The Impacts of Gustiness on the Evolution of Surface Gravity Waves

Abstract

Surface gravity waves are formed by kinetic energy transfer across the air-sea interface. Significant improvements have been made in understanding the influence of wind on the energy input of waves. However, the impact of gustiness remains underexplored, and little is known about the mechanisms through which gusts alter the wavy surface. In this study, we utilize three-months observational data collected during the 2010 Impact of Typhoons on the Ocean in the Pacific experiment to investigate the relationship between waves and gustiness. Results show that gustiness increases sea roughness and wave energy, leading to wave development beyond the theoretical peak of Pierson-Moskowitz spectrum. We further find that the Hasselmann enhancement factor linearly increases with gustiness, indicating gustiness alters the wave development. We suggest that this occurs via two pathways, first, through direct coupling between swell and gustiness which increases wave-wave interaction, and second through instantaneous reduction in wave age.