Study of Evolving Young Wind Waves Under Steady Wind Forcing

In this work, a comprehensive experiment is conducted to investigate the spatio-temporal variability of young wind waves under steady wind forcing. The experimental setup included a wave tank equipped with a wind blower capable of generating a wide range of wind velocities. Wave elevation was measured at various airflow rates and fetches using a capacitance-type wave gauge. The spatial growth rates of young waves at different frequencies were assessed by analyzing wave gauge records taken at multiple fetches. In every case of wind blowing, the growing wave field exhibited strong nonhomogeneity, with an increase in wave energy along the wave channel accompanied by a decrease in frequency. Notably, the findings from the experiments reveal that young wind waves lose their temporal coherence within three local dominant wave periods, regardless of wind velocity and fetch. The limited temporal and spatial coherence of gravity-capillary and short wind waves has significant implications for radar remote sensing of the ocean surface.