Correlation of micro-and macroscopic structures of wind waves

Simultaneous measurements were conducted in a wind-wave tank of the ripple slopes with an optical instrument and of the carrier-wave profiles with a wave-height gage. The experiments were conducted with steady winds of various velocities blowing over pre-existing regular surface waves. The data were analyzed to determine the slope distributions of ripples located on various portions of the carrier-wave profile. In the surface-tension governing regime of wind-wave interaction, the leeward face of the long wave was found to be much rougher than the windward face. The parasitic capillaries were concentrated on the upper half of the leeward face at a lower wind velocity, and moved downward at higher wind velocities. In the gravity governing regime, the difference in roughness between the leeward and the windward faces became smaller. However, the roughnesses on the leeward face were concentrated on the lower half of the wave profile.