抄録
When winds blow over the surface of sea where steady comparatively strong currents exist, energy fed from the winds to waves per one wave length is increased or decreased according as the waves travel against the currents or down the currents. Consequently, wave height of a single train of sine waves must be increased or decreased by a factor derived from the hydrodynamical equations, compared with the case of waves generating on a still water surface. The rates of increase or decrease of a significant height for waves with random phase generating on a surface of currents have been derived. The rates are found to be related to U cos θ/v where U cos θ is the component of the current velocity in the direction of waves and v the anemometer wind speed. Results of actual wave observations made by Ryofu-maru IGY cruise, June 1957 on the sea off the Sanriku district, Japan, show rough agreement with the above theory.
