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Your search keyword '"Reniers, A. J. H. M."' showing total 146 results
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146 results on '"Reniers, A. J. H. M."'

2. Submesoscale dispersion in the vicinity of the Deepwater Horizon spill

Author

Poje, Andrew C., Özgökmen, Tamay M., Lipphardt, Jr., Bruce, Haus, Brian K., Ryan, Edward H., Haza, Angelique C., Reniers, A. J. H. M., Olascoaga, Josefina, Novelli, Guillaume, Beron-Vera, Francisco J., Chen, Shuyi, Mariano, Arthur J., Jacobs, Gregg, Hogan, Pat, Coelho, Emanuel, Kirwan, Jr., A. D., Huntley, Helga, and Griffa, Annalisa

Subjects
Physics - Atmospheric and Oceanic Physics, 76-XX
Abstract

Reliable forecasts for the dispersion of oceanic contamination are important for coastal ecosystems, society and the economy as evidenced by the Deepwater Horizon oil spill in the Gulf of Mexico in 2010 and the Fukushima nuclear plant incident in the Pacific Ocean in 2011. Accurate prediction of pollutant pathways and concentrations at the ocean surface requires understanding ocean dynamics over a broad range of spatial scales. Fundamental questions concerning the structure of the velocity field at the submesoscales (100 meters to tens of kilometers, hours to days) remain unresolved due to a lack of synoptic measurements at these scales. \textcolor{black} {Using high-frequency position data provided by the near-simultaneous release of hundreds of accurately tracked surface drifters, we study the structure of submesoscale surface velocity fluctuations in the Northern Gulf Mexico. Observed two-point statistics confirm the accuracy of classic turbulence scaling laws at 200m$-$50km scales and clearly indicate that dispersion at the submesoscales is \textit{local}, driven predominantly by energetic submesoscale fluctuations.} The results demonstrate the feasibility and utility of deploying large clusters of drifting instruments to provide synoptic observations of spatial variability of the ocean surface velocity field. Our findings allow quantification of the submesoscale-driven dispersion missing in current operational circulation models and satellite altimeter-derived velocity fields., Comment: 9 pages, 6 figures

Published
2014
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9. Measurements of morphodynamics of a sheltered beach along the Dutch Wadden Sea.

Author

van der Lugt, Marlies A., Bosma, Jorn W., de Schipper, Matthieu A., Price, Timothy D., van Maarseveen, Marcel C. G., van der Gaag, Pieter, Ruessink, Gerben, Reniers, Ad J. H. M., and Aarninkhof, Stefan G. J.

Subjects
BEACHES, BARRIER islands, TIDAL currents, COMPOSITION of sediments, SERVER farms (Computer network management), BEACH erosion, TURBIDITY
Abstract

A field campaign was carried out at a sheltered sandy beach with the aim of gaining new insights into the driving processes behind sheltered beach morphodynamics. Detailed measurements of the local hydrodynamics, bed-level changes and sediment composition were collected at a man-made beach on the leeside of the barrier island Texel, bordering the Marsdiep basin that is part of the Dutch Wadden Sea. The dataset consists of (1) current, wave and turbidity measurements from a dense cross-shore array and a 3 km alongshore array; (2) sediment composition data from beach surface samples; (3) high-temporal-resolution RTK-GNSS beach profile measurements; (4) a pre-campaign spatially covering topobathy map; and (5) meteorological data. This paper outlines how these measurements were set up and how the data have been processed, stored and can be accessed. The novelty of this dataset lies in the detailed approach to resolve forcing conditions on a sheltered beach, where morphological evolution is governed by a subtle interplay between tidal and wind-driven currents, waves and bed composition, primarily due to the low-energy (near-threshold) forcing. The data are publicly available at 4TU Centre for Research Data at: 10.4121/19c5676c-9cea-49d0-b7a3-7c627e436541. [ABSTRACT FROM AUTHOR]

Published
2024
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11. Measurements of morphodynamics of a sheltered beach along the Dutch Wadden Sea.

Author

van der Lugt, Marlies A., Bosma, Jorn W., de Schipper, Matthieu A., Price, Timothy D., van Maarseveen, Marcel C. G., van der Gaag, Pieter, Ruessink, B. Gerben, Reniers, Ad J. H. M., and Aarninkhof, Stefan G. J.

Subjects
BEACHES, BARRIER islands, TIDAL currents, COMPOSITION of sediments, SEDIMENT transport, BEACH erosion, TURBIDITY
Abstract

A field campaign was carried out at a sheltered sandy beach with the aim of gaining new insights into the driving processes behind sheltered beach morphodynamics. Detailed measurements of the local hydrodynamics, bed level changes and sediment composition were collected at the man-made beach on the leeside of the barrier island Texel, bordering the Marsdiep basin that is part of the Dutch Wadden Sea. The data set consists of (1) current, wave and turbidity measurements from a dense cross-shore array and a 3 km alongshore array, (2) sediment composition data from beach surface samples, (3) high-temporal-resolution RTK-GNSS beach profile measurements, (4) a pre-campaign spatially covering bathy-topo map and (5) meteorological data. This manuscript outlines how these measurements were set up and how the data have been processed, stored and can be accessed. The novelty of this data set lies in the detailed approach to resolve forcing conditions on a sheltered beach, where sediment transport is governed by a strong interplay between tidal currents, waves and bed composition, primarily due to the low-energy (near-threshold) forcing. [ABSTRACT FROM AUTHOR]

Published
2023
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20. Novel sediment sampling method provides new insights into vertical grain size variability due to marine and aeolian beach processes.

Author

van IJzendoorn, Christa O., Hallin, Caroline, Cohn, Nicholas, Reniers, Ad J. H. M., and De Vries, Sierd

Subjects
EOLIAN processes, BEACHES, SEDIMENT sampling, GRAIN size, PARTICLE size distribution, SEDIMENT transport
Abstract

In sandy beach systems, the aeolian sediment transport can be governed by the vertical structure of the sediment layers at the bed surface. Here, data collected with a newly developed sand scraper is presented to determine high‐resolution vertical grain size variability and how it is affected by marine and aeolian processes. Sediment samples at up to 2 mm vertical resolution down to 50 mm depth were collected at three beaches: Waldport (Oregon, USA), Noordwijk (the Netherlands) and Duck (North Carolina, USA). The results revealed that the grain size in individual layers can differ considerably from the median grain size of the total sample. The most distinct temporal variability occurred due to marine processes that resulted in significant morphological changes in the intertidal zone. The marine processes during high water resulted both in fining and coarsening of the surface sediment. Especially near the upper limit of wave runup, the formation of a veneer of coarse sediment was observed. Although the expected coarsening of the near‐surface grain size during aeolian transport events was observed at times, the opposite trend also occurred. The latter could be explained by the formation and propagation of aeolian bedforms within the intertidal zone locally resulting in sediment fining at the bed surface. The presented data lays the basis for future sediment sampling strategies and sediment transport models that investigate the feedbacks between marine and aeolian transport, and the vertical variability of the grain size distribution. [ABSTRACT FROM AUTHOR]

Published
2023
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24. Relationship between three-dimensional radiation stress and Vortex-Force representations

Author

Nguyen, D. T. Reniers, A. J. H. M. Roelvink, D. and Nguyen, D. T. Reniers, A. J. H. M. Roelvink, D.

Abstract

In numerical ocean models, the effect of waves on currents is usually expressed by either vortex-force or radiation stress representations. In this paper, the differences and similarities between those two representations are investigated in detail in conditions of both conservative and nonconservative waves. In addition, comparisons between different sets of equations of mean motion that apply different representations of wave-induced forcing terms are included. The comparisons are useful for selecting a suitable numerical ocean model to simulate the mean current in conditions of waves combined with currents.

Published
2021
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26. Measurements of hydrodynamics, sediment, morphology and benthos on Ameland ebb-tidal delta and lower shoreface

Author

van Prooijen, Bram C., primary, Tissier, Marion F. S., additional, de Wit, Floris P., additional, Pearson, Stuart G., additional, Brakenhoff, Laura B., additional, van Maarseveen, Marcel C. G., additional, van der Vegt, Maarten, additional, Mol, Jan-Willem, additional, Kok, Frank, additional, Holzhauer, Harriette, additional, van der Werf, Jebbe J., additional, Vermaas, Tommer, additional, Gawehn, Matthijs, additional, Grasmeijer, Bart, additional, Elias, Edwin P. L., additional, Tonnon, Pieter Koen, additional, Santinelli, Giorgio, additional, Antolínez, José A. A., additional, de Vet, Paul Lodewijk M., additional, Reniers, Ad J. H. M., additional, Wang, Zheng Bing, additional, den Heijer, Cornelis, additional, van Gelder-Maas, Carola, additional, Wilmink, Rinse J. A., additional, Schipper, Cor A., additional, and de Looff, Harry, additional

Published
2020
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29. Sandbars in Motion

Author

Stive, Marcel J. F. and Reniers, Ad J. H. M.

Published
2003

30. PIV measurements of the bottom boundary layer under nonlinear surface waves

Author

Henriquez, M., Reniers, A. J H M, Ruessink, B. G., Stive, M. J F, Proceskunde, and Coastal dynamics, Fluvial systems and Global change

Subjects
Physics, Nearshore morphology, Environmental Engineering, Vortex tube, Turbulence, Bar (music), Flow (psychology), Magnitude (mathematics), Ocean Engineering, Mechanics, Bottom shear stress, Wave bottom boundary layer, Physics::Fluid Dynamics, Flume, Vortex tubes, Boundary layer, Particle image velocimetry, Geotechnical engineering, Nonlinear waves
Abstract

Sediment in the nearshore is largely mobilized in the wave bottom boundary layer (wbbl) hereby emphasizing the importance of this relatively thin layer to nearshore morphology. This paper presents a laboratory experiment where hydrodynamic properties of the wbbl were quantified by measuring flow velocities using Particle Image Velocimetry. The bottom of the wave flume was rigid with a single bar profile. The measurements consisted of the velocities of the wbbl with a resolution in the order of 10 points in time and space for skewed and asymmetric waves. In the wbbl there was significant transformation of velocity skewness and asymmetry. Negative wbbl streaming was generated by asymmetric waves. Boundary layer development and generation of vortex tubes were observed. The velocity measurements included the turbulent components resulting in quantification of turbulent stresses that were of similar magnitude as the viscous stresses.

Published
2014

41. Modeling cross-shore sandbar behavior on the timescale of weeks

Author

Ruessink, B. G. Kuriyama, Y. Reniers, A. J. H. M. Roelvink, J. A. Walstra, D. J. R.

Subjects
modelling, sandbars, waves
Abstract

We compare predictions of a coupled, wave-averaged, cross-shore wavescurrents-bathymetric evolution model to observations of onshore and offshore nearshore sandbar migration. The observations span a 10- and 44-day period with onshore/ offshore bar migration at Duck, North Carolina, and at Hasaki, Kashima Coast, Japan, respectively, a 3.5-month period of onshore bar migration at Duck, and a 22-day period of offshore bar migration at Egmond, Netherlands. With best fit parameter values the modeled temporal evolution of the cross-shore bed profiles agrees well with the observations. Model skill, defined as 1 minus the ratio of prediction to no-change error variances, ranges from 0.50 at Egmond to 0.88 for the prolonged onshore bar migration at Duck. Localized (in time and space) reductions in model skill coincide with alongshore variations in the observed morphology. Consistent with earlier observations, simulated offshore bar migration takes place during storms when large waves break on the bar and is due to the feedback between waves, undertow, suspended sediment transport, and the sandbar. Simulated onshore bar migration is predicted for energetic, weakly to nonbreaking conditions and is due to the feedback between near-bed wave skewness, bedload transport, and the sandbar, with negligible to small effects of bound infragravity waves and near-bed streaming. Under small waves and conditions, when breaking and nonbreaking conditions alternate with the tide, the sandbar is predicted to remain stationary. The intersite differences in the optimum parameter values are, at least partly, induced by insensitivity to parameter variations, parameter interdependence, and errors in the offshore wave forcing.

Published
2007

42. Submesoscale dispersion in the vicinity of the Deepwater Horizon spill

Author

Poje, Andrew C., primary, Özgökmen, Tamay M., additional, Lipphardt, Bruce L., additional, Haus, Brian K., additional, Ryan, Edward H., additional, Haza, Angelique C., additional, Jacobs, Gregg A., additional, Reniers, A. J. H. M., additional, Olascoaga, Maria Josefina, additional, Novelli, Guillaume, additional, Griffa, Annalisa, additional, Beron-Vera, Francisco J., additional, Chen, Shuyi S., additional, Coelho, Emanuel, additional, Hogan, Patrick J., additional, Kirwan, Albert D., additional, Huntley, Helga S., additional, and Mariano, Arthur J., additional

Published
2014
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45. Modeling Multi‐Fraction Coastal Aeolian Sediment Transport With Horizontal and Vertical Grain‐Size Variability

Author

IJzendoorn, C. O., Hallin, C., Reniers, A. J. H. M., and Vries, S.

Abstract

Grain size affects the rates of aeolian sediment transport on beaches. Sediment in coastal environments typically consists of multiple grain‐size fractions and exhibits spatiotemporal variations. Still, conceptual and numerical aeolian transport models are simplified and often only include a single fraction that is constant over the model domain. It is unclear to what extent this simplification is valid and if the inclusion of multi‐fraction transport and spatial grain‐size variations affects aeolian sediment transport simulations and predictions of coastal dune development. This study applies the numerical aeolian sediment transport model AeoLiS to compare single‐fraction to multi‐fraction approaches for a range of grain‐size distributions and spatial grain‐size scenarios. The results show that on timescales of days to years, single‐fraction simulations with the median grain size, D50, often give similar results to multi‐fraction simulations, provided the wind is able to mobilize all fractions within that time frame. On these timescales, vertical variability in grain size has a limited effect on total transport rates, but it does influence the simulation results on minute timescales. Horizontal grain‐size variability influences both the total transport rates and the downwind bed grain‐size composition. The results provide new insights into the influence of beach sediment composition and spatial variability on total transport rates toward the dunes. The findings of this study can guide the implementation of grain‐size variability in numerical aeolian sediment transport models. The growth of coastal dunes is caused by the wind, which moves sand from the beach to the dunes. The sand grains on the beach have different sizes. For instance, the size of the sand grains can vary from the waterline to the start of the dunes. Small sand grains are more easily picked up by the wind than larger, heavier grains. Thus, the size of sand grains and how they are spread over the beach can impact how much sand is moved by the wind. We use computer simulations to calculate how much sand is moved by the wind under different conditions. We investigate how different assumptions about the grain size on the beach influence these calculations. The results show that the calculations with one single sand size, in most cases, give comparable results to simulations with more complicated sand size variations. The simplified approach is beneficial because it reduces the need for detailed field data of grain sizes for future calculations. The effects of multi‐fraction transport and spatial grain‐size variations were examined with the numerical aeolian transport model AeoLiSThe D50can be used as a representative grain size in aeolian sediment transport modeling on a time scale of days to yearsThe bed surface grain size in the upwind source area might be the most relevant to include in aeolian sediment transport models The effects of multi‐fraction transport and spatial grain‐size variations were examined with the numerical aeolian transport model AeoLiS The D50can be used as a representative grain size in aeolian sediment transport modeling on a time scale of days to years The bed surface grain size in the upwind source area might be the most relevant to include in aeolian sediment transport models

Published
2023
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