Observations of the Subsurface Structure of TKE Dissipation Rates Near the Martha's Vineyard Coastal Observatory

We present observations of subsurface turbulent kinetic energy (TKE) dissipation rates under moderate‐to‐strong wind forcing on the western North Atlantic shelf. Estimates derived using the structure function method show a clear enhancement relative to law‐of‐the‐wall expectations in the upper water column, with convergence toward rigid‐wall scaling at greater depths. This near‐surface enhancement is consistent with wind energy input into the wave field, suggesting that wave breaking is the primary driver. The data reveal a two‐layer structure: an approximately constant TKE dissipation rate near surface, followed by a region where dissipation decays with depth as . This profile aligns with previous observations by Terray et al. (1996), https://doi.org/10.1175/1520‐0485(1996)026<0792:EOKEDU>2.0.CO;2 and Sutherland and Melville (2015), https://doi.org/10.1175/jpo‐d‐14‐0133.1 . The constant dissipation layer is confined to the upper portion of the water column, extending to depths less than approximately one‐third of the significant wave height. Below this layer, dissipation remains elevated relative to background levels, with the enhancement extending to depths of 5–6 times the significant wave height. We propose that this deeper extent defines the wave‐affected layer driven by breaking and transport processes, while the approximately constant dissipation region marks the breaking layer dynamically constrained by wave breaking. Therefore, under open ocean conditions, the temporal and spatial scales of the breaking layer should be representative of the higher‐frequency waves that dominate wave breaking.