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RQM/MEOPAR TReX Graduate Students & Postdoc Awards
Eddies, or deviations from the mean flow, are crucial in the redistribution of the important oceanic quantities such as heat, salt, nutrients from submesoscale to the ocean basin itself (Rypina et al., 2016). Especially in a highly dynamical coastal region with massive sediment transport and significant freshwater influence (e.g., St. Lawrence River Estuary), these lateral mixing and diffusion process could locally dominate the spreading and dispersion of nutrients, contaminants and sediments, which are important for the marine environment and ecosystem. Conventionally, the efficiency of eddies in tracer transport has been represented by eddy diffusion, and this diffusion provided a simple and effective way to account for the unresolved and under resolved scales of motion in the numerical models. Thus, a valid and correct estimation of diffusivity coefficients are very important for the numerical simulation of the tracer dispersion under a specific coastal ocean setting. Therefore, my research project uses a few different methods to estimate the diffusivity coefficients and dispersion regimes at the St. Lawrence river mouth from radar-based surface velocities as a complementary to the drifter-derived diffusivities. Then further validate these estimations by comparing the reproduced simulation of dye spreading in the radar domain with observed dye concentrations along the R/V track.
