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

A Gem of Untold Worth: Pages Torn out from Albert Defant's Physical Oceanography, V.II.

I have tried to at least review all the literature I can lay my hands on, about anything having to do with tides.  Several books, and a number of papers stand apart.  Another time, I plan to generate a list.  Real Soon Now (TM).  Among books, one of the classic textbooks of Oceanography is the 1961 two-volume Physical Oceanography, by Albert Defant. In Volume 2 are found lengthy treatments of various aspects of tides.  It is available in English translation on Archive.org, in various formats: Defant. Physical Oceanography, V. II.  No other book has gone to that much extent, particularly in discussion of the features of tides of various locations around the world.

As I prefer printed books, I checked volume II out from the UC Berkeley Libraries.  A troubling revelation was received.

It has been my unfortunate observation that not all academics are community minded.  At UCSB, for example, many of the previously numerous volumes dealing with fishing have been stolen or otherwise have disappeared.  Of those that remained as of about 1983-1984, I found several with pages removed, presumably because of their overriding usefulness to someone---hopefully who would make a contribution to the greater body of knowledge, to compensate for this selfish act.

More distressing was to find pages torn out in exactly two places in one copy of Defant's volume II from the UC Berkeley Library. These pages I was able to locate in the Internet Archive (archive.org), as *tif files; I printed these pages out and placed them in the books so they would be available to anyone who referred to this book in the future---possibly me!  

Bookmarks left in Defant by an astute reader

Beyond the thoughtless act of removing these pages, the perpetrator left behind a bookmark: once I had noticed these pages were missing: the content of the missing pages was astounding.  May I turn a blind eye to copyrights?  Well, I think this book is no longer covered by those draconian and troublesome restrictions; I shall present the missing pages here.

The first page was an accounting of Harmonic Constituents. 

The first of these two pages is the most important: a listing of Principal harmonic components (constituents).  All of these images are *.tif files.  You may click on them to enlarge them, and they are printable.

 2.  Pages later in the book: remarkable!  How to interpret the above.

 I do not know who removed these pages.  One can appreciate their unique value, even from the distance of over 50 years.

In the Caroline Islands, experts value their knowledge---particularly of navigation, fishing, or cures---highly.  They fear to share it with others, lest it be squandered, and their personal power diminished.  A traditional expert will choose very carefully whom he may train in his knowledge or skills.  Likewise, A prospective pupil, would cultivate the expert's favor, even to the extent of sharing a fish with a navigator every time he goes fishing, for tens of years!  Eventually, the expert may take the hopeful understudy aside and offer to tutor him.  This is a very serious matter.

Likewise in Western society, knowledge is jealously guarded.  Beyond arcane practices in academic culture, and, say, the scribbled handwriting and esoteric vocabulary, or even shoptalk among craftsmen, many more examples could be adduced.

I cannot know what was going through the mind of the thief of these pages.  Perhaps this was in a time preceding xerox machines.  Or maybe he had no change, was late for his ride, or faced a deadline that he or she could not make without this precious knowledge.  Did a librarian---whose annoying dispositions used to be legendary---refuse to check the book out to our aspirant to this knowledge?

Unfortunately, I cannot render judgement on this seemingly callous and self-serving act.  The outcome, though, is a positive one: I might not have made such careful note of these pages, had they not been missing.

It's good stuff.
 

San Francisco, Hawaii, and Guam exhibit seasonal modes on Tide vs Time of Day graphs

I started to make these graphs because I want to understand the nature of the seasonality of the lowest and highest tides. One of my professors, Roy Tsuda opened my eyes to certain aspects of tidal zonation, and, somehow, to the idea that there is some kind of seasonality to tides.  MY interest in the Tidepool, in all of the Intertidal have biased my point of view toward the times of lowest LLW during different months of the year.  However, as the graph of Kawaihae, Hawaii shows, some sites show more variation in HHW (Higher High Water) through the year.

These graphs take a certain amount of manual data manipulation to generate times of day from the times of the tide predictions. I will be making more of them.  In his book Sea Level Science, David Pugh discusses various varieties and aspects of tides.  Especially, Albert Defant's Physical Oceanography, Volume II gives detailed discussions.  One of these, or perhaps others, certainly will have information about the astronomical and oceanographic factors behind the differences in these profiles. 


Looking at these, I know there is more to learn about this.  I'm willing to have posters printed, if anyone is interested.   One possibility would be a large poster with several such graphs.   I've tried to use colorblind-friendly colors, but this is a work in progress.   For one thing, gri does not have the same color palette support as R.  And for another, there are a number of varieties of color blindness, each of them just as different from the next, as from my own "Normal" color vision.   What would these look like to a stomatopod (with 10 cone types, I think)?

San Francisco

 

Kawaihae, Hawaii Island

 

Apra Harbor, Guam

Article: High Tide Flooding Days in 2018

https://www.noaa.gov/media-release/us-ties-record-for-number-of-high-tide-flooding-days-in-2018

Distribution plots of times of day of high and low tides. A work in progress.

Roy Tsuda, professor of Marine Botany at the University of Guam, is an enthusiast of tides.  His lecture on the ideas of one of his professors, Max Doty about intertidal zonation made an impression on me.  I'm not sure now, some 35 years later, whether he had something to do with instilling me a strong interest in the times of high and low tides.   I think he did.

In Chuuk Lagoon, I learned that at the time when "a pwopwooisor" (the tide was pregnant or swollen [pwopwo} in the morning [isor], certain bivalves are ripe to eat---with a growth of orange matter, obviously eggs.  I also heard a casual remark that "the tide has changed" in reference to the times of high and low tides.

How to graph this relationship, to analyze and grow our understanding?  Ideas pop out of the graphs, ideas the inkling that prodded me to start in the first place.  These are distribution plots, not a track through time, like a tide calendar.  I want to see what times of day are the tides highest or lowest, and during which months?  When it takes several years to produce something, is it  a work in progress? 

Time of day is the independent variable, the X axis.  Predicted heights are the dependent variable. Different colors encode the months. 

Studying some of the graphs it is apparent that  a "month" is not a natural division of time; in certain cases there are what look like different modes within a "month."  A lunar calendar might work better.  Or maybe not.  Tides are complicated.  Traditional fishermen, without the benefit of calendars, ephemerides, or clocks, understand the division of time in a more practical sense.  

Seasons of High and Low TIdes

This is an important topic.  I will not discuss it.  Here is a graph I have been working on to try to understand this question.  What times are highest and lowest tides?  Is there a seasonal difference?

This may make better sense than the accompanying post.

This is still a work in progress.  In this instance I am manually inducing "jitter" by using differing increments of time for the predictions for each month.  This is not ideal yet.  

The original with a gray background.  Better for printing.  Still a work in progress.   Are these colors colorblind friendly?