Naked Science Forum

Life Sciences => The Environment => Topic started by: Karen W. on 26/03/2008 08:24:48

Title: What happens with tides as the seasons change?
Post by: Karen W. on 26/03/2008 08:24:48

I don't eactly know what happens as the seasons change. how are the tides effected by the seasons change, or are they!!

Does it have t do with planetary alignment, and how it effects or changes gravity or what?

Title: What happens with tides as the seasons change?
Post by: techmind on 26/03/2008 12:54:23

The timing and height of tides is dominated by the motion of the sun and moon. The level of "extremity" of tide (ie difference between high and low tide) undergoes a 28-day cycle. Within this cycle, "spring tides" are the more extreme tides, while "neap tides" are the less extreme. Effectively the height of the water arises from a "beating" between gravitational effects of the 24hour cycle of the sun and the not-quite 24h cycle of the moon (because of the 28day cycle). As discussed on other threads there are all sorts of local coastal effects (eg in the English Channel, North Sea etc) owing to channelling of water around the land.

(In the UK at least) tides are especially extreme at the equinoxes, i.e. Easter and late-September, and are generally weaker towards mid-winter and mid-summer. I'm not exactly sure of the geometry of why this should be so. I'm guessing it probably has to do with the sun and moon having similar tracks across the sky at that time of year?
I have some familiarity with time-tables for south Devon; in one area equinox spring tides can span about 5.5m while neap tides may only be a couple of metres.

Title: What happens with tides as the seasons change?
Post by: Karen W. on 26/03/2008 20:41:10

Thanks techmind... It is certainly more complicated then I had thought!! Lol... I have a couple questions but need a few minutes to ask them properly!

Title: What happens with tides as the seasons change?
Post by: lyner on 18/04/2008 21:45:42

Quote

(In the UK at least) tides are especially extreme at the equinoxes, i.e. Easter and late-September, and are generally weaker towards mid-winter and mid-summer. I'm not exactly sure of the geometry of why this should be so. I'm guessing it probably has to do with the sun and moon having similar tracks across the sky at that time of year?

Tides are strongest when the Sun and Moon lie on a line through the Earth. This is around the Equinoxes. When there are eclipses (solar or lunar) there will be very extreme tidal levels. It's amazing that relatively small angles seem to make such a difference; it must be due to vector addition of forces.