394 



Tides in the Mediterranean and Adjacent Seas 



is the independent diurnal tide of the entire Mediterranean. If we assume 

 for the latter at an arbitrary locality a range rj x = a^osiat— *[), for the 

 co-oscillating tide r\ 2 = a 2 cos(<rt— x' 2 ), then -n — r\ x + r\ 2 = Hcos(at— x) in 

 which 



// 



sin (V — x 2 ) 

 sin(%i — x 2 ) 



and a* = H 



sin(V— x[) 

 sin(i<2—xi) 



Table 48 gives us H and x and with x[ which for the independent tide (re- 

 duced to the central meridian of 15° E.) is approximately 90°, and x 2 which 



40 



30 



20- 



10 



-10 



20 



Fig. 165. Distribution of the amplitudes and phases of the semi-diurnal partial tides in the 



Mediterranean. 



is the reduced ^-number of Cadiz, we can compute the amplitudes of the 

 two components for every locality. The result can be found in Fig. 166. 

 For the co-oscillation there are two nodal lines, one between Cadiz and 

 Gibraltar, i.e. in the Strait of Gibraltar itself, the second one between the 

 Tyrrhenian and the Ionian Seas, probably in the Straits of Tunis and Messina. 

 The independent tide shows, beginning at Cadiz where it must be zero, an 

 increase towards the east, then a decrease to the only nodal line in or east 

 of the Ionian Sea. 



The distribution of the nodal lines and amplitudes of the semi-diurnal 

 and diurnal tides allow a complete explanation of the observed variations 

 in the character of the tide in the Mediterranean. The small ratio of 010 

 in Cadiz is opposed by the large value of 2 13 at Alicante. This can be 



