Estimation of Surface Gravity Waves from Subsurface Pressure Records for Estuarine Basins

摘要

According to small-amplitude theory, the surface gravity-wave energy spectrum can be estimated from a subsurface pressure-fluctuation spectrum by applying a factor K that compensates for the attenuation of surface-wave amplitude as the depth below the water surface and the wave frequency increase. There are a number of linear and nonlinear environmental factors, however, that cause K to be invalid over most of the spectrums frequency range. Numerous attempts have been made to empirically derive a valid correction factor n that could be applied to K to give a better estimate of the surface spectrum. This report discusses some of the reasons why the empirical factors vary so greatly and recommends Graces' (1978) equation for n as a function of the non-dimensional frequency parameter kh specifically for use in an estuarine environment.