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Storm Surge Storm Surge: the abrupt bulge of water driven ashore by a storm.

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Presentation on theme: "Storm Surge Storm Surge: the abrupt bulge of water driven ashore by a storm."— Presentation transcript:

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3 Storm Surge Storm Surge: the abrupt bulge of water driven ashore by a storm

4 Seiche: Pendulum-like rocking of water in an enclosed area For example: water sloshing in a bucket, bathtub or bay

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6 Causes of Seiches: Winds Change in atmospheric pressure Example: Lake Geneva Constant breezes pushed the water to one end of the lake. When the wind subsided, the water is released to rock back and forth

7 Tsunami or Seismic Sea Waves: Long-wavelength, shallow-water progressive waves caused by the rapid displacement of ocean water Japanese: Tsu = harbor, nami = wave Tsunami caused by the suddeen vertical movement of Earth along faults are properly called seismic sea waves can also be caused by landslides, icebergs falling from glaciers, eruptions, and other displacements

8 Due to the extremely low steepness and the waves very long period, a tsunami will pass unnoticed beneath ships at sea (1 to 2 feet total wave height) At shore the wave height greatly increases (as high as 100 feet) The wave is a fast, onrushing flood of water, not the huge, plunging breaker of popular folklore http://www.asiantsunamivideos.com/ Tsunami Warning Network

9 Tides: periodic, short-term changes in the height of the ocean surface at a particular place caused by a combination of the gravitational force of the moon and the sun and the motion of the Earth With a wavelength that can equal half of Earth’s circumference, tides are the longest of all waves. Forced waves: never free of the forces that cause them

10 In case you didn’t know: The Earth and the moon do not smash into each other because they are in a stable orbit The Earth-moon system revolves once a month (27.3 days) around the system’s center of mass

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13 High tide: The high water position corresponding to a tidal crest Low tide: The low water position corresponding to a tidal crest Lunar tide: tides caused by gravitational and inertial interaction of the moon and Earth Tidal day: 24 hours and 50 minutes (each tide arrives 50 minutes later each day) Also, the moon does not stay right over the equator throughout the year, tides fluctuate depending on location Solar Tide: caused by the gravitational and inertial interaction of the sun and Earth

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15 Spring Tide: large tides caused by the linear alignment of the sun, Earth, and moon. Occur at two- week intervals corresponding to the new and full moons. Very high high tides and very low low tides Neap Tide: occur when the moon, Earth, and the sun form a right angle. Also occur at two-week intervals but with not very high high tides and not very low low tides

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17 As Earth turns, land masses get in the way The shape of the ocean basin also has an influence, combined they create: Semidiurnal Tides: two high tides and two low tides of nearly equal level each lunar day Diurnal Tides: one high and one low

18 Tidal Bore: will form in some inlets exposed to great tidal fluctuations, true tidal wave: steep wave moving upstream generated by the action of the tidal crest in the enclosed area of a river mouth


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