Article
Oceanography
Elizabeth C. Fine, Matthew H. Alford, Jennifer A. MacKinnon, John B. Mickett
Summary: Concurrent mooring and microstructure observations in the Beaufort Sea revealed low turbulent kinetic energy dissipation rates, with finescale parameterization accurately estimating shear to strain ratios and dissipation rates. Depths with high shear showed the largest discrepancies, while near-inertial waves were observed at depths greater than 200 m, but did not show elevated dissipation rates or heat fluxes.
JOURNAL OF PHYSICAL OCEANOGRAPHY
(2021)
Article
Geosciences, Multidisciplinary
Ritabrata Thakur, Brian K. Arbic, Dimitris Menemenlis, Kayhan Momeni, Yulin Pan, W. R. Peltier, Joseph Skitka, Matthew H. Alford, Yuchen Ma
Summary: We propose improvements to the modeling of the vertical wavenumber spectrum of internal gravity waves in regional ocean simulations. Our study focuses on the sensitivity of the model to mixing parameters and compares the results to observations. The findings suggest that improving the mixing parameters can enhance the representation of internal wave dynamics.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Mechanics
Yohei Onuki, Sylvain Joubaud, Thierry Dauxois
Summary: A new technique was developed to assess internal wave-driven mixing in the ocean through direct numerical simulations of stratified turbulence. The study found that the external wave can directly supply energy for turbulence and mixing, and the mixing coefficient tends to increase with the Fr number of the external wave. Disturbances in the model go through two stages, converting wave energy into turbulence energy and eventually dissipating it.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
J. Labarbe, P. Le Gal, U. Harlander, S. Le Dizes, B. Favier
Summary: This paper presents a numerical analysis of the instability in horizontally sheared Poiseuille flow with vertical stratification. The study extends the previous work on the linear instability of this configuration and investigates nonlinear regimes through direct numerical simulations. The results show that the flow loses its vertical homogeneity through a secondary bifurcation and exhibits intermittent dynamics with bursting events and localized shear instabilities.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
Vassili Issaev, N. Williamson, S. W. Armfield, S. E. Norris
Summary: This study investigates the dynamics and parameterization of mixing in temporally evolving turbulent open-channel flow through direct numerical simulations. Three different mixing regimes are observed and the relationship between the mixing coefficient, flux Richardson number, and the gradient Richardson number is analyzed. Scaling relationships between Ri(g) and Fr are derived, and differences in the scaling of L-E/L-O with Fr-1 in the intermediate regime are discussed.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
G. D. Portwood, S. M. de Bruyn Kops, C. P. Caulfield
Summary: This study investigates the impact of turbulent dynamic range on active scalar mixing in stably stratified turbulence and proposes a model framework for irreversible diapycnal mixing under high Reynolds number conditions.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Geosciences, Multidisciplinary
Junbiao Tu, Daidu Fan, Zhiyu Liu, William Smyth
Summary: This study obtained estimates of the flux Richardson number R-f in a strongly turbulent, sediment-stratified estuarine flow. The parameterization based on the turbulent Froude number Fr-t was found to be the most effective.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Oceanography
Elizabeth C. Fine, Sylvia T. Cole
Summary: As Arctic sea ice declines, wind energy is having increasing impacts on the Arctic ocean, potentially affecting ocean mixing, stratification, and turbulent heat fluxes. There are relationships between near-inertial energy and ice concentration and draft, influenced by the vertical scales of internal wave energy.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2022)
Article
Oceanography
Till M. Baumann, Ilker Fer, Kirstin Schulz, Volker Mohrholz
Summary: Direct observations of turbulent mixing in the Arctic Ocean are difficult, so Finescale Parameterization (FS) has been used to quantify turbulence. The study found that FS performs well in most conditions, but is less suitable in highly stratified environments.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2023)
Article
Oceanography
Ming-Huei Chang, Yu-Hsin Cheng, Yu-Yu Yeh, Yiing Jang Yang, Sen Jan, Chih-Lun Liu, Takeshi Matsuno, Takahiro Endoh, Eisuke Tsutsumi, Jia-Lin Chen, Xinyu Guo
Summary: Complex small-scale processes and energetic turbulence are observed at a sill located on the I-Lan Ridge that spans across the strong Kuroshio off Taiwan. The current speed above the sill is strong and unsteady due to the Kuroshio being modulated by the semidiurnal tide. Turbulent mixing generates isothermal domes with different vertical scales during low and high tides. The hydraulic characteristics modulated by tides influence the small-scale processes occurring on the leeward side of the sill.
JOURNAL OF PHYSICAL OCEANOGRAPHY
(2022)
Article
Mechanics
C. J. Lloyd, R. M. Dorrell, C. P. Caulfield
Summary: A simulation of stably stratified plane Poiseuille flow at moderate Reynolds and Richardson numbers reveals the dynamics described as a series of internal waves with linear dispersion relationship in the channel core. The visualizations show the presence of hairpin vortices dominating the outer region and being different from the ones observed in unstratified boundary layer flows. Outer region ejection events induced by high amplitude waves transport the hairpin vortices into the channel core, generating high-amplitude internal waves, high dissipation, and wave breaking.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
H. Lam, A. Delache, F. S. Godeferd
Summary: The study focuses on the strong stratification regime of stably stratified turbulence and the viscosity-affected stratified state, decomposing the three-dimensional velocity-density fields into internal gravity waves (IGWs) and eddy motion. Separate evolution equations for IGWs and eddies are established. At Re-b around 1, a significant exchange of energy from IGWs to eddies is observed, while for Re-b > 1, the dynamics of IGWs and eddies appear to be separate with no global energy exchange. The mixing due to eddies is found to be four times greater than that due to waves at the largest Re-b considered.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Miles M. P. Couchman, Stephen M. de Bruyn Kops, Colm-cille P. Caulfield
Summary: Understanding the role of stable density interfaces in turbulent mixing in density-stratified fluids is crucial in geophysical fluid dynamics. By analyzing the correlations between the vertical density gradient ??/?z, the dissipation rates of kinetic energy e, and the scalar variance ? in a single forced direct numerical simulation of stratified turbulence, we find that significant mixing occurs in anisotropic statically stable regions of the flow. Our findings suggest that current parametrizations of turbulent mixing may be biased by undersampling and that further investigation into the role of stable density interfaces is needed.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
Young R. Yi, Jeffrey R. Koseff
Summary: In this study, we revisit and extend the turbulent Froude number scaling for the mixing coefficient by incorporating the effects of mean shear. Through the use of different datasets and simulations, we propose a revised scaling that better applies to vertically sheared turbulence with stable stratification, while also considering additional effects such as radiative heating/cooling and changes in shear direction.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Tanmay Agrawal, Siva Heramb Peddada, Vamsi Krishna Chalamalla
Summary: The study explores the behavior of partial- and full-depth buoyant gravity currents in a linearly stratified medium, finding that in supercritical flow, the velocity exceeds long wave speed producing Kelvin-Helmholtz billows and internal solitary waves. In subcritical flow, the velocity is slower than long wave speed, resulting in the disappearance of Kelvin-Helmholtz billows and solitary waves, and the presence of vertically propagating high-mode internal waves.
Article
Oceanography
Hauke Blanken, Charles Hannah, M. Klymak Jody, Tamas Juhasz
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2020)
Article
Oceanography
A. D. Nelson, B. K. Arbic, D. Menemenlis, W. R. Peltier, M. H. Alford, N. Grisouard, J. M. Klymak
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2020)
Article
Oceanography
Alejandra Sanchez-Rios, R. Kipp Shearman, Jody Klymak, Eric D'Asaro, Craig Lee
DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS
(2020)
Article
Multidisciplinary Sciences
Jacob O. Wenegrat, Leif N. Thomas, Miles A. Sundermeyer, John R. Taylor, Eric A. D'Asaro, Jody M. Klymak, R. Kipp Shearman, Craig M. Lee
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2020)
Article
Oceanography
Olavo B. Marques, Matthew H. Alford, Robert Pinkel, Jennifer A. MacKinnon, Jody M. Klymak, Jonathan D. Nash, Amy F. Waterhouse, Samuel M. Kelly, Harper L. Simmons, Dmitry Braznikov
Summary: Internal tides generated south of New Zealand can propagate over a thousand kilometers before impinging on the continental slope of Tasmania. In situ observations and model results highlight additional features of the internal tide, such as bottom-enhanced tidal energy over small-scale bathymetric corrugations. Despite long-range propagation, the variability in energy density on the slope is mainly accounted for by the spring-neap cycle, indicating a complex interference between remote and local tides.
JOURNAL OF PHYSICAL OCEANOGRAPHY
(2021)
Editorial Material
Oceanography
Jerome A. Smith, Paola Cessi, Ilker Fer, Gregory Foltz, Baylor Fox-Kemper, Karen Heywood, Nicole Jones, Jody Klymak, Joseph LaCasce
JOURNAL OF PHYSICAL OCEANOGRAPHY
(2020)
Article
Oceanography
Jody M. Klymak, Dhruv Balwada, Alberto Naveira Garabato, Ryan Abernathey
Summary: The study emphasizes the importance of internal drag from topography and proposes a simple parameterization scheme. Simulations show that the parameterization accurately predicts drag under different forcing parameters and replicates the effect of rough bathymetry on eddies in wind-driven channel flows.
JOURNAL OF PHYSICAL OCEANOGRAPHY
(2021)
Article
Oceanography
Lina M. Rotermund, William J. Williams, Jody M. Klymak, Yongsheng Wu, Randall K. Scharien, Christian Haas
Summary: Tides in the Kitikmeot Sea are heavily influenced by seasonal sea-ice formation and blocking in a strait, leading to significant tidal damping during wintertime sea-ice cover. The dynamics of the M-2 and K-1 tides show different patterns, with both tidal constituents dominated by Atlantic tides entering through Victoria Strait. The smaller K-1 tide is less diverted into subsidiary channels compared to the M-2 tide, propagating further into the region and resulting in larger tidal height in Coronation Gulf.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2021)
Article
Oceanography
Saurav Sahu, Susan E. Allen, Gonzalo S. Saldias, Jody M. Klymak, Li Zhai
Summary: A shortage of dissolved oxygen in seawater can impact marine life and ecosystems, with low oxygen conditions driven by local productivity and remote changes in source waters. Research reveals that a low-oxygen dense pool observed over the mid-shelf off southwest Vancouver Island primarily originates from the California Undercurrent and offshore waters from the Washington shelf.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2022)
Article
Oceanography
Amy F. Waterhouse, Tyler Hennon, Eric Kunze, Jennifer A. MacKinnon, Matthew H. Alford, Robert Pinkel, Harper Simmons, Caitlin B. Whalen, Elizabeth C. Fine, Jody Klymak, Julia M. Hummon
Summary: Internal waves are mainly generated by wind, tide-topography interactions, and balanced flow-topography interactions. Observations of vertical shear and calculations of total shear variance and vertical asymmetry ratio indicate that downgoing shear variance dominates in the upper 600 m of the water column globally, while the distribution is almost equal below 600 m depth.
JOURNAL OF PHYSICAL OCEANOGRAPHY
(2022)
Article
Oceanography
Gunnar Voet, Matthew H. Alford, Jesse M. Cusack, Larry J. Pratt, James B. Girton, Glenn S. Carter, Jody M. Klymak, Shuwen Tan, Andreas M. Thurnherr
Summary: The energy and momentum balance of an abyssal overflow across a major sill in the Samoan Passage is estimated using towed sections and numerical simulation. The flow driven by the density anomaly across the sill gains energy from pressure work and potential energy. Half of this energy is transferred into kinetic energy while the other half is lost to dissipation and pressure work. Internal waves radiate upward but dissipate most of their energy within the overflow layer. Form drag and topographic drag contribute to energy dissipation and momentum flux divergence.
JOURNAL OF PHYSICAL OCEANOGRAPHY
(2023)
Article
Geosciences, Multidisciplinary
J. M. Jackson, K. Holmes, J. M. Klymak, L. Bianucci, W. Evans, W. C. Floyd, C. G. Hannah, A. Hare, D. Wan
Summary: Using observational data and a 2-D model, this study demonstrates the impact of an Arctic outflow event in February 2019 on water temperature and oxygen levels in Bute Inlet, British Columbia. The findings suggest that this local mechanism might counteract the effects of climate change and create a refuge for marine life. Moreover, the frequency of outflow events has shown a recent increase.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Oceanography
Jody M. Klymak, Susan E. Allen, Stephanie Waterman
Summary: Observations on the southern Vancouver Island shelf reveal a significant exchange of water between the shelf and offshore areas, particularly near a semi-permanent recirculation feature known as the Juan de Fuca Eddy. This eddy occurs where the shelf widens abruptly due to a bank, and consists of a mixture of offshore and coastal water. The water in this eddy is well-mixed but maintains some stratification, either due to rapid mixing or a long residence time. Despite its uniformity, there is a narrow temperature-salinity front offshore that shows no sign of instability. Cross-front transport and hydraulic jumps are observed during a survey over a bank. Upstream of the eddy, there is an equatorward along-shelf current that separates from the shelf and is replaced by offshore water in the lee of the bank, as evidenced by satellite images of cool coastal water being ejected offshore.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2023)
Review
Environmental Sciences
Caitlin B. Whalen, Casimir de Lavergne, Alberto C. Naveira Garabato, Jody M. Klymak, Jennifer A. MacKinnon, Katy L. Sheen
NATURE REVIEWS EARTH & ENVIRONMENT
(2020)
Article
Physics, Fluids & Plasmas
John Lodise, Tamay Ozgokmen, Rafael C. Goncalves, Mohamed Iskandarani, Bjorn Lund, Jochen Horstmann, Pierre-Marie Poulain, Jody Klymak, Edward H. Ryan, Cedric Guigand
Review
Meteorology & Atmospheric Sciences
Wei Zhang, Yu Sun, Yapeng Wu, Junyu Dong, Xiaojiang Song, Zhiyi Gao, Renbo Pang, Boyu Guoan
Summary: This study employed a spatiotemporal deep-learning method to correct biases in numerical ocean wave forecasts. By using a correction model driven by both wave and wind fields and a novel pixel-switch loss function, the corrected results performed well in different seasons and improved the accuracy of the original forecasts.