2012 年 68 巻 2 号 p. I_36-I_40
If current effects on waves (CEW) are considered, the offshore extent of rip currents can be significantly suppressed by wavenumber modulation associated with wave ray bending (Weir et al., 2011). In the present study, a two-dimensional shallow-water model based on Regional Oceanic Modeling System (ROMS) with wave effects on slowly-evolving littoral currents through a vortex-force formalism, coupled tightly with WKB refraction equations, is used to examine dynamic effects essential to development of rip currents. If CEW is taken into consideration, wave ray bending occurs with a modified wavenumber field that changes the alongshore pressure gradient force and the cross-shore component of acceleration due to wave breaking through wave shoaling, leading to the reduction of the extent of rip current.