Monday, January 08, 2018

The full moon and storm Eleanor in a tide gauge

The weather seems to be in the news a lot in the first few weeks of 2018.

The difference in temperature between my friends in Australia and east coast America seems to be about 60C compared to which our blighty weather seems comparatively mild.

But we did get storm Eleanor blow through around the time of the full moon which led to fears of a storm surge on top of a spring tide and so the Thames Barrier had to be closed.

Previously I'd posted how closing the barrier could be read in the behaviour of the flow and this time I kept an eye on the live tides at Chelsea to see what the impact would be.

From what I understand (via Twitter) the barrier was closed at 12:15 and it can be seen that there is a sudden dip in the water height at Chelsea, but not at the same time. It seemed to take 45 minutes for there to be a significant change in the height, but then there are several miles from the barrier to this gauge.

After the dip, the levels continued to rise but more slowly, due to the Thames river flow rather than incoming tide, with a maximum delta from predicted height of 2.23m - though the flow had been less than predicted anyway. Danger averted the barrier opened when the water levels equalised later in the day.

So lots of factors from the moon to the weather to one of London's largest infrastructure assets all influencing one simple gauge.

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