![]() The successive high or low tides are approximately of the same height.Īlthough tides occur twice a day, their interval is not exactly 12 hours. The most common tidal pattern, featuring two high tides and two low tides each day.Tides based on Frequency Semi-diurnal tide Tides may be grouped into various types based on their frequency of occurrence in one day or 24 hours or based on their height.Tides vary in their frequency, direction and movement from place to place and also from time to time.Because there are two high tides and two low tides every day (slightly more than a 24 hour period) then a tide must come in within about a six hour period.The highest tides in the world occur in the Bay of Fundy in Nova Scotia, Canada.When the tide is channeled between islands or into bays and estuaries they are called tidal currents (tidal bore is one such tidal current). Funnel-shaped bays greatly change tidal magnitudes.The shape of bays and estuaries along a coastline can also magnify the intensity of tides.When tidal bulges hit the mid-oceanic islands they become low. ![]() The tidal bulges on wide continental shelves, have greater height.On the surface of the earth, the horizontal tide generating forces are more important than the vertical forces in generating the tidal bulges.Irregularities in the configuration of the oceans.Uneven distribution of water over the globe.Changes in position of the sun and moon in relation to the earth.The movement of the moon in relation to the earth.It creates the second bulge away from the moon.įactors Controlling the Nature and Magnitude of Tides Hence, there is a net force away from the moon. On the opposite side of the earth, the attractive force is less, as it is farther away from the moon, the centrifugal force is dominant.On the surface of the earth, nearest the moon, pull or the attractive force of the moon is greater than the centrifugal force, and so there is a net force causing a bulge towards the moon.the gravitational attraction of the moon and the centrifugal force. ![]()
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