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opencc-by-4.0May 2023View details →

Magnetic and sedimentological properties of siliciclastic cave sediments from the Peștera cu Oase Cave

Magnetic and sedimentological properties of siliciclastic cave sediments from the Peștera cu Oase Cave (South Carpathians, Romania: 45.030009° N, 21.835320° E, 617 m). Further details can be found in Panaiotu et al. (2013).

Longitudinal transport of suspended sediment in the Modaomen Estuary of the Pearl River: effects of river, tide, and mouth bar: Datasets

This dataset supplements the article: Longitudinal transport of suspended sediment in the Modaomen Estuary of the Pearl River: effects of river, tide, and mouth bar, submitted to Marine Geology Contact information: Dr. Liu, F., School of Ocean Engineering and Technology, Sun Yat-sen University, Guangzhou, 510275, China. Email: <a href="mailto:liuf53@mail.sysu.edu.cn">liuf53@mail.sysu.edu.cn</a> (Liu, Feng) Brief view of the dataset Hydrodynamics, suspended sediment concentration and salinity distribution were measured at three fixed stations along the longitudinal direction of the estuary. The stations were located at Guadingjiao (M1), inside the bar (M2), and outside the bar (M3), and sampling was simultaneously conducted at neap tide (NT) from July 31 to August 1 and spring tide (ST) from August 8 to August 9 in 2017. All observation data has been compiled to include data from the surface to the bottom six layers within 26 hours. This directory contains the following datasets. M10731.xlsx: Current velocity, current direction, salinity and SSC during neap tide at Station M1  M10808.xlsx: Current velocity, current direction, salinity and SSC during spring tide at Station M1  M20731.xlsx: Current velocity, current direction, salinity and SSC during neap tide at Station M2 M20808.xlsx: Current velocity, current direction, salinity and SSC during spring tide at Station M2 M30731.xlsx: Current velocity, current direction, salinity and SSC during neap tide at Station M3 M30808.xlsx: Current velocity, current direction, salinity and SSC during spring tide at Station M3

Evaluating a poroelastic model via pore pressure signals in seafloor sediments [data set]

The csv files consist of pressure data collected off the coast of Camp Pendleton between 10 February 2021 and 25 February 2021, and include both pore pressure data from two instrumented surrogates and pressure data from a Nortek Signature. Timestamps are in posix time; pressure is in kPa. The time series for Surrogate A are prefixed "surrA"; those for Surrogate B are prefixed "surrB". The Nortek Signature time series is prefixed "Sig1000".

Pandrin&Bertoldi - DEMs and Sediment Flux from Pi Flume experiments

# Pandrin and Bertoldi dataset ## Topografic surveys and sediment flux measurements from laboratory flume experiments. This dataset contains the outputs of the experiments performed with a laforatory flume at the University of Trento (Italy) by Enrico Pandrin and Walter Bertoldi The dataset contains the following folders and files: - DEMs folder: in this folder all the topographic surveys are collected. Each sub-folder represents a different flowing discharge. Inside each sub-folder there are 10 DEMs taken at equal timesteps. The DEMs are presented after a detrending process, so for each DEM the initial slope is subtracted.   - SED_FLUX folder: as above, each sub-folder represents a different flowing discharge. Inside each sub-folder there is a .ods file that contains sediment flux data over time. - TOC.ods file: is the Table Of Contents that summarize for each experiment the main run parameters and the experimental setup parameters

Dataset accompanying the publication "Transport and retention of micro-Polystyrene in coarse riverbed sediments: Effects of flow velocity, particle and sediment sizes"

The dataset in this repository is accompanying the publication "Transport and retention of micro-Polystyrene in coarse riverbed sediments: Effects of flow velocity, particle and sediment sizes" (in Microplastics and Nanoplastics, 2023, submitted 09.06.2023) The repository contains the raw image files of all sample filters which were scanned using the fluorescence imaging system ChemiDoc and used to analyse the infiltration behaviour of microplastic polystyrene in the manuscript. In addition, we provide the resulting data from the particle identification and geometric analysis which were derived from the raw data using ImageJ in tabular excel format. The data is structured in folders following the naming of the columns from the manuscript.

opencc-by-sa-4.0Jun 2023View details →

The sequence of motions of water and sediment in a single plunging breaker on a sandy beach

In memoriam Gerard Pichel (1948-2023), a champion of expert, lay, and tacit knowledge   This deposit, having <a href="https://doi.org/10.5281/zenodo.7601924" target="_blank" rel="noopener">10.5281/zenodo.7601924</a> as entry DOI, distributes the sequence of images of a single breaker plunging onto a sandy beach on a windless day. This cover page gives an extended commentary. The still frames have been extracted from an <a href="https://commons.wikimedia.org/wiki/File:P%C3%A1jara_-_Morro_Jable_-_Playa_del_Matorral_(0)_09.ogv" target="_blank" rel="noopener">impromptu video in the Wikimedia Commons</a> (Vincentz 2013) showing remarkably clearly a shoaling wave that steepens suddenly, grows into a sequence of narrowly spaced plunging breakers, and dissolves in spray and foam. Also clearly visible are the sand stirred and suspended in the foreshore and, upon close inspection, that entrained within the curling wave. <h3>Deposit content</h3> <ul> <li>A redistribution of the unprocessed <a href="https://commons.wikimedia.org/wiki/File:P%C3%A1jara_-_Morro_Jable_-_Playa_del_Matorral_(0)_09.ogv" target="_blank" rel="noopener">source video</a> (Vincentz 2013);</li> <li>Three hundred ninety distortion-free colour pictures of 1240x670 pixels, in PNG lossless format, 40ms apart (25 fps);</li> <li>Four videos reassembling these processed pictures at different playback speeds (as fast as the physical time, and two-, four- and eightfold slower); they can be viewed in this <a href="https://youtube.com/playlist?list=PLV5KQfKi7EFge-1gDEMyPGOlNCEQ9QDNM&feature=shared" target="_blank" rel="noopener">YouTube playlist</a>;</li> <li>The script used for image extraction and manipulation.</li> </ul> <h3>Motivation</h3> These images may have informative, didactic and aesthetic value for those intrigued by shore dynamics and wave mechanics, whether initiated or uninitiated. Although the recording concerns a single wave event, even experts risk becoming the least alert to the intricacies of reality. By slow degrees, clinging to unavoidable simplifications may turn expertise into complacency and blunt the genuine appreciation of ground truth (<a href="https://doi.org/10.1057/jos.2008.7" target="_blank" rel="noopener">Salt 2008</a>). After all, all research approaches suffer from limitations that make it difficult to distil widely applicable knowledge from complex evidence. For example, experiments are constrained by geometry and by the scaling laws of sand grains; simulations, by modelling three-phase turbulent interactions with very short scales; and parametrizations of field campaigns, by trading off general against locally relevant information. Every avenue of investigation thus leaves us with something to desire. On the upside, appreciating the challenges in foreshore science and engineering does not necessarily require continuous first-hand experience on the beach. It is therefore hoped that this dataset stimulates appreciation, contemplation, investigation and/or study. <h3>Dataset licensing</h3> (Re-)using the material of this deposit is permitted free of charge under a licence <a href="https://creativecommons.org/licenses/by-sa/4.0/" target="_blank" rel="noopener">CC BY-SA (attribution and share-alike) 4.0</a>. This is in keeping with the CC <a href="https://wiki.creativecommons.org/wiki/ShareAlike_compatibility" target="_blank" rel="noopener">compatibility conditions</a> and the share-alike restriction from the original video of Vincentz 2013, published under a licence <a href="https://creativecommons.org/licenses/by-sa/3.0/deed.en" target="_blank" rel="noopener">CC BY-SA 3.0</a>. See §4.1 about how to cite this work. <h3>Dataset description</h3> The ensuing sections describe: <ol> <li>the qualitative physics;</li> <li>the procedure of image extraction and manipulation;</li> <li>the content and arrangement of the dataset;</li> <li>the citation format, version information, and vision for this deposit.</li> </ol> <h1>1. Physical description</h1> An abridged version of this section is also available from the <a href="https://www.coastalwiki.org/wiki/Plunging_wave_in_slow_motion" target="_blank" rel="noopener">Coastal Wiki</a>.  <h2>1.1 Location</h2> Vincentz (2013) places the video location at the sandy beach <a href="https://es.wikipedia.org/wiki/Playa_del_Matorral" target="_blank" rel="noopener">Playa del Matorral</a>. This is in the locality <a href="https://en.wikipedia.org/wiki/Morro_Jable" target="_blank" rel="noopener">Morro Jable</a> (<a href="https://www.openstreetmap.org/?mlat=28.050897&mlon=-14.352003" target="_blank" rel="noopener">28.050897°, -14.352003°</a>; municipality of <a href="https://en.wikipedia.org/wiki/P%C3%A1jara" target="_blank" rel="noopener">Pájara</a>) in the island of Fuerteventura, Canary Islands, Spain. The precise geolocation of the images is unknown. The Playa del Matorral faces SSW and SE and thus, roughly speaking, the African coast. The region is tidal: the water-level excursion at the nearby Puerto del Rosario is reported to be 2.3 m at springs and 1.6 m at neaps (NGA 2022, p.258). It is hence conceivable but not demonstrable that the flood tide may have contributed to the wave recorded in the video. The <a href="https://emodnet.ec.europa.eu/geoviewer/#?layers=12996:1:0,12997:1:0,12995:1:1,13005:1:1&basemap=ebwbl&active=12997&bounds=-14.480427655259211,27.951455702530858,-14.218911276738245,28.10884469989302&filters=" target="_blank" rel="noopener">EMODnet bathymetry</a> shows that seabed declines fairly steeply, approximately down to -500 m within 2 km or less from the mean sea level line. The development of a plunging breaker indicates in itself that the beach is behaving as a reflective one. Qualitatively, the closeness to the shore of the breaking line, the narrow shoreface, and the collision of backwash and incoming waves are additional indicators of a steep beach profile (Komar 1998). If present at all, sand bars do not appear to affect the breaking process. Inferences on the local beach profile seem purely speculative, although the particular profile may cause the peculiar behaviour of this one breaker, for example because of a submerged step close to the plunge point. In a steady beach configuration, these plunging waves must bring ashore sufficient sediment to compensate for the offshore transport down the steep slope. <h2>1.2 Calendar</h2> The <a href="https://commons.wikimedia.org/wiki/File:P%C3%A1jara_-_Morro_Jable_-_Playa_del_Matorral_(0)_09.ogv" target="_blank" rel="noopener">record at Wikimedia Commons</a> only attributes the video the date ‘11 February 2013’. The time stamp of the video file is '16 October 2013'. It is then likely that the former date indicates when the video has been taken. Since the Playa del Matorral faces both east and west, the skylight illumination does not provide clues as for the time of the day. The stage of the tide cannot be estimated either. All in all, the precise time and date are of little relevance for the small-scale development of the single wave seen in the video. <h2>1.3 Description of motion</h2> Contemplated in its entirety, the recording conveys the dramatic impression of a prototypical plunging wave dissolving explosively in spray and foam on a natural beach. The onset and development of breakers in the shoreface awes us because of the rapidity, dynamic range, and chaotic and cyclic behaviours embedded in their motion. The scales of motion interleaved in the the mixture of water, sand and air within such a sudden and rapid event become clearer thanks to the still frames and to the slowed-down videos. Although inferences about features out of view remain somehow speculative, the qualitative details in the recording reveal distinctive features and stages of development: <ol> <li>Waves shoal with long arrival times. A single episode of breaking occurs as if in the isolation of a solitary wave, discounting that here the backrush of each wave feedbacks into the next wave's steepening. Extrapolating the evidence from the recording, this breaking might actually mark a small-amplitude swell, or edge wave, with a period of 13-16 seconds;</li> <li>The recording is taken on a windless day, and no extensive surf zone confuses the nearshore zone seaward of the plunge point;</li> <li>The sand stirred and suspended in the foreshore is visible both in the swash and in the water raised and curled as the wave breaks;</li> <li>The backrush from the previously broken wave has largely returned seawards when a fresh plunger engulfs the foreshore; this emphasises the cycling behaviour expected in a wave also as regards the sand motion;</li> <li>The breaking does not unfold as a single wave form seamlessly steepening, curling, and collapsing after a single point of instability has been touched. Instead, while advancing over the small plunge distance, the steep wave face spawns new crests of water that surge ahead and leave behind the previous crest. The trailing crests, nonetheless, impinge on the back of the leading wave face and break behind. The breaking of this 'single breaker' is, in fact, remarkably composite and nonlinear;</li> <li>Because of the considerable steepening, the plunging waves engulf as considerable a volume of air, which produces in turn a dramatic explosion of spray.</li> </ol> This evidence on a natural beach can usefully be contrasted with the laboratory studies of <a href="https://doi.org/10.1002/2013JC009324" target="_blank" rel="noopener">Sumer et al (2013)</a> who compare the breaking of a train of plunging waves in a flume with and without a sand bed; and with the laboratory study of <a href="https://doi.org/10.1306/D4267B36-2B26-11D7-8648000102C1865D" target="_blank" rel="noopener">Hafsteinsson et al (2017)</a> who organise systematic observations of spilling, plunging and surging breakers in a narrow channel with a uniform bed slope. Finally, the following table comments on some twenty still frames. Selecting these frames entailed the dilemma of choosing times when a process either just initiates or is already developed enough to be recognisable; the pictures may thus regard both situations. The division into columns reflects fairly loosely a visual separation between either side of a fictional breaker line. I have strived to restrict the commentary to the phenomenological description of the sole free surface (hence avoiding inferences about the underlying flow patterns, however inviting, if self-evident). Please take note that the table only provides orientation and may be revised incrementally without notice later; see §4.2 on versions for substantive edits. <h3>Table. Commentary of selected still frames</h3> <table> <tbody> <tr> <th>Frame</th> <th>Time (ms)</th> <th>Surf and swash on the foreshore</th> <th>Shoaling and breaking</th> </tr> </tbody> <tbody> <tr> <td>1</td> <td>0</td> <td>The swash of the previously broken wave covers the beach face. Water returns from the limit of wave uprush as a thin sheet of white water. A wide band of foamy water advances shorewards upon that; its front rolls up irregularly, with foamy filaments ejected upwards. Sand in suspension can be inferred from brown-shaded longshore streaks.</td> <td>A wide band of ripple-free water separates the foamy shoreward waters from the incoming shoaling waves. Short-crested wavelets populate the surface seawards of this middle band.</td> </tr> <tr> <td>28</td> <td> 1080 [+1080] </td> <td>The thin film on the upper foreshore has retreated significantly. Rolling water marks the edge of the thicker uprush. The ejection of filaments has terminated.</td> <td>The crest of a shoaling wave emerges over the image width; individual short-crested waves ride upon it. To the right, secondary fronts develop within a small cross-shore distance; subsequently, the foremost wave face hides their development from view.</td> </tr> <tr> <td>48</td> <td> 1880 [+800] </td> <td>The thin sheet of backrush water is exhausted. The foamy uprush starts to retreat.</td> <td>Extant ripples and wavelets still ride on the wave face as the latter steepens further.</td> </tr> <tr> <td>94</td> <td> 3720 [+1840] </td> <td>The water contour and surface are smooth on the landward edge. Hills and knobs of circulating white water populate the lower foreshore.</td> <td>The shoaling wave advances. Its face has steepened up considerably and cannot support extant ripples any longer; its surface becomes progressively smoother.</td> </tr> <tr> <td>107</td> <td> 4240 [+520] </td> <td>The white water retreats farther seawards. An edge with the deeper swash water steepens slightly. The disappearance of foam reveals the sand suspended in the swash.</td> <td>The front wave has travelled a short distance further shoreward and is very nearly vertical. Its crest is nearly horizontal and still sharply delineated; its contour starts to break up just afterwards.</td> </tr> <tr> <td>113</td> <td> 4480 [+240] </td> <td>Ditto.</td> <td> The height of the crest varies alongshore; the part to the right attains its summit and its contour starts to break up. </td> </tr> <tr> <td>126</td> <td> 5000 [+520] </td> <td>The landward edge of the swash steepens further and the face of this backwash shows a sand-rich mixture. The white water from the rear swash overtops this steep edge at places.</td> <td>The crest in the middle of the image attains its summit. Its break-up projects spray and translucent streaks of water upwards. Detached water hangs in the air because the crest drops faster than its fall speed. Rear waves catching up with the breaker, hence not on view, may also affect the break-up of the crest.</td> </tr> <tr> <td>129</td> <td> 5120 [+120] </td> <td>Ditto.</td> <td> The fragmented fringe previously at the fore is left behind by a new face and crest that have surged forward. The water mass is translucent enough to show patches and streaks of suspended sand raising to the full height of the wave face. Streaks of bubbles dragged upward from the swash indicate that the wave steepening draws water from the foreshore. </td> </tr> <tr> <td>141</td> <td> 5600 [+480] </td> <td>The swash front is a dense mixture of sand and water. Much of the white water on top of the rear swash has become rarefied and is dragged seawards by the raising breaker.</td> <td>The contour of the crest is wavy and has several local summits. The fragmentation into streaks, droplets and spray is intense; spray is ejected upwards, up to the level of the horizon. Conceivably, a wave front at the rear impinges the rear of the front wave.</td> </tr> <tr> <td>149</td> <td> 5920 [+320] </td> <td>Ditto.</td> <td>The wave base travels shorewards while the crest curls over. Dense clouds of sand entrained in suspension help identify the onset of a definite curling motion, accompanied by the marked lowering of the fringe height. A new crest fringe appears to surge forward from the parent wave, as seen previously.</td> </tr> <tr> <td>157</td> <td> 6240 [+320] </td> <td>The foreshore water is rich in suspended sand and poor in entrained air. The water surface is relatively flat.</td> <td>The crest at the front is curling forward. Visible in the background is also the curling of a trailing wave, confirming the composite nature of this breaker.</td> </tr> <tr> <td>159</td> <td> 6320 [+80] </td> <td>Ditto.</td> <td>The first foam of the curling water touches down upon the shallow swash water in a downward jet. It bounces on the beach face immediately afterwards. The same occurs in other positions with a time lag. Spray is still suspended in the air.</td> </tr> <tr> <td>168</td> <td> 6680 [+360] </td> <td>The backrush is, to an approximation, at its seaward visible limit.</td> <td>The plunging water has touched down over the image width. The water that is curling over is laden with sand. The splash generated by the rebound is projected shorewards and raises as high as the wave plunging at the same time. Farther seaward, a narrowly spaced train of short-crested waves is shoaling.</td> </tr> <tr> <td>175</td> <td> 6960 [+280] </td> <td>The swash is a thick layer of sand-rich mixture and has a flat surface.</td> <td>The splash generates pervasive spray and foam, high enough to hide the view of shoaling waves in the littoral. An inconspicuous hole in the wall of spray to the right of the image is a notable exception to that.</td> </tr> <tr> <td>186</td> <td> 7400 [+440] </td> <td>The spray of the breaker has engulfed all the sand suspended in the foreshore.</td> <td>White water (foam, bubbles and droplets) is propelled forwards and engulfs the sand-rich backrush on the foreshore, dominating the view.</td> </tr> <tr> <td>196</td> <td> 7800 [+400] </td> <td>The bulk of the splash water has collapsed. The surface is highly fragmented with plenty of ejections and rebounds, priming a fresh swash line to run up the beach face. The colour shades in the foreshore indicate abundant sand in suspension.</td> <td>At the rear of the previous plunge point, the trailing plunging wave rolls across the surf zone. Farther behind, to the left of the image, patches of white water erupt through the free surface. Overall, the height of waves and spray does not hinder the view of littoral waters: no shoaling waves are developing as yet.</td> </tr> <tr> <td>202</td> <td> 8040 [+240] </td> <td>The white water bounces on the shoreface forming patches of varying height. Foamy filaments break up into large drops. The breakers previously hidden from view are visible as a sequence of troughs. Mixtures of sand and foam are also visible to the left. The uprush advances above the saturated foreshore.</td> <td>Most spray has settled. The trailing waves stay low as they break and undergo eruptions of white water especially under their crests.</td> </tr> <tr> <td>250</td> <td> 9960 [+1920] </td> <td>White water runs up the foreshore vigorously. The ejection of filaments has died off almost completely and the water surface is crossed by foamy wavelets. The edge of the swash glides over the wet foreshore and leaps over at times. The seaward boundary of the white water is a sharp ridge moving slowly seawards.</td> <td>No shoaling wave emerges from the rear waters.</td> </tr> <tr> <td>291</td> <td> 11600 [+1640] </td> <td>In the upper foreshore a uniform milky film replaces the irregular patches of foam and sediment. In the middle of the surf, ephemeral fronts of white water sweep the foreshore, while rolling up and plunging.</td> <td>Ditto.</td> </tr> <tr> <td>336</td> <td> 13480 [+1880] </td> <td>The surf consists of the landward film of white water, sweeping the upper foreshore, and of the thicker seaward water. White water rolls up and breaks at the knobbly edge between these two regions.</td> <td>Qualitatively, this frame shows a remarkable similarity with frame 1, as for the extents of the run-up water and the ripple-free surface in the shoreface.</td> </tr> <tr> <td>390</td> <td> 15560 [+2080] </td> <td>The film of backrush water is exhausted almost completely. The edge of the swash is a gently rolling line. The surf area is fairly uniformly smooth.</td> <td>The water seaward of the surf is free of ripples for some distance. Farther seawards, ripples populate the surface; slightly steepened wave forms prelude to the crest of a fresh shoaling waves, like in frame 1.</td> </tr> </tbody> </table> <h1>2. Image manipulation</h1> <h2>2.1 Toolbox</h2> Four open-source utilities have been used to produce this dataset: (1) `<a href="https://ffmpeg.org/ffprobe.html" target="_blank" rel="noopener">ffprobe version 4.2.7</a>` to determine the video properties; (2) `<a href="http://ffmpeg.org/about.html" target="_blank" rel="noopener">ffmpeg version 4.2.7</a>` to extract the stills from the video; (3,4) `convert` and `identify` from the <a href="https://imagemagick.org/" target="_blank" rel="noopener">ImageMagick tools version 6.9.10-23</a> to manipulate the stills and determine an image’s property respectively. The developers of these utilities claim that they run on a variety of operating system. Here all image processing has been carried out with, and proved to run successfully on, Linux. <h2>2.2 Source video: specifications and characteristics</h2> The source video is ogv format. The logical size of the image (improperly called resolution) is 1270x720 pixels; this corresponds to a pixel count of 914,400 (commercially presented as 0.9MP) and, approximately, to a 16:9 aspect ratio. The recording lasts (nominally) 15.6 seconds at a frame rate of 25 fps and contains 390 still frames spaced 0.04 s (40 ms) apart. The effective duration is 15.56 s. The operator holds the camera with a firm hand and the images are well lit and sharp. On close inspection, four glitches become apparent: <ol> <li> Lens distortion: the sea horizon is slightly curved upwards at the edges of the image, which indicates pincushion distortion (the image-to-object magnification rate increases away from the lens centre); </li> <li> Tilt: the camera view has a small anticlockwise roll angle with respect to the horizontal, whereby the sea horizon slopes slightly downwards to the right; </li> <li> Glare: the brightness of the images increases between approximatively 4 and 8 seconds of the recording; this overall glare is visible in the lightness of the sky and is arguably caused by the camera automatic diaphragm as it adjusts to the light reflected by the wave breaking; </li> <li> Motion: the horizon slightly shifts upwards at the tail of the video: this is most likely caused by the beach sand yielding under the operator’s weight as the uprush arrives and retreats on the foreshore. </li> </ol> The first two imperfections are remedied by manipulating the image, as described next. <h2>2.3 Frame extraction with ffmpeg</h2> The 390 still frames are extracted to as many stand-alone image files using the `ffmpeg` utility, which preserves the logical size of the frames. The image files are saved in tiff format. This format was chosen so that the tool `convert` does not bump into some memory restrictions encountered when manipulating png files as in next subsection. The output frames have a default pixel resolution of 72 dpi, which determines the expected physical size of the frame when printed. (The tool `convert` can also change this resolution by means of resampling, as described below.) The output file sizes vary slightly in the range 1307kB-1360 kB (base-10 file size) or 1276-1328 KiB (base-2 file size). The output colour format is standard RGB (sRGB), with a colour depth of 8 bit (256 shades available per colour channel). All 390 tiff images take 524MB (or 500MiB) of memory space. They are input for the `convert` utility as described next. They are not distributed with this deposit, but can be recreated with the script provided below as the need be. <h2>2.4 Frame manipulation with convert</h2> The sequence of `convert` operations to improve the final still frames is: <ol> <li> rotate the image to compensate for the tilt (target: the horizon is symmetric with respect to the vertical axis through the image centre); </li> <li> apply barrel distortion to the image to compensate the pincushion-type lens distortion (target: the horizon is a straight line); </li> <li> crop the image canvas (target: eliminate the vignetting due to the previous manipulations). </li> </ol> In theory, the correct order of operations should be 2-1-3. The bias of lens distortion is caused by the camera hardware and affects the entire field of view, regardless of how the camera is held. Determining the parameters of the compensating (barrel) distortion should thus have taken into account the distortion present in the entire field of view. This would have required evaluating the effect of lens distortion with a picture of a test card, such as a chessboard pattern. Here, however, the aim is mainly an aesthetic correction rather than extracting spatial information from the scene. Straightening up the horizon line is sufficient and can be done after having rotated the image, to the same visual effect obtained with the correct order. The logical size of all 390 manipulated images is 1240x670 pixels (aspect ratio 1.85). Their (default) resolution of 72 dpi (2.834 × 2.834 pixels/mm) means that their print size is 437.5 × 236.4 millimetres. The file sizes in png format vary in the range 750-1168 kB (732-1140 KiB). The complete set of images is 383 MB (365 MiB) large. These files are part of the deposit and their arrangement and naming are explained in Section 3. <h2>2.5 Script</h2> The script that performed the image extraction and manipulation is part of the deposit (named script-image-extraction+manipulation.sh). The script is written in GNU bash, version 5.0.17(1). Aside from the image-processing utilities already mentioned, the script also calls standard tools distributed in the GNU coreutils, version 8.30. GNU bash is a standard command-line interpreter in several Linux and MacOS distributions. Windows users could run it after installing the terminal emulator <a href="https://gitforwindows.org/" target="_blank" rel="noopener">Git for Windows</a>, for example. (Mac users, whose default shell interpreter is zsh, will experience troubles with # indicating comments in bash; please refer to this <a href="https://support.apple.com/en-au/HT208050" target="_blank" rel="noopener">Apple support article</a> on how to adjust that to bash.) The comments in the script, beside giving ‘sailing directions’, can serve as pseudocode if one wants to code the same workflow in another scripting language. Do not run this script blindly (some commands delete files). The script is divided into three sections. The first section defines the file paths, command parameters and other flags used in the remaining two sections, which deal with the image extraction and the image manipulation respectively. With this structure, the latter two sections need not to be edited for the script to do its job. The parameters and flags are set to the values used for this deposit and can be adjusted (the input and output paths should, for sure). Also, some commands only display information on the input and output documents before and after the processing. Among the possible usages, for example, one could change the default image resolution (dpi=72) to obtain images with a larger physical size by means of resampling, or change the output image format. Goes without saying: peruse the script and read the helps and manuals of the attending commands first. <h1>3. Data arrangement</h1> <h2>3.1 Images</h2> The 390 png images are arranged in 15 zip archives, each containing one second worth of motion and hence 25 files (except for the 15 files of the last 0.56 seconds). The archive names indicate the beginning of the respective interval as lapsed time in milliseconds. The name format is t[nnnnn]ms.zip: for example, the archive t05000ms.zip contains the still frames between 5 and 5.960 seconds. The grand total size of the zip archives is 381 MB (363 MiB); the size of the individual archives varies in the range 16-29 MB (15-27 MiB). The name of the files inside the archives indicates the frame progressive number and the lapsed time in milliseconds in the format f[nnn]-t[nnnnn]ms.png. Note that the frame number starts from 1 and the lapsed time from 0. The deposit also includes, outside of the archives, the images at each second (the first file in each archive) in the way of covers that help pick up the time interval and zipped archive of interest. The covers name convention is the same as the archives (for example, t05000ms.png shows the first image contained in t05000ms.zip). You can preview these cover images in the section Files below. <h2>3.2 Videos</h2> The original, unprocessed video (Pájara_-_Morro_Jable_-_Playa_del_Matorral_(0)_09.ogv, 73 MB, 70 MiB) is also redistributed with this deposit and should be credited to Vincentz 2013 (see the section Licence for the conditions). Additionally, the processed images have been assembled in a video with the same duration as the original, and then in three more videos whose playback time is two-, four- and eightfold the physical time. These mp4 files have a name patterned as breaker-video1-slow1x.mp4. They are overlain by the frame number, the physical elapsed time, and the playback slow-down so as to help identify especially interesting frames. These slowed-down videos can be viewed in <a href="https://youtube.com/playlist?list=PLV5KQfKi7EFge-1gDEMyPGOlNCEQ9QDNM&feature=shared" target="_blank" rel="noopener">this YouTube playlist</a>. They are 8 (8), 11 (10), 13 (13) and 20 (19) MB (MiB) large respectively; their lengths are 22", 38", 1'9", and 2'11". Take note that making a video out of individual images implies dropping and duplicating frames. In particular, a slowed-down video is created by filling the longer playback time with frames interpolated from the baseline images. A slowed-down video helps gain appreciation of a rapid process, but cannot produce insight into events occurring at a faster rate than 40 ms anyhow. Therefore, the best representation of the ground truth must always be sought in the smallest recording units, that is, the individual 390 images taken at a rate of 25 fps. <h1>4. This deposit</h1> <h2>4.1 How to cite this work</h2> This commentary and dataset are indexed with a DOI <a href="https://doi.org/10.5281/zenodo.7601924">10.5281/zenodo.7601924</a>. The citation text is available in different styles in the box Share, to the upper right of this web page. (Goes without saying that grey literature should be acknowledged also in peer-reviewed literature.) <h2>4.2 Versions</h2> Major numbers indicate changes in the deposit content, minor numbers significant changes in the deposit Description (this web-based document you are reading now). A major version change implies Zenodo issuing a new DOI. The DOI <a href="https://doi.org/10.5281/zenodo.7601924">10.5281/zenodo.7601924</a> always points to the latest version. The table below displays the history of versions. This deposit has been created on 11 Feb 2023. I adjust the date of publication of the deposit to the latest version, so that the automatic citations provided by Zenodo report consistent date/version information. <h3>List of versions</h3> <table> <tbody> <tr> <th>v2.5</th> <td>24/01/2025</td> <td>Revise licensing terms</td> <td><a href="../record/8070591">https://zenodo.org/record/8070591</a></td> </tr> <tr> <th>v2.4</th> <td>09/03/2024</td> <td>Revise §1</td> <td><a href="../record/8070591">https://zenodo.org/record/8070591</a></td> </tr> <tr> <th>v2.3</th> <td>18/09/2023</td> <td>Add link to video playlist</td> <td><a href="../record/8070591">https://zenodo.org/record/8070591</a></td> </tr> <tr> <th>v2.2</th> <td>22/07/2023</td> <td>Complete table in §1.3</td> <td><a href="../record/8070591">https://zenodo.org/record/8070591</a></td> </tr> <tr> <th>v1.2</th> <td>22/06/2023</td> <td>Strip description after v2.1</td> <td><a href="../record/7601925">https://zenodo.org/record/7601925</a></td> </tr> <tr> <th>v2.1</th> <td>22/06/2023</td> <td>Add videos of dataset</td> <td><a href="../record/8070591">https://zenodo.org/record/8070591</a></td> </tr> <tr> <th>v1.1</th> <td>21/06/2023</td> <td>Add commentary to §1</td> <td><a href="../record/7601925">https://zenodo.org/record/7601925</a></td> </tr> <tr> <th>v1.0</th> <td>11/02/2023</td> <td>Publish images</td> <td><a href="../record/7601925">https://zenodo.org/record/7601925</a></td> </tr> </tbody> </table> <h2>4.3 Next</h2> The current wish-list contains: a) linking the script to a GitHub repository if its complexity grows; b) comment the state of the free surface using the terminology of Brocchini and Peregrine (2001), even though their study was prompted by spilling breakers; c) include other videos; d) publish videos in ogv format.

dryad40/100

Data for: Prevalent fingerprint of marine macroalgae in Arctic surface sediments

Macroalgal forests export much of their production, partly supporting food webs and carbon stocks beyond their habitat, but evidence of their contribution in sediment carbon stocks is poor. We test the hypothesis that macroalgae contribute to carbon stocks in arctic marine sediments. We used environmental DNA (eDNA) fingerprinting on a large-scale set of surface sediment samples from Greenland and Svalbard. We evaluated eDNA results by comparing with traditional survey and tracer methods. The eDNA-based survey identified macroalgae in 94% of the sediment samples covering shallow nearshore areas to 1,460 m depth and 350 km offshore, with highest sequence abundance nearshore and with dominance of brown macroalgae. Overall, the eDNA results reflected the potential source communities of macroalgae and eelgrass assessed by traditional surveys, with the most abundant orders being common among different methods. A stable isotope analysis showed a considerable contribution from macroalgae in sediments although with high uncertainty, highlighting eDNA as a great improvement and supplement for documenting macroalgae as a contributor to sediment carbon stocks. Conclusively, we provide evidence for a prevalent contribution of macroalgal forests in arctic surface sediments, nearshore as well as offshore, identifying brown algae as main contributors.

opencc-zeroJun 2023View details →

opencc-by-4.0Dec 2022View details →

Date set for the manuscript: The Role of Sediment Gas Storage in the Methane Dynamics of a Shallow Freshwater Reservoir

The dataset supports the findings of the manuscript entitled: Linking Sediment Gas Storage to the Methane Dynamics in a Shallow Freshwater Reservoir. The manuscript presents results based on in-situ monitoring at the main pre-dam of the Wupper reservoir. The reservoir is located in Germany and the monitoring was conducted from March 2020 to November 2021. The main goal of the monitoring was to measure the spatial variability of methane fluxes and its dynamics in the reservoir. The methane budget of the reservoir was then analysed in combination with estimates of the amount of free gas stored in the sediment matrix, which were derived from acoustic observations. The findings are discussed in the manuscript. Therefore, the dataset provided as an xlsx file includes separate sheets for: <ul> <li>Sediment measurements of potential methane production (PMP), loss on ignition (LOI), dissolved methane (CH4) in porewater, carbon and nitrogen content.</li> <li>Gas content in the sediment estimated from maximum acoustic backscatter for 2020 and 2021 for the reservoir spatial grid.</li> <li>Monthly time-series of methane fluxes (oxidation, diffusion, ebullition, and potential flux at the sediment water interface - PSWI) for each monitoring location and for the reservoir (average of all monitoring locations) with the inclusion of degassing at the dam overflow and advective methane transport (Net-export) by inflow and outflow.</li> <li>Time series of daily mean values of ebullition and environmental parameters monitored in the reservoir.</li> </ul> Explanations and units are provided in column labels. NaN refers to missing data. In this version (Version 2), the calculation of the PSWI has been corrected. It is now calculated as the vertically integrated potential methane production over the top 30 cm layer of the sediment.

Dinoflagellate cysts and benthic foraminifera from surface sediments of Svalbard fjords and shelves as paleoenvironmental indicators

Supplementary Table 1. Seasonally averaged sea-ice cover, SST and SSS data used for the multivariate statistical analysis. Supplementary Table 2. Relative abundances of individual dinoflagellate cyst taxa, total cyst concentration [cysts g-1], and relative abundance of auto- and heterotrophic cysts at each station. Supplementary Table 3. Relative abundances of individual benthic foraminifera taxa, total benthic foraminifera concentration [forams g-1], and relative abundance of calcareous and agglutinated benthic foraminifera at each station.

opencc-by-4.0Dec 2022View details →

Dense vegetation hinders sediment transport towards saltmarsh interiors - Supporting data and source code (Part I: Pre-processing)

This is Part I of the supporting data and source code for the paper entitled "Dense vegetation hinders sediment transport towards saltmarsh interiors", submitted to Limnology and Oceanography Letters. It contains all input and output files to generate the simulation grids.

opencc-by-4.0Sep 2023View details →

Suspended sediment load and bedload flux from the Glacier d'Otemma proglacial forefield (summers 2020 and 2021)

The Glacier d’Otemma proglacial margin, located in the Swiss Alps at an altitude of about 2450 m a.s.l. (45.93423 N, 7.41160 E), is characterized by a ca. 1 km long by 200 m wide active braided forefield. In this setting we installed two gauging stations for the monitoring of both suspended sediment and bedload transport within the proglacial margin: GS1 at about 350 m from the glacier terminus and GS2 at the forefield outlet. Monitoring stations were equipped with water pressure sensors (CS451 from Cambell Scientific), turbidity probes (OBS300+ from Cambell Scientific) and geophones (3-components PE-6/B from Sensor Nederland connected to a DiGOS DATA-CUBE type 2 logger). Water discharge were determined following modalities described in Müller and Miesen (2022). Suspended loads were quantified using a conventional turbidity-suspended sediment concentration relationship, while bedload transport was derived seismically using the geophysical Fluvial model inversion (FMI) algorithm developed in Dietze et al. (2018). The dataset covers summers 2020 and 2021.  Further details on data aquisition and post-processing techniques are available in Mancini et al. (2023).

FIG. 2 in Two new species of Achnanthidium Kützing (Achnanthidiaceae) from the Quaternary sediments of the Colônia basin, Southeast Brazil

FIG. 2. — Achnanthidium ectorianum Marquardt & C.E.Wetzel, sp. nov. Population from the type locality. SEM: A-E, external views, raphe valve; F, internal view, raphe valve. Scale bars: A, 4 µm; B-F, 5 µm.

FIG. 7 in Two new species of Achnanthidium Kützing (Achnanthidiaceae) from the Quaternary sediments of the Colônia basin, Southeast Brazil

FIG. 7. — Achnanthidium craterianum Marquardt & C.E.Wetzel, sp. nov. Population from the type locality. SEM: A-D, internal views; A-C, raphe valve; B, detail of helictoglossa, apical striae, and areolae; C, detail of the central area and transapical striae; D, rapheless valve. Scale bars: 1 µm.

FIG. 5 in Two new species of Achnanthidium Kützing (Achnanthidiaceae) from the Quaternary sediments of the Colônia basin, Southeast Brazil

FIG. 5. — Achnanthidium craterianum Marquardt & C.E.Wetzel, sp. nov. Population from the type locality. LM micrographs, size diminution series: A-U, raphe valve; V-AH, raphless valve; AI-AJ, frustules in girdle view. Scale bar: 10 μm.

FIG. 1 in Two new species of Achnanthidium Kützing (Achnanthidiaceae) from the Quaternary sediments of the Colônia basin, Southeast Brazil

FIG. 1. — Achnanthidium ectorianum Marquardt & C.E.Wetzel, sp. nov. Population from the type locality. LM micrographs, size diminution series: A-T, raphe valve; U-AM, raphless valve; AN, frustules in girdle view. Scale bar: 10 μm.

FIG. 4 in Two new species of Achnanthidium Kützing (Achnanthidiaceae) from the Quaternary sediments of the Colônia basin, Southeast Brazil

FIG. 4. — Achnanthidium ectorianum Marquardt & C.E.Wetzel, sp. nov. Population from the type locality. SEM: A-C, external views, rapheless valve; D-E, internal views, rapheless valve; F, girdle view. Scale bars: A, 3 µm; B-F, 5 µm.

FIG. 8 in Two new species of Achnanthidium Kützing (Achnanthidiaceae) from the Quaternary sediments of the Colônia basin, Southeast Brazil

FIG. 8. — Achnanthidium craterianum Marquardt & C.E.Wetzel, sp. nov. Population from the type locality. SEM: A-C, girdle views. Scale bars: 1 µm.

opencc-by-nc-4.0Oct 2023View details →

Combining active and passive temperature signals for estimating sediment depths

This dataset contains the results of the experimental campaign and how data were collected on the the <a href="https://co-udlabs.eu/">Co-UDlabs</a> Transnational Access project: Characterization of thermal properties in sediment samples from urban drainage systems with temperature probes, by Langeveld et al. The Transnational Access project was funded under the European Union’s Horizon 2020 research and innovation programme under grant agreement No 101008626. The experiments were designed to further develop an innovative methodology for measuring sediment bed deposits in UDS based on temperature data analysis (<a href="https://doi.org/10.5281/zenodo.7258998">Anta et al., 2022</a>; <a href="https://doi.org/10.1039/D2EW00820C">Regueiro-Picallo et al., 2023</a>). Particularly, the aim of these experiments was to prove the application of this methodology for measuring sewer sediment accumulation. Therefore, the main tasks of this project were the development of a system based on active temperature sensors and its application in the measurement of sediment thermal properties of UDS. Furthermore, this system included additional temperature sensors installed at different height locations to allow the estimation of the sediment depth. The purpose of these measurements is to deepen the understanding of sedimentation and sediment transport processes. The data are described so that others can use and reproduce.