tides in the ocean off the open- 

 ings are also small. 



4. The Tides of the Irish Sea 



In the Irish Sea, the oscillating area is situated between the line Cape 

 Clear — Scilly Islands in the south and the line Tory Island — Hynish Point 

 in the north; consequently, it comprises the St. George Channel, the Irish 

 Sea and the North Channel. 



The Irish Sea can be treated in exactly the same way as the English Channel. 



