Seasonal Distribution of the Time of Day of HIgh and LowTides

ERRATUM:  A previous post of a graph for Kawaihae is in serious error: the timezone was not accounted for.  Correction in preparation.


The following graphs are the result of my attempt to visualize the way that lower low tides and higher high tides are distributed in time.  What do they say about the tides?  Especially striking to me is their overall shapes.  H. A. Marmer's study of the various nature of mixed tides is pertinent.

Marmer, Fig. 3

"The mixed type of tide merits more detailed consideration since this type comprises a great variety of different forms.  These different forms may, however, be grouped into three large classes, namely those which feature the difference between the morning and afternoon tides chiefly in the low waters, those which feature it chiefly in the high waters, and those which feature it in approximately equal degree in both the high and low waters."  

H. H. Marmer. 1931.  Tidal Characteristics from Harmonic Constants.  The International Hydrographic Review 2. 

In the above graph, Marmer refers to Seattle, Honolulu, and San Diego as examples of these three categories of tide regime.  

The making of the following began from a desire to understand the distribution of higher and lower tides from a seasonal perspective.  Perhaps they will also do, to elaborate on the theme of Marmer.  The distribution of times over the seasons seem remarkably bimodal.  The different forms of these three mixed tides is striking.  There is much more to Marmer's analysis, perhaps best left for another time.  

Seattle, WA: Differences in Low Waters.

Transitional between Seattle and La Jolla.

Differences in both high and low waters