A METHOD TO ASSESS THE IMPACT OF CLIMATE CHANGE ON BEACH TOPOGRAPHY

Abstract

 To clarify the effect of climate change on beach topography, we analyzed future changes of wave climate in Kochi coast and Tottori coast. We proposed a method to assess the impact of climate change on beach topography separately for typhoon and non-typhoon periods by wave simulation for each of 2, 000 typhoons in the present and future climates using d4PDF, and estimating future changes in wave energy and wave direction together with wave projection data. In Kochi coast, the influence of typhoons is more dominant than that of the non-typhoon period and increases further in the future climate, while in Tottori coast, the influence of typhoons increases to the same degree as that of the non-typhoon period in the future climate, although the influence of the non-typhoon period is significant in the present climate. We also confirmed that future changes in longshore sediment transport will be more strongly influenced by wave direction because the direction and the east-west ratio of sediment transport change due to future changes of wave direction. The probabilistic assessment method proposed in this study could be applicable to other coasts affected by occasional typhoons.