New simulations improves interpretation of high-resolution satellite imagery of surface water

High-resolution satellite imagery of surface water can enable a better understanding of small-scale water dynamics, yet these submesoscale dynamics remain an open question for researchers.

To better understand the mechanisms behind surface ocean turbulence, Maalouly et al. simulated submesoscale water dynamics.

The team found that “non-geostrophic” ocean currents at small scales cause tracer particles to cluster in cyclonic frontal regions, which is consistent with drifter observations. Interestingly, the motions of these currents did not significantly affect the large-scale separation of these particles, underscoring the importance of submesoscale processes in understanding local particle behavior. This finding may have broader implications for ocean circulation and turbulent transport.

“The critical insight here is that the Surface Water and Ocean Topography (SWOT) satellite geostrophic fields, which measure the dynamics of surface oceans, do not account for non-geostrophic motions, and consequently, particle advection using these fields would not reflect the observed particle clustering in the ocean,” author Michael Maalouly said. “Conversely, particle dispersion statistics can be relied upon to some extent, as they remain unaffected by the absence of these non-geostrophic dynamics. To the best of our knowledge, this study appears to be novel in its examination of the influence of non-geostrophic dynamics’ intensity on Lagrangian transport.”

The team employed a model based on the Surface Quasi-Geostrophic model that includes non-geostrophic dynamics related to ocean fronts, introducing Lagrangian tracer particles into the flow to understand the trajectory and behavior of those particles.

Maalouly said the team has more avenues to explore, such as looking into more realistic simulations.

Source: “Particle dispersion and clustering in surface ocean turbulence with ageostrophic dynamics,” by Michael Maalouly, Guillaume Lapeyre, Bastien Cozian, Gilmar Mompean, and Stefano Berti, Physics of Fluids (2023). The article can be accessed at https://doi.org/10.1063/5.0174665 .