Wave evolution across the Louisiana shelf

Observations and third-generation wave model hindcasts of ocean surface gravity waves propagating across the Louisiana shelf show that the effects of the mud environment on wave evolution are complex and episodic. Whereas low-frequency waves (0.04–0.20 Hz) show a consistent decay similar to earlier studies, the presence of mud also appears to suppress the development of short waves (0.20–0.25 Hz) under fetch-limited growth conditions. Significant suppression of wave development under wind-forced conditions is found to occur almost exclusively during easterly winds when satellite images show the Atchafalaya mud plume extends into the study area. These results suggest that episodic sediment suspension events with high mud concentrations in the upper water column can affect the evolution of wind waves.

► New observations of wave transformation across the Louisiana inner shelf are presented. ► Analysis and model comparison suggests that effects of mud on waves are episodic. ► Presence of mud affects wave energy balance during fetch-limited wave growth conditions. ► Wave growth in shallow water during fetch-limited conditions is affected by the dynamics of the Atchafalaya mud plume.