17.3 Storm Surges
Storm winds blowing over shallow, continental shelves pile water against the coast. The increase in sea level is known as a storm surge. Several processes are important:
See Jelesnianski (1967, 1970) and §15.5 for a description of storm-surge models SPLASH and Sea, Lake, and Overland Surges from Hurricanes SLOSH used by the National Hurricane Center and §15.5.
To a crude first approximation, wind blowing over shallow water causes a slope in the sea surface proportional to wind stress.
where ζ is sea level, x is horizontal distance, H is water depth, T0 is wind stress at the sea surface, ρ is water density; and g is gravitational acceleration.
If x = 100 km, U = 40 m/s, and H = 20 m, values typical of a hurricane offshore of the Texas Gulf Coast, then ζ = 2.7 Pa, and z = 1. 3 m at the shore. Figure 17.9 shows the frequency of surges at the Netherlands and a graphical method for estimating the probability of extreme events using the probability of weaker events.
|Department of Oceanography, Texas A&M University
Robert H. Stewart, email@example.com
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Updated on November 15, 2006