Eddies and the Transition Layer in Hawaiʻi
How mesoscale and submesoscale interactions structure the ocean between the mixed layer and the interior
About this project
The ocean transition layer — the region between the turbulent mixed layer and the quiescent interior — remains one of the least constrained regimes in upper ocean dynamics. Within this layer, mesoscale stirring, submesoscale instabilities, and internal waves all act to redistribute heat, salt, and energy across density surfaces. Despite its central role in controlling mixing, tracer transport, and acoustic propagation, the processes that govern it are poorly resolved in both observations and models.
The Hawaiian archipelago is a particularly good example of a region where these processes are active and accessible. The islands intercept the North Equatorial Current and disrupt the trade winds, generating a persistent field of lee eddies. Simultaneously, remotely generated eddies propagating from the eastern Pacific modify stratification and tracer distributions throughout the archipelago. This two-source eddy environment produces a richly structured transition layer between 100 and 400 m depth that presents a clear opportunity to study cross-scale interactions under well-defined forcing conditions.
Our work addresses three questions: where does thermohaline variance transition from stirring to dissipation, how do lee eddies structure the transition layer and generate submesoscale variability along isopycnals, and whether energy cascades forward to dissipation or feeds back to the mesoscale. These questions have direct implications for how tracers are transported and where acoustic propagation conditions are set.
Approach
We combine existing observations from the HOT program, PacIOOS, and NOAA glider surveys with targeted fieldwork using Seagliders, Wirewalkers, and microstructure profilers. Observations are interpreted alongside high-resolution regional model output to evaluate mixing scales and energy transfers across the mesoscale–submesoscale boundary.
Interested in joining this project?
We are looking for graduate students interested in observational physical oceanography, autonomous platforms, and upper ocean dynamics. If this work sounds like a good fit, please reach out.