If Earth and the Moon are aligned so that the Moon is north or south of Earth's equator, one tidal bulge will be in the Northern Hemisphere and one in the Southern Hemisphere. A point in the middle latitudes passes through only one crest and one trough during each tidal day. This type of diurnal tide is called a declination tide, because the Moon is said to have declination when it stands above or below the equator and not perpendicular to it.
The Sun also influences declination tides when it is aligned over 23.5 degrees north or south latitude at the summer and winter solstice. The variation causes the bulge created by the Sun to oscillate north to south, making a more diurnal Sun tide during the winter and summer months. The Moon's declination is at 28.5 degrees north to south latitude, and because
The Bay of Fundy (between New Brunswick and Nova Scotia, Canada) experiences the highest tidal range in the world. At low tide (shown here), coastal waters are temporarily reduced to mud flats.
the orbit is inclined 5 degrees to the Earth and Sun orbit, it takes 18.6 years for the Moon to complete its cycle of maximum declination.
Also, the Moon does not move around Earth in a perfectly circular orbit and Earth does not circle the Sun at a constant distance. In the Northern Hemisphere, Earth is closer to the Sun in the winter months, so the solar tides play a greater role as a tide producer in the winter than summer.
Read more: Tides - building, river, sea, depth, oceans, effects, important, largest, system, wave, effect, marine, Pacific http://www.waterencyclopedia.c...s.html#ixzz1PP3J3DI7