Alex Ayet

CNRS Researcher (CRCN)
Signal-Images-Physics (Sigma-Phy) team
Grenoble Images Speech Signal and Control laboratory (GIPSA-lab)
Grenoble, France
Send an email alex.ayet@(remove)normalesup.org


I am a (permanent) CNRS researcher in the Sigma-Phy team at GIPSA-lab (Grenoble). Previously, I was a post-doctoral researcher at the globc and TROPIC²S teams, respectively at CERFACS and CNRM (Toulouse). I completed my PhD in physical oceanography in the SIAM team at LOPS, IFREMER (Brest), on the topic of theoretical models for wind-wave interactions.

[PhD manuscript PDF]

I work on theoretical aspects of air-sea interactions in the presence of waves, with an emphasis on momentum and heat fluxes variability, and how these might impact large scale atmospheric circulation. My research interest lies in the intersection between applied mathematics and geophysics. In particular on theoretical models for air-sea interactions, and statistical and machine learning approaches to geophysics mixing satellite data and numerical models. I have a strong interest in developing methods and results that can be applied to climate or weather forecasting.

I am also a member of Atécopol Toulouse, an interdisciplinary political ecology lab.

Remote sensing of atmospheric turbulence and air-sea interactions

Satelite images of the sea-surface roughness (SAR images and visible sunglint images) contain information on the instantaneous variations of near-surface winds and currents (through their interaction with surface roughness - wind-waves). I work on statistical methods to analyse these images and extract physical information (laws) on atmospheric turbulence (both dry and moist) and on how it is affected by ocean currents and temperature fronts.

Surface boundary layer turbulence, fluxes and wind-waves

Surface momentum fluxes at the air-sea interface depend on the interaction between atmospheric turbulence in the surface boundary layer (first 10m) and wind-waves. Turbulence generates waves which in turn affect turbulence. This coupled mechanism is complex because it is multiscale: waves of different wavelengths affect turbulence at different scales, through different physical processes. From a parameterization standpoint, this implies uncertainties on the environmental parameters driving air-sea fluxes. I addressed (during my PhD) and continue to address these problems using theoretical turbulence models describing this multiscale complexity.

The physical mechanisms driving the interaction between atmospheric turbulence and wind-waves depend on the scale of the waves, and can affect both the turbulent streamlines (dark arrows) and the vortical coherent structures (red tubes). Check out my review for more !