The history and technical capabilities of Argus

Holman, Robert A.; Stanley, John M.

doi:10.1016/j.coastaleng.2007.01.003

Cited by 496 publications

(386 citation statements)

References 32 publications

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“…For example, some of the first observations of surf beat were made by Tucker (1950) at this site. In 1996 Perranporth was chosen as the site for the UK's first ARGUS video station (Davidson et al, 1997;Holman and Stanley, 2007) and these cameras remain operational to the present day. A series of swash experiments using arrays of in-situ instrumentation have been carried out on the high tide beach (Butt and Russell, 1999;Butt et al, 2001Butt et al, , 2002Butt et al, , 2007Masselink et al, 2005;Masselink and Russell, 2006;Lanckriet et al, 2014;Puleo et al, 2014a, b).…”

Section: Description Of Study Areamentioning

confidence: 99%

Role of wave forcing, storms and NAO in outer bar dynamics on a high-energy, macro-tidal beach

et al. 2014

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Outer sand bar dynamics on a high-energy macro-tidal beach were investigated using long-term (multi-year) field datasets of intertidal morphology and offshore bathymetry. Utilising a 15-year time-series of Argus video images, five distinct outer bar types were identified: Mega Rip, Longshore, Crescentic, Crescentic Attached and Welded. The most common classification was Crescentic Attached, with the outer bar oscillations being out of phase with the inner bar oscillations, as would be expected for the shore-normal wave approach at this site. The outer bar had a typical amplitude of 0.5-1 m and a longshore wavelength of 600 m. Changes in outer bar morphology were related to measured and modelled nearshore wave data. However, the outer bar morphology changed over a much longer time scale (monthly-to-annual) than the daily-to-weekly variations in wave height and period. An extended duration of energetic wave action was required to bring about an upstate bar transition to the Longshore or Mega Rip state, where the bar then remained arrested for a significant amount of time, requiring several months of low wave conditions to induce a down state transition through Crescentic to Welded. This slow morphological response is explained by extended relaxation times attributed to the large tidal range at the study site where the outer bar morphology is only active for part of the tidal cycle (several hours around low tide). The configuration and position of the outer bar were related: the more upstate (downstate) bar types being associated with a more offshore (onshore) bar position. The detrended outer bar position was significantly related to a forcing term based on wave power and disequilibrium of the dimensionless fall velocity with offshore (onshore) bar migration occurring when wave conditions were more (less) energetic that the antecedent conditions. The upstate end member (Longshore or Mega Rip) was attained sometime during the winter months for 14 out of the 16 years of monitoring; the outer bar remained attached to the low tide shoreline over the winter 2005/2006 and 2010/2011. These two winters with incomplete upstate cycles were characterised by the lowest winter wave conditions and negative winter North Atlantic Oscillation (NAO) indices, suggesting that the winter NAO is correlated with both beach state and nearshore bar configuration. KEYWORDS

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Section: Description Of Study Areamentioning

confidence: 99%

Role of wave forcing, storms and NAO in outer bar dynamics on a high-energy, macro-tidal beach

et al. 2014

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“…Most studies suggest using a longer averaging period, usually 10 min TIMEX [4,28,36,39,43,65,68] to 15 min [69]. The methodological choice of long period time-averaged images is based on the time period of wave groups and the fact that a longer exposure enables a more complete "storage" of the processes on the beach such as wave breaking [21] that generate foam at the shoreline or over bars.…”

Section: Shoreline Detection and Elevation Analysesmentioning

confidence: 99%

LiDAR Validation of a Video-Derived Beachface Topography on a Tidal Flat

et al. 2017

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Increasingly used shore-based video stations enable a high spatiotemporal frequency analysis of shoreline migration. Shoreline detection techniques combined with hydrodynamic conditions enable the creation of digital elevation models (DEMs). However, shoreline elevations are often estimated based on nearshore process empirical equations leading to uncertainties in video-based topography. To achieve high DEM correspondence between both techniques, we assessed video-derived DEMs against LiDAR surveys during low energy conditions. A newly installed video system on a tidal flat in the St. Lawrence Estuary, Atlantic Canada, served as a test case. Shorelines were automatically detected from time-averaged (TIMEX) images using color ratios in low energy conditions synchronously with mobile terrestrial LiDAR during two different surveys. Hydrodynamic (waves and tides) data were recorded in-situ, and established two different cases of water elevation models as a basis for shoreline elevations. DEMs were created and tested against LiDAR. Statistical analysis of shoreline elevations and migrations were made, and morphological variability was assessed between both surveys. Results indicate that the best shoreline elevation model includes both the significant wave height and the mean water level. Low energy conditions and in-situ hydrodynamic measurements made it possible to produce video-derived DEMs virtually as accurate as a LiDAR product, and therefore make an effective tool for coastal managers.

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“…Five types of images were collected: snapshot, time exposure (Timex, averaging 2 Hz frames collected over a period of 10 min, Fig. 3), variance (standard deviation of same image series), brightest and darkest (the brightest and darkest intensities seen at each pixel during the ten-minute sample period (Holman and Stanley, 2007). The images were collected every half hour of daylight during the experiment.…”

Section: Remote Sensing Argus Systemmentioning

confidence: 99%