3 - Sea level fluctuations and changes
from Part II - Coastal Processes
Summary
Synopsis
While the incident wave climate is the dominant process variable controlling changes in coastal form and evolution, changes in the relative level of the land and the water body, on a variety of time scales, can greatly influence the effect of these processes and the way in which coastal; evolution occurs. Dynamic changes in sea level on the order of hours to a few decades reflect response of the water surface to meteorological and oceanographic processes as well as tides and can be thought of as periodic or episodic deviations about mean sea level. They affect the level at which wave action occurs and may also lead to horizontal movements of water in tidal and other currents. They thus have an effect on coastal erosion, transportation and deposition. In addition to tides produced by the gravitational force of the moon and the sun, short-term fluctuation in sea level occur as a result of storm surge, seasonal variations in pressure and wind patterns and changes in weather patterns on a scale of years to decades such as the El Niño Southern Oscillation (ENSO) cycle in the Pacific. These fluctuations are also extremely significant ecologically, both directly through exposure and coverage of the intertidal zone and indirectly because of the movements of water and nutrients associated with the water level fluctuations.
- Type
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- Introduction to Coastal Processes and Geomorphology , pp. 19 - 51Publisher: Cambridge University PressPrint publication year: 2009