Analysis of the scale of errors in nearshore bathymetric data

Plant, Nathaniel G.; Holland, Kieran; Puleo, Jack A.

doi:10.1016/s0025-3227(02)00497-8

Cited by 129 publications

(101 citation statements)

References 25 publications

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“…Several surveys were carried out in quick succession during June and October 2011 associated with two intense field campaigns investigating rip currents on Perranporth beach Scott et al, 2014), but most surveys were taken quasi-regularly every 2 months. Data from the two regions were combined into a 1.2 km x 1.2 km area and Loess-interpolated (Plant et al, 2002) to achieve 10-m grid resolution.…”

Section: Collection and Analysis Of Morphological Data Setmentioning

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: Collection and Analysis Of Morphological Data Setmentioning

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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“…ripples and megaripples, as our model cannot simulate the dynamics of these morphological features. Instead, we analyse and simulate the general trend of the beach profile, the high-frequency bed perturbations being filtered using loess interpolation techniques (Plant et al, 2002).…”

Section: Descriptions Of Test Series Cmentioning

confidence: 99%

Numerical modelling of pronounced sloping beach profile evolution: comparison with the large-scale BARDEX II experiment

Dubarbier

Castelle

Marieu

et al. 2013

Journal of Coastal Research

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“…We interpolated the available bed profiles to a regular cross-shore grid with 5 m spacing using a scale-controlled linear smoother [Plant et al, 2002] to remove measurement errors and small bathymetric features unresolved by the observations and the model (e.g., bed ripples). During interpolation we ignored measurement values collected near the pier pilings because of local scour.…”

Section: Datamentioning

confidence: 99%

Numerical predictability experiments of cross‐shore sandbar migration

Ruessink¹,

Kuriyama²

2008

Geophysical Research Letters

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[1] Surf zone sandbars, common features along the world's sandy coastlines, continuously change their position in response to time-variable offshore wave conditions. Processbased predictions of cross-shore sandbar migration, relevant to the understanding of autonomous and artificially altered evolution of beaches, are intrinsically imprecise because of uncertainty in the model equations and, potentially, the sensitive dependence on the initial bathymetry. However, the magnitude of the resulting predictability limit and its dominant source are unknown. Here we show that cross-shore sandbar migration on the time scale of years is deterministically forced rather than deterministically chaotic, and that the unpredictability of sandbar migration results primarily from model inadequacy during major wave events. Because the unpredictability of sandbar migration is related to the stochastic nature of the forcing, the predictability limit is not a fixed value but depends on the timing of the wave event. We anticipate that detailed experiments to understand nearshore evolution from the underlying first principles will eventually pay off by extending the range of plausible simulated behavior and, consequently, will increase our ability to understand and predict how coasts may respond to changing climate.

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Analysis of the scale of errors in nearshore bathymetric data

Cited by 129 publications

References 25 publications

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

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

Numerical modelling of pronounced sloping beach profile evolution: comparison with the large-scale BARDEX II experiment

Numerical predictability experiments of cross‐shore sandbar migration

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