A multiscale framework for air-sea interaction

Understanding tropical cyclones´ intensification represents a crucial challenge for the scientific community.

A pivotal role in this process is played by sea spray, which is the myriad of droplets generated by the wind breaking the sea surface.

Once ejected, these droplets can be transported across the atmospheric boundary layer, where they modulate the mass and heat exchanges between the ocean and the atmosphere.

Given the wide range of scales involved in the problem, from drops to atmospheric forcing, and the difficulty in performing field measurements at high wind speed, a physical understanding is lacking. In this project, we propose to develop a new insight into the physics of sea spray at high wind speed.

In particular, we aim to construct a rigorous framework that accounts for the different length scales involved, from small drops formed by wind tearing to larger oceanic scales.

Spray formation and evaporation will be considered by solving the physics from microns to meters scales and by including the effects of a strong turbulent wind shear at the ocean surface.

These simulations will inform a coarse-grained model which solves for an ensemble of breaking waves forced by realistic wind speed at kilometric scales. The final aim is to propose a new formulation for ocean-atmosphere fluxes under high wind speed.

Overall, we will cover up to six orders of magnitude of length scales, reveal the fundamental physics of sea spray and address relevant geophysical challenges.