Data from: A predictable component of the internal tide on a narrow continental shelf
Data files
Sep 29, 2026 version files 50.58 GB
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adcp_data.mat
155.04 MB
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alongshore_waypoints.mat
722 B
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bt_qbt_cycles.mat
3.36 KB
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ctw_predictability.mat
242.30 MB
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exportImage.tiff
13.73 MB
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fall.zip
19.95 GB
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free_surface_unstrat.mat
108.07 MB
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obs_profiles_exact.mat
1.80 KB
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README.md
13.56 KB
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site_comparison.mat
39.38 KB
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spring.zip
19.88 GB
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unstratified.zip
10.23 GB
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unsurf_grid.mat
2.57 MB
Abstract
This dataset contains model output and observational data supporting the analyses in Okun et al., "Coastal internal tides can be predictable when observed as coastal trapped waves" (Geophysical Research Letters). The deposit includes three-dimensional velocity, temperature, and salinity fields from SUNTANS hydrostatic model simulations of M2-forced coastal trapped waves (CTWs) in the Southern California Bight. Three simulations are provided: fall stratification, spring stratification, and unstratified (homogeneous density). The CTW field is isolated by subtracting the unstratified case from each stratified case. Also included are the unstructured model grid, a pre-computed diagnostics file containing all quantities needed to reproduce the publication figures (Hovmoller diagrams, phase speed estimates, barotropic-to-baroclinic conversion rates, baroclinic energy flux, and Nash et al. (2012) skill scores), seven-year ADCP velocity records from three inner-shelf sites near San Diego (originally described in Okun et al. (2025), doi:10.1029/2024JC021591), and an ETOPO 2022 bathymetry subset.
Authors
Kevin Okun, Andrew J. Lucas, Eiji Masunaga, Geno Pawlak
Scripps Institution of Oceanography, University of California San Diego
Description
This dataset supports the analyses and figures in:
Okun, K., A. J. Lucas, E. Masunaga, and G. Pawlak, A predictable component of the internal tide on a narrow continental shelf, Geophysical Research Letters.
The deposit contains processed output from three-dimensional SUNTANS hydrodynamic model simulations of M2-forced coastal trapped waves (CTWs) in the Southern California Bight (SCB), along with seven-year ADCP observations used to evaluate predictability. Three simulation cases are included: unstratified, fall stratification, and spring stratification. The CTW field is isolated by subtracting the unstratified simulation from each stratified case.
The loose .mat files are everything required to reproduce the paper's figures; the three zip archives contain the full 3D model output for complete reanalysis.
Analysis code
The MATLAB code to reproduce all analyses and figures is archived on Zenodo: doi:10.5281/zenodo.19486718. Its README documents which data files each script requires and the run order. The analysis code is available at https://github.com/kevin-okun/ctw-predictability.
File descriptions
Computed diagnostics
| File | Size | Format | Description |
|---|---|---|---|
ctw_predictability.mat |
231 MB | MATLAB v7.3 (HDF5) | All quantities computed by ctw_predictability_analysis.m. Contains: model grid, coastal coordinate system, Cardiff cross-shore transect data, Hovmoller diagrams of depth-averaged CTW alongshore velocity, phase speed and wavelength estimates, BT-BC conversion rate, depth-integrated baroclinic energy flux, baroclinic fraction of CTW velocity, M2 criticality, QBT kinetic energy ratio, Nash et al. (2012) skill scores in depth-resolved and QBT projections, and ADCP amplitude comparisons. |
Model-observation comparison products
| File | Size | Format | Description |
|---|---|---|---|
site_comparison.mat |
39 KB | MATLAB | Model-vs-ADCP M2 comparison at the three sites (structs: sites, model, obs, profiles, prop, prop_nbhd, meta). Model CTW and free-surface M2 amplitude/phase fits at the three site grid cells, observed quasi-barotropic tidal (QBT) M2 fits, robust neighborhood phases, and inter-site propagation lags. Self-describing: see meta.readme inside the file. Produced by extract_site_comparison.m and addendum_robust_phase.m. |
obs_profiles_exact.mat |
2 KB | MATLAB | Observed fall M2 QBT amplitudes refit at the exact M2 period (12.4206 hr), per depth bin and depth-averaged, plus the exact-period pooled surface-tide amplitude. Self-describing (meta field). Produced by refit_obs_profiles_exact.m. |
bt_qbt_cycles.mat |
3 KB | MATLAB | Season-matched mean M2 cycle comparison underlying Fig. S3: model and observed amplitudes and phases (relative to the local surface-tide M2 crest) for the QBT and barotropic (BT) velocities, plus the observed phase-composite cycles. Self-describing (meta.readme). Produced by compare_bt_qbt_cycles.m. |
free_surface_unstrat.mat |
103 MB | MATLAB v7.3 | Free surface elevation from the unstratified simulation [time x cells], m. Barotropic-tide phase reference for the Fig. S3 comparison. Also contained in unstratified.zip; provided loose so Fig. S3 can be reproduced without downloading the full archive. |
Grid and auxiliary files
| File | Size | Format | Description |
|---|---|---|---|
unsurf_grid.mat |
2.5 MB | MATLAB | Unstructured triangular grid for visualization. Fields: tri (triangle connectivity), xp, yp (node coordinates, m), xv, yv (cell-center coordinates, m), depth (cell depths, m), dz (vertical layer thicknesses, m). |
alongshore_waypoints.mat |
722 B | MATLAB | Waypoints (x, y in m) defining the coastal corridor used to construct the alongshore coordinate system. |
exportImage.tiff |
13 MB | GeoTIFF | ETOPO 2022 Global Relief Model, 15 arc-second resolution, subset covering the Southern California Bight. Used as the background bathymetry in Fig. 1a. Source: NOAA National Centers for Environmental Information, doi:10.25921/fd45-gt74. |
Observational data
| File | Size | Format | Description |
|---|---|---|---|
adcp_data.mat |
148 MB | MATLAB | Seven-year (2017--2024) ADCP velocity records from three sites on the 33 m isobath: Point Loma (32.699N, 117.275W), La Jolla (32.833N, 117.307W), and Cardiff (33.015N, 117.302W). Fields per site: VVYir (alongshore velocity, m/s, depth x time), VVXir (cross-shore velocity), TTSi (time, MATLAB datenum), PPi (bottom pressure, dbar), H (water depth, m). Originally described in Okun et al. (2025), doi:10.1029/2024JC021591. |
3D model output
The full 3D output is packaged in three zip archives, one per simulation case. All fields are [time x depth x cells] (248 hourly snapshots, 100 depth levels, ~57,700 cells) except free surface, which is [time x cells]. MATLAB v7.3 format.
fall.zip (18.6 GB) -- Fall stratification:
| File | Size | Description |
|---|---|---|
u_fall.mat |
5.0 GB | Eastward velocity, m/s. |
v_fall.mat |
5.0 GB | Northward velocity, m/s. |
temperature_fall.mat |
4.7 GB | Temperature, degrees C. |
salinity_fall.mat |
4.0 GB | Salinity, PSU. |
free_surface_fall.mat |
104 MB | Free surface elevation, m. |
spring.zip (18.5 GB) -- Spring stratification:
| File | Size | Description |
|---|---|---|
u_spring.mat |
5.0 GB | Eastward velocity, m/s. |
v_spring.mat |
5.0 GB | Northward velocity, m/s. |
temperature_spring.mat |
4.7 GB | Temperature, degrees C. |
salinity_spring.mat |
3.9 GB | Salinity, PSU. |
free_surface_spring.mat |
103 MB | Free surface elevation, m. |
unstratified.zip (9.5 GB) -- Unstratified:
| File | Size | Description |
|---|---|---|
u_unstrat.mat |
4.8 GB | Eastward velocity, m/s. |
v_unstrat.mat |
4.8 GB | Northward velocity, m/s. |
free_surface_unstrat.mat |
103 MB | Free surface elevation, m (also provided loose; see above). |
Model Description
Simulations use the three-dimensional, hydrostatic SUNTANS model (Fringer et al., 2006) configured over an unstructured triangular grid spanning the SCB from northern Baja California (~30.5N) to Long Beach (~33.8N), following the domain and grid of Masunaga et al. (2023). The grid contains approximately 57,700 horizontal cells with 100 vertical levels (geometric stretching, rstretch = 1.04). The model is forced with M2 barotropic tidal velocities at the open boundaries.
Three cases are run:
- Fall: Initialized with fall stratification derived from SPRAY glider climatology merged with World Ocean Atlas 2023.
- Spring: Initialized with spring stratification from the same sources.
- Unstratified: Homogeneous density, same forcing and domain.
Runtime parameters: dt = 15 s, 59,280 steps (~10.3 days of simulation), MY2.5 turbulence closure, nu_H = 1.0 m2/s. Output saved hourly (every 240 steps), 248 snapshots.
Reproducing Results
Figure reproduction only (~500 MB download)
Download ctw_predictability.mat, unsurf_grid.mat, alongshore_waypoints.mat, exportImage.tiff, adcp_data.mat, site_comparison.mat, obs_profiles_exact.mat, and free_surface_unstrat.mat. Then run:
plot_ctw_predictability % Figs. 1-3, 5, S1, S2, Animation S1
make_fig4_decomposition % Fig. 4
compare_bt_qbt_cycles % Fig. S3
Full reanalysis (~46 GB download)
Download all files and unzip the three archives. Then run:
ctw_predictability_analysis % all diagnostics (~2-4 hours, ~40 GB RAM)
extract_site_comparison % model-vs-ADCP site extraction
addendum_robust_phase % run once: robust neighborhood phases
refit_obs_profiles_exact % exact-period observed amplitudes
plot_ctw_predictability
make_fig4_decomposition
compare_bt_qbt_cycles
See the code README on Zenodo for details.
Related Publications
- Okun, K., A. J. Lucas, E. Masunaga, and G. Pawlak, A predictable component of the internal tide on a narrow continental shelf, Geophysical Research Letters.
- Okun, K., A. J. Lucas, G. Pawlak, and E. Masunaga (2025), Semidiurnal inner shelf flow in the Southern California Bight, Journal of Geophysical Research: Oceans, doi:10.1029/2024JC021591.
- Masunaga, E., M. H. Alford, A. J. Lucas, and A. R.-M. Freudmann (2023), Numerical simulations of internal tide dynamics in a steep submarine canyon, Journal of Physical Oceanography, 53(11), 2669--2686, doi:10.1175/JPO-D-23-0040.1.
- Fringer, O. B., M. Gerritsen, and R. L. Street (2006), An unstructured-grid, finite-volume, nonhydrostatic, parallel coastal ocean simulator, Ocean Modelling, 14(3--4), 139--173, doi:10.1016/j.ocemod.2006.03.006.
External Data Sources
- ETOPO 2022: NOAA National Centers for Environmental Information, doi:10.25921/fd45-gt74.
- World Ocean Atlas 2023: NOAA National Centers for Environmental Information (temperature and salinity climatologies used for initial conditions).
- SPRAY glider climatology: Scripps Institution of Oceanography (used for initial stratification profiles).
License
This dataset is made available under the Creative Commons CC0 1.0 Universal Public Domain Dedication.