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Post by kentyeti on Aug 26, 2016 8:55:20 GMT
I'm well aware of what a spring tide is, Aust Wharf and Parkgate on the Dee Estuary give some superb spectacles when they occur. Shellness on Sheppey to some extent too.
And their cause is when the sun, moon and earth align twice every month, increasing the gravitational force on the seas.
But we only get really high tides as a result a few times a year. Partly due to weather conditions: a high pressure and wind blowing the sea off the land will see a significant reduction in the high tide level, and vice versa.
What I am not totally clear about is, even taking account of the weather as above, is why more of the twice a month spring tides don't see very high tide levels.
Anyone got any suggestions please?
Cheers,
Bryan
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Post by ayjay on Aug 26, 2016 20:59:54 GMT
What I am not totally clear about is, even taking account of the weather as above, is why more of the twice a month spring tides don't see very high tide levels. Anyone got any suggestions please? Cheers, Bryan The very high spring tides are when all the other factors that produce a spring tide coincide with the equinoxes.
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Post by accipiter on Aug 27, 2016 6:22:00 GMT
Presumably the same thing that causes the seven bore which is a new moon or full moon that varies due to the fact that there is a nine-year cycle. The cycle runs as follows:
Highest tides occur following a new moon
The highest tides at new and full moons are approximately equal
Highest tides occur following a full moon
The highest tides at new and full moons are approximately equal.
The cycle then starts again.
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Post by kentyeti on Aug 29, 2016 10:40:30 GMT
Thanks guy, that helps. The distance of the moon form the earth is also a key factor.
Cheers,
Bryan
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