Tides in the Mediterranean and Adjacent Seas 



393 



reduced to the 15° E. meridian proved to be nearly constant and this applies 

 in part to the amplitude, so that we can group the separate localities and 

 obtain average values for the Tyrrhenian, Ligurian and Ionian Sea. The 

 result is tabulated in Table 48.* 



Table 48. Harmonic constants for separate 

 oscillating areas in the Mediterranean 

 (x referred to 15°E.) 



From one group to another the phase of the semi-diurnal tide varies 

 by nearly 1 80°, so that one has three nodal lines in the longitudinal oscillation 

 of the entire Mediterranean which is in accord with the theory. Figure 165 

 shows this in the form of a graph for the M 2 , S 2 and K x tides. The ampli- 

 tudes also correspond to the values derived previously for the various semi- 

 diurnal tides. Therefore, this theory can be regarded as complete. 



The data gained by harmonic analysis are also useful for the investiga- 

 tion of the diurnal tides of the Mediterranean. The reduced phases of the 

 diurnal components like K x , P x and O x show a steady increase from west 

 to east. This points to an interference of two non synchronous standing 

 waves, one of which originates from the co-oscillation of the Mediterranean 

 with the external tide through the Strait of Gibraltar, whereas the other one 



* Sterneck reduced the phase to the 15°E. meridian by using the equation g l5 ° = 

 = x + o-/15°(15°— X) which is wrong. He did the same for the Adria (see p. 400). The Mediter- 

 ranean being small, the deviation from the values according to the correct formula is not great 

 (although in Alexandria it is 2°), but this equation cannot be used for greater distances. 



