Compare tide heights : Dover, Newlyn, Milford Haven

I had tide data from the British Oceanographic Data Centre for March 1967 for another purpose.
This very simple comparison offered itself of the hourly profile of tidal seawater heights for the three locations of Dover, Newlyn and Milford Haven.

Dover:

Newlyn:

Milford Haven:

Abbreviations and definitions:

• HWDover - time of High Water at Dover
• hour = hr; hours = hrs
• the tidal cycle is 12hours and 25minutes; typically considered from one high water to the next high water but can be from any juncture in the tide cycle - hence HWDover+6hrs to HWDover-6hrs represents a complete tide cycle anywhere

The ports

Dover

is the "reference" port for tidal stream atlases - tidal stream charts are always a set of 13 from HWDover-6hrs through HWDover to HWDover+6hrs

Newlyn

is used for nautical and on-land cartographic reference purposes because the tides are judged very consistent and the terrain is considered very geologically stable - it's on the Lands End granite

Milford Haven

is a remarkable natural harbour and a major terminal for oil tankers

Observations about the tide graphs

All three locations show the two-week cycle of Neaps<=>Springs in-step - as expected.

Newlyn, home of the famous tide Newlyn gauge, has the smallest tidal range and the outer-envelope profile of the highest and lowest tides is notably smooth.

Milford Haven is seen to have a larger tidal range by something like a metre, while its outer-envelope profile of the highest and lowest tides is also smooth.

Dover has a tide range which looks intermediate between those of Newlyn and Milford Haven - but the outer profile of the highest tides and of the lowest tides is irregular / "ragged".
That is not the most fortunate characteristic for a "reference port" regarding tides.

I'm not equipped to explain all this.
It is just a simple opportunity which happened to presented itself to me to obtain these graphs.

Finishing note

This is comparing like-with-like from around 55 years ago. Seawater levels are seen to be rising and that would offer a good project to someone; to compare historic data at various intervals and current data. Which for sure scientists (oceanographers?) are doing.

(R. Smith, 28Jul2022)