Tides in the Mediterranean and Adjacent Seas 



43i 



160° 



60° 



130° 140° 150° 160° 170° 



Fig. 184. Co-tidal lines of the M 2 tide and range 2(M 2 + 5 2 ) in m for the Sea of Okhotsk. 

 (Phase referred to the 135E. L. Meridian) (Ogura). 



This presentation is not very reliable, but they contain all that can be derived 

 from the coastal observations. 



The semi-diurnal tide wave progresses from the Pacific Ocean through the 

 Kuril Islands; along the islands the phase retards H h going from the south- 

 west to the north-east, the amplitude increases in the same direction from 50 

 to 80 cm. Consequently, the co-oscillation of the water-masses of the adjacent 

 sea does not have the same phase, which complicates conditions somewhat. 

 The rectangular shape of the whole sea reminds one of North Sea, but its 

 dimensions are far larger. With a length of about 1600 km (1000 miles) an 

 opening around 700 km (440 miles) wide, and an average depth of 200 m 

 (660 ft), the period of the free oscillations is approximately 24 h, so that v 

 has the value of about 2. This means that the semi-diurnal tides have two 

 nodal lines which the rotation of the earth transforms into amphidromies. 

 In fact, the map of Ogura shows two amphidromies, both displaced to the 

 west, one with its centre in front of Sakhalin, the other one in the shallow 

 north-western bay. Sterneck (1922, p. 145) has assumed only one amphi- 

 dromy in the central part of the sea. The decrease in range in the vicinity 

 of the amphidromies shows that their presence is real. Only new observations 

 on the coast of Kamchatka will decide whether the center of the outer am- 

 phidromy is not located farther out at sea. 



