Data from: Finescale measurements of Kelvin-Helmholtz instabilities at a Kuroshio seamount
Data files
Oct 15, 2025 version files 155.99 MB
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README.md
27.52 KB
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supporting_data.zip
155.96 MB
Abstract
Data supporting the results presented in 'Finescale measurements of Kelvin-Helmholtz instabilities at a Kuroshio seamount', Journal of Physical Oceanography DOI 10.1175/JPO-D-24-0235.1
Fine-scale properties of Kelvin–Helmholtz (KH)-like shear instabilities on the trailing edge of a nonlinear lee wave generated by the Kuroshio impinging on a seamount were measured using a towed CTD chain, shipboard ADCP, and echosounder. Lee-wave vertical velocity amplitudes vary in phase with the upstream semidiurnal along-stream current. The instabilities are analogous to atmospheric billows induced by a recirculation on the trailing edge of mountain lee waves. A total of 135 KH billows were identified in a 4-day-long time series roughly 300 m downstream of the center of the lee wave. The KH billows have heights H=52+-11 m, widths L=162+-72 m, and aspect ratios H/L=0.39+-0.18. Positive reduced shear squared S2-4N2 (where S is the vertical shear magnitude and N is the buoyancy frequency) in the shear-stratified billows suggests actively growing instabilities, with comparable contributions from across- and along-flow vertical shear. Billow cores are convectively unstable (N2<0). Large turbulent kinetic energy dissipation rates O(10-5) W/kg are inferred from density overturns. Density, shear, and inferred turbulence properties vary with billow aspect ratios. As H/L increases, density gradients smear out. For 122 billows with H/L<0.6, dissipation rates increase by one order of magnitude with increasing H/L. These observations of 1-m vertical and 5-m horizontal resolution billow structures and density overturn dissipation rates can provide a reference for future high-Reynolds-number direct numerical simulations.
Dataset DOI: 10.5061/dryad.pg4f4qs3b
Description of the data and file structure
Data to accompany the article "Fine-Scale Measurements of Kelvin–Helmholtz Instabilities at a Kuroshio Seamount" (Journal of Physical Oceanography, DOI 10.1175/JPO-D-24-0235.1) by Anda Vladoiu, Ren-Chieh Lien, Eric Kunze, Barry Ma, Sebastian Essink, Yiing Jang Yang, Ming-Huei Chang, Sen Jan, Jia-Lin Chen, Kai-Chieh Yang, and Yu-Yu Yeh.
Contact Anda Vladoiu (avladoiu@uw.edu) for additional information.
Files and variables
File: supporting_data.zip
The .zip archive contains .mat processed data files used in creating the figures in the article. Please see article for detailed data description and processing methods.
Descriptions of each .mat file, corresponding to distinct figures, are below, with units in square brackets. Each file contains structures pertaining to variables plotted in each figure panel, named in alphabetical order.
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FIG. 1. (a) Spatial survey (red line) across a seamount between Taiwan to the northwest and Green Island to the southeast, with AVISO 0.125deg sea-surface-height-inferred geostrophic currents illustrating the Kuroshio (gray arrows). Background color illustrates bathymetry, and the white contour illustrates the 450-m isobath. (b) TCTD chain temperature transect across the seamount; gray contours are isopycnals; the black vertical dotted line is the time series station; the red vertical dotted line is the upstream 300-kHz ADCP mooring; black arrow illustrates Kuroshio mean direction; black contours mark isobaths every 50 m. (b ) Zoom-in on instabilities in the black rectangle in (b).
file: Fig1.mat
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Structure "Fig1a" contains variables:
"lat" = section latitude [degN]
"lon" = section longitude [degE]
"Ug_lon" = geostrophic velocity longitude [degE]
"Ug_lat" = geostrophic velocity latitude [degN]
"Ug_u" = geostrophic zonal velocity [m/s]
"Ug_v" = geostrophic meridional velocity [m/s]
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Structure "Fig1b" contains:
structure "sigma1" = section first isopycnal contour
"Fig1b.sigma1.lat" = latitude [degN]
"Fig1b.sigma1.lon" = longitude [degE]
"Fig1b.sigma1.z" = depth [m]
structures "sigma2", ... "sigma8" are the same as "sigma1", for deeper isopycnal contours
variables:
"timeseries_lat" = timeseries latitude [degN]
"timeseries_lon" = timeseries longitude [degE]
"mooring_lat" = mooring latitude [degN]
"mooring_lon" = mooring longitude [degE]
"T_lon" = temperature longitude [degE]
"T_lat" = temperature latitude [degN]
"T_z" = temperature depth [m]
"T" = temperature [degC]
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Structure "Fig1bp" contains variables:
"T_x" = temperature distance [m]
"T_z" = temperature depth [m]
"T" = temperature [degC]
"sigma_x" = density distance [m]
"sigma_z" = density depth [m]
"sigma" = density [kg/m^3]
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FIG. 2. Example (a),(c),(e) TCTD temperature and (b),(d),(f) echosounder backscatter time series at the black vertical dotted line in Fig. 1b; gray contours in (a), (c), and (e) are isopycnals every 0.2 kg/m3 ; each of the three times series corresponds to 1000-m distance inferred from mean along-stream velocity.
file: Fig2.mat
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Structure "Fig2a" contains variables:
"time" = time [matlab time]
"z" = depth [m]
"T" = temperature [degC]
"sigma" = density [kg/m^3]
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Structure "Fig2b" contains variables:
"time" = time [matlab time]
"z" = depth [m]
"backscatter" = backscatter [db]
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Structure "Fig2c" contains variables:
"time" = time [matlab time]
"z" = depth [m]
"T" = temperature [degC]
"sigma" = density [kg/m^3]
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Structure "Fig2d" contains variables:
"time" = time [matlab time]
"z" = depth [m]
"backscatter" = backscatter [db]
#
Structure "Fig2e" contains variables:
"time" = time [matlab time]
"z" = depth [m]
"T" = temperature [degC]
"sigma" = density [kg/m^3]
#
Structure "Fig2f" contains variables:
"time" = time [matlab time]
"z" = depth [m]
"backscatter" = backscatter [db]
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FIG. 3. Example profiles at the location marked by the dotted vertical white (gray) line in Figs. 13b (Fig. 14d). (a) Measured (black) and depth-sorted (gray) potential density profile. (b) Shear-unstable patch thickness LKWB (blue), absolute value of Thorpe displacements |dTh| (gray), overturn Thorpe-scale LTh (black), and 5-m binned Thorpe-scale lTh (red). (c) The N2 (gray), S2KWB/4 (light blue), N2KWB (blue), patch-weighted N2E (black), and 5-m weighted N2E (red). (d) Reduced-shear (blue), overturn patch Thorpe scale (black) and 5-m patch Thorpe scale (red) dissipation rates, and vertical temperature gradient kz spectrum inferred dissipation rate (green). (e) Vertical wavenumber kz spectrum for vertical temperature gradient Tz, raw (thin) and corrected for vertical interpolation (thick), with best fit (black dotted line).
file: Fig3.mat
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Structure "Fig3a" contains variables:
"sigma_theta_z" = potential density depth [m]
"sigma_theta" = potential density [kg/m^3]
"sigma_theta_s_z" = depth-sorted potential density depth [m]
"sigma_theta_s" = depth-sorted potential density [kg/m^3]
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Structure "Fig3b" contains variables:
"deltaTh_z" = Thorpe displacement depth [m]
"deltaTh" = Thorpe displacement [m]
"z" = depth [m]
"L_KWB" = shear-unstable thickness [m]
"L_Th" = overturn patch Thorpe scale [m]
"l_Th" = 5-m Thorpe scale [m]
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Structure "Fig3c" contains variables:
"N2_z" = buoyancy frequency depth [m]
"N2" = buoyancy frequency [s^-2]
"z" = depth [m]
"S2_4_KWB" = vertical shear magnitude divided by 4 [s^-2]
"N2_KWB" = unstable patch buoyancy frequency [s^-2]
"N2_E" = overturn-weighted buoyancy frequency [s^-2]
"N2_E_tilde" = 5-m weighted buoyancy frequency [s^-2]
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Structure "Fig3d" contains variables:
"eps_Tz_z" = depth [m]
"eps_Tz" = vertical temperature gradient epsilon [W/kg]
"z" = depth [m]
"eps_KWB" = reduced shear dissipation rate epsilon [W/kg]
"eps_Th" = overturn Thorpe scale epsilon [W/kg]
"eps_Th_tilde" = 5-m Thorpe scale epsilon [W/kg]
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Structure "Fig3e" contains variables:
"kz" = vertical wavenumber [cpm]
"Phi" = raw vertical temperature gradient spectrum [degC^2/m^2 /cpm]
"Phi_corr" = interpolation corrected vertical temperature gradient spectrum [degC^2/m^2 /cpm]
"fit" = spectrum least-squares fit [degC^2/m^2 /cpm]
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FIG. 4. (a) Four dissipation rate microstructure profiles (solid curves) from Yeh et al. (2024, their Figs. 3 and 4); the profiles cross KH-like billows identified in echosounder backscatter and are located immediately downstream of the seamount close to the TCTD time series station (Yeh survey T05-black, T07-orange, T03-red, T09-purple). Dissipation rates (squares and circles) were estimated from VMP CTD profiles interpolated on a 1-m vertical-resolution depth grid, using the same method as for the TCTD. TCTD time series dissipation rate histogram (teal) for bins with at least 10 points is shown for reference. (b) Probability density functions for microstructure dissipation rate (black), overturn Thorpe scale dissipation rate (black), 5-m patch Thorpe scale dissipation rate (red), and TCTD time series dissipation rate (teal); only depths where there are Thorpe-scale estimates are included for microstructure profiles. (c) Scatterplot of microstructure and Thorpe-scale dissipation rates, with depth in color.
file: Fig4.mat
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Structure "Fig4a" contains variables:
"z_VMP" = depth [m]
"eps_VMP_black" = microstructure dissipation rate epsilon [W/kg]
"eps_VMP_yellow" = microstructure dissipation rate epsilon [W/kg]
"eps_VMP_red" = microstructure dissipation rate epsilon [W/kg]
"eps_VMP_purple" = microstructure dissipation rate epsilon [W/kg]
"eps_Th_VMPctd_black" = VMP CTD overturn Thorpe scale dissipation rate epsilon [W/kg]
"eps_Th_tilde_VMPctd_black" = VMP CTD 5-m Thorpe scale dissipation rate epsilon [W/kg]
"eps_Th_VMPctd_yellow" = VMP CTD overturn Thorpe scale dissipation rate epsilon [W/kg]
"eps_Th_tilde_VMPctd_yellow" = VMP CTD 5-m Thorpe scale dissipation rate epsilon [W/kg]
"eps_Th_VMPctd_red" = VMP CTD overturn Thorpe scale dissipation rate epsilon [W/kg]
"eps_Th_tilde_VMPctd_red" = VMP CTD 5-m Thorpe scale dissipation rate epsilon [W/kg]
"eps_Th_VMPctd_purple" = VMP CTD overturn Thorpe scale dissipation rate epsilon [W/kg]
"eps_Th_tilde_VMPctd_purple" = VMP CTD 5-m Thorpe scale dissipation rate epsilon [W/kg]
"eps_Th_TCTD" = towed CTD chain 5-m Thorpe scale dissipation rate epsilon [W/kg]
"eps_Th_TCTD_z" = towed CTD chain depth [m]
"eps_Th_TCTD_histogram" = towed CTD chain 5-m Thorpe scale dissipation rate histogram [counts]
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Structure "Fig4b" contains histograms line objects.
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Structure "Fig4c" contains variables:
"eps_VMP" = microstructure dissipation rate epsilon [W/kg]
"eps_Th_VMPctd" = VMP CTD 5-m Thorpe scale dissipation rate epsilon [W/kg]
"z" = depth [m]
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FIG. 5. Example section of measured (a) echosounder backscatter, (b) TCTD temperature, (c) along-stream velocity anomaly with (c ) vertical profile of section-mean along-stream velocity , (d) across-stream velocity (positive out of the page), and (e) vertical velocity, for a typical lee-wave transect. In all panels, black contours are isopycnals, the black dotted vertical line marks the location of the time series station, and the red dotted vertical line marks the location of the upstream ADCP mooring. Distance is positive downstream of the highest seamount peak.
file: Fig5.mat
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Structure "Fig5a" contains variables:
"x" = distance [m]
"z" = depth [m]
"backscatter" = backscatter [db]
"sigma_x" = potential density distance [m]
"sigma_z" = potential density depth [m]
"sigma" = potential density [kg/m^3]
#
Structure "Fig5b" contains variables:
"x" = distance [m]
"z" = depth [m]
"temperature" = temperature [degC]
"sigma_x" = potential density distance [m]
"sigma_z" = potential density depth [m]
"sigma" = potential density [kg/m^3]
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Structure "Fig5c" contains variables:
"x" = distance [m]
"z" = depth [m]
"ualong_anom" = along-stream velocity anomaly [m/s]
"sigma_x" = potential density distance [m]
"sigma_z" = potential density depth [m]
"sigma" = potential density [kg/m^3]
#
Structure "Fig5cp" contains variables:
"z" = depth [m]
"ualong_mean" = mean along-stream velocity [m/s]
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Structure "Fig5d" contains variables:
"x" = distance [m]
"z" = depth [m]
"uacross" = across-stream velocity [m/s]
"sigma_x" = potential density distance [m]
"sigma_z" = potential density depth [m]
"sigma" = potential density [kg/m^3]
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Structure "Fig5e" contains variables:
"x" = distance [m]
"z" = depth [m]
"w" = vertical velocity [m/s]
"sigma_x" = potential density distance [m]
"sigma_z" = potential density depth [m]
"sigma" = potential density [kg/m^3]
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FIG. 6. Example section of observed (a) stratification , (b) vertical shear magnitude, (c) reduced-shear, and (d) Thorpe-scale inferred turbulent kinetic energy dissipation rate, for a typical lee-wave transect. In all panels, black contours are isopycnals. Distance is positive downstream of the highest seamount peak.
file: Fig6.mat
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Structure "Fig6a" contains variables:
"x" = distance [m]
"z" = depth [m]
"N2" = log10 buoyancy frequency squared [s^-2]
"sigma_x" = potential density distance [m]
"sigma_z" = potential density depth [m]
"sigma" = potential density [kg/m^3]
#
Structure "Fig6b" contains variables:
"x" = distance [m]
"z" = depth [m]
"S2_4" = log10 vertical shear magnitude divided by 4 [s^-2]
"sigma_x" = potential density distance [m]
"sigma_z" = potential density depth [m]
"sigma" = potential density [kg/m^3]
#
Structure "Fig6c" contains variables:
"x" = distance [m]
"z" = depth [m]
"reducedshear" = reduced shear [s^-2]
"sigma_x" = potential density distance [m]
"sigma_z" = potential density depth [m]
"sigma" = potential density [kg/m^3]
#
Structure "Fig6d" contains variables:
"x" = distance [m]
"z" = depth [m]
"eps_Th" = log10 overturn Thorpe scale dissipation rate epsilon [W/kg]
"sigma_x" = potential density distance [m]
"sigma_z" = potential density depth [m]
"sigma" = potential density [kg/m^3]
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FIG. 7. The 15-section median (a) vertical velocity, (b) stratification , (c) vertical shear, (d) reduced-shear, and (e) Thorpe-scale turbulent kinetic energy dissipation rate . In all panels, black contours are the 15-section mean isopycnals. Only bins with at least three points are shown.
file: Fig7.mat
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Structure "Fig7a" contains variables:
"x" = distance [m]
"z" = depth [m]
"w" = vertical velocity [m/s]
"sigma_x" = potential density distance [m]
"sigma_z" = potential density depth [m]
"sigma" = potential density [kg/m^3]
#
Structure "Fig7b" contains variables:
"x" = distance [m]
"z" = depth [m]
"N2" = log10 buoyancy frequency squared [s^-2]
"sigma_x" = potential density distance [m]
"sigma_z" = potential density depth [m]
"sigma" = potential density [kg/m^3]
#
Structure "Fig7c" contains variables:
"x" = distance [m]
"z" = depth [m]
"S2_4" = log10 vertical shear magnitude divided by 4 [s^-2]
"sigma_x" = potential density distance [m]
"sigma_z" = potential density depth [m]
"sigma" = potential density [kg/m^3]
#
Structure "Fig7d" contains variables:
"x" = distance [m]
"z" = depth [m]
"reducedshear" = reduced shear [s^-2]
"sigma_x" = potential density distance [m]
"sigma_z" = potential density depth [m]
"sigma" = potential density [kg/m^3]
#
Structure "Fig7e" contains variables:
"x" = distance [m]
"z" = depth [m]
"eps_Th" = log10 overturn Thorpe scale dissipation rate epsilon [W/kg]
"sigma_x" = potential density distance [m]
"sigma_z" = potential density depth [m]
"sigma" = potential density [kg/m^3]
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FIG. 8. (a) Section-median along-stream velocity 500 m upstream of the seamount peak (blue) and angle of the upper 150-m mean current (red). (b) Lee-wave center position relative to the seamount peak (blue) and lee-wave width (red), inferred from depth-mean SADCP vertical velocity (solid) and isopycnal local maximum depth (dashed–dotted). (c) Bandpassed along-stream semidiurnal and diurnal plus semidiurnal tidal velocity below 100-m depth (blue) from the upstream mooring during the transects. SADCP vertical velocity averaged over upper 75th percentiles of the leewave upwelling and downwelling between 50- and 250-m depth for each transect (red). (d) Median (circles) and mean (curve) Thorpe-scale dissipation rates between 50- and 250-m depth within 1 km downstream of the lee-wave center for each transect.
file: Fig8.mat
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Structure "Fig8a" contains variables:
"time" = matlab time [days]
"ualong_upstr" = upstream along-stream velocity [m/s]
"theta_U" = Kuroshio direction [deg]
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Structure "Fig8b" contains variables:
"time" = matlab time [days]
"xleewave_w" = lee wave center position from vertical velocity [m]
"xleewave_sigma" = lee wave center position from isopycnal [m]
"Dxleewave_w" = lee wave width from vertical velocity [m]
"Dxleewave_sigma" = lee wave width from isopycnal [m]
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Structure "Fig8c" contains variables:
"time" = matlab time [days]
"D2" = upstream semidiurnal tidal velocity [m/s]
"D1D2" = upstream diurnal plus semidiurnal tidal velocity [m/s]
"w_time" = matlab time [days]
"w" = vertical velocity [m/s]
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Structure "Fig8d" contains variables:
"time" = matlab time [days]
"eps_Th_mean" = mean overturn Thorpe scale dissipation rate epsilon [W/kg]
"eps_Th_median" = median overturn Thorpe scale dissipation rate epsilon [W/kg]
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FIG. 9. Estimation method for two billow heights H, widths L, and braid angles (solid red vertical, horizontal, and diagonal lines, respectively) based on TCTD absolute vertical temperature gradient profile time series converted to distance using mean along-stream velocity. Billow outer contours are illustrated in dashed–dotted red and core contours in dashed red. Potential density contours (black) are every 0.1 kg/m3 .
file: Fig9.mat
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Structure "Fig9" contains variables:
"x" = distance [m]
"z" = depth [m]
"Tz" = absolute vertical temperature gradient [degC/m]
"sigma" = potential density [kg/m^3]
"billow1_core_x" = billow1 core distance [m]
"billow1_core_z" = billow1 core depth [m]
"billow1_x" = billow1 distance [m]
"billow1_z" = billow1 depth [m]
"billow1_H_z" = billow1 height depth [m]
"billow1_H_x" = billow1 height distance [m]
"billow1_L_z" = billow1 width depth [m]
"billow1_L_x" = billow1 width distance [m]
"billow1_braid_z" = billow1 width depth [m]
"billow1_braid_x" = billow1 braid distance [m]
"billow2_L_x" = billow2 distance [m]
"billow2_L_z" = billow2 depth [m]
"billow2_braid_z" = billow1 width depth [m]
"billow2_braid_x" = billow1 braid distance [m]
"billow2_core_x" = billow1 core distance [m]
"billow2_core_z" = billow1 core depth [m]
"billow2_z" = billow1 depth [m]
"billow2_x" = billow1 distance [m]
"billow2_H_z" = billow1 height depth [m]
"billow2_H_x" = billow1 height distance [m]
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FIG. 10. Billow (a) aspect ratio H/L, (c) width L, (e) height H, (b) billow-median depth z, (d) SADCP vertical velocity w, and (f) Thorpe-scale dissipation rate, as functions of SADCP along-stream velocity.
file: Fig10.mat
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Structure "Fig10a" contains variables:
"HL" = aspect ratio H/L
"ualong" = along-stream velocity [m/s]
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Structure "Fig10b" contains variables:
"z" = depth [m]
"ualong" = along-stream velocity [m/s]
#
Structure "Fig10c" contains variables:
"L" = width [m]
"ualong" = along-stream velocity [m/s]
#
Structure "Fig10d" contains variables:
"w" = vertical velocity [m/s]
"ualong" = along-stream velocity [m/s]
#
Structure "Fig10e" contains variables:
"H" = height [m]
"ualong" = along-stream velocity [m/s]
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Structure "Fig10f" contains variables:
"eps_Th" = overturn Thorpe-scale dissipation rate epsilon [W/kg]
"ualong" = along-stream velocity [m/s]
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FIG. 11. (a),(e),(i) TCTD buoyancy frequency squared , (b),(f),(j) reduced shear squared, (c),(g),(k) Thorpe-scale overturn patch inferred dissipation rates, and (d),(h),(l) and 5-m patch dissipation rate. Example billows with different aspect ratios (height/width H/L) representative of the 25th, 50th, and 75th percentiles, respectively: H/L=0.23 in (a)–(d), H/L=0.36 in (e)–(h), and H/L=0.63 in (i)–(l). Downstream coordinate x and depth z are both normalized by width L.
Fig11.mat
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Structure "Fig11a" contains variables:
"x" = distance [m]
"z" = depth [m]
"N2" = log10 buoyancy frequency squared [s^-2]
#
Structure "Fig11b" contains variables:
"x" = distance [m]
"z" = depth [m]
"reducedshear" = reduced shear [s^-2]
#
Structure "Fig11c" contains variables:
"x" = distance [m]
"z" = depth [m]
"eps_Th" = log10 overturn Thorpe-scale dissipation rate epsilon [W/kg]
#
Structure "Fig11d" contains variables:
"x" = distance [m]
"z" = depth [m]
"eps_Th_tilde" = log10 5-m Thorpe-scale dissipation rate epsilon [W/kg]
#
Structure "Fig11e" contains variables:
"x" = distance [m]
"z" = depth [m]
"N2" = log10 buoyancy frequency squared [s^-2]
#
Structure "Fig11f" contains variables:
"x" = distance [m]
"z" = depth [m]
"reducedshear" = reduced shear [s^-2]
#
Structure "Fig11g" contains variables:
"x" = distance [m]
"z" = depth [m]
"eps_Th" = log10 overturn Thorpe-scale dissipation rate epsilon [W/kg]
#
Structure "Fig11h" contains variables:
"x" = distance [m]
"z" = depth [m]
"eps_Th_tilde" = log10 5-m Thorpe-scale dissipation rate epsilon [W/kg]
#
Structure "Fig11i" contains variables:
"x" = distance [m]
"z" = depth [m]
"N2" = log10 buoyancy frequency squared [s^-2]
#
Structure "Fig11j" contains variables:
"x" = distance [m]
"z" = depth [m]
"reducedshear" = reduced shear [s^-2]
#
Structure "Fig11k" contains variables:
"x" = distance [m]
"z" = depth [m]
"eps_Th" = log10 overturn Thorpe-scale dissipation rate epsilon [W/kg]
#
Structure "Fig11l" contains variables:
"x" = distance [m]
"z" = depth [m]
"eps_Th_tilde" = log10 5-m Thorpe-scale dissipation rate epsilon [W/kg]
#
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FIG. 12. (a),(e),(i) TCTD buoyancy frequency squared, (b),(f),(j) reduced-shear, (c),(g),(k) Thorpe-scale overturn patch inferred dissipation rates , and (d),(h),(l) 5-m patch dissipation rates. Median properties of composite billows for aspect ratios 0.1<H/L<0.3 in (a)–(d) (48 billows), 0.3<H/L<0.5 in (e)–(h) (58 billows), and H/L>0.5 in (i)–(l) (29 billows). Downstream coordinate x and depth z are both normalized by width L.
file: Fig12.mat
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Structure "Fig12a" contains variables:
"x" = distance [m]
"z" = depth [m]
"N2" = log10 buoyancy frequency squared [s^-2]
#
Structure "Fig12b" contains variables:
"x" = distance [m]
"z" = depth [m]
"reducedshear" = reduced shear [s^-2]
#
Structure "Fig12c" contains variables:
"x" = distance [m]
"z" = depth [m]
"eps_Th" = log10 overturn Thorpe-scale dissipation rate epsilon [W/kg]
#
Structure "Fig12d" contains variables:
"x" = distance [m]
"z" = depth [m]
"eps_Th_tilde" = log10 5-m Thorpe-scale dissipation rate epsilon [W/kg]
#
Structure "Fig12e" contains variables:
"x" = distance [m]
"z" = depth [m]
"N2" = log10 buoyancy frequency squared [s^-2]
#
Structure "Fig12f" contains variables:
"x" = distance [m]
"z" = depth [m]
"reducedshear" = reduced shear [s^-2]
#
Structure "Fig12g" contains variables:
"x" = distance [m]
"z" = depth [m]
"eps_Th" = log10 overturn Thorpe-scale dissipation rate epsilon [W/kg]
#
Structure "Fig12h" contains variables:
"x" = distance [m]
"z" = depth [m]
"eps_Th_tilde" = log10 5-m Thorpe-scale dissipation rate epsilon [W/kg]
#
Structure "Fig12i" contains variables:
"x" = distance [m]
"z" = depth [m]
"N2" = log10 buoyancy frequency squared [s^-2]
#
Structure "Fig12j" contains variables:
"x" = distance [m]
"z" = depth [m]
"reducedshear" = reduced shear [s^-2]
#
Structure "Fig12k" contains variables:
"x" = distance [m]
"z" = depth [m]
"eps_Th" = log10 overturn Thorpe-scale dissipation rate epsilon [W/kg]
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Structure "Fig12l" contains variables:
"x" = distance [m]
"z" = depth [m]
"eps_Th_tilde" = log10 5-m Thorpe-scale dissipation rate epsilon [W/kg]
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FIG. 13. Example 2-h billow-train time series: (a) echosounder backscatter, (b) TCTD temperature, (c) buoyancy stratification, (d) reduced shear squared, (e) reduced shear turbulent kinetic energy dissipation rate, (f) overturn patch Thorpe-scale turbulent kinetic energy dissipation rate, and (g) 5-m patch Thorpe-scale turbulent kinetic energy dissipation rate . In all panels, thin black contours are isopycnals every 0.2 kg/m3.
file: Fig13.mat
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Structure "Fig13a" contains variables:
"time" = matlab time [days]
"z" = depth [m]
"sigma" = potential density [kg/m^3]
"backscatter" = backscatter [db]
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Structure "Fig13b" contains variables:
"time" = matlab time [days]
"z" = depth [m]
"sigma" = potential density [kg/m^3]
"T" = temperature [degC]
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Structure "Fig13c" contains variables:
"time" = matlab time [days]
"z" = depth [m]
"sigma" = potential density [kg/m^3]
"N2" = log10 buoyancy frequency squared [s^-2]
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Structure "Fig13d" contains variables:
"time" = matlab time [days]
"z" = depth [m]
"sigma" = potential density [kg/m^3]
"reducedshear" = reduced shear [s^-2]
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Structure "Fig13e" contains variables:
"time" = matlab time [days]
"z" = depth [m]
"sigma" = potential density [kg/m^3]
"eps_KWB" = log10 reduced-shear dissipation rate epsilon [W/kg]
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Structure "Fig13f" contains variables:
"time" = matlab time [days]
"z" = depth [m]
"sigma" = potential density [kg/m^3]
"eps_Th" = log10 overturn Thorpe-scale dissipation rate epsilon [W/kg]
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Structure "Fig13g" contains variables:
"time" = matlab time [days]
"z" = depth [m]
"sigma" = potential density [kg/m^3]
"eps_Th_tilde" = log10 5-m Thorpe-scale dissipation rate epsilon [W/kg]
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FIG. 14. (a) Buoyancy stratification and vertical shear magnitude; (b) unstable shear growth rate and total energy available for turbulence production; (c) overturn patch Thorpe-scale inferred dissipation rates (black) and 5-m patch dissipation rates (red), reduced-shear inferred dissipation rate (blue), and vertical temperature gradient spectrum inferred dissipation rate (green); and (d) instability length scales and billow aspect ratios (gray circles).
file: Fig14.mat
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Structure "Fig14a" contains variables:
"time" = matlab time [days]
"N2_E_median" = median overturn-weighted buoyancy frequency squared [s^-2]
"N2_E_mean" = mean overturn-weighted buoyancy frequency squared [s^-2]
"N2_KWB_median" = median unstable shear patch buoyancy frequency squared [s^-2]
"N2_KWB_mean" = mean unstable shear patch buoyancy frequency squared [s^-2]
"N2_E_tilde_median" = median 5m-weighted buoyancy frequency squared [s^-2]
"N2_E_tilde_mean" = mean 5m-weighted buoyancy frequency squared [s^-2]
"S2_4_KWB_median" = median unstable shear patch vertical shear magnitude divided by 4 [s^-2]
"S2_4_KWB_mean" = mean unstable shear patch vertical shear magnitude divided by 4 [s^-2]
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Structure "Fig14b" contains variables:
"time" = matlab time [days]
"sigmaKH_median” = median unstable shear growth rate [s^-1]
"sigmaKH_mean” = mean unstable shear growth rate [s^-1]
"deltaE_median” = median energy available for turbulent production [m^2 s^-2]
"deltaE_mean” = mean energy available for turbulent production [m^2 s^-2]
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Structure "Fig14c" contains variables:
"time" = matlab time [days]
"epsilon_Th_tilde_median” = median 5-m Thorpe scale dissipation rate epsilon [W/kg]
"epsilon_Th_tilde_mean” = mean 5-m Thorpe scale dissipation rate epsilon [W/kg]
"epsilon_KWB_median” = median reduced shear dissipation rate epsilon [W/kg]
"epsilon_KWB_mean” = mean reduced shear dissipation rate epsilon [W/kg]
"epsilon_Th_median” = median overturn patch Thorpe scale dissipation rate epsilon [W/kg]
"epsilon_Th_mean” = median overturn patch Thorpe scale dissipation rate epsilon [W/kg]
"epsilon_Tz” = vertical temperature gradient dissipation rate epsilon [W/kg]
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Structure "Fig14d" contains variables:
"time" = matlab time [days]
“l_Th_median” = median 5-m Thorpe scale [m]
“l_Th_mean” = mean 5-m Thorpe scale [m]
“L_Th_median” = median overturn patch Thorpe scale [m]
“L_Th_mean” = mean overturn patch Thorpe scale [m]
“L_KWB_median” = median unstable shear patch thickness [m]
“L_KWB_mean” = mean unstable shear patch thickness [m]
“HL_time” = aspect ratio matlab time [days]
“HL” = aspect ratio
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FIG. 15. (a) Billow-median Thorpe-scale inferred dissipation rate as a function of positive billow-median reduced-shear. (b) Billow-median ratio of Thorpe scale to unstable shear-layer thickness as a function of gradient Froude number. In both panels, color indicates billow aspect ratio H/L.
file: Fig15.mat
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Structure "Fig15a" contains variables:
“reducedshear” = reduced shear [s^-2]
“eps_Th” = overturn patch Thorpe scale dissipation rate epsilon [W/kg]
“HLratio” = aspect ratio
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Structure "Fig15b" contains variables:
“Fr” = Froude number
“LThLKWBratio” = Thorpe scale and unstable shear scale ratio
“HLratio” = aspect ratio