Jul 2026· Journal of Physical Oceanography· 0 citations
Abstract
Direct observations of coherent turbulent structures at the base of the ocean surface boundary layer are rare. Here, we present a unique dataset from a drifting thermistor chain that captured temperature structures associated with mixed layer and transition layer turbulence. Following a storm with wind speeds up to 15 m s
−1
, the mixed layer deepened from 35 to 45 m depth over 6 days. Within the transition layer we observe temperature fluctuations indicative of shear-driven turbulence, including features consistent with Kelvin-Helmholtz and Holmboe instabilities. We examine the size and frequency of these structures in the context of the surface forcing, identifying four distinct regimes based on wind, wave, and surface heat flux magnitude. Thorpe scale–based estimates of entrainment velocity align with the observed mixed layer deepening when averaged over the upper portion of the transition layer. This rare observational dataset offers new insight into the mechanisms controlling mixing at the base of the mixed layer and provides a valuable benchmark for future numerical studies of stratified turbulence that resolve turbulent overturns.
Current understanding of the role of ocean variability in air-sea exchange is constrained to large and mesoscale dynamics. Oceanic fronts and filaments with horizontal spatial scales of order 0.1 to 10 km-denoted submesoscale-are challenging to observe due to their fast-evolving flow and small spatiotemporal scales of...
I. Uchoa, J. Wenegrat, A. Kinsella et al.· Proceedings of the National...· 0 citations
Understanding mixing at density interfaces is essential for predicting transport in stratified environmental flows. Laboratory studies have mostly relied on steady, spatially uniform forcing, whereas turbulence in nature is intermittent and heterogeneous. Here, we present experiments on a two-layer salt-stratified flui...
No'e Clavier, Hugo Pradel, R. Volk et al.· 0 citations
Abstract Content of image described in text. At large scales, the Reynolds stress tensor exhibits notable anisotropy, a key feature of all wall-bounded turbulent flows. Yet, how the drivers of this anisotropy evolve with shearing and thermal stratification in the atmospheric surface layer (ASL) remains a daunting chall...
Ivana Stiperski, G. Katul, E. Bou‐Zeid et al.· Journal of Fluid Mechanics· 0 citations
Several series of numerical experiments were conducted to generate a mesoscale eddy in a deep rotating basin (4000 m deep) with stratification typical of mid- and low-latitude of the World Ocean, including an upper mixed layer, a density jump layer, and a main pycnocline. A sea level anomaly driven by Ekman transport c...
V. Zhurbas, N. Kuzmina· Fundamental and Applied Hydr...· 0 citations
