A universal form for shoreline run‐up spectra?

摘要: Time series of shoreline run-up on two natural beaches have been measured by using a time-lapse camera. Spectra these time and other spectra Suhayda (1972) suggest that for the frequency band over which incident waves are large enough to break universal ‘saturation’ form vertical spectrum occurs, with energy density E(ƒ) = [∈ˆcsgβ2/(2πƒ)2]2, where g is gravitational acceleration, β beach slope, ƒ (in hertz). Parameter ∈ˆcs(Δƒ)½ nondimensional constant, found value about 1, Δƒ bandwidth in surf zone. This result discussed relation previous laboratory experiments theories, based monochromatic waves, existence limiting amplitude standing formed reflection at shoreline. related critical parameter ∈cs ∈csgβ2/(2πƒ)2. A possible interpretation terms given percentage exceedances downslope acceleration gβ2. In this we assumed Gaussian distribution acceleration. assumption cannot be tested directly, but observed functions elevation it may need modified. Departures from athigher lower frequencies briefly discussed.