GULF OF MEXICO 



107 



Figure 28. — Combination of daily and semidaily 

 constituent tides with equal ranges. 



26 to 29 in figure 23. The middle diagram repre- 

 sents the case in which the high waters of the two 

 constituents occur at the same time, the resultant 

 tide featuring the inequality in the high waters. 

 The lower diagram represents the condition when 

 the two constituents are at sea level at the same 

 time. The inequality is now distributed equally 

 in the high and the low waters, exemplified by the 

 tide at Key West on August 26 and 27 in figure 24. 



Thus far, we have considered only the combina- 

 tion of component tides of equal ranges. What is 

 the character of the tide resulting from the com- 

 bination of daily and semidaily components of 

 unequal ranges? 



In figure 29, three cases are considered, the time 

 or phase relations between the two constituents 

 remaining the same, the two constituents being 

 taken so that they are at sea level at the same 



Figure 29. — Combination of semidaily and daily 

 constituent tides with different ranges. 



instant. In the upper diagram of figure 29, the 

 daily constituent is taken with a range twice that 

 of the semidaily, in the middle diagram the ratio 

 is 3 to 1 and in the lower diagram 4 to 1 . With a 

 ratio of 2 to 1, the upper diagram shows the re- 

 sultant tide to be one with but one higl and one 

 low water but featuring a relatively long stand 

 halfway between high and low water. With in- 

 creasing ratios, that is with relatively larger daily 

 constituents, the stand becomes shorter and shorter 

 as the middle and lower diagrams show. With a 

 ratio of 4 to 1 the resultant curve approximates 

 the shape of the daily constituent. 



If in figure 29 the time relations between the two 

 components were taken differently, the shapes of 

 the resultant tides would be somewhat different. 

 Without going into further detail it is clear that 



