11:45 AM - 12:00 PM
[AOS19-05] Nearshore wave–current interaction effects on wave power density near Japan
Keywords:Wave resource assessment, Wave–current interactions, Wave power density, Doppler-shift, NOAA WAVEWATCH III
For countries with extensive coastlines such as Japan, energy harvested from surface ocean waves has the potential to be a notable source of green energy. Along many southern parts of Japan however, a strong Kuroshio current flows near the coastline, with surface velocities routinely exceeding 1 m/s. Wave-current interactions (WCI) in such regions can significantly modify the wave resource both locally and remotely and is a source of epistemic uncertainty in many assessments.
In order to quantify these nearshore effects, comparisons are conducted here between long-term (21 years) and high-resolution (1 km) wave resource assessments of Japan with and without WCIs included (Webb et al., 2020). The wave resource assessment (named TodaiWW3) is based on NOAA WAVEWATCH III (version 4.18) simulations using NCEP and JAMSTEC forcings, and includes a new Doppler-shifted wave power density formulation.
In general, short-term differences in wave power due to changes in the wave field alone can be exceptional (over 80%), while longer-term differences are often offset by the Doppler-shift in the group velocity. In this study, the largest long-term differences occur in the nearshore Kuroshio region, with overall differences (and relative differences) between 21-year climatologies of wave power density reach 3 kW/m (and approximately 20%). Further details of the comparison will be discussed, including the underlying mechanisms of change and the role of the Doppler-shift in the wave power density equation.
References:
A. Webb, T. Waseda, and K. Kiyomatsu, 2020. A high-resolution, long-term wave resource assessment of Japan with wave–current effects. Renewable Energy, 161:1341–1358. doi:10.1016/j.renene.2020.05.030.
In order to quantify these nearshore effects, comparisons are conducted here between long-term (21 years) and high-resolution (1 km) wave resource assessments of Japan with and without WCIs included (Webb et al., 2020). The wave resource assessment (named TodaiWW3) is based on NOAA WAVEWATCH III (version 4.18) simulations using NCEP and JAMSTEC forcings, and includes a new Doppler-shifted wave power density formulation.
In general, short-term differences in wave power due to changes in the wave field alone can be exceptional (over 80%), while longer-term differences are often offset by the Doppler-shift in the group velocity. In this study, the largest long-term differences occur in the nearshore Kuroshio region, with overall differences (and relative differences) between 21-year climatologies of wave power density reach 3 kW/m (and approximately 20%). Further details of the comparison will be discussed, including the underlying mechanisms of change and the role of the Doppler-shift in the wave power density equation.
References:
A. Webb, T. Waseda, and K. Kiyomatsu, 2020. A high-resolution, long-term wave resource assessment of Japan with wave–current effects. Renewable Energy, 161:1341–1358. doi:10.1016/j.renene.2020.05.030.