Thanks for the info. Are you guys wearing wetsuits all year. Water temps ever get in board short range for summer? Looks like this Sunday you will get some waist + . Let me know how it is.
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Mar 6, 2014, 08:40 PM #21Junior Member
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- Feb 2014
Mar 6, 2014, 08:47 PM #22
Essentially tides are driven by the gravitational effects of the moon's orbit of the earth and to a lesser extent that of the sun. That is why most of us experience two high and two low tides per day at a period of roughly 12 hours and 25 minutes. However, some places only experience one high and one low tide per day. Still haven't grasped that one.
The tide differential is more related to bathymetry though I imagine lattitude could have some effect as well. By bathymetry I mean more than just the under water ocean floor contours that we usually think of but also the effect of other land masses and the interconnection of other bodies of water. Basically anything that effects the movement of water so I suppose you could also include ocean currents and winds into the mix.
As you can see there are a ton of factors involved. That is why all tide charts are really forecasts and shouldn't be considered absolute values. Interesting stuff but I still can't get my head around it all. Here's a neat chart I found on Wikipedia that shows the extremeness of tides around the world and the text that accompanied it. You can see one of the hot spots of extreme variation is on the Pacific coast of Central America as sisurfdogg experienced.
The M2 tidal constituent. Amplitude is indicated by color, and the white lines are cotidal differing by 1 hour. The curved arcs around the amphidromic points show the direction of the tides, each indicating a synchronized 6-hour period. Tidal ranges generally increase with increasing distance from amphidromic points. The colors indicate where tides are most extreme (highest highs, lowest lows), with blues being least extreme. In almost a dozen places on this map the lines converge. Notice how at each of these places the surrounding color is blue, indicating little or no tide. These convergent areas are called amphidromic points. Tide waves move around these points, counterclockwise in the N. Hemisphere and clockwise in the S. Hemisphere
Sorry to continue derailing this thread but at least I'm not blathering on about avatars...
Mar 6, 2014, 08:48 PM #23
Anywayz, the much lower tide difference at the equator is primarily due to the relationship of the earth's equatorial plane and the orbital plane of the moon. Tides themselves are affected by many factors, including coastline, bathymetry, and continental shelf, as well as where the sun and the moon reside specific to a given region.
Largest tides in the world are in Nova Scotia and Maine is pretty damn close and also has a lot of the same similarities with these factors.
There are solar tides and lunar tides, so the moon is not the only guiding force at work here. If the moon disintegrates tomorrow or is blown up by a meteor, we will still experience solar tides although much smaller since now those two celestial beings aren't working in concert.
The moon and the earth are basically playing tug of war with the earth's water and since the moon's upward pull is greater, we get the lunar effect on tides.
Little known fact: The Great Lakes have tides, but only a few inches so it's basically considered non-tidal.
Mar 6, 2014, 08:49 PM #24
Woah. Valhalla and I posted the same thing just about at the same time. That's either creepy or brilliant.
Mar 6, 2014, 08:51 PM #25
Mar 6, 2014, 08:52 PM #26
Mar 6, 2014, 08:59 PM #27
Mar 6, 2014, 09:40 PM #28
The water won't touch 70 degrees. There could be a couple days it gets close to that depending on currents, but you'll likely want that 3/2 most of the time. To avoid the crowds it's best to go early morning so that's another reason to sport the 3/2.
Mar 6, 2014, 10:20 PM #29
Mar 6, 2014, 10:57 PM #30
Thanks for the info. Pretty cool map too. I've always known they were mainly caused by the moon but couldn't figure out why some places were affected so much more.
From the looks of the map it seems like the places with the biggest differential are near some type of choke point that would inhibit the movement of massive amounts of water. Almost like how a siphon works by "dragging" the larger mass of liquid behind the initial outflow.
Sheesh, I'm sure there's better terms for what I was saying but I never made it to that class