Atomix - User contributions [en]

Level 1 data (velocity profilers)

2026-07-15T19:04:51Z

CynthiaBluteau:

The required dimensions and variables for the first processing level within NetCDF ATOMIX format for ADCP velocity measurements are described below. This processing level contains the raw measurements recorded by the instrument. If sampling is in [[Burst sampling|burst mode]], the measurements from individual [[Burst sampling|bursts]] are appended together.

Only a few attributes for each variable are listed since the page's purpose is to describe the information layout within each NetCDF file. Please refer to the {{FontColor|bg=#fca1fd|text= [[NetCDF_parameter|complete list]]}} for the additional attributes related to each variable (e.g., units, bounds, cell_methods).

=Dimensions=
<div class="mw-collapsible" id="raw" data-collapsetext="Collapse" data-expandtext="Expand dimensions">
<br>

{| class="wikitable sortable"
|-
! Short name
! Standard name
! Dimensions
! Comments
|-
| TIME
| time
| TIME
| Units in Days since reference time specified in variable attribute
|-
| Z_DIST
| distance_from_sensor_along_vertical
| Z_DIST
| bin centre distance (in meters) from the transducer along the instrument's vertical axis
|-
| N_BEAM
| unique_identifier_for_each_beam
| N_BEAM
| Array of 1 to number of beams (3 to 5 typically)
|}
</div>

=Variables=
<div class="mw-collapsible" id="raw" data-collapsetext="Collapse" data-expandtext="Expand variables">
<br>
==Required variables==
{| class="wikitable"
|-
! Short name
! Standard name
! Dimensions
! Comments and units
|-
| R_VEL
| water_radial_velocity_of_scatterers_
towards_instrument.
| TIME, Z_DIST, N_BEAM
| Units in m/s. Corresponds to <math> b </math> in [[Nomenclature]]
|-
| R_VEL_FLAGS
| water_radial_velocity_of_scatterers_
towards_instrument_status_flag
| TIME, Z_DIST, N_BEAM
| Boolean flags (8 bit, 0-255) to represent one of 8 possible reasons for rejection. {{FontColor|fg=white|bg=red|text= Link to own flagging page}}
|-
| THETA
| beam_angle_from_instrument_z_axis
| N_BEAM
| Units in degrees, positive (usually ~20-30<math>^\circ</math>)
|-
| BIN_SIZE
| instrument_measurement_volume_bin_size
| N_BEAM
| vertical size of the ADCP bins. Usually the same for all 4 beams, but 5th beam can vary.
|-
| colspan="4" style="text-align:center; font-weight:bold; background-color:#f9eddd" | '''Quality-control variables recorded by acoustic-Doppler instruments''' <math>\ddagger</math>
|-
| ABSIC
| backscatter_intensity
| TIME, Z_DIST, N_BEAM
| Units of counts
|-
| CORR
| correlation_magnitude_from_each_acoustic_beam
| TIME, Z_DIST, N_BEAM
| Unit of counts
|-
| colspan="4" style="text-align:center; font-weight:bold; background-color:#f9eddd" | '''Platform motion variables''' <math>\dagger</math>
|-
| HEADING
| platform_yaw_angle
| TIME
| degrees, clockwise from true North
|-
| PITCH
| platform_pitch_angle
| TIME
| degrees
|-
| ROLL
| platform_roll_angle
| TIME
| degrees
|-
| colspan="4" style="text-align:center; font-weight:bold; background-color:#f9eddd" | '''Optional variables''' <math>\dagger\dagger</math>
|-
| BURST_NUMBER
| unique_identifier_for_each_burst
| TIME
| Integers of 1, 2, etc to designate which [[Burst sampling|burst]] the velocities are associated with. Only required when measuring in burst-mode.
|-
| PROFILE_NUMBER
| unique_identifier_for_each_profile
| TIME
| This variable identifies each record (velocity) profile
|-
| colspan="4" | <math>\ddagger</math> Quality-control variable names are consistent for those onboard RDI Teleydyne ADCPs. Nortek has CORRN (noise correlation as a % instead of counts) detailed in the [[Level_1_data_(velocity_point-measurements)#Variables|ADV Level 1 variables]].

<math>\dagger</math> Motion variables are necessary for structure function analysis for situating the bins relative the vertical (gravity). These variables do enable converting measurements into geographical.

<math>\dagger\dagger</math> BURST_NUMBER is only required when measuring in bursts e.g., 18 min of continuous measurements every hour. Can omit if continuously sampled.
PROFILE_NUMBER is essentially an integer proxy for TIME.
|}

==Optional ancillary variables==

{| class="wikitable sortable"
|-
! Short name
! Standard name
! Dimensions
! Comments
|-
| PRES
| sea_water_pressure
| TIME
| dbar, equals 0 at the sea surface and positive down.
|-
| TEMP*
| sea_water_temperature
| TIME
| degrees_Celsius, in-situ temperature ITS-90 scale
|-
| colspan="4" | *Data from concurrent sensors may be optionally included e.g., salinity, dissolved oxygen. Kinematic viscosity of seawater needs to be calculated during processing,
|}

</div>

=Group attributes (metadata)=
<div class="mw-collapsible" id="raw_att" data-expandtext="Expand group attributes" data-collapsetext="Collapse attributes">
<br>
This section describes attributes that may provide additional information about how the data was processed and manipulated at this stage.
{| class="wikitable"
|-
! Attribute name
! Purpose
! Suggested content
|-
| processing_level
| Boilerplate about the ATOMIX Level 1 content.
| <blockquote>''This group includes the raw measurements from the recorder and ancillary measurements required for quality-controlling them using the manufacturer's recommendations.''</blockquote>
|-
| comment (optional)
| Information is pertinent to problems in the raw data files during collection.
| Examples: Stitching of files, corruption of binary files that were recovered by the manufacturer, etc.
|}
</div>

----
Return to [[Dataset requirements for ADCP structure function]]

Go to [[Level 2 data (velocity profilers)| Level 2 segmented]]

Level 2 data (velocity point-measurements)

2026-07-08T22:09:47Z

CynthiaBluteau:

The required dimensions and variables for the '''Level 2 segmented''' processing level within NetCDF ATOMIX format for velocity measurements are described below.

Only a few attributes for each variable are listed since the page's purpose is to describe the information layout within each NetCDF file. Please refer to the {{FontColor|bg=#fca1fd|text= [[NetCDF_parameter|complete list]]}} for the additional attributes related to each variable (e.g., units, bounds, cell_methods).

__TOC__

=Dimensions=
<div class="mw-collapsible" id="raw" data-collapsetext="Collapse" data-expandtext="Expand dimensions">
<br>
The number of velocity instruments (N_VEL_INSTRUMENT) is here for completeness, but the benchmarks examples will have measurements only from one instrument stored.

{| class="wikitable sortable"
|-
! Short name
! Standard name
! Dimensions
! Comments
|-
| TIME
| time
| TIME
| Units in Days since 1950-01-01T00:00:00Z. Provide bounds attribute to designate the variable containing the limits of each segment ([http://cfconventions.org/cf-conventions/v1.6.0/cf-conventions.html#methods-applied-to-a-timeseries-ex see CF-compliant example]).
|-
| N_SAMPLE
| unique_identifier_for_each_
sample_within_the_segment
| N_SAMPLE
| Max value is the segment length (seconds) multiplied by the sampling rate
|-
| N_VEL_COMPONENT
| unique_identifier_for_each_
velocity_component
| N_VEL_COMPONENT
| Maximum of 3 for u,v, w (east, north, up) velocities
|-
| colspan="4" style="text-align:center; font-weight:bold; background-color:#f9eddd"| Optional variables <math>\ddagger</math>
|-
| N_VEL_INSTRUMENT
| unique_identifier_for_each_
velocity_instrument
| N_VEL_INSTRUMENT
| Required only if storing multiple synchronized instruments in the same file
|}
</div>

=Variables=
<div class="mw-collapsible" id="raw" data-collapsetext="Collapse" data-expandtext="Expand variables">
<br>
{| class="wikitable"
|-
! Short name
! Standard name
! Dimensions
! Comment
|-
| UVW_VEL
| water_velocity_in_the_
analysis_frame_of_reference
| TIME, N_SAMPLE, N_VEL_COMPONENT, N_VEL_INSTRUMENT
| This may be [[Rotation of the velocity measurements|rotated]] in the direction of the mean flow, or left in XYZ_VEL if relying only on the vertical component when estimating <math>\varepsilon</math>. {{FontColor|fg=red|text=Please specify the analysis frame of reference}} in the variable attribute and/or group's attribute.
|-
| UVW_VEL_FLAGS
| water_velocity_in_the_
analysis_frame_of_reference_status_flag
| TIME, N_SAMPLE, N_VEL_COMPONENT, N_VEL_INSTRUMENT
| Enumerated flag that denotes if and how missing samples were replaced
|-
| UVW_VEL_DETRENDED
| water_velocity_
in_the_analysis_frame_of_reference_detrended
| TIME, N_SAMPLE, N_VEL_COMPONENT, N_VEL_INSTRUMENT
| These velocities in the analysis frame of reference have been detrended. The signal may include surface wave, motion contamination, in addition to the turbulence signal. {{FontColor|fg=red|text=Please specify how}}.
|-
| [[Level_1_data_(velocity_point-measurements)#Required_height_variable|HEIGHT or DEPTH]]<math>\dagger</math>
| See [[Level_1_data_(velocity_point-measurements)#Required_height_variable|Level 1 table]]
| TIME, N_VEL_INSTRUMENT
|
|-
| colspan="4" style="text-align:center; font-weight:bold; background-color:#f9eddd"| Optional variables <math>\ddagger</math>
|-
| ROT_AXIS
| angle_of_rotation_from_east_to_x
| TIME, N_VEL_COMPONENT, N_VEL_INSTRUMENT
| Rotation axis [i,j,k] in the geographical coordinates system used to [[Rotation of the velocity measurements|rotate from the geographical to the analysis frame of reference]].
|-
| ROT_ANGLE
| axis_of_rotation_from_east_to_x
| TIME, N_VEL_INSTRUMENT
| Angle of rotation from geographical coordinates to the analysis frame of reference around the rotation axis.
|-
| BURST_NUMBER <math>\dagger\dagger</math>
| unique_identifier_for_each_burst
| TIME, N_VEL_INSTRUMENT
| Only required when measuring in burst-mode. Integers of 1, 2, etc to designate which burst the velocities are associated with.
|-
| colspan="4" |
<math>\ddagger</math> One could re-write for convenience the optional variables in [[Level_1_data_(velocity_point-measurements)#Optional_variables|Level 1]] after segmenting them into smaller chunks. For instance, PRES (pressure) would be fairly common in surface wave studies.

<math>\dagger</math> A variable situating the instruments in the water column is required. This may be a nominal depth (or height) or a time-varying depth or height above the bottom.

<math>\dagger\dagger</math> Variable required only when measuring in bursts e.g., 18 min of continuous measurements every hour.
|}
</div>

=Group attributes (metadata)=
<div class="mw-collapsible" id="raw_att" data-expandtext="Expand group attributes" data-collapsetext="Collapse attributes">

This section describes attributes that may provide additional information about how the data was processed and manipulated at this stage.

{| class="wikitable"
|-
! Attribute name
! Purpose
! Suggested content
|-
| processing_level
| Boilerplate about the content of the NetCDF group.
| <blockquote>''In this group, quality-controlled and despiked velocities have been split into smaller segments for processing, and are often [[Rotation of the velocity measurements|rotated into flow's frame of reference]]. Detrending may occur at this step if this wasn't completed at the previous processing level.''</blockquote>
|-
| segment_length
| Provide length in seconds of each segment
| Usually about 300 to 600 s dependent on [[Time_and_length_scales_of_turbulence|time and length scales of turbulence]]
|-
| segment_overlap_proportion
| Provide proportion overlap of each segment, i.e., window overlap
| Often set to 0 or 0.5
|-
| colspan="4" style="text-align:center; font-weight:bold; background-color:#f9eddd"| Optional group attributes <math>\ddagger</math>
|-
| detrending_method
| Specify which filter or technique was used to detrend velocities, which is required for spectral and turbulence analysis.
| Some examples include <blockquote>''High-pass YY order butterworth filter with XX seconds cutoff frequency on the entire burst/timeseries''</blockquote> <blockquote>''Linear detrending on each segment''</blockquote>
|-
| analysis_frame_of_reference
| Specify the coordinate systems (e.g., geographical, instrument, or flow frame reference) used for analysis since the inertial subrange constants depends on the longitudinal, transverse and vertical component.
| Some possible options <blockquote>''Geographical coordinates</blockquote>
<blockquote>Instrument coordinates</blockquote>
<blockquote>rotated in the direction of mean flow</blockquote>
<blockquote>rotated along the bathymetry/principal component''</blockquote>
|-
| rotation_method
| The basis of [[Rotation of the velocity measurements|rotation]] (if performed) for the turbulence analysis. Were the velocities left in the measurement frame of reference? Was a new frame of reference defined that is more representative of the site conditions (e.g., cross-shelf or along-shelf). Were the velocities rotated over each segment (horizontal plane only i.e., vertical mean velocity was near zero)?
| State whether the mean vertical velocity was assumed to be zero (flat bottom), and if the rotation depended on the measured velocities or was prescribed. For example, <blockquote>''Velocities were rotated into the segment's mean velocity direction (including the contributions from vertical component)''</blockquote>
<blockquote>''Velocities were rotated in the horizontal plane according to the segment's mean horizontal velocity''</blockquote>
<blockquote>''Velocities were not rotated. Analysis relied on the vertical component in the intrument's measurement system.''</blockquote>
|-
| comment (optional)
| Any additional information pertinent to other users who test their algorithms against the file.
|
|}
</div>

----

Return to: [[Level 1 data (velocity point-measurements)|Level 1 raw]]

Go to: [[Level_3_data_(velocity_point-measurements)|Level 3 spectra]]
[[Category:Velocity point-measurements]]

Template:ReviewStage

2026-07-08T22:09:19Z

CynthiaBluteau:

Template:ReviewStage

2026-07-08T22:07:43Z

CynthiaBluteau:

<includeonly>

{| class="wikitable" style="font-weight:bold;"
|- style="font-weight:normal;"
! colspan="2" style="background-color:#ffffc7;" | Page status: {{{toreview|}}}
|-
! style="background-color:#fffff0;" | Author(s):
| {{{authors|}}}
|-
! style="background-color:#fffff0;" | Reviewer(s):
| {{{reviewer|}}}
|-
! style="background-color:#fffff0;" | Comment:
| {{{comment|}}}
|-
|}


{{#if: {{{toreview|}}} | [[Category:{{{toreview}}}]] }}


{{#if: {{{instrument_type|}}} | [[Category:{{{instrument_type}}}]] }}

</includeonly>

<noinclude>
This is the "ReviewStage" template.

It can be called as:
<pre>
{{ReviewStage
|instrument_type=
|toreview=
|reviewer=
|authors=
|comment=
}}
</pre>

=== Parameters ===
* <nowiki>|instrument_type=</nowiki> — Instrument type (e.g., ADV).
* <nowiki>|toreview=</nowiki> — Review status (e.g., Needs review, Reviewed).
* <nowiki>|reviewer=</nowiki> — Name(s) of reviewer(s).
* <nowiki>|authors=</nowiki> — Name(s) of author(s).
* <nowiki>|comment=</nowiki> — Any notes or comments.

=== Behavior ===
This template categorizes the page under:
* <nowiki>[[Category:instrument_type]]</nowiki>
* <nowiki>[[Category:toreview]]</nowiki>

This version does not require PageForms or Arrays and is safe for long‑term use.
</noinclude>

Time and length scales of turbulence

2026-07-08T21:37:12Z

CynthiaBluteau: /* High wavenumber limit */

{{ADV processing
|instrument_type=ADV
|level=level 1 raw, level 2 segmented and quality controlled, level 3 spectra
}}
The length and time scales of turbulence must be considered when analysing turbulence measurements. The scales at which the turbulence subranges, both the viscous and inertial subrange, exist depend on the flow properties. These characteristics of the flow influence various decisions when processing velocity measurements for turbulence computations such as:
* [[Segmenting datasets]]
* [[Detrending time series]]

==Lengthscales==
[[File:Velocity timescales.png|400px|thumb|Example velocities from an instrument impacted by tides and surface waves, which are presented as variance preserving spectra. The instrument is tens of meters off the bottom on the continental shelf in stratified waters with a buoyancy period of 9 min. Turbulence analysis is concerned with time scales larger than the buoyancy period]]

=== High wavenumber limit===
The wavenumber (length scale) limits depend on the sought quantity <math>\varepsilon</math>, and also the kinematic viscosity <math>\nu</math>:

<math>L_K=\left(\frac{\nu^3}{\varepsilon}\right)^{1/4}</math>

=== Low wavenumber limit ===
Of the order of the largest overturn sizes...
* Stratified waters Lo
* Near a boundary <math>L_Z=0.39z_w</math> via von karman's constant of 0.39 and zw the distance to said boundary.
* Sheared flows can also swap Lo with Ls (Corrsin). Ls = Lz in a pure log-law of the wall flow!

==Timescales==
Can use the equation <math>\tau=(L^2/\varepsilon)^{1/3}</math> and dump your favourite turbulent length scale. In stratified waters, this amounts to 1/N.

Turbulent kinetic energy dissipation

2026-07-08T21:34:47Z

CynthiaBluteau:

{{DefineConcept
|parameter_name=<math>\varepsilon</math>
|description=Viscous dissipation rate of turbulent kinetic energy per unit mass
|article_type=Concept
|instrument_type=Velocity point-measurements, Velocity profilers, Shear probes
}}
The dissipation rate, for short, is main quantity ATOMIX seeks to improve.

Turbulent kinetic energy dissipation

2026-07-08T21:34:28Z

CynthiaBluteau:

Preparing quality-controlled velocities

2026-07-08T21:32:17Z

CynthiaBluteau:

{{ADV processing
|instrument_type=ADV
|level=level 2 segmented and quality controlled
}}
After the raw velocities are quality-controlled and optionally despiked, velocities must be further processed before analysing the turbulence spectra. The main steps to prepare the quality-controlled velocities for turbulence analysis are the following:
# [[Replacement strategies for missing velocities | Replace missing samples]] discarded during quality-control
# [[Segmenting datasets]] in preparation to estimate velocity spectra
# [[Rotation of the velocity measurements|Rotate the measurements]] into the flow's frame of reference
# [[Decomposing velocity measurements|Decompose the velocities]] into the mean and turbulence

When measuring velocities continuously or in long [[Burst sampling|bursts]], some individuals may also [[Detrending time series|detrend the time series]] before beginning any of these processing steps.

-----
Return to [[Data processing of raw measurements]]

Continue to [[Spectral estimates and identifying the inertial subrange]]

Data processing of raw measurements

2026-07-08T21:31:48Z

CynthiaBluteau:

Velocity despiking

2026-07-08T21:29:26Z

CynthiaBluteau: /* Phase-space thresholding methods */

{{ADV processing
|instrument_type=ADV
|level=level 1 raw
}}

Any measured signal may be contaminated by spikes. These spikes are typically short-lived and transient, which result in sudden change in the [[:Media:Velocities spike.png| measured velocities]]. These spikes must be removed because they can alter quite dramatically the [[:Media:Despike spectra.png|velocity spectra]], which is then used for fitting [[Velocity inertial subrange model|inertial subrange model]].

=Overview =
Spikes in velocities measured by [[Acoustic-Doppler Velocimeters| acoustic-Doppler velocimeters]] can result from aliasing of the Doppler signal, in particular when pulses become contaminated by reflecting from complex objects and boundaries <ref name="GoringNikora">{{Cite journal|authors= D. G. Goring and V.I. Nikora|journal_or_publisher= Journal of Hydraulic Engineering|paper_or_booktitle= Despiking Acoustic Doppler Velocimeter Data
|year= 2002|doi= 10.1061/􏰠ASCE􏰐0733-9429􏰠2002􏰐128:1􏰠117􏰐}}</ref>. Several techniques exist for despiking:
* [[#Phase-space thresholding methods|Phase-space thresholding]] applied to [[Acoustic-Doppler Velocimeters| acoustic-Doppler velocimeters]] <ref name="GoringNikora"/>
* [[#Filter based methods|Filter-based despiking methods]] such as those used in atmospheric turbulence studies <ref name="Starkenburg">{{Cite journal|authors= D. Starkenburg, S. Metzger, G.J. Fochesatto, J.G Alfieri, R. Gens, A. Prakash and J. Cristobal|journal_or_publisher= J. Atmos. Oceanic Technoly|paper_or_booktitle= Assessment of Despiking Methods for Turbulence Data in Micrometeorology
|year= 2016|doi= 10.1175/JTECH-D-15-0154.1􏰐}}</ref>. The subgroup is investigating in particular the median filter despiking technique <ref name="Brock">{{Cite journal|authors=F.V. Brock|journal_or_publisher= J. Atmos. Oceanic Technoly|paper_or_booktitle= A nonlinear filter to remove impulse noise from meteorological data
|year= 1986|doi= 10.1175/1520-0426(1986)003,0051:ANFTRI.2.0.CO;2􏰐}}</ref>.

<div><ul>
<li style="display: inline-block; vertical-align: top;"> [[File:Velocities spike.png|thumb|none|350px|Example velocities measured by an [[Acoustic-Doppler Velocimeters| acoustic-Doppler velocimeters]]]] </li>
<li style="display: inline-block; vertical-align: top;"> [[File:Despike spectra.png|thumb|none|350px|Example velocity spectra before and after removing spikes. The variance of the despiked signal has reduced by 12% even though there were 30 spikes]] </li>
</ul></div>

=Filter based methods=
This category of methods is quite common in the literature and has been reviewed extensively by others <ref name="GoringNikora"/><ref name="Starkenburg"/>. These methods compare the original signal against a smoothed version, and values exceeding a threshold are deemed spikes. Most commonly, the threshold is applied to the time series of [[:Media:Smoothed velocities.png|velocity differences]] obtained by subtracting the smoothed velocities from the original spiky signal.

[[File:Smoothed velocities.png|400px|thumb|Example velocities before and after smoothing (top). Filter-based despiking methods use the difference between these two signals to identify spikes (bottom).]]

===Filter choice===
In the 1970s, scientists developed methods based on nonlinear median filters
<ref>{{Cite journal|authors=A.E. Beaton, J.W. Tukey|journal_or_publisher= Technometrics|paper_or_booktitle= The fitting of power series, meaning polynomials, illustrated on band-spectroscopic data
|year= 1974|doi=10.1080/00401706.1974.10489171}}</ref>. These filters are less biased by spikes than other linear operations such as low-pass Butterworth filters<ref name="Starkenburg"/>. The moving median filter, for example, only requires a window length, i.e, the number of points over which to calculate the median. This window length must be longer than the duration of spikes, which can span consecutive samples. This number must also be sufficiently short to compute a reasonable local median (see Table 1 of Starkenburg et al 2016<ref name="Starkenburg"/>). The challenge then becomes determining the threshold for identifying spikes.

===Identifying the threshold===
Some filter-based methods use thresholds based on a factor of the original time series' standard deviation (e.g., Tukey method discussed by Goring & Nikora<ref name="GoringNikora"/>). The results of the analysis then become sensitive to this choice of factor. A more automated means to identify the threshold was proposed by Brock (1986)<ref name="Brock"/> using a [[:Media:Threshold logic Brock1986.png|histogram of velocity differences]] (the original minus the smoothed signal). The local minimums on either side from the center define the positive and negative thresholds. Velocity differences exceeding these thresholds are deemed to be spikes.

[[File:Threshold logic Brock1986.png|400px|thumb|Histogram of velocity differences between the original (spiky) and smoothed signals. The local minimum denotes the lower and upper thresholds for identifying spikes. The standard deviation of the original time series is 2 cm/s, while the thresholds are -4.8 and 5.3 cm/s.]]

=Phase-space thresholding methods=
The methods of Goring and Nikora<ref name="GoringNikora"/> was developed specifically for acoustic-doppler velocity measurements. The other papers referenced above include methods for turbulence measurements for other systems such as eddy-correlation. The JTECH paper by Starkenburg et al. (2016)<ref name="Starkenburg"/> review a number of methods, including those of Goring and Nikora. Starkenburg et al. (2016) deemed median-based filtering a more robust means of filtering data since it can handle missing points more easily, and handles better time series with evidence of low-frequency coherent turbulent structures.

=Notes=
<references/>
-----
Return to [[Velocity_point-measurements|Velocity point-measurements' welcome page]]

Velocity despiking

2026-07-08T20:57:48Z

CynthiaBluteau:

{{ADV processing
|instrument_type=ADV
|level=level 1 raw
}}

Any measured signal may be contaminated by spikes. These spikes are typically short-lived and transient, which result in sudden change in the [[:Media:Velocities spike.png| measured velocities]]. These spikes must be removed because they can alter quite dramatically the [[:Media:Despike spectra.png|velocity spectra]], which is then used for fitting [[Velocity inertial subrange model|inertial subrange model]].

=Overview =
Spikes in velocities measured by [[Acoustic-Doppler Velocimeters| acoustic-Doppler velocimeters]] can result from aliasing of the Doppler signal, in particular when pulses become contaminated by reflecting from complex objects and boundaries <ref name="GoringNikora">{{Cite journal|authors= D. G. Goring and V.I. Nikora|journal_or_publisher= Journal of Hydraulic Engineering|paper_or_booktitle= Despiking Acoustic Doppler Velocimeter Data
|year= 2002|doi= 10.1061/􏰠ASCE􏰐0733-9429􏰠2002􏰐128:1􏰠117􏰐}}</ref>. Several techniques exist for despiking:
* [[#Phase-space thresholding methods|Phase-space thresholding]] applied to [[Acoustic-Doppler Velocimeters| acoustic-Doppler velocimeters]] <ref name="GoringNikora"/>
* [[#Filter based methods|Filter-based despiking methods]] such as those used in atmospheric turbulence studies <ref name="Starkenburg">{{Cite journal|authors= D. Starkenburg, S. Metzger, G.J. Fochesatto, J.G Alfieri, R. Gens, A. Prakash and J. Cristobal|journal_or_publisher= J. Atmos. Oceanic Technoly|paper_or_booktitle= Assessment of Despiking Methods for Turbulence Data in Micrometeorology
|year= 2016|doi= 10.1175/JTECH-D-15-0154.1􏰐}}</ref>. The subgroup is investigating in particular the median filter despiking technique <ref name="Brock">{{Cite journal|authors=F.V. Brock|journal_or_publisher= J. Atmos. Oceanic Technoly|paper_or_booktitle= A nonlinear filter to remove impulse noise from meteorological data
|year= 1986|doi= 10.1175/1520-0426(1986)003,0051:ANFTRI.2.0.CO;2􏰐}}</ref>.

<div><ul>
<li style="display: inline-block; vertical-align: top;"> [[File:Velocities spike.png|thumb|none|350px|Example velocities measured by an [[Acoustic-Doppler Velocimeters| acoustic-Doppler velocimeters]]]] </li>
<li style="display: inline-block; vertical-align: top;"> [[File:Despike spectra.png|thumb|none|350px|Example velocity spectra before and after removing spikes. The variance of the despiked signal has reduced by 12% even though there were 30 spikes]] </li>
</ul></div>

=Filter based methods=
This category of methods is quite common in the literature and has been reviewed extensively by others <ref name="GoringNikora"/><ref name="Starkenburg"/>. These methods compare the original signal against a smoothed version, and values exceeding a threshold are deemed spikes. Most commonly, the threshold is applied to the time series of [[:Media:Smoothed velocities.png|velocity differences]] obtained by subtracting the smoothed velocities from the original spiky signal.

[[File:Smoothed velocities.png|400px|thumb|Example velocities before and after smoothing (top). Filter-based despiking methods use the difference between these two signals to identify spikes (bottom).]]

===Filter choice===
In the 1970s, scientists developed methods based on nonlinear median filters
<ref>{{Cite journal|authors=A.E. Beaton, J.W. Tukey|journal_or_publisher= Technometrics|paper_or_booktitle= The fitting of power series, meaning polynomials, illustrated on band-spectroscopic data
|year= 1974|doi=10.1080/00401706.1974.10489171}}</ref>. These filters are less biased by spikes than other linear operations such as low-pass Butterworth filters<ref name="Starkenburg"/>. The moving median filter, for example, only requires a window length, i.e, the number of points over which to calculate the median. This window length must be longer than the duration of spikes, which can span consecutive samples. This number must also be sufficiently short to compute a reasonable local median (see Table 1 of Starkenburg et al 2016<ref name="Starkenburg"/>). The challenge then becomes determining the threshold for identifying spikes.

===Identifying the threshold===
Some filter-based methods use thresholds based on a factor of the original time series' standard deviation (e.g., Tukey method discussed by Goring & Nikora<ref name="GoringNikora"/>). The results of the analysis then become sensitive to this choice of factor. A more automated means to identify the threshold was proposed by Brock (1986)<ref name="Brock"/> using a [[:Media:Threshold logic Brock1986.png|histogram of velocity differences]] (the original minus the smoothed signal). The local minimums on either side from the center define the positive and negative thresholds. Velocity differences exceeding these thresholds are deemed to be spikes.

[[File:Threshold logic Brock1986.png|400px|thumb|Histogram of velocity differences between the original (spiky) and smoothed signals. The local minimum denotes the lower and upper thresholds for identifying spikes. The standard deviation of the original time series is 2 cm/s, while the thresholds are -4.8 and 5.3 cm/s.]]

=Phase-space thresholding methods=
'''Elaborate here''' on the methods of Goring and Nikora<ref name="GoringNikora"/>, which was developed specifically for acoustic-doppler velocity measurements. The other papers referenced above include methods for turbulence measurements for other systems such as eddy-correlation. The JTECH paper by Starkenburg et al. (2016)<ref name="Starkenburg"/> review a number of methods, including those of Goring and Nikora. Starkenburg et al. (2016) deemed median-based filtering a more robust means of filtering data since it can handle missing points more easily, and handles better time series with evidence of low-frequency coherent turbulent structures.

* Requires first [[Detrending time series|detrending]] the time serie
* Recursive/iterative process
* Universal threshold based on ..

=Notes=
<references/>
-----
Return to [[Velocity_point-measurements|Velocity point-measurements' welcome page]]

Time and length scales of turbulence

2026-07-08T20:50:07Z

CynthiaBluteau: /* Lengthscales */

{{ADV processing
|instrument_type=ADV
|level=level 1 raw, level 2 segmented and quality controlled, level 3 spectra
}}
The length and time scales of turbulence must be considered when analysing turbulence measurements. The scales at which the turbulence subranges, both the viscous and inertial subrange, exist depend on the flow properties. These characteristics of the flow influence various decisions when processing velocity measurements for turbulence computations such as:
* [[Segmenting datasets]]
* [[Detrending time series]]

==Lengthscales==
[[File:Velocity timescales.png|400px|thumb|Example velocities from an instrument impacted by tides and surface waves, which are presented as variance preserving spectra. The instrument is tens of meters off the bottom on the continental shelf in stratified waters with a buoyancy period of 9 min. Turbulence analysis is concerned with time scales larger than the buoyancy period]]

=== High wavenumber limit===
For instance, the wavenumber (length scale) limits depend on the sought quantity <math>\varepsilon</math>, and also the kinematic viscosity <math>\nu</math>:

<math>L_K=\left(\frac{\nu^3}{\varepsilon}\right)^{1/4}</math>

=== Low wavenumber limit ===
Of the order of the largest overturn sizes...
* Stratified waters Lo
* Near a boundary <math>L_Z=0.39z_w</math> via von karman's constant of 0.39 and zw the distance to said boundary.
* Sheared flows can also swap Lo with Ls (Corrsin). Ls = Lz in a pure log-law of the wall flow!

==Timescales==
Can use the equation <math>\tau=(L^2/\varepsilon)^{1/3}</math> and dump your favourite turbulent length scale. In stratified waters, this amounts to 1/N.

Level 1 data (velocity point-measurements)

2026-07-08T20:45:09Z

CynthiaBluteau:

The required dimensions and variables for the first processing level within NetCDF ATOMIX format for velocity measurements are described below. This processing level contains the raw measurements recorded by the instrument. If sampling is in [[Burst sampling|burst mode]], the measurements from individual [[Burst sampling|bursts]] are appended together.

Only a few attributes for each variable are listed since the page's purpose is to describe the information layout within each NetCDF file. Please refer to the {{FontColor|bg=#fca1fd|text= [[NetCDF_parameter|complete list]]}} for the additional attributes related to each variable (e.g., units, bounds, cell_methods).

=Dimensions=
<div class="mw-collapsible" id="raw" data-collapsetext="Collapse" data-expandtext="Expand dimensions">
<br>
The number of velocity instruments [N_VEL_INSTRUMENT] is here for completeness, but the benchmarks examples will have measurements only from one instrument stored.

{| class="wikitable sortable"
|-
! Short name
! Standard name
! Dimensions
! Comments
|-
| TIME
| time
| TIME
| Units in Days since 1950-01-01T00:00:00Z
|-
| TIME_HPR
| time_of_heading_pitch_roll
| TIME_HPR
| Heading, pitch and roll (tilt) sensors measure always at 1Hz for Vector ADV
|-
| N_VEL_COMPONENT
| unique_identifier_for_each_velocity_component
| N_VEL_COMPONENT
| Maximum of 3 for u,v, w (east, north, up) velocities
|-
| colspan="4" style="text-align:center; font-weight:bold; background-color:#f9eddd"| Optional variables <math>\ddagger</math>
|-
| N_VEL_INSTRUMENT
| unique_identifier_for_each_velocity_instrument
| N_VEL_INSTRUMENT
| Required only if storing multiple synchronized instruments in the same file
|}

</div>

=Variables=
<div class="mw-collapsible" id="raw" data-collapsetext="Collapse" data-expandtext="Expand variables">
<br>
==Required variables==
{| class="wikitable"
|-
! Short name
! Standard name
! Dimensions
! Comments and units
|-
| XYZ_VEL <math>\ddagger</math>
| water_velocity_measured_in_
instrument_coordinates
| TIME, N_VEL_COMPONENT, N_VEL_INSTRUMENT
| Units in m/s variables are water_velocity_measured_in_ <blockquote>''geographical_coordinates (ENU)''</blockquote> <blockquote>''beam_coordinates (BEAM)''</blockquote>
|-
| XYZ_VEL_FLAGS
| water_velocity_measured_in_
instrument_coordinates_status_flags
| TIME, N_VEL_COMPONENT, N_VEL_INSTRUMENT
| CF-compliant 8-bit (0-255) boolean flag that designates why a velocity sample was discarded.
|-
| [[Level_1_data_(velocity_point-measurements)#Required_height_variable|HEIGHT or DEPTH]]<math>\dagger</math>
| See [[Level_1_data_(velocity_point-measurements)#Required_height_variable|table below]]
| TIME, N_VEL_INSTRUMENT
| Units always in meters
|-
| BURST_NUMBER<math>\dagger\dagger</math>
| unique_identifier_for_each_burst
| TIME
| Integers of 1, 2, etc to designate which [[Burst sampling|burst]] the velocities are associated with.
|-
| colspan="4" style="text-align:center; font-weight:bold; background-color:#f9eddd" | '''Platform motion variables'''
|-
| HEADING
| platform_yaw_angle
| TIME_HPR, N_VEL_INSTRUMENT
| degrees, clockwise from true North
|-
| PITCH
| platform_pitch_angle
| TIME_HPR, N_VEL_INSTRUMENT
| degrees
|-
| ROLL
| platform_roll_angle
| TIME_HPR, N_VEL_INSTRUMENT
| degrees
|-
| colspan="4" style="text-align:center; font-weight:bold; background-color:#f9eddd" | '''Quality-control variables usually available with acoustic-Doppler instruments'''
|-
| ABSIC
| backscatter_intensity_from_each_acoustic_beam
| TIME, N_VEL_COMPONENT, N_VEL_INSTRUMENT
| count
|-
| SNR
| signal_noise_ratio_from_each_acoustic_beam
| TIME, N_VEL_COMPONENT
| decibel
|-
| CORRN
| noise_correlation_percent_from_each_acoustic_beam
| TIME, N_VEL_COMPONENT, N_VEL_INSTRUMENT
| percent
|-
| colspan="4" | <math>\ddagger</math> Some manufacturers record quality-control variables (e.g., CORRN) in the instrument coordinate system. For example, Nortek records these variables in the instrument XYZ frame of reference. It's best to record the data in that coordinate system.

<math>\dagger</math>A variable situating the instruments in the water column is required. This may be a nominal depth (or height) or a time-varying depth or height above the bottom.

<math>\dagger\dagger</math> Variable required only when measuring in [[Burst sampling|bursts]] e.g., 18 min of continuous measurements every hour.
|}

== Required height variable ==
Height or depth-related variables (only 1x is required). These variables locate the instrument vertically from a boundary (e.g, surface or ice). A negative value implies it's below the boundary. Units are always in meters. Can also provide a constant value in time representing the nominal height and/or depth.

{| class="wikitable sortable"
|-
! Short name
! Standard name
! Dimensions
|-
| HEIGHT_AB
| height_above_bottom
| TIME, N_VEL_INSTRUMENT
|-
| DEPTH
| depth_below_surface
| TIME, N_VEL_INSTRUMENT
|}

==Optional ancillary variables==

{| class="wikitable sortable"
|-
! Short name
! Standard name
! Dimensions
! Comments
|-
| PRES
| sea_water_pressure
| TIME, N_VEL_INSTRUMENT
| dbar, equals 0 at the sea surface and positive down.
|-
| TEMP*
| sea_water_temperature
| TIME
| degrees_Celsius, in-situ temperature ITS-90 scale
|-
| colspan="4" | *Data from concurrent sensors may be optionally included e.g., salinity, dissolved oxygen (e.g., eddy-correlation system). Kinematic viscosity of seawater needs to be calculated during processing,
|}
</div>

=Group attributes (metadata)=
<div class="mw-collapsible" id="raw_att" data-expandtext="Expand group attributes" data-collapsetext="Collapse attributes">
<br>
This section describes attributes that may provide additional information about how the data was processed and manipulated at this stage.
{| class="wikitable"
|-
! Attribute name
! Purpose
! Suggested content
|-
| processing_level
| Boilerplate about the ATOMIX Level 1 content.
| <blockquote>''This group includes the raw measurements from the recorder and ancillary measurements required for quality-controlling them using the manufacturer's recommendations.''</blockquote>
|-
| despiking_method
| Specify which despiking technique (if any) was applied to the dataset. Include citation if possible.
| <blockquote>''Velocities were despiked using Goring Nikora phase-space thresholding technique applied on [[Detrending_time_series|detrended timeseries]]. Time series were detrended using XX technique.''</blockquote>
|-
| comment (optional)
| Information is pertinent to problems in the raw data files during collection.
| Examples: Stitching of files, corruption of binary files that were recovered by the manufacturer, etc.
|}
</div>

----
Return to [[NetCDF velocimeters format]]

Go to next level: [[Level_2_data_(velocity_point-measurements)|Level 2 quality controlled and segmented]]
[[Category:Velocity point-measurements]]

Template:ADV processing

2026-07-08T20:37:29Z

CynthiaBluteau:

<includeonly>

{{#if: {{{instrument_type|}}} | [[Category:{{{instrument_type}}}]] }}

{{#if: {{{level|}}} | [[Category:{{{instrument_type}}} {{{level}}}]] }}

</includeonly>

<noinclude>
This is the "ADV processing" template.

It can be called as:
<pre>
{{ADV processing
|instrument_type=ADV
|level=level 1 raw
}}
</pre>

=== Parameters ===
* <nowiki>|instrument_type=</nowiki> — Instrument type (e.g., ADV).
* <nowiki>|level=</nowiki> — Processing level description (e.g., <nowiki>level 1 raw, or level 3 spectra</nowiki>).

=== Behavior ===
This template categorizes the page under:
* <nowiki>[[Category:instrument_type]]</nowiki>
* <nowiki>[[Category:instrument_type level]]</nowiki>

This version does not require PageForms or Arrays.
</noinclude>

Template:ADV processing

2026-07-08T20:28:38Z

CynthiaBluteau:

<includeonly>

{{#if: {{{instrument_type|}}} | [[Category:{{{instrument_type}}}]] }}

{{#if: {{{level|}}} | [[Category:{{{instrument_type}}} {{{level}}}]] }}

</includeonly>

<noinclude>
This is the "ADV processing" template.

It can be called as:
<pre>
{{ADV processing
|instrument_type=ADV
|level=level 1 raw
}}
</pre>

=== Parameters ===
* <nowiki>|instrument_type=</nowiki> — Instrument type (e.g., ADV).
* <nowiki>|level=</nowiki> — Processing level description (e.g., <nowiki>level 1 raw</nowiki>).

=== Behavior ===
This template categorizes the page under:
* <nowiki>[[Category:instrument_type]]</nowiki>
* <nowiki>[[Category:instrument_type level]]</nowiki>

This version does not require PageForms or Arrays.
</noinclude>

Template:ADV processing

2026-07-08T20:27:09Z

CynthiaBluteau:

<includeonly>


{{#if: {{{instrument_type|}}} | [[Category:{{{instrument_type}}}]] }}


{{#if: {{{level|}}} |
{{#if: {{#pos:{{{level}}},}} |

{{#foreach: {{{level}}} | , | levelitem |
[[Category:{{{instrument_type}}} {{levelitem}}]]
}}
|

[[Category:{{{instrument_type}}} {{{level}}}]]
}}
}}

</includeonly>

<noinclude>
This is the "ADV_processing" template.

It can be called manually as:
<pre>
{{ADV_processing
|level=1,2,3
|instrument_type=ADV
}}
</pre>

=== Parameters ===
* <nowiki>|instrument_type=</nowiki> — The instrument type (e.g., ADV).
* <nowiki>|level=</nowiki> — One or more processing levels.
- Single value: <nowiki>1</nowiki>
- Multiple values: <nowiki>1,2,3</nowiki>

=== Behavior ===
This template automatically categorizes the page under:
* <nowiki>[[Category:instrument_type]]</nowiki>
* <nowiki>[[Category:instrument_type level]]</nowiki> for each level provided.

This version does not require PageForms or Arrays and is safe for long‑term use.

</noinclude>

Velocity point-measurements

2026-07-08T20:25:21Z

CynthiaBluteau:

= Welcome to the velocity point-measurements subgroup! =
This subgroup addresses best practices in obtaining [[turbulent kinetic energy dissipation]] rate estimates from time series of velocities measured at a point in space. Our recommendations are designed for measurements collected by any manufacturer, provided the data quality is sufficient for resolving the [[Velocity inertial subrange model|inertial subrange]] of the velocity spectra.

{|class="wikitable" style="margin-left: auto; margin-right: auto; border: none; text-align:center;"
|[[File:Advprocessing.png|180px|link=Flow chart for velocity point-measurements|Flow chart for velocity point-measurements]]
|[[File:Benchmark adv netcdf.png|370px|link=NetCDF velocimeters format|NetCDF velocimeters format]]
|[[File:TIC Leopold 1.jpg|150px|link=benchmark datasets for velocity measurements|benchmark datasets]]
|-
|[[Flow chart for velocity point-measurements|Flow chart for data processing]]
|[[NetCDF velocimeters format |NetCDF dataset format]]
|[[benchmark datasets for velocity measurements|Benchmark datasets]]
|}

We will provide [[benchmark datasets for velocity measurements|benchmarks for velocity measurements]] unaffected by surface waves. These [[benchmark datasets for velocity measurements|benchmarks]] will be a resource for the Ocean Mixing Community to evaluate routines in any programming language. These [[benchmark datasets for velocity measurements|benchmarks]] will be limited to instruments fixed in space. We will nonetheless include appropriate references to the existing literature on handling moored instruments.

----
[[Category:Velocity point-measurements]]

Velocity inertial subrange model

2026-07-08T20:24:32Z

CynthiaBluteau: /* Models influenced by surface waves */

{{DefineConcept
|description=The inertial subrange separates the energy-containing production range from the viscous dissipation range.
|article_type=Fundamentals
|instrument_type=Velocity point-measurements, Velocity profilers
}}
== Model for steady-flows ==
This theoretical model predicts the spectral shape of velocities in wavenumber space.

<math>\Psi_{Vj}(\hat{k})=a_jC_k\varepsilon^{2/3}\hat{k}^{-5/3}</math>

[[File:InertialSubrangeSchematic.png|thumb|Sketch of velocity power density spectrum in log-log space. The inertial subrange's -5/3 slope is highlighted. The vertical axis represents <math>\Psi_{Vj}(\hat{k})</math>. Large scale [[#anisotropy|turbulence anisotropy]] in low energy flow may alter the expected spectral shape]]

Here <math>\hat{k}</math> is expressed in rad/m and <math>Vj</math> represents the velocities <math>V</math> in direction <math>j</math>. <math>C_k</math> is the empirical Kolmogorov universal constant of C
= 1.5 <ref name="Sreenivasan">{{Cite journal
|authors= K. R. Sreenivasan
|journal_or_publisher= Phys. Fluids
|paper_or_booktitle= On the universality of the Kolmogorov constant
|year= 1995
|doi= 10.1063/1.868656
}}</ref>. Amongst the three direction, the spectra deviates by the constant <math>a_j</math>:
<ref name="Pope">{{Cite journal
|authors= S.B Pope
|journal_or_publisher= Cambridge Univ. Press
|paper_or_booktitle= Turbulent flows
|year= 2000
|doi= 10.1017/CBO9780511840531
}}</ref>

* In the longitudinal direction, i.e., the direction of mean advection (j=1), <math>a_1=\frac{18}{55}</math>
* In the other directions <math>a_2=a_3=\frac{4}{3}a_1</math>

== Inertial subrange collapse and <span id="anisotropy">anisotropy</span> ==
Near boundaries or low energy environments--defined as flows with a small separation between the large turbulent overturns <math>L</math> and the smallest (Kolmogorov)-- tends to adversely impact our ability to estimate <math>\varepsilon</math> from the lower wavenumbers. In certain cases, the velocity spectra may not have a sufficiently developed inertial subrange to estimate <math>\varepsilon</math> <ref name="Gargett.etal1984">{{Cite journal
|authors= A. E. Gargett, T. R. Osborn, and P.W. Nasmyth
|journal_or_publisher= J. Fluid. Mech.
|paper_or_booktitle= Local isotropy and the decay of turbulence in a stratified fluid
|year= 1984
|doi=10.1017/S0022112084001592
}}</ref><ref name="Bluteau.etal2011">{{Cite journal
|authors= C.E. Bluteau, N.L. Jones, and G. Ivey
|journal_or_publisher= Limnol. Oceanogr.: Methods
|paper_or_booktitle= Estimating turbulent kinetic energy dissipation using the inertial subrange method in environmental flows
|year= 2011
|doi=10:4319/lom.2011.9.302
}}</ref>.

[[Velocity inertial subrange model#anisotropy|Anisotropic velocity spectra]] are exhibited when the largest turbulence scales are less than {{FontColor|fg=white|bg=red|text=XX}} times the Kolmogorov length scale, may inhibit using the vertical velocity component to derive <math>\varepsilon</math>. In these situations, it may be possible to use the longitudinal velocity component (see Bluteau et al. 2011<ref name="Bluteau.etal2011"/>), which requires the user to [[Rotation of the velocity measurements|rotate the velocity]] in the direction of the mean flow.

[[File:Anisotropy.png|center|thumbnail|600px|Example of how [[Velocity inertial subrange model#anisotropy| turbulence anisotropy]] influences the velocity spectral shapes. This instrument was located very close to the bed (0.15 m) in a shallow waterway less than 2 m deep, which results in the vertical velocity's inertial subrange being reduced by the flattening of the spectra at wavenumbers of 10 cpm (0.1m scales). Strong stratification (or shear) is another mechanism that shortens the inertial subrange at the lower wavenumbers<ref name="Bluteau.etal2011"/>. The wavenumber at which its impact is felt is approximately <math>L_o/3</math> where <math>L_o</math> is the Ozmidov length scale.]]

== Notes ==

Template:DefineConcept

2026-07-08T20:23:30Z

CynthiaBluteau:

<includeonly>

{| class="wikitable"
|-
! Short definition of {{FULLPAGENAME}} {{#if: {{{parameter_name|}}} | ({{{parameter_name}}}) | }}
|-
| {{{description}}}
|}
<small>This is the common definition for {{FULLPAGENAME}}, but other definitions may be discussed within the wiki.</small>

[[Category:Concept]]

{{#if: {{{instrument_type|}}} | [[Category:{{{instrument_type}}}]] }}

</includeonly>

<noinclude>
This is the "DefineConcept" template, which formats the data supplied through the [[Form:DefineConcept|DefineConcept form]].

The page's name is the full name of the concept/definition, while a short name (or acronym) can be provided as the parameter_name. The instrument_type variable is passed using the form only to avoid creating new categories through typing mistakes.

The form enables categorizing the pages under these two types:
* Concept (short reusable definitions)
* Fundamentals

=== Using the template directly (not recommended) ===
<pre>
{{DefineConcept
|parameter_name=
|description=
|instrument_type=
}}
</pre>

</noinclude>

Benchmark datasets for velocity measurements

2026-07-08T20:12:10Z

CynthiaBluteau:

These datasets are currently located in [https://doi.org/10.5281/zenodo.16798905 Zenodo].

{| class="wikitable"
|+Summary of potential benchmark datasets for testing existing and future algorithms
|-
! style="width: 12%"| Dataset name
! Total depth
! Deployment distance from boundary
! Background median speed
! <math>\varepsilon</math> range
! Stratification/shear information
! style="width: 20%"| Comment
|-
! Units
! [m]
! [m]
! [m/s]
! [W/kg]
!
!
|-
| Tidal Slough ADV
| 2.8
| 0.45
| 0.15
| 1e-7 to 1e-5
| Unstratified, but shear-induced anisotropy
| Viscous subrange is occasionally resolved. Another ADV at 0.15 m shows wrapping issues.
|-
| Tidal Shelf ADV
| 250
| 0.4
| 0.26
| 1e-7 to 1e-4
| Stratified bottom log-layer
| High-quality dataset with phase wrapping. It overlaps with an ADCP Signature benchmark.
|-
| Underice MAVS
| 353
| 5
| 0.03
| 3e-9 to 7e-8
| Weak stratification
| Under-ice boundary layer, MAVS suspended 5 m beneath the ice
|-
| Tidal MAVS
| 20
| 1.45
| 1.1
| 3e-4 to 1e-3
| Weak stratification
| Strong tidal flows
|}

[[Category:Velocity point-measurements]]

Template:Cite journal

2026-05-13T16:38:10Z

CynthiaBluteau:

<includeonly>
{{{authors}}}. {{{year}}}. {{{paper_or_booktitle}}}. {{{journal_or_publisher}}}. doi:{{{doi}}}
</includeonly>

<noinclude>
== Usage ==
This template formats a journal citation for use inside <nowiki><ref></ref></nowiki> tags.

=== Basic example ===
To cite a journal article, place the following inside your text:
<pre>
<nowiki>
<ref name="EmeryThomson2001">{{Cite journal
|authors=Emery, W. J., and R. E. Thomson
|year=2001
|paper_or_booktitle=Data analysis methods in physical oceanography, 2nd edition, Section 5.6.7–5.6.8
|journal_or_publisher=Elsevier
|doi=(ISBN)9780080477008
}}</ref>
</nowiki></pre>

This will produce a numbered reference in the text and a formatted entry in the Notes section.

=== Displaying the reference list ===
At the bottom of the page, add:

<nowiki>
== References ==
</nowiki>

This will display all citations defined with <nowiki><ref></ref></nowiki> tags.

=== Template parameters ===
* <nowiki>|authors=</nowiki> — Full author list, formatted exactly as desired.
* <nowiki>|year=</nowiki> — Publication year.
* <nowiki>|paper_or_booktitle=</nowiki> — Title of the paper or chapter.
* <nowiki>|journal_or_publisher=</nowiki> — Journal name or publisher.
* <nowiki>|doi=</nowiki> — DOI or ISBN.

This template does not require any extensions and is safe for long‑term use.
</noinclude>

<noinclude>
This template formats journal citations without requiring any extensions.
Usage example:<ref name="Example">{{Cite journal
|authors=Lastname, A., and B. Lastname
|year=2020
|paper_or_booktitle=Title of the paper
|journal_or_publisher=Journal Name
|doi=10.1234/example
}}</ref>
=References=
</noinclude>

Template:Cite journal

2026-05-13T16:37:15Z

CynthiaBluteau:

<includeonly>
{{{authors}}}. {{{year}}}. {{{paper_or_booktitle}}}. {{{journal_or_publisher}}}. doi:{{{doi}}}
</includeonly>

<noinclude>
== Usage ==
This template formats a journal citation for use inside <nowiki><ref></ref></nowiki> tags.

=== Basic example ===
To cite a journal article, place the following inside your text:

<pre>
<ref name="EmeryThomson2001">{{Cite journal
|authors=Emery, W. J., and R. E. Thomson
|year=2001
|paper_or_booktitle=Data analysis methods in physical oceanography, 2nd edition, Section 5.6.7–5.6.8
|journal_or_publisher=Elsevier
|doi=(ISBN)9780080477008
}}</ref>
</pre>

This will produce a numbered reference in the text and a formatted entry in the Notes section.

=== Displaying the reference list ===
At the bottom of the page, add:

<nowiki>
== References ==
<references/>
</nowiki>

This will display all citations defined with <nowiki><ref></ref></nowiki> tags.

=== Template parameters ===
* <nowiki>|authors=</nowiki> — Full author list, formatted exactly as desired.
* <nowiki>|year=</nowiki> — Publication year.
* <nowiki>|paper_or_booktitle=</nowiki> — Title of the paper or chapter.
* <nowiki>|journal_or_publisher=</nowiki> — Journal name or publisher.
* <nowiki>|doi=</nowiki> — DOI or ISBN.

This template does not require any extensions and is safe for long‑term use.
</noinclude>

Template:Cite journal

2026-05-13T16:35:23Z

CynthiaBluteau:

Template:Cite journal

2026-05-13T16:34:30Z

CynthiaBluteau:

Template:Cite journal

2026-05-13T16:34:06Z

CynthiaBluteau: /* References */

Template:Cite journal

2026-05-13T16:33:51Z

CynthiaBluteau:

Template:Cite journal

2026-05-13T16:32:57Z

CynthiaBluteau:

Template:Cite journal

2026-05-13T16:30:41Z

CynthiaBluteau: /* Displaying the reference list */

<includeonly>
{{{authors}}}. {{{year}}}. {{{paper_or_booktitle}}}. {{{journal_or_publisher}}}. doi:{{{doi}}}
</includeonly>

<noinclude>
== Usage ==
This template formats a journal citation for use inside <ref></ref> tags.

=== Basic example ===
To cite a journal article, place the following inside your text:

<nowiki>
<ref name="EmeryThomson2001">{{Cite journal
|authors=Emery, W. J., and R. E. Thomson
|year=2001
|paper_or_booktitle=Data analysis methods in physical oceanography, 2nd edition, Section 5.6.7–5.6.8
|journal_or_publisher=Elsevier
|doi=(ISBN)9780080477008
}}</ref>
</nowiki>

This will produce a numbered reference in the text and a formatted entry in the Notes section.

=== Displaying the reference list ===
At the bottom of the page, add:

<nowiki>
== References ==
</nowiki>

This will display all citations defined with <nowiki><ref></ref></nowiki> tags.

=== Template parameters ===
* <nowiki>|authors=</nowiki> — Full author list, formatted exactly as desired.
* <nowiki>|year=</nowiki> — Publication year.
* <nowiki>|paper_or_booktitle=</nowiki> — Title of the paper or chapter.
* <nowiki>|journal_or_publisher=</nowiki> — Journal name or publisher.
* <nowiki>|doi=</nowiki> — DOI or ISBN.

This template does not require any extensions and is safe for long‑term use.
</noinclude>

<noinclude>
This template formats journal citations without requiring any extensions.
Usage example:<ref name="Example">{{Cite journal
|authors=Lastname, A., and B. Lastname
|year=2020
|paper_or_booktitle=Title of the paper
|journal_or_publisher=Journal Name
|doi=10.1234/example
}}</ref>
</noinclude>

Template:Cite journal

2026-05-13T16:29:16Z

CynthiaBluteau:

<includeonly>
{{{authors}}}. {{{year}}}. {{{paper_or_booktitle}}}. {{{journal_or_publisher}}}. doi:{{{doi}}}
</includeonly>

<noinclude>
== Usage ==
This template formats a journal citation for use inside <ref></ref> tags.

=== Basic example ===
To cite a journal article, place the following inside your text:

<nowiki>
<ref name="EmeryThomson2001">{{Cite journal
|authors=Emery, W. J., and R. E. Thomson
|year=2001
|paper_or_booktitle=Data analysis methods in physical oceanography, 2nd edition, Section 5.6.7–5.6.8
|journal_or_publisher=Elsevier
|doi=(ISBN)9780080477008
}}</ref>
</nowiki>

This will produce a numbered reference in the text and a formatted entry in the Notes section.

=== Displaying the reference list ===
At the bottom of the page, add:

<nowiki>
== Notes ==
<references/>
</nowiki>

This will display all citations defined with <nowiki><ref></ref></nowiki> tags.

=== Template parameters ===
* <nowiki>|authors=</nowiki> — Full author list, formatted exactly as desired.
* <nowiki>|year=</nowiki> — Publication year.
* <nowiki>|paper_or_booktitle=</nowiki> — Title of the paper or chapter.
* <nowiki>|journal_or_publisher=</nowiki> — Journal name or publisher.
* <nowiki>|doi=</nowiki> — DOI or ISBN.

This template does not require any extensions and is safe for long‑term use.
</noinclude>

<noinclude>
This template formats journal citations without requiring any extensions.
Usage example:<ref name="Example">{{Cite journal
|authors=Lastname, A., and B. Lastname
|year=2020
|paper_or_booktitle=Title of the paper
|journal_or_publisher=Journal Name
|doi=10.1234/example
}}</ref>
</noinclude>

Template:Cite journal

2026-05-13T16:10:30Z

CynthiaBluteau:

<includeonly>
{{{authors}}}. {{{year}}}. {{{paper_or_booktitle}}}. {{{journal_or_publisher}}}. doi:{{{doi}}}
</includeonly>

<noinclude>
This template formats journal citations without requiring any extensions.
Usage example:<ref name="Example">{{Cite journal
|authors=Lastname, A., and B. Lastname
|year=2020
|paper_or_booktitle=Title of the paper
|journal_or_publisher=Journal Name
|doi=10.1234/example
}}</ref>
</noinclude>

Template:Cite journal

2026-05-13T16:10:04Z

CynthiaBluteau:

<includeonly>
{{{authors}}}. {{{year}}}. {{{paper_or_booktitle}}}. {{{journal_or_publisher}}}. doi:{{{doi}}}
</includeonly>

<noinclude>
This template formats journal citations without requiring any extensions.
Usage example:

<ref name="Example">{{Cite journal
|authors=Lastname, A., and B. Lastname
|year=2020
|paper_or_booktitle=Title of the paper
|journal_or_publisher=Journal Name
|doi=10.1234/example
}}</ref>
</noinclude>

Template:Cite journal

2026-05-13T16:09:25Z

CynthiaBluteau:

<noinclude>
This is the "Cite journal" template. It can be used to format textbooks and publications. DOI have issues displaying when there are less than ( <nowiki><</nowiki>) and greater than <nowiki>></nowiki>operators.

By default, the formatted references will appear at the bottom of the page. It's good practice to place a section <nowiki>==Notes==</nowiki> at the bottom of the page.

The template can be called in the following format if not using the form:
<pre>
{{Cite journal
|authors=
|journal_or_publisher=
|paper_or_booktitle=
|year=
|doi=
}}
</pre>

For example doing
<pre>
<ref name="Sreenivasan">{{Cite journal
|authors= K. R. Sreenivasan
|journal_or_publisher= Phys. Fluids
|paper_or_booktitle= On the universality of the Kolmogorov constant
|year= 1995
|doi= 10.1063/1.868656
}}</ref>
</pre>
will create a citation <ref name="Sreenivasan">{{Cite journal
|authors= K. R. Sreenivasan
|journal_or_publisher= Phys. Fluids
|paper_or_booktitle= On the universality of the Kolmogorov constant
|year= 1995
|doi= 10.1063/1.868656
}}</ref>.
You can continue referring to it using <nowiki><ref name="Sreenivasan"></nowiki> that will reuse the correct reference <ref name="Sreenivasan"/>.

<includeonly>
{{{authors}}}. {{{year}}}. {{{paper_or_booktitle}}}. {{{journal_or_publisher}}}. doi:{{{doi}}}
</includeonly>

<noinclude>
This template formats journal citations without requiring any extensions.
</noinclude>

Template:Cite journal

2026-05-13T16:07:38Z

CynthiaBluteau:

Quality control measures

2026-05-05T22:15:53Z

CynthiaBluteau:

Some elements of quality control can only be done after spectra have been computed and should be done before final estimates of <math>\varepsilon</math> are reported:

* Reject time series segments as inadequate for turbulence analysis
** List them here or link to new pages?
* Reject spectra (or parts of spectra)
** Spectral slope of fitted spectral observations (?)
** Misfit criteria

* Identify frame interferences from the epsilon vales
* Plot spectra from all three velocity components to check for [[Large-scale turbulence anisotropy]]
* Determine the measurement noise levels in the time-domain {{FontColor|fg=white|bg=red|text=This is currently not implemented, would be best done on each segments at level 2}}

Here are other quality indicators based on the estimated <math>\varepsilon</math>:
* Propagated error from the confidence level of the spectra

-----
Return to [[Spectral estimates and identifying the inertial subrange]]
[[Category:Velocity point-measurements]]

Data processing of raw measurements

2026-05-05T22:15:00Z

CynthiaBluteau:

{{ADV processing
|instrument_type=ADV
|level=level 1 raw
}}
The following are specific recommendations for processing raw measurements, which are non-specific to a brand/make of instrument. As such, initial removal of bad data based on recommendations of the instrument manufacturer should be performed first (e.g. removing data with low correlation). Following that, you must:

* [[Velocity despiking|Despike the velocity observations]]
* [[Phase unwrapping]] if required
* Identify whether there is [[interference from the instrument frame]], and under which conditions

----
Return to [[Flow chart for velocity point-measurements]]

Continue to [[Preparing quality-controlled velocities]]

Data processing of raw measurements

2026-05-05T21:59:52Z

CynthiaBluteau:

{{ADV processing
|instrument_type=ADV
|level=level 1 raw
}}
The following are specific recommendations for processing raw measurements, which are non-specific to a brand/make of instrument. As such, initial removal of bad data based on recommendations of the instrument manufacturer should be performed first (e.g. removing data with low correlation). Following that, you must:

* [[Velocity despiking|Despike the velocity observations]]
* [[Phase unwrapping]] if required
* Identify whether there is [[interference from the instrument frame]], and under which conditions
* Determine the measurement noise levels in the time-domain {{FontColor|fg=white|bg=red|text=This is currently not implemented, would be best done on each segments at level 2}}

----
Return to [[Flow chart for velocity point-measurements]]

Continue to [[Preparing quality-controlled velocities]]

Flow chart for velocity point-measurements

2026-05-05T21:40:20Z

CynthiaBluteau:

The subgroup will provide recommendations and [[benchmark datasets for velocity measurements|benchmark datasets]] that can be used to assess processing algorithm at various stages of estimating <math>\varepsilon</math>:
[[File:Advprocessing.png|400px|thumb|Placeholder for complete flow chart for processing velocity point-measurements.]]

# [[Data processing of raw measurements|Data processing of raw velocities]]
# [[Preparing quality-controlled velocities|Segmenting and preparing quality-controlled velocities]] for spectral computations
# [[Compute_the_spectra|Spectral estimates]]
# [[Estimate epsilon|Estimating <math>\varepsilon</math>]] and its associated [[Quality control measures|quality control measures]]

These four processing levels coincide with the hierarchal format of the ATOMIX [[NetCDF velocimeters format]] used for archiving the [[benchmark datasets for velocity measurements|benchmark datasets]].

----
Return to [[Velocity point-measurements]]

[[Category:Velocity point-measurements]]

Flow chart for velocity point-measurements

2026-05-05T21:38:42Z

CynthiaBluteau:

The subgroup will provide recommendations and [[benchmark datasets for velocity measurements|benchmark datasets]] that can be used to assess processing algorithm at various stages of estimating <math>\varepsilon</math>:
[[File:Advprocessing.png|400px|thumb|Placeholder for complete flow chart for processing velocity point-measurements.]]

# [[Data processing of raw measurements|Data processing of raw velocities]]
# [[Preparing quality-controlled velocities|Segmenting and preparing quality-controlled velocities]] for spectral computations
# [[Spectral estimates]]
# [[Estimate epsilon|Estimating <math>\varepsilon</math>]] and its associated [[Quality control measures|quality control measures]]

These four processing levels coincide with the hierarchal format of the ATOMIX [[NetCDF velocimeters format]] used for archiving the [[benchmark datasets for velocity measurements|benchmark datasets]].

----
Return to [[Velocity point-measurements]]

[[Category:Velocity point-measurements]]

How to use and contribute

2026-05-05T21:35:44Z

CynthiaBluteau: /* Peer-review and commenting */

We collated [[Editing tips|editing tips]] for the wiki collected from other sources and individual's experiences using the wiki. The information below provides some brief guidelines on creating and commenting ATOMIX's wiki pages.

== Creating and editing wiki pages ==
Existing ATOMIX group members may [[Create and edit wiki|create and edit]] existing wiki pages provided they have a user account.

=== Naming of new pages ===
Please follow the same [https://en.m.wikipedia.org/wiki/Wikipedia:Article_titles guidelines] as Wikipedia when providing titles for any wiki pages.
* Avoid starting titles with articles and prepositions (e.g., avoid "The" and "A")
* No acronyms unless they well known (e.g., ADCP)
* First letter is capitalised
* Title should reflect the content of the page, and not be chosen to match nicely with the text that links to it.

=== Linking (piping) pages ===
You can link to internal wiki pages via alternate text. For example writing <nowiki>[[Turbulence spectrum| turbulence page]]</nowiki> will link the words [[Turbulence spectrum| turbulence page]] to an internal page called Turbulence spectrum.

=== Format of new page ===
All pages should start with an introduction or lead of some sort, unless you're using the concept/fundamental form.

==Watching pages==
Each user has under their account profile their list of [[Special:Watchlist|watched pages]]. By default, all pages that you edit are "watched", but you can edit which ones and control how (if) you are notified about edits of these pages as they occur.

== Peer-review and commenting ==
* Each page has a discussion page associated with it that allows users to discuss content about the page.
** These discussion pages are '''not''' for tracking or versioning your edits. There's a "history" toggle you can use for this purpose.
* Please take a look at [[Talk:How_to_use_and_contribute|discussion page]] for help on threaded comments to use on discussion pages.
** Using 4 tildes <nowiki>~~~~</nowiki> will sign your username and date automatically

==Citing and references==
* To streamline formatting of published papers, please follow the instructions from the [[Template:Cite_journal| Cite journal]] template within the <nowiki><ref></ref></nowiki> tags.

* By default, the formatted references will appear at the bottom of the page. It's good practice to place a section <nowiki>==Notes==</nowiki> at the bottom of the page.

* The <nowiki><references/></nowiki> tag inserts the text of all the citations which have defined using <nowiki><ref></ref></nowiki>tags up to that point in the page.

==Categorizing information==
There are a few categories for organising pages. Whenever possible, please include the subgroup categories:
* [[:Category:Shear_probes]]
* [[:Category:Velocity_point-measurements]]
* [[:Category:Velocity_profilers‏‎]]
at the bottom of the page when not using "edit with forms" such as those associated with
* [[:Category:Concept]] and [[:Category:Fundamentals]] pages.

To add a category use <nowiki>[[Category|Name_of_category]]</nowiki>.

This page uses the <nowiki>[[Category|Help]]</nowiki>

[[Category:Help]]

Flow chart for velocity point-measurements

2026-05-05T21:28:48Z

CynthiaBluteau:

The subgroup will provide recommendations and [[benchmark datasets for velocity measurements|benchmark datasets]] that can be used to assess processing algorithm at various stages of estimating <math>\varepsilon</math>:
[[File:Advprocessing.png|400px|thumb|Placeholder for complete flow chart for processing velocity point-measurements.]]

# [[Data processing of raw measurements|Data processing of raw velocities]]
# [[Preparing quality-controlled velocities|Segmenting and preparing qaqc velocities]] for spectral computations
# [[Spectral estimates and identifying the inertial subrange]]
# [[Estimate epsilon|Estimating <math>\varepsilon</math>]] and its associated [[Quality control measures|quality control measures]]

These four processing levels coincide with the hierarchal format of the ATOMIX [[NetCDF velocimeters format]] used for archiving the [[benchmark datasets for velocity measurements|benchmark datasets]].

----
Return to [[Velocity point-measurements]]

[[Category:Velocity point-measurements]]

Flow chart for velocity point-measurements

2026-05-05T21:28:22Z

CynthiaBluteau:

The subgroup will provide recommendations and [[benchmark datasets for velocity measurements|benchmark datasets]] that can be used to assess processing algorithm at various stages of estimating <math>\varepsilon</math>:
[[File:Advprocessing.png|400px|thumb|Placeholder for complete flow chart for processing velocity point-measurements.]]

# [[Data processing of raw measurements|Data processing of raw velocities]]
# [[Preparing quality-controlled velocities|Segmenting and preparing qaqc velocities]] for spectral computations
# [[Spectral estimates and identifying the inertial subrange]]
# [[Estimate epsilon|Estimating <math>\varepsilon</math>]] and associated [[Quality control measures|quality control measures]]

These four processing levels coincide with the hierarchal format of the ATOMIX [[NetCDF velocimeters format]] used for archiving the [[benchmark datasets for velocity measurements|benchmark datasets]].

----
Return to [[Velocity point-measurements]]

[[Category:Velocity point-measurements]]

Benchmark datasets for velocity measurements

2026-05-05T21:21:12Z

CynthiaBluteau:

These datasets are currently located in [https://doi.org/10.5281/zenodo.16798905 Zenodo].
They will eventually be housed at the BODC center.

{| class="wikitable"
|+Summary of potential benchmark datasets for testing existing and future algorithms
|-
! style="width: 12%"| Dataset name
! Total depth
! Deployment distance from boundary
! Background median speed
! <math>\varepsilon</math> range
! Stratification/shear information
! style="width: 20%"| Comment
|-
! Units
! [m]
! [m]
! [m/s]
! [W/kg]
!
!
|-
| Tidal Slough ADV
| 2.8
| 0.45
| 0.15
| 1e-7 to 1e-5
| Unstratified, but shear-induced anisotropy
| Viscous subrange is occasionally resolved. Another ADV at 0.15 m shows wrapping issues.
|-
| Tidal Shelf ADV
| 250
| 0.4
| 0.26
| 1e-7 to 1e-4
| Stratified bottom log-layer
| High-quality dataset with phase wrapping. It overlaps with an ADCP Signature benchmark.
|-
| Underice MAVS
| 353
| 5
| 0.03
| 3e-9 to 7e-8
| Weak stratification
| Under-ice boundary layer, MAVS suspended 5 m beneath the ice
|-
| Tidal MAVS
| 20
| 1.45
| 1.1
| 3e-4 to 1e-3
| Weak stratification
| Strong tidal flows
|}

[[Category:Velocity point-measurements]]

Benchmark datasets for velocity measurements

2026-05-05T21:18:46Z

CynthiaBluteau:

These datasets are currently located in [https://doi.org/10.5281/zenodo.16798905 Zenodo]. They will eventually be housed at the BODC center.

{| class="wikitable"
|+Summary of potential benchmark datasets for testing existing and future algorithms
|-
! style="width: 12%"| Dataset name
! Total depth
! Deployment distance from boundary
! Background median speed
! <math>\varepsilon</math> range
! Stratification/shear information
! style="width: 20%"| Comment
|-
! Units
! [m]
! [m]
! [m/s]
! [W/kg]
!
!
|-
| Tidal Slough ADV
| 2.8
| 0.45
| 0.15
| 1e-7 to 1e-5
| Unstratified, but shear-induced anisotropy
| Viscous subrange is occasionally resolved. Another ADV at 0.15 m shows wrapping issues.
|-
| Tidal Shelf ADV
| 250
| 0.4
| 0.26
| 1e-7 to 1e-4
| Stratified bottom log-layer
| High-quality dataset with phase wrapping. It overlaps with an ADCP Signature benchmark.
|-
| Underice MAVS
| 353
| 5
| 0.03
| 3e-9 to 7e-8
| Weak stratification
| Under-ice boundary layer, MAVS suspended 5 m beneath the ice
|-
| Tidal MAVS
| 20
| 1.45
| 1.1
| 3e-4 to 1e-3
| Weak stratification
| Strong tidal flows
|}

[[Category:Velocity point-measurements]]

Benchmark datasets for velocity measurements

2026-05-05T21:15:48Z

CynthiaBluteau:

These datasets are currently located in [https://doi.org/10.5281/zenodo.16798905 Zenodo]. and will eventually be housed at the BODC center.

{| class="wikitable"
|+Summary of potential benchmark datasets for testing existing and future algorithms
|-
! style="width: 12%"| Dataset name
! Total depth
! Deployment distance from boundary
! Background median speed
! <math>\varepsilon</math> range
! Stratification/shear information
! style="width: 20%"| Comment
|-
! Units
! [m]
! [m]
! [m/s]
! [W/kg]
!
!
|-
| Tidal Slough ADV
| 2.8
| 0.45
| 0.15
| 1e-7 to 1e-5
| Unstratified, but shear-induced anisotropy
| Viscous subrange is occasionally resolved. Another ADV at 0.15 m shows wrapping issues.
|-
| Tidal Shelf ADV
| 250
| 0.4
| 0.26
| 1e-7 to 1e-4
| Stratified bottom log-layer
| High-quality dataset with phase wrapping. It overlaps with an ADCP Signature benchmark.
|-
| Underice MAVS
| 353
| 5
| 0.03
| 3e-9 to 7e-8
| Weak stratification
| Under-ice boundary layer, MAVS suspended 5 m beneath the ice
|-
| Tidal MAVS
| 20
| 1.45
| 1.1
| 3e-4 to 1e-3
| Weak stratification
| Strong tidal flows
|}

[[Category:Velocity point-measurements]]

Benchmark datasets for velocity measurements

2026-05-04T16:47:23Z

CynthiaBluteau:

These datasets are currently located in a [https://doi.org/10.5281/zenodo.16798905|Zenodo], and will eventually be housed at the BODC center.

{| class="wikitable"
|+Summary of potential benchmark datasets for testing existing and future algorithms
|-
! style="width: 12%"| Dataset name
! Total depth
! Deployment distance from boundary
! Background median speed
! <math>\varepsilon</math> range
! Stratification/shear information
! style="width: 20%"| Comment
|-
! Units
! [m]
! [m]
! [m/s]
! [W/kg]
!
!
|-
| Tidal Slough ADV
| 2.8
| 0.45
| 0.15
| 1e-7 to 1e-5
| Unstratified, but shear-induced anisotropy
| Viscous subrange is occasionally resolved. Another ADV at 0.15 m shows wrapping issues.
|-
| Tidal Shelf ADV
| 250
| 0.4
| 0.26
| 1e-7 to 1e-4
| Stratified bottom log-layer
| High-quality dataset with phase wrapping. It overlaps with an ADCP Signature benchmark.
|-
| Underice MAVS
| 353
| 5
| 0.03
| 3e-9 to 7e-8
| Weak stratification
| Under-ice boundary layer, MAVS suspended 5 m beneath the ice
|-
| Tidal MAVS
| 20
| 1.45
| 1.1
| 3e-4 to 1e-3
| Weak stratification
| Strong tidal flows
|}

[[Category:Velocity point-measurements]]

Benchmark datasets for velocity measurements

2026-05-04T16:46:28Z

CynthiaBluteau:

These datasets are currently located in a [https://doi.org/10.5281/zenodo.16798905| Zenodo], and will eventually be housed at the BODC center.

{| class="wikitable"
|+Summary of potential benchmark datasets for testing existing and future algorithms
|-
! style="width: 12%"| Dataset name
! Total depth
! Deployment distance from boundary
! Background median speed
! <math>\varepsilon</math> range
! Stratification/shear information
! style="width: 20%"| Comment
|-
! Units
! [m]
! [m]
! [m/s]
! [W/kg]
!
!
|-
| Tidal Slough ADV
| 2.8
| 0.45
| 0.15
| 1e-7 to 1e-5
| Unstratified, but shear-induced anisotropy
| Viscous subrange is occasionally resolved. Another ADV at 0.15 m shows wrapping issues.
|-
| Tidal Shelf ADV
| 250
| 0.4
| 0.26
| 1e-7 to 1e-4
| Stratified bottom log-layer
| High-quality dataset with phase wrapping. It overlaps with an ADCP Signature benchmark.
|-
| Underice MAVS
| 353
| 5
| 0.03
| 3e-9 to 7e-8
| Weak stratification
| Under-ice boundary layer, MAVS suspended 5 m beneath the ice
|-
| Tidal MAVS
| 20
| 1.45
| 1.1
| 3e-4 to 1e-3
| Weak stratification
| Strong tidal flows
|}

[[Category:Velocity point-measurements]]

Benchmark datasets for velocity measurements

2026-05-04T16:33:00Z

CynthiaBluteau:

These datasets are currently located in a [https://doi.org/10.5281/zenodo.16798905], and will eventually be housed at the BODC center.

{| class="wikitable"
|+Summary of potential benchmark datasets for testing existing and future algorithms
|-
! style="width: 12%"| Dataset name
! Total depth
! Deployment distance from boundary
! Background median speed
! <math>\varepsilon</math> range
! Stratification/shear information
! style="width: 20%"| Comment
|-
! Units
! [m]
! [m]
! [m/s]
! [W/kg]
!
!
|-
| Tidal Slough ADV
| 2.8
| 0.45
| 0.15
| 1e-7 to 1e-5
| Unstratified, but shear-induced anisotropy
| Viscous subrange is occasionally resolved. Another ADV at 0.15 m shows wrapping issues.
|-
| Tidal Shelf ADV
| 250
| 0.4
| 0.26
| 1e-7 to 1e-4
| Stratified bottom log-layer
| High-quality dataset with phase wrapping. It overlaps with an ADCP Signature benchmark.
|-
| Underice MAVS
| 353
| 5
| 0.03
| 3e-9 to 7e-8
| Weak stratification
| Under-ice boundary layer, MAVS suspended 5 m beneath the ice
|-
| Tidal MAVS
| 20
| 1.45
| 1.1
| 3e-4 to 1e-3
| Weak stratification
| Strong tidal flows
|}

[[Category:Velocity point-measurements]]

Benchmark datasets for velocity measurements

2026-05-04T16:29:46Z

CynthiaBluteau: Updated

These datasets are temporarily in a [http://gofile.me/5BB4l/2dqqVVDUZ|read-only folder], and will eventually be housed at the BODC center with a DOI.

{| class="wikitable"
|+Summary of potential benchmark datasets for testing existing and future algorithms
|-
! style="width: 12%"| Dataset name
! Total depth
! Deployment distance from boundary
! Background median speed
! <math>\varepsilon</math> range
! Stratification/shear information
! style="width: 20%"| Comment
|-
! Units
! [m]
! [m]
! [m/s]
! [W/kg]
!
!
|-
| Tidal Slough ADV
| 2.8
| 0.45
| 0.15
| 1e-7 to 1e-5
| Unstratified, but shear-induced anisotropy
| Viscous subrange is occasionally resolved. Another ADV at 0.15 m shows wrapping issues.
|-
| Tidal Shelf ADV
| 250
| 0.4
| 0.26
| 1e-7 to 1e-4
| Stratified bottom log-layer
| High-quality dataset with phase wrapping. It overlaps with an ADCP Signature benchmark.
|-
| Underice MAVS
| 353
| 5
| 0.03
| 3e-9 to 7e-8
| Weak stratification
| Under-ice boundary layer, MAVS suspended 5 m beneath the ice
|-
| Tidal MAVS
| 20
| 1.45
| 1.1
| 3e-4 to 1e-3
| Weak stratification
| Strong tidal flows
|}

[[Category:Velocity point-measurements]]

Benchmark datasets for velocity measurements

2026-05-04T16:22:30Z

CynthiaBluteau:

These datasets are temporarily in a [http://gofile.me/5BB4l/2dqqVVDUZ|read-only folder], and will eventually be housed at the BODC center with a DOI.

{| class="wikitable"
|+Summary of potential benchmark datasets for testing existing and future algorithms
|-
! style="width: 12%"| Dataset name
! Total depth
! Deployment height above bottom
! Background speed
! <math>\varepsilon</math> range
! Stratification/shear information
! style="width: 20%"| Comment
|-
! Units
! [m]
! [m]
! [m/s]
! [W/kg]
!
!
|-
| Tidal Slough ADV
| 2.8
| 0.45
| 0.15-0.2
| 1e-8 to 1e-5
| Unstratified, but shear-induced anisotropy
| Viscous subrange is occasionally resolved. Another ADV at 0.15 m shows wrapping issues.
|-
| Tidal Shelf ADV
| 250
| 0.4
| <0.65
| 1e-7 to 1e-5
| Stratified bottom log-layer
| High-quality dataset with phase wrapping. It overlaps with an ADCP Signature benchmark.
|-
| Underice MAVS
| 353
| 248
| 0.05
| 1e-8 to 1e-6
| Weak stratification
| Under-ice boundary layer, MAVS suspended 5m depth
|-
| Tidal MAVS
| 20
| 1.45
| 0.9 to 1.1
| 1e-3
| Weak stratification
| Strong tidal flows
|}

[[Category:Velocity point-measurements]]

Benchmark datasets for ADCP structure function

2025-01-05T00:25:15Z

CynthiaBluteau:

This page provides an overview of the benchmark dataset for instruments that measure velocity profiles e.g., [[Acoustic-Doppler Current Profilers|acoustic-Doppler current profilers]] from diverse suppliers and models.

== Datasets available ==
Selection and preparation of benchmark datasets are a work in progress! These benchmark datasets will cover a range of marine environments, background stratification, and flow fields. They are temporarily in this [http://gofile.me/5BB4l/sApY8EvAp|read-only folder] and will eventually be housed at the BODC center with a DOI.

{| class="wikitable"
|+Summary of potential benchmark datasets for testing existing and future algorithms
|-
! style="width: 12%"| Dataset name
! Instrument
! Total depth
! Deployment height above bottom
! Background speed
! <math>\varepsilon</math> range
! Stratification/shear information
! style="width: 20%"| Comment
|-
!
! Make and Model
! [m]
! [m]
! [m/s]
! [W/kg]
!
!
|-
| Signature5beam_TidalShelf
| Nortek Signature1000
| 254
| 0.3
| <math>\lesssim</math> 0.3
|
| stratified boundary layer
| pretty average
|
|-
| RDI4beam_TidalChannel_GP130620BPb
| RDI Teledyne 600kHz
| 23
| 0.5
| 2.5
| 7e-6 to 2e-4
| unstratified
| high quality data
|
|-
| RDIWH600_CANDYFLOSS_TOP
| RDI Workhorse 600 kHz
| 145
| 125
|
| 1e-7
| region of surface wave influence
| good
|
|-
| RDIWH600_CANDYFLOSS_BEDFRAME
| RDI Workhorse 600kHz
| 145
| 1
|
| 1e-7
| bottom boundary layer on NW European shelf
| good
|
|-
| AQD_Windermere_BEDFRAME
| Nortek Aquadopp 1MHz
| 40
| 0.4
| <0.1
| 1e-9 to 1e-8
| lake bottom boundary layer
| good
|
|}

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