13 Mar 2015

Spring and neap high tides...

The recent spring high tide. Spring tides don't just happen in spring, they confusingly occur twice a month throughout summer, autumn and winter too.

And here's a neap high tide from a sunny January:

So a spring tide means high high tides and low low tides. Neap tides give you low high tides and high low tides. Got that? The comparison of Spring and Neap low tides is here.

Other factors can affect the final height of a high or low tide; if the wind is blowing onshore it can drive more water ashore and raise the tide level. Atmospheric pressure can affect the tides too; high pressure crushes the tide bump down, low atmospheric pressure allows the sea surface to rise, so pressure can increase or decrease the tidal height by as much as 30 cm.

No comments: