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• 15:13, 11 July 2022 CynthiaBluteau talk contribs created page Velocity decontamination by cospectral methods (Created new page to deal with moored instrument scope)
• 14:31, 11 July 2022 CynthiaBluteau talk contribs uploaded a new version of File:Spectra computation.png (Added labels for the fft-length, degrees of freedom and nyquist frequency <math>f_N</math>)
• 02:11, 11 July 2022 CynthiaBluteau talk contribs created page File:Spectra computation.png (Velocity spectra estimated from a 128-s long segment of observations. The original spectra (black) were estimated using 7 fft blocks, each 32 s long with a 50% overlap and Hanning window applied in the time-domain on each block. The colored lines are the same spectra but obtained using an alternate spectral averaging strategy. The purple has 58 degrees of freedom.)
• 02:11, 11 July 2022 CynthiaBluteau talk contribs uploaded File:Spectra computation.png (Velocity spectra estimated from a 128-s long segment of observations. The original spectra (black) were estimated using 7 fft blocks, each 32 s long with a 50% overlap and Hanning window applied in the time-domain on each block. The colored lines are the same spectra but obtained using an alternate spectral averaging strategy. The purple has 58 degrees of freedom.)
• 20:59, 10 July 2022 CynthiaBluteau talk contribs created page File:ADV fft length.png (Contours represent the log of the fft-length required to resolve the non-dimensional wavenumber [rad/m] indicated in each panel's title. The contours are plotted as a function of <math>\varepsilon</math> and speed past the sensor u. The fft-length controls the lowest frequency that is resolved by the spectra. The bottom panel (c) shows the fft-length that begins to resolve the viscous subrange i.e., the end of the inertial subrange. The middle panel shows the fft-length to resolve 1 decade'...)
• 20:59, 10 July 2022 CynthiaBluteau talk contribs uploaded File:ADV fft length.png (Contours represent the log of the fft-length required to resolve the non-dimensional wavenumber [rad/m] indicated in each panel's title. The contours are plotted as a function of <math>\varepsilon</math> and speed past the sensor u. The fft-length controls the lowest frequency that is resolved by the spectra. The bottom panel (c) shows the fft-length that begins to resolve the viscous subrange i.e., the end of the inertial subrange. The middle panel shows the fft-length to resolve 1 decade'...)
• 18:21, 5 July 2022 CynthiaBluteau talk contribs created page File:Anisotropy.png (Example of how turbulence anisotropy influenced the 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 is another mechanism that shortens the inertial subrange at the lower wavenumbers. The wavenumber at which i...)
• 18:21, 5 July 2022 CynthiaBluteau talk contribs uploaded File:Anisotropy.png (Example of how turbulence anisotropy influenced the 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 is another mechanism that shortens the inertial subrange at the lower wavenumbers. The wavenumber at which i...)
• 17:41, 5 July 2022 CynthiaBluteau talk contribs created page File:SegmentAnisotropyLowE.png (Example spectra for the Under-ice MAVS dataset. About 17h worth of segments are shown, and each spectrum was constructed from 1024 s (17.06 min) worth of data, which was split into FFT-length of 512s (4096 samples). The speeds past the sensor are of the order of a few cm/s. The combination of low <math>\varepsilon</math> and low speeds requires using relatively long segments to compute the spectra. The spectra are also impacted by vibrations and vortex shedding that are contaminating the meas...)
• 17:41, 5 July 2022 CynthiaBluteau talk contribs uploaded File:SegmentAnisotropyLowE.png (Example spectra for the Under-ice MAVS dataset. About 17h worth of segments are shown, and each spectrum was constructed from 1024 s (17.06 min) worth of data, which was split into FFT-length of 512s (4096 samples). The speeds past the sensor are of the order of a few cm/s. The combination of low <math>\varepsilon</math> and low speeds requires using relatively long segments to compute the spectra. The spectra are also impacted by vibrations and vortex shedding that are contaminating the meas...)
• 16:35, 5 July 2022 CynthiaBluteau talk contribs created page File:Segment anisotropy.png (Example spectra for the Tidal shelf high-quality dataset. About 3h worth is shown, and each spectrum was constructed from 128 s (2.13min) worth of data, which was split into FFT-length of 32 s (2048 samples). The speeds past the sensor vary from a minimum of 0.3 m/s and a maximum of 0.8 m/s. The combination of high <math>\varepsilon<\math> and fast speeds enables using short segments to compute the spectra.)
• 16:35, 5 July 2022 CynthiaBluteau talk contribs uploaded File:Segment anisotropy.png (Example spectra for the Tidal shelf high-quality dataset. About 3h worth is shown, and each spectrum was constructed from 128 s (2.13min) worth of data, which was split into FFT-length of 32 s (2048 samples). The speeds past the sensor vary from a minimum of 0.3 m/s and a maximum of 0.8 m/s. The combination of high <math>\varepsilon<\math> and fast speeds enables using short segments to compute the spectra.)
• 15:22, 5 July 2022 CynthiaBluteau talk contribs uploaded a new version of File:Spectra replacement strategies.png (Added panel labels)
• 15:02, 5 July 2022 CynthiaBluteau talk contribs created page File:Spectra replacement strategies.png (Spectral estimated from the data presented as a timeseries but using different replacement strategies commonly found in the literature. The original time series refers to the data before removing (randomly) samples)
• 15:02, 5 July 2022 CynthiaBluteau talk contribs uploaded File:Spectra replacement strategies.png (Spectral estimated from the data presented as a timeseries but using different replacement strategies commonly found in the literature. The original time series refers to the data before removing (randomly) samples)
• 14:59, 5 July 2022 CynthiaBluteau talk contribs created page File:Timeseries replacement strategies.png (Example velocity time series where we randomly removed data in varying length gaps. Only the example of 1min (480 samples at 8Hz sampling) are illustrated. Removing chunks of 8 continuous samples (1s) looks identical to the original time series and is not illustrated.)
• 14:59, 5 July 2022 CynthiaBluteau talk contribs uploaded File:Timeseries replacement strategies.png (Example velocity time series where we randomly removed data in varying length gaps. Only the example of 1min (480 samples at 8Hz sampling) are illustrated. Removing chunks of 8 continuous samples (1s) looks identical to the original time series and is not illustrated.)
• 01:46, 5 July 2022 CynthiaBluteau talk contribs created page Category:ADV level 2 segmented and quality controlled (Created page with "These pages describe some of the concepts and processing steps that are applied to level 2 data in preparation for spectral estimates")
• 23:51, 3 July 2022 CynthiaBluteau talk contribs created page Replacement strategies for missing velocities (Created page with "{{ADV processing |instrument_type=ADV |level= }}")
• 00:22, 2 July 2022 CynthiaBluteau talk contribs created page Talk:Tentative benchmarks for shear probes (Created page with "New priority table for discussion ~~~~ {| class="wikitable sortable" |- ! Filename Prefix ! Platform ! Instrument ! Region ! PI (ATOMIX) ! Comment ! Volunteer testers |- |...")
• 14:45, 23 March 2022 CynthiaBluteau talk contribs uploaded a new version of File:IDM dimensional.png (Added a smaller velocity of 0.05m/s for the secondary x-axes)
• 15:21, 8 March 2022 CynthiaBluteau talk contribs uploaded a new version of File:Frame of reference adv.png (Changed colors after some comments..)
• 15:00, 8 March 2022 CynthiaBluteau talk contribs uploaded a new version of File:Frame of reference adv.png (Changed font sizes and colors, reduced figure size too.)
• 17:56, 7 March 2022 CynthiaBluteau talk contribs uploaded File:Frame of reference adv.png (Examples of measured velocities from two ADVs highlighting that their x-axis may be un-aligned with the flow's principal components. The blue dots and lines (direction of principal axes) are for a 5-min subset of the entire timeseries (about a day's wo...)
• 16:13, 5 March 2022 CynthiaBluteau talk contribs uploaded File:Advprocessing.png (Flowchart sketch for the landing page)
• 00:57, 3 March 2022 CynthiaBluteau talk contribs uploaded File:Benchmark adv netcdf.png (sketch of NetCDF format for point-velocity measurements)
• 22:13, 2 March 2022 CynthiaBluteau talk contribs uploaded a new version of File:IDM dimensional.png (Again, trying to fix the issue when printing the figure...)
• 22:11, 2 March 2022 CynthiaBluteau talk contribs uploaded a new version of File:IDM dimensional.png (Fixed the labels)
• 20:12, 17 December 2021 CynthiaBluteau talk contribs uploaded File:CBluteau.jpg (Profile picture.)
• 16:02, 7 December 2021 CynthiaBluteau talk contribs uploaded File:Velocity spectra fft segment.png (Accompanies File:Velocitie_fft_segment.png to illustrate the impact of increased FFT in the "smoothness" of the spectra and loss of spectral information at the lowest frequencies. Error bars also reduce with the increasing number of FFTs. The green...)
• 15:58, 7 December 2021 CynthiaBluteau talk contribs uploaded File:Velocitie fft segment.png (Vertical velocity records (8192 samples at 8Hz) to illustrate the use of smaller subsets of to compute FFTs. 50% overlap and hanning window applied to each fft-segment of data. The 15 FFTs example (cold color tones) uses 1024 samples (128 s) of records...)
• 18:40, 1 December 2021 CynthiaBluteau talk contribs uploaded File:Velocity timescales.png (Example velocity observations from an instrument impacted by tides and surface waves, which are presented as variance preserving spectra. The goal is to highlight when turbulence subranges begin in the grand scheme of physical processes that impact vel...)
• 00:40, 1 December 2021 CynthiaBluteau talk contribs uploaded a new version of File:IDM dimensional.png (Fixed the labelling)
• 00:36, 1 December 2021 CynthiaBluteau talk contribs uploaded File:IDM dimensional.png (Wavenumber limit of the inertial subrange of velocity for different epsilon. The corresponding frequencies for different speeds past the sensor are also shown.)
• 20:59, 29 November 2021 CynthiaBluteau talk contribs uploaded File:Short spectra.png (Spectra of the short_timeseries.png to highlight the impact of detrending the entire timeseries first before segmenting onto 8.53 min (2048 samples))
• 20:56, 29 November 2021 CynthiaBluteau talk contribs uploaded File:Short detrend timeseries.png (The detrended version of File:short_timeseries.png)
• 20:55, 29 November 2021 CynthiaBluteau talk contribs uploaded File:Short timeseries.png (Same as long_timeseries but showing only the first 512 s of data at 4Hz.)
• 17:22, 29 November 2021 CynthiaBluteau talk contribs uploaded File:Long timeseries.png (Example of velocities subsampled at 4Hz. Original timeseries measured at 64Hz, but lower sampling rate would be sufficient for IDM analysis. The different lines represent the results of various detrending.)
• 00:31, 25 November 2021 CynthiaBluteau talk contribs uploaded a new version of File:Threshold logic Brock1986.png (Fixed the threshold so that the local minimum is used for identifying thresholds, as opposed to the local minimum that reaches zero (ideal!))
• 21:21, 24 November 2021 CynthiaBluteau talk contribs uploaded File:Threshold logic Brock1986.png (Conceptual figure showing how the threshold for identifying spikes is set by Brock 1986 (JTECH). It involves a histogram of the velocity differences)
• 21:17, 24 November 2021 CynthiaBluteau talk contribs uploaded a new version of File:Smoothed velocities.png (Fixed legends, and identified the spikes on the bottom panel.)
• 20:33, 24 November 2021 CynthiaBluteau talk contribs uploaded a new version of File:Smoothed velocities.png (Fixed the misleading legend "noisy" with spiky, and added the differentiated signal as an extra panel)
• 20:14, 24 November 2021 CynthiaBluteau talk contribs uploaded File:Smoothed velocities.png (Example velocities from ADV but with a smoothed signal to illustrate how filter-based despiking techniques operate. The smoothing shown applies a nonlinear median filter, i.e., a moving median calculated over 5 samples. The median filter is less biased...)
• 19:03, 24 November 2021 CynthiaBluteau talk contribs uploaded File:Despike spectra.png (Example velocity spectra before and after removing a modest number of spikes (30x over 4096 samples))
• 18:34, 24 November 2021 CynthiaBluteau talk contribs uploaded a new version of File:Velocities spike.png (Increased font size and reduced size.)
• 18:22, 24 November 2021 CynthiaBluteau talk contribs uploaded File:Velocities spike.png (Example time series of longitudinal velocities with added spikes)
• 18:48, 22 November 2021 CynthiaBluteau talk contribs uploaded a new version of File:SF atomix ADCP.png
• 18:45, 22 November 2021 CynthiaBluteau talk contribs uploaded File:SF atomix ADCP.png (Sketch of variables used for calculating Dll along ADCP beams)
• 23:22, 13 October 2021 CynthiaBluteau talk contribs uploaded File:Fig9 SV94.png (Placeholder figure for the turbulence spectrum taken from Saddoughi, S., & Veeravalli, S. (1994). Local isotropy in turbulent boundary layers at high Reynolds number. Journal of Fluid Mechanics, 268, 333-372. doi:10.1017/S0022112094001370)
• 00:50, 24 April 2021 CynthiaBluteau talk contribs moved page Form:Netcdf glossary to Form:NetcdfGlossary (Issues with spaces)