Wave Refraction at Redondo Beach, California (Comparison of Field Measurements with Models).

摘要

The U.S. Army Corps of Engineers has investigated various measures for storm damage reduction at Redondo Beach/King Harbor, CA. Numerical models have been used to investigate the effects of local bathymetry on the transformation of deepwater swell. Documents produced by the U.S. Army Engineer District, Los Angeles, point out discrepancies between these model computations and observations during actual storms in 1983 and 1988. The Los Angeles District also questioned the accuracy of theoretical models in general, for areas of complex bathymetry such as Redondo Beach, and argued that the results from the RCPWAVE model 'misrepresent actual conditions.' There has been a growing consensus to call for the testing of model capabilities. This report responds to that call, and compares results from the refraction model RCPWAVE to measured waves near the Redondo breakwaters. The study also compares results from the spectral refection model STWAVE against tile same measurements. Results of these comparisons are as follows: (a) Computations from both RCPWAVE and STWAVE are in poor agreement (low correlation coefficients) with the field measurements for H > 1.5 m. (b) RCPWAVE tends to overestimate wave heights in general. (c) STWAVE wave heights appear to be more accurate than RCPWAVE, but their underestimations may be unacceptable in some cases. (d) Both the field measurements and the model computations indicate no significant tidal influence on wave transformation. (e) Field measurements fail to support the wave-height relationship H = kH(o) inherent in the model computations. (f) Correlation changes significantly with increasing measured wave height. Therefore, extrapolation of the present results beyond those measured (3.3 m for maximum Ho) requires caution.