This paper discusses topographical effect on nearshore wave climate using measured and hindcast data over a decade at 4 neighboring coastal stations. The main conclusions are that wave climate at the coastal area greatly varies due to the sheltering effect of the surrounding geophysical conditions and that a long term wave hindcast system with use of a high topographical resolution under input conditions of ECMWF analysis surface wind data produces an accurate and quick estimate of wave climate changing location by location.
It is of crucial importance to properly estimate long term wave characteristics, the so-called wave climate at a coastal sea area, for the utilization of wave energy, the analysis of beach process related to coastal sediment transport and so on. Yamaguchi et al. (1997, 2000)and Hatada et al. (1998, 2000a, 2000b)have established a long term wave hindcast system using a shallow water wave prediction model based on a backward ray tracing, in which 6 hourly ECMWF(European Centre for Medium-range Weather Forecasts) analysis surface wind data over the period of 20 years from 1979 to 1998 is consecutively given as input data. Comparison with the measurement data or the ECMWF analysis data produced by WAM over long years has verified that the system using a nesting grid with high topographical resolution enables a proper and quick evaluation of wave climate over 20 years at several locations not only in open sea but also in coastal waters around the Japanese sea areas of the Northwestern Pacific Ocean and that the accuracy is comparable to that of the WAM-based system, specifically much higher for coastal waves (Hatada et al., 2000b).
