Subject: Re: Dutch provincial North sea<br/>
Date: Dec 17, 2001 @ 17:16<br/>
Author: ps1966nl (&quot;ps1966nl&quot; &lt;smaardijk@...&gt;)<br/>
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<div id="ygrps-yiv-398702973">Grant Hutchison wrote:<br/>
<br/>
<blockquote><span title="ireply"> &gt;&gt; Low low water is the lower of the two daily tides (most places, <br/>
 </span></blockquote>most of the time, the two tides differ in height). Low low water <br/>
spring is the same measure applied to the spring tide - the <br/>
lowest/highest tide of the (lunar) month. The measurement is usually <br/>
meaned over a period of years.<br/>
As a datum, it seems to be favoured in Belgium and the Netherlands,<br/>
for some reason. &lt;&lt;<br/>
<br/>
OK, thank you. The autor of that text didn&#39;t know this either, <br/>
judging from the quotation marks.<br/>
<br/>
<blockquote><span title="ireply"> &gt;&gt; It&#39;s a pretty low tide, but not the absolute lowest you can get -<br/>
 </span></blockquote>spring tides are lower in January (when the Earth is closest to the<br/>
sun); when the moon is at its closest to the Earth; and during an<br/>
eclipse (when the gravitational pull of moon and sun are perfectly<br/>
aligned). Put all those factors together on the same day and you get a<br/>
&quot;king perigean eclipse tide&quot;. Mark your diary for the next one - 18<br/>
January 3089. &lt;&lt;<br/>
<br/>
With global warming and/or all sorts of possible changes in the <br/>
climate and all that, it possibly won&#39;t account for much, though.<br/>
<br/>
Peter S.</div>