Collaborative Research: Wind turbulence over shoaling surface waves and their impact on air-sea fluxes

This project will investigate the exchange of momentum and energy across the air-water interface at the sea surface using a wave-following Large Eddy Simulation (LES) in combination with flow visualization tools in a wind-wave facility. The overall objective is to better understand modulation and possible enhancement of drag coefficient due to shoaling waves.

The results will contribute to the development of accurate parameterizations of sea state dependent air-sea fluxes, which can be incorporated in the ongoing coupling efforts for atmosphere-wave-ocean weather and climate models (storm surge models in particular). The project includes linkages with education and outreach initiatives at the University of Rhode Island and University of Delaware.

These include training for graduate students in science education pedagogy, effective outreach strategies, and science communication; summer fellowships in Research Education for Undergraduates (REU); Laboratory visits for schoolchildren and other groups; and open houses.

In coastal waters both observational and modeling studies show that the drag coefficient is significantly enhanced by shoaling waves as waves slow down and become steeper. However, the existing models significantly underestimate the shoaling wave effect. This project will investigate how the shape of shoaling waves is modified by wind forcing and how that wave shape alters the wind (turbulence) field above the wave.

The PIs hypothesize that coupled interaction between wave shape and wind forcing enhances the drag coefficient over shoaling waves. To test this, they will combine high resolution laboratory observations and large eddy simulation (LES). The LES results will be validated against observations and extended to investigate the impact of shoaling waves on scalar fluxes.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.