![]() ![]() Complicating effects needed to account for real tides: standing waves and Coriolis effects.Forced-wave nature of the tides, which accounts for the phase lags observed.How the Earth’s rotation under the tidal bulges accounts for the observed tidal variations. ![]() Forces involved in generating the tides, and the origin of the tidal bulge.Here’s the plan of action for this section on the tides: (It might trouble you, though, that the times of high and low tides are not coincident with the times when the moon is overhead more on that later.) This was known in ancient times, and probably in even more distant prehistoric times. It doesn’t take much brilliance on anybody’s part to relate the tides to the moon, because of identity of tidal periods and lunar periods. What would you observe? In most places, you would find regular and systematic fluctuations in water level with dominant “periods” of about half a day or about one day, together with more subtle longer-term patterns on time scales of months and even years.Īnd if you then set up a similar tide gauge in a different place, you would find the same general effect (and the same frequency) but with differences in details of the shape of the time record, and also differences in timing of highs and lows.Īs you all know, these effects you’re observing are the tides. Go to any seacoast and build a tide gauge to obtain a record of sea level as a function of time (over a period of weeks or months) by somehow damping out or averaging over or filtering out the effects of waves on time scales of seconds and storms on time scales of days to weeks. ![]()
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |