高潮災害における副振動の影響

抄録

The effect of long period oscillation (LPO) is usually neglected for storm surge prediction because it is hidden behind high waves. We observed a big LPO (amplitude was about 0.5m and period was about 5 minute) at Shimohaya Bay in Wakayama Prefecture in a storm. The LPO in storm surge condition would raise the water level of 0.5m, which causes the increase of wave overtopping and wave force on coastal structures. Power spectra of wind and wave group were compared with that of LPO. Periods of around 5 minutes are predominant in sea wind and wave group, and they are sameas the resonance period of Shimohaya Bay.