Tides in the Mediterranean and Adjacent Seas 425 



stations in the open ocean to guarantee the course of the co-tidal and co-range 

 lines. This is not true for the southern section of the Hwang Hai and the 

 Tung Hai. In Figs. 180 and 181 the most recent results have been compiled 

 in a chart covering the entire South China Sea. 



The crest of the semi-diurnal wave, coming from the Pacific Ocean, reaches 

 the chain of islands of the Ryu-Kyu almost simultaneously at about 7 h 

 (referred to the meridian of 135 E.). The range at spring tide 2(M 2 + S 2 ) 

 is about 180 cm near the north-eastern islands, and about 125 cm near the 

 south-western islands. The tide wave penetrates with a wide front into the 

 East China Sea and till the opening into the Yellow Sea (from Shanghai 

 to the southern tip of Korea) it has apparently the nature of a progressive 

 wave. It reaches this line with the phase h, while the amplitude increases 

 to nearly 8 2 ft (250 cm). The interior sea, up to the central section of the 

 Gulf of Liaotung, can then be regarded as a canal with many curves, with 

 a length of about 1600 km and a mean depth of about 50 m. The natural 

 period with an opening correction will be of the order of magnitude of 

 about 46 h, so that for the semi-diurnal tides the v =3-7 and for the diurnal 

 tides v = 18. We can, therefore, expect for the semi-diurnal tides four nodal 

 lines for the diurnal tides two nodal lines. The rotation of the earth will 

 transform them into amphidromies. This is, in fact, the tidal picture shown 

 in Figs. 180 and 181. For the M 2 tide, the southern section of the Yellow 

 Sea oscillates with the phase h at the opening in such a way that at the 

 south coast of the Shantung Peninsula the phase is 6 h. The northern section 

 of the Yellow Sea and the Strait of Chilli co-oscillate with the co-tidal line 3| h 

 (south-east coast of the Liaotung Peninsula 9\ h). The Po Hai (Gulf of Chili) 

 then oscillates with the phase 1 1 i h and, finally, the Gulf of Liaotung, with 

 the co-tidal line h, so that in the central section there is again the phase 6 h. 



The K x tide behaves similarly. Here the entire East China Sea has the 

 phase 14| h with ranges 2{K x + O x ) of 70-80 cm. The entire Yellow Sea is 

 then covered by a large amphidromy, the northern section oscillating with 

 the phase 22 h. The second amphidromy lies at the western end of the Strait 

 of Chili and covers the entire Po Hai and the Gulf of Liaotung. 



An accurate hydrodynamical theory of the tides of the entire East China 

 Sea has not yet been given. Analyses of separate parts can be found in 

 Ogura (1926, p. 167; 1933, p. 269), who has studied the oscillations of the 

 Gulf of Liaotung, considering the Coriolis force and friction, and who 

 was able to obtain a very good agreement with the observations. The tidal 

 phenomenon of the entire East China Sea is almost exclusively conditioned 

 by those water-masses which penetrate through the canals between the Ryu- 

 Kyu islands within a ha'f-tidal period and then flow out again within the 

 following half tidal period. The straits between Formosa and the Continent, 

 and also the Strait of Tsushima, are less important, as is shown by the follow- 

 ing table. 



