Strangely high 'highest' tide
On 23/09/2020 20:29, Graham Easterling wrote:
That wasn't the reason, I say so for 2 reasons
1. The north coast of Devon / Cornwall was also affected (look at Ifracombe..)
2. Even on the south coast I've never noticed an easterly of that strength have much affect in Mount's Bay even when it's occurring, let alone 2 days later when what breeze there was was an offshore NE. What swell left in Mount's Bay was a longish period low swell, clearly of fairly distant west Atlantic origin. (I mention the low long period swell om Weather & Climate).
I think the only feedback I had that comes close to explaining the anomalous tides, is your hurricane effect Len. That would explain both coasts being similarly affected, and there was a long period swell, albeit small, as I mentioned on Weather & Climate. The period suggesting a west Atlantic origin.
Even then I find it surprising considering so many factors being against it..
Norman's post about MSL rise is interesting though, especially since I've now reread the article on Newlyn observations I linked to. It does suggest that benign conditions will tend to show actual readings biased high.
Graham
Penzance
I know nothing of tides in the Severn Estuary, perhaps it could be a
separate local east wind surge situation there, hugging the coast perhaps.
Perhaps Ilfracombe would show an excess height but not Avonmouth.
You need a good fetch , even with gale force wind to induce enough
windstress to the sea surface , hence surge, to be detectable on tide
gauges beyond normal storm induced jitter.
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Global sea level rise to 2100 from curve-fitted existing altimetry data
http://diverse.4mg.com/slr.htm
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