Quantifying robustness of mixing diagnostics inferred from satellite altimetry

Satellite altimetry offers an unprecedented view of the global surface ocean eddy field. This is achieved by estimating geostrophic velocities directly from fluctuations in sea-surface elevation relative to the geoid. In recent years, a number of studies have made use of altimetry data to advect virtual tracers and floats, and thus infer mixing diagnostics in the surface ocean. However, the reliability of these diagnostics is unclear: in particular, the effect of unresolved scales on eddy transport processes cannot be quantified.

In this work, we examine a range of Eulerian and Lagrangian mixing diagnostics in simulations of quasi-geostrophic and surface quasi-geostrophic turbulence and directly probe their dependence on sampling resolution. In this way, we aim to quantify the robustness of altimetry-inferred mixing diagnostics.