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In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Physical Oceanography | Glaciology | Theoretical and Applied Mechanics | Climate Change Processes | Fluidisation and Fluid Mechanics | Interdisciplinary Engineering | Ocean Engineering | Applied Mathematics | Atmospheric Sciences | Control Systems, Robotics and Automation | Physical Geography and Environmental Geoscience | Oceanography | Numerical Computation | Earth Sciences not elsewhere classified | Numerical Solution of Differential and Integral Equations | Turbulent Flows | Maritime Engineering |
Climate Change Models | Effects of Climate Change and Variability on Antarctic and Sub-Antarctic Environments (excl. Social Impacts) | Expanding Knowledge in the Earth Sciences | Ecosystem Assessment and Management of Coastal and Estuarine Environments | Antarctic and Sub-Antarctic Oceanography | Wave Energy | Physical and Chemical Conditions of Water in Marine Environments | Global Effects of Climate Change and Variability (excl. Australia, New Zealand, Antarctica and the South Pacific) (excl. Social Impacts) | Expanding Knowledge in the Mathematical Sciences
Publisher: Elsevier BV
Date: 2009
Publisher: AIP Publishing
Date: 09-2018
DOI: 10.1063/1.5050262
Abstract: Hydroelastic interactions between regular water waves and floating freshwater ice are investigated using laboratory experiments for a range of incident wave periods and steepnesses. It is shown that only incident waves with sufficiently long period and large steepness break up the ice cover and that the extent of breakup increases with increasing period and steepness. Furthermore, it is shown that an increasing proportion of the incident wave propagates through the ice-covered water as the period and steepness increase, indicating the existence of a positive feedback loop between the ice breakup and increased wave propagation.
Publisher: AIP Publishing
Date: 12-2017
DOI: 10.1063/1.5003310
Abstract: Collisions between two thin floating disks forced by regular water waves are studied for a range of wave litudes and lengths, using laboratory wave basin experiments and a mathematical model. Three collision regimes are identified from the experiments in terms of collision frequency and strength, and the collisions are shown to be caused by drift for short incident wavelengths and relative surge motion between the disks for longer incident waves. The model is based on slope-sliding theory for the wave-induced disk motions and rigid-body collisions. It is shown to predict collision frequencies and velocities accurately for intermediate–long incident wavelengths. Incorporating drift and wave scattering forces into the model is shown to capture the collision behaviours for short incident wavelengths.
Publisher: Elsevier BV
Date: 04-2017
Publisher: American Physical Society (APS)
Date: 24-06-2020
Publisher: American Geophysical Union (AGU)
Date: 11-2009
DOI: 10.1029/2009GL040676
Publisher: The Open Journal
Date: 30-03-2021
DOI: 10.21105/JOSS.02939
Publisher: Cambridge University Press (CUP)
Date: 13-06-2017
DOI: 10.1017/JOG.2017.27
Publisher: Cambridge University Press (CUP)
Date: 20-01-2017
DOI: 10.1017/JFM.2016.855
Abstract: Linear potential-flow theory is used to study loads imposed on finite line arrays of rigid, bottom-mounted, surface-piercing, vertical cylinders by surface water waves. Perturbations in the cylinder locations are shown to d the resonant loads experienced by the unperturbed array. A relationship is established between the d ing and the phenomenon of Anderson localisation. Specifically, the Rayleigh–Bloch waves responsible for the resonant loads are shown to attenuate along the array when perturbations are introduced, resulting in localisation when the attenuation rate is sufficiently large with respect to the array length. Further, an efficient solution method for line arrays is introduced that captures the Rayleigh–Bloch wave modes supported by unperturbed arrays from the scattering characteristics of an in idual cylinder.
Publisher: Cambridge University Press (CUP)
Date: 29-01-2018
DOI: 10.1017/JFM.2017.857
Abstract: Water wave overwash of a step by small steepness, regular incident waves is analysed using a computational fluid dynamics (CFD) model and a mathematical model, in two spatial dimensions. The CFD model is based on the two-phase, incompressible Navier–Stokes equations, and the mathematical model is based on the coupled potential-flow and nonlinear shallow-water theories. The CFD model is shown to predict vortices, breaking and overturning in the region where overwash is generated, and that the overwash develops into fast-travelling bores. The mathematical model is shown to predict bore heights and velocities that agree with the CFD model, despite neglecting the complicated dynamics where the overwash is generated. Evidence is provided to explain the agreement in terms of the underlying agreement of mass and energy fluxes.
Publisher: Springer Science and Business Media LLC
Date: 05-07-2019
Publisher: American Geophysical Union (AGU)
Date: 03-2020
DOI: 10.1029/2019JC015418
Abstract: High temporal resolution in situ measurements of pancake ice drift are presented, from a pair of buoys deployed on floes in the Antarctic marginal ice zone during the winter sea ice expansion, over 9 days in which the region was impacted by four polar cyclones. Concomitant measurements of wave‐in‐ice activity from the buoys are used to infer that the ice remained unconsolidated, and pancake ice conditions were maintained over at least the first 7 days. Analysis of the data shows (i) the fastest reported ice drift speeds in the Southern Ocean (ii) high correlation of drift velocities with the surface wind velocities, indicating absence of internal ice stresses km from the ice edge where remotely sensed ice concentration is 100% and (iii) presence of a strong inertial signature with a 13 hr period. A Lagrangian free drift model is developed, including a term for geostrophic currents that reproduce the 13 hr period signature in the ice motion. The calibrated model provides accurate predictions of the ice drift for up to 2 days, and the calibrated parameters provide estimates of wind and ocean drag for pancake floes under storm conditions.
Publisher: Elsevier BV
Date: 2012
Publisher: Cambridge University Press (CUP)
Date: 09-02-2016
DOI: 10.1017/JFM.2016.21
Abstract: A theoretical model is used to study wave energy attenuation and directional spreading of ocean wave spectra in the marginal ice zone (MIZ). The MIZ is constructed as an array of tens of thousands of compliant circular ice floes, with randomly selected positions and radii determined by an empirical floe size distribution. Linear potential flow and thin elastic plate theories model the coupled water–ice system. A new method is proposed to solve the time-harmonic multiple scattering problem under a multidirectional incident wave forcing with random phases. It provides a natural framework for tracking the evolution of the directional properties of a wave field through the MIZ. The attenuation and directional spreading are extracted from ensembles of the wave field with respect to realizations of the MIZ and incident forcing randomly generated from prescribed distributions. The averaging procedure is shown to converge rapidly so that only a small number of simulations need to be performed. Far-field approximations are investigated, allowing efficiency improvements with negligible loss of accuracy. A case study is conducted for a particular MIZ configuration. The observed exponential attenuation of wave energy through the MIZ is reproduced by the model, while the directional spread is found to grow linearly with distance. The directional spreading is shown to weaken when the wavelength becomes larger than the maximum floe size.
Publisher: American Physical Society (APS)
Date: 10-01-2023
Publisher: Copernicus GmbH
Date: 15-05-2023
DOI: 10.5194/EGUSPHERE-EGU23-11652
Abstract: This work presents a new method for quantifying the Antarctic marginal ice zone (MIZ). The MIZ acts as an interface between the open Southern Ocean and the consolidated inner pack, and is generally described as area of sea ice affected by ocean surface waves. We use standalone CICE6, which includes a floe size distribution with atmospheric, oceanic and wave forcing, to simulate the evolution of Antarctic sea ice from 2010 & #8211 2020. CICE output variables were categorised as static (sea ice concentration, age, thickness, etc.),& thermodynamic, and dynamic. Unsupervised statistical methods were used to classify distinct sea ice regions and then to identify the dominant processes which contribute to the spatial and temporal variance of Antarctic sea ice cover. The unsupervised sea ice classification agrees with recent MIZ extent estimations using altimetry observations of wave attenuation. The addition of floe size information enhanced our MIZ classification to include high concentration pancake fields (which are promoted by waves). These results support the inclusion of floe size within sea ice modelling, and the importance of multi-variate approaches to describe sea ice.
Publisher: Elsevier BV
Date: 07-2018
Publisher: Copernicus GmbH
Date: 09-01-2019
Abstract: Abstract. The size distribution of pancake ice floes is calculated from images acquired during a voyage to the Antarctic marginal ice zone in the winter expansion season. Results show that 50 % of the sea ice area is made up of floes with diameters of 2.3–4 m. The floe size distribution shows two distinct slopes on either side of the 2.3–4 m range, neither of which conforms to a power law. Following a relevant recent study, it is conjectured that the growth of pancakes from frazil forms the distribution of small floes (D .3 m), and welding of pancakes forms the distribution of large floes (D m).
Publisher: IOP Publishing
Date: 04-2022
Abstract: Sea ice can attenuate Southern Ocean swell before it reaches Antarctic ice shelves and imposes flexural stresses, which promote calving of outer ice-shelf margins and influence ice shelf stability. An algorithm is developed to identify sea ice-free corridors that connect the open Southern Ocean to Antarctic ice shelves from daily satellite sea ice concentration data between September 1979 and August 2019. Large swell in the corridors available to impact the ice shelves is extracted from spectral wave model hindcast data. For a selection of ice shelves around the Antarctic coastline, corridors are assessed in terms of duration and areal extent. The availability of large swell to impact certain ice shelves through the corridors is evaluated from spectral wave data for daily statistical properties and the number of large swell days per year. Results integrated over a large number of ice shelves are used to assess overall trends. Large variations are found between in idual ice shelves for both corridors and available swell, with contrasting trends between the West and East Antarctic Ice Sheet. The findings indicate ice shelves likely to experience prolonged periods of appreciable outer margin flexure due to large swell action, such as the Fimbul, Shackleton and Ross Ice Shelves, which could exacerbate climate-driven weakening and decreasing buttressing capacity, with implications for sea-level rise.
Publisher: American Association for Cancer Research (AACR)
Date: 31-03-2023
DOI: 10.1158/1078-0432.22477947
Abstract: Supplementary Figures 1_6
Publisher: Society for Industrial & Applied Mathematics (SIAM)
Date: 2015
DOI: 10.1137/140973906
Publisher: Springer Science and Business Media LLC
Date: 06-08-2022
DOI: 10.1038/S41467-022-32036-2
Abstract: The marginal ice zone is the dynamic interface between the open ocean and consolidated inner pack ice. Surface gravity waves regulate marginal ice zone extent and properties, and, hence, atmosphere-ocean fluxes and ice advance/retreat. Over the past decade, seminal experimental c aigns have generated much needed measurements of wave evolution in the marginal ice zone, which, notwithstanding the prominent knowledge gaps that remain, are underpinning major advances in understanding the region’s role in the climate system. Here, we report three-dimensional imaging of waves from a moving vessel and simultaneous imaging of floe sizes, with the potential to enhance the marginal ice zone database substantially. The images give the direction–frequency wave spectrum, which we combine with concurrent measurements of wind speeds and reanalysis products to reveal the complex multi-component wind-plus-swell nature of a cyclone-driven wave field, and quantify evolution of large- litude waves in sea ice.
Publisher: Cambridge University Press (CUP)
Date: 02-05-2007
DOI: 10.1017/S002211200700537X
Abstract: The problem of linear wave scattering by an ice sheet of variable thickness floating on water of variable quiescent depth is considered by applying the Rayleigh–Ritz method in conjunction with a variational principle. By using a multi-mode expansion to approximate the velocity potential that represents the fluid motion, Porter & Porter ( J. Fluid Mech . vol. 509, 2004, p. 145) is extended and the solution of the problem may be obtained to any desired accuracy. Explicit solution methods are formulated for waves that are obliquely incident on two-dimensional geometry, comparisons are made with existing work and a range of new ex les that includes both total and partial ice-cover is considered.
Publisher: International Glaciological Society
Date: 2015
Abstract: A new ocean wave/sea-ice interaction model is proposed that simulates how a directional wave spectrum evolves as it travels through an arbitrary finite array of circular ice floes, where wave/ ice dynamics are entirely governed by wave-scattering effects. The model is applied to characterize the wave reflection and transmission properties of a strip of ice floes, such as an ice edge band. A method is devised to extract the reflected and transmitted directional wave spectra produced by the array. The method builds upon an integral mapping from polar to Cartesian coordinates of the scattered wave components. Sensitivity tests are conducted for a row of floes randomly perturbed from a regular arrangement. Results for random arrays are generated using ensemble averaging. A realistic ice edge band is then reconstructed from field experiment data. Simulations show good qualitative agreement with the data in terms of transmitted wave energy and directional spreading. In particular, it is observed that short waves become isotropic quickly after penetrating the ice field.
Publisher: International Glaciological Society
Date: 2015
Abstract: A new numerical implementation is proposed for a wave-ice interaction model. It is applied to an idealized transect geometry. Wave attenuation due to ice floes and wave-induced ice fracture are both included in the model. The new method alleviates the need for subgrid spatial or temporal discretizations, thereby facilitating future integration of wave-ice interactions into large-scale coupled models.
Publisher: International Society of Offshore and Polar Engineers
Date: 09-2021
Publisher: The Royal Society
Date: 24-06-2009
Abstract: Flexural oscillations of floating sea ice sheets induced by ocean waves travelling at the boundary between the ice and the water below can propagate great distances. But, by virtue of scattering, changes of ice thickness and other properties encountered during the journey affect their passage, notwithstanding attenuation arising from several other naturally occurring agencies. We describe here a two-dimensional model that can simulate wave scattering by long (approx. 50 km) stretches of inelastic sea ice, the goal being to replicate heterogeneity accurately while also assimilating supplementary processes that lead to energy loss in sea ice at scales that are amenable to experimental validation. In work concerned with scattering from solitary or juxtaposed stylized features in the sea ice canopy, reflection and transmission coefficients are commonly used to quantify scattering, but on this occasion, we use the attenuation coefficient as we consider that it provides a more helpful description when dealing with long sequences of adjoining scatterers. Results show that scattering and viscosity both induce exponential decay and we observe three distinct regimes: (i) low period, where scattering dominates, (ii) high period, where viscosity dominates, and (iii) a transition regime. Each regime’s period range depends on the sea ice properties including viscosity, which must be included for the correct identification of decay rate.
Publisher: Oxford University Press (OUP)
Date: 18-12-2014
DOI: 10.1093/QJMAM/HBU024
Publisher: Elsevier BV
Date: 2019
Publisher: Society for Industrial & Applied Mathematics (SIAM)
Date: 2011
DOI: 10.1137/10080662X
Publisher: American Geophysical Union (AGU)
Date: 28-07-2014
DOI: 10.1002/2014GL060809
Publisher: Cambridge University Press (CUP)
Date: 21-02-2020
DOI: 10.1017/JFM.2020.75
Publisher: AIP Publishing
Date: 09-2023
DOI: 10.1063/5.0161920
Publisher: Elsevier BV
Date: 12-2015
Publisher: The Royal Society
Date: 10-2021
Abstract: A solution method is developed for a linear model of ice shelf flexural vibrations in response to ocean waves, in which the ice shelf thickness and seabed beneath the ice shelf vary over distance, and the ice shelf/sub–ice-shelf cavity are connected to the open ocean. The method combines a decomposition of the ice shelf displacement profile at a prescribed frequency of motion into mode shapes of free vibrations, a finite-element method for the cavity water motion and a non-local operator to connect to the open ocean. An investigation is conducted into the effects of ice shelf thickening, seabed shoaling and the grounding-line conditions on time-harmonic ice shelf vibrations, induced by regular incident waves in the swell regime. Furthermore, results are given for ice shelf vibrations in response to irregular incident waves by superposing time-harmonic responses, and ocean-to-ice-shelf transfer functions are derived. The findings add to evidence that ice shelves experience appreciable flexural vibrations in response to swell, and that ice shelf thickening and seabed shoaling can have a considerable influence on predictions of how ice shelves respond to ocean waves.
Publisher: Cambridge University Press (CUP)
Date: 28-09-2010
DOI: 10.1017/S0022112010004039
Abstract: An efficient solution method is presented for linear and time-harmonic water-wave scattering by two classes of a three-dimensional hydroelastic system. In both cases, the fluid domain is of infinite horizontal extent and finite depth. The fluid surface is either open, except in a finite region where it is covered by a thin-elastic plate, which represents an ice floe, or fully covered by a plate, except in a finite region where it is open, which represents an ice polynya. The approach outlined herein permits the boundary between the ice-covered and free-surface fluid regions to be described by an arbitrary smooth curve. To solve the governing equations of the full three-dimensional linear problem, they are first projected onto the horizontal plane by using an approximation theory that combines an expansion of the vertical motion of the fluid in a finite set of judiciously chosen modes with a variational principle. This generates a system of two-dimensional partial differential equations that are converted into a set of one-dimensional integro-differential equations using matrices of Green's functions, which are solved numerically through an application of the Galerkin technique. A numerical results section justifies the consideration of an arbitrarily shaped boundary by comparing the response of differently shaped floes and polynyas over a range of relevant wavenumbers. Comparisons are made in terms of the magnitude and direction of the far-field scattering response, and also the maximum average curvature of the floe and the maximum wave elevation within the polynya.
Publisher: Oxford University Press (OUP)
Date: 04-12-2009
Publisher: Cambridge University Press (CUP)
Date: 16-04-2013
DOI: 10.1017/JFM.2013.124
Abstract: Validation of a linear numerical model of wave interactions with floating compliant discs is sought using data obtained from the wave basin experiments reported in Part 1 (Montiel et al. J. Fluid Mech. , vol. 723, 2013, pp. 604–628). Comparisons are made for both single-disc tests and the two-disc tests in which wave interactions between discs are observed. The deflection of the disc or discs is separated into the natural modes of vibration in vacuo . The decomposition allows the rigid-body motions and flexural motions to be analysed separately. Rigid-body motions are accurately replicated by the numerical model but, although passable agreement is found, the litudes of flexural modes are consistently overestimated. Extensions of the numerical model are used to discount the experimental configuration as a source of the discrepancies. An enhanced viscoelastic model for the discs is also proposed, which results in improved model/data agreement for the flexural motions but cannot account for all of the disagreement.
Publisher: Cambridge University Press (CUP)
Date: 16-04-2013
DOI: 10.1017/JFM.2013.123
Abstract: A series of wave basin experiments is reported that investigates the flexural response of one or two floating thin elastic discs to monochromatic waves. The work is motivated by numerical model validation. Innovative techniques are used to ensure the experimental configuration is consistent with the model. This demands linear motions, time-harmonic conditions, homogeneity of the plate and the restriction of horizontal motions of the disc or discs. An optical remote sensing device is employed to record the deflection of the discs accurately. Tests involving a single disc and two discs are conducted for a range of disc thicknesses, incident wave steepnesses, frequencies and, in the case of two discs, geometrical arrangements. A data processing technique is used to decompose the raw data into its spectral harmonics and filter the higher-order components. Pointwise comparisons of the linear first-order component of the experimental deflection with numerical predictions are presented. Satisfying agreement is found, although the model consistently over predicts the deflection. Disc–disc interactions are observed in the two-disc tests. A brief discussion of the shortcomings of the pointwise analysis, with associated possible sources of discrepancy, provides a link to the study reported in Part 2 (Montiel et al. J. Fluid Mech. , vol. 723, 2013, pp. 629–652).
Publisher: American Geophysical Union (AGU)
Date: 12-06-2019
DOI: 10.1029/2019GL082457
Publisher: Copernicus GmbH
Date: 19-12-2016
DOI: 10.5194/TC-2016-270
Abstract: Abstract. Impacts of wave-induced breakup of Antarctic sea ice on ice concentration and volume are investigated using a modified version of the CICE sea ice model, run in standalone mode from 1979–2010. Model outputs show that breakup reduces ice concentration by up to 0.3–0.4 in a vicinity of the ice edge during the summer, and total ice volume by over 500 km3.
Publisher: Oxford University Press (OUP)
Date: 24-07-2008
Publisher: Elsevier BV
Date: 04-2017
Publisher: Elsevier BV
Date: 11-2013
Publisher: Elsevier BV
Date: 2016
Publisher: The Royal Society
Date: 12-09-2022
Abstract: Perspectives are discussed on future directions for the field of marginal ice zone (MIZ) dynamics, based on the extraordinary progress made over the past decade in its theory, modelling and observations. Research themes are proposed that would shift the field’s focus towards the broader implications of MIZ dynamics in the climate system. In particular, pathways are recommended for research that highlights the impacts of trends in the MIZ on the responses of Arctic and Antarctic sea ice to climate change. This article is part of the theme issue ‘Theory, modelling and observations of marginal ice zone dynamics: multidisciplinary perspectives and outlooks’.
Publisher: American Geophysical Union (AGU)
Date: 12-2010
DOI: 10.1029/2009JC005982
Abstract: A three‐dimensional model of wave scattering by a large array of floating thin elastic plates is used to predict the rate of ocean wave attenuation in the marginal ice zone in terms of the properties of the ice cover and the incoming wavefield. This is regarded as a small step toward assimilating interactions of ocean waves with areas of sea ice into oceanic general circulation models. Numerical results confirm previous findings that attenuation is predominantly affected by wave period and by the average thickness of the ice cover. It is found that the shape and distribution of the floes and the inclusion of an Archimedean draft has little impact on the attenuation produced. The model demonstrates a linear relationship between ice cover concentration and attenuation. An additional study is conducted into the directional evolvement of the wavefield, where collimation and spreading can both occur, depending on the physical circumstances. Finally, the attenuation predicted by the new three‐dimensional model is compared with an existing two‐dimensional model and with two sets of experimental data, with the latter producing convincing agreement.
Publisher: The Royal Society
Date: 12-09-2022
Abstract: The marginal ice zone (MIZ) is the dynamic interface between the open ocean and sea ice-covered ocean. It is characterized by interactions between surface gravity waves and granular ice covers consisting of relatively small, thin chunks of sea ice known as floes. This structure gives the MIZ markedly different properties to the thicker, quasi-continuous ice cover of the inner pack that waves do not reach, strongly influencing various atmosphere–ocean fluxes, especially the heat flux. The MIZ is a significant component of contemporary sea ice covers in both the Antarctic, where the ice cover is surrounded by the Southern Ocean and its fierce storms, and the Arctic, where the MIZ now occupies vast expanses in areas that were perennial only a decade or two ago. The trend towards the MIZ is set to accelerate, as it reinforces positive feedbacks weakening the ice cover. Therefore, understanding the complex, multiple-scale dynamics of the MIZ is essential to understanding how sea ice is evolving and to predicting its future. This article is part of the theme issue ‘Theory, modelling and observations of marginal ice zone dynamics: multidisciplinary perspectives and outlooks’.
Publisher: Elsevier BV
Date: 11-2013
Publisher: Copernicus GmbH
Date: 27-03-2022
DOI: 10.5194/EGUSPHERE-EGU22-3373
Abstract: & & Over the last three decades there have been two catastrophic disintegrations events on the Antarctic peninsula, the Larsen A ice shelf in 1995 and the Larsen B in 2002, alongside the Wilkins ice shelf which underwent multiple partial disintegrations between 1998& #8212 .& Previous research into these events indicated that there had been prolonged periods where the Larsen and Wilkins Ice Shelves were without a sea-ice buffer to protect them from ocean swell in the leadup to their respective disintegrations. Swell potentially acted as a trigger mechanism to each shelf to disintegrated, as they had already been destabilised by surface flooding, fracturing, thinning and other glaciological factors.& & & & This study will focus on the algorithm we developed which calculates the time where an ice shelf is without a local sea ice buffer (& #8220 exposure& #8221 ), the size of the ocean which could directly propagate waves into the shelf (& #8220 corridor& #8221 ) and the maximum wave height of swell which is directed towards the shelf in the corridor. An analysis of the last forty-one years showed that there was a large variation over in idual ice shelves for both exposure and the available swell, due to the impact of polynyas, ice tongues and fast-ice growth which can protect the ice shelf. On a regional scale, the East Antarctic Ice Shelf and West Antarctic Ice Shelf had opposing trends, with the West Antarctic Ice Shelf recording a weak increasing trend of exposure and available swell.& &
Publisher: Elsevier BV
Date: 03-2023
Publisher: Cambridge University Press (CUP)
Date: 12-09-2018
DOI: 10.1017/JFM.2018.648
Abstract: A structure capable of substantially lifying water waves over a broad range of frequencies at selected locations is proposed. The structure consists of a small number of C-shaped cylinders in a line array, with the cylinder properties graded along the array. Using linear potential-flow theory, it is shown that the energy carried by a plane incident wave is lified within specified cylinders for wavelengths comparable to the array length and for a range of incident directions. Transfer-matrix analysis is used to attribute the large lifications to excitation of local Rayleigh–Bloch waves and gradual slowing down of their group velocity along the array.
Publisher: AIP Publishing
Date: 04-2015
DOI: 10.1063/1.4916573
Abstract: An experimental model is used to validate a theoretical model of a sea ice floe’s flexural motion, induced by ocean waves. A thin plastic plate models the ice floe in the experiments. Rigid and compliant plastics and two different thicknesses are tested. Regular incident waves are used, with wavelengths less than, equal to, and greater than the floe length, and steepnesses ranging from gently sloping to storm-like. Results show the models agree well, despite the overwash phenomenon occurring in the experiments, which the theoretical model neglects.
Publisher: The Royal Society
Date: 24-08-2011
Abstract: Exponential attenuation of ocean surface waves in ice-covered regions of the polar seas is modelled in a two-dimensional, linear setting, assuming that the sea ice behaves as a thin-elastic plate. Attenuation is produced by natural features in the ice cover, with three types considered: floes, cracks and pressure ridges. An inelastic d ing parameterization is also incorporated. Efficient methods for obtaining an attenuation coefficient for each class of feature, involving an investigation of wave interaction theory and averaging methods, are sought. It is found that (i) the attenuation produced by long floes can be obtained from the scattering properties of a single ice edge and (ii) wave interaction theory in ice-covered regions requires evanescent and d ed-propagating motions to be included when scattering sources are relatively nearby. Implications for the integration of this model into an oceanic general circulation model are also discussed.
Publisher: Elsevier BV
Date: 2012
Publisher: Elsevier BV
Date: 05-2021
Publisher: Springer Science and Business Media LLC
Date: 06-2018
DOI: 10.1038/S41586-018-0212-1
Abstract: Understanding the causes of recent catastrophic ice shelf disintegrations is a crucial step towards improving coupled models of the Antarctic Ice Sheet and predicting its future state and contribution to sea-level rise. An overlooked climate-related causal factor is regional sea ice loss. Here we show that for the disintegration events observed (the collapse of the Larsen A and B and Wilkins ice shelves), the increased seasonal absence of a protective sea ice buffer enabled increased flexure of vulnerable outer ice shelf margins by ocean swells that probably weakened them to the point of calving. This outer-margin calving triggered wider-scale disintegration of ice shelves compromised by multiple factors in preceding years, with key prerequisites being extensive flooding and outer-margin fracturing. Wave-induced flexure is particularly effective in outermost ice shelf regions thinned by bottom crevassing. Our analysis of satellite and ocean-wave data and modelling of combined ice shelf, sea ice and wave properties highlights the need for ice sheet models to account for sea ice and ocean waves.
Publisher: The Royal Society
Date: 20-08-2018
Abstract: Three-dimensional scattering of ocean surface waves in the marginal ice zone (MIZ) is determined in the time domain. The solution is found using spectral analysis of the linear operator for the Boltzmann equation. The method to calculate the scattering kernel that arises in the Boltzmann model from the single-floe solution is also presented along with new identities for the far-field scattering, which can be used to validate the single-floe solution. The spectrum of the operator is computed, and it is shown to have a universal structure under a special non-dimensionalization. This universal structure implies that under a scaling wave scattering in the MIZ has similar properties for a large range of ice types and wave periods. A scattering theory solution using fast Fourier transforms is given to find the solution for directional incident wave packets. A numerical solution method is also given using the split-step method and this is used to validate the spectral solution. Numerical calculations of the evolution of a typical wave field are presented. This article is part of the theme issue ‘Modelling of sea-ice phenomena’.
Publisher: American Geophysical Union (AGU)
Date: 30-09-2022
DOI: 10.1029/2022JC018707
Abstract: In the marginal ice zone (MIZ), where ocean waves and sea ice interact, waves can produce flows of water across ice floe surfaces in a process known as wave overwash. Overwash potentially influences wave propagation characteristics, floe thermodynamics, and floe surface biological and chemical processes. However, the extent of the MIZ affected by overwash and its dependence on prevailing wave and ice conditions is unknown. In this paper, we propose a model of overwash extent caused by irregular incoming waves into a MIZ consisting of a random floe field. We validate the overwash extent model against laboratory experiments. We use the model to study mild to extreme incoming waves to floe field characteristics of the spring–summer ice retreat and autumn–winter ice advance and with compact ice edges. Overwash is typically predicted to extend a few kilometers and is generally greater for the autumn–winter advance than the spring–summer retreat. The model predictions provide a basis for improved understanding of the impacts of ocean waves on the ice cover. We also apply the model to incoming waves and a floe field with a diffuse ice edge representative of conditions during a field experiment, predicting overwash extents up to 16 km. During the field experiment, the wave and ice floe properties were intermittently monitored by a camera system, demonstrating how the sparse field data available on overwash can be advanced.
Publisher: Copernicus GmbH
Date: 08-2018
DOI: 10.5194/TC-2018-155
Abstract: Abstract. The size distribution of pancake ice floes is calculated from images acquired during a voyage to the Antarctic marginal ice zone in the winter expansion season. Results show that 50 % of the sea ice area is made up by floes with diameters 2.3–4 m. The floe size distribution shows two distinct slopes on either side of the 2.3–4 m range. It is conjectured that growth of pancakes from frazil forms the distribution of small floes (D 4 m).
Publisher: International Glaciological Society
Date: 2015
Abstract: A theoretical model and an experimental model of surge motions of an ice floe due to regular waves are presented. The theoretical model is a modified version of Morrison’s equation, valid for small floating bodies. The experimental model is implemented in a wave basin at a scale 1:100, using a thin plastic disc to model the floe. The processed experimental data display a regime change in surge litude when the incident wavelength is approximately twice the floe diameter. It is shown that the theoretical model is accurate in the high-wavelength regime, but highly inaccurate in the low-wavelength regime.
Publisher: The Royal Society
Date: 02-09-2019
Abstract: Energy lification in square-lattice arrays of C-shaped low-frequency resonators, where the resonator radii are graded with distance, is investigated in the two-dimensional linear acoustics setting for both infinite (in one dimension) and finite arrays. Large lifications of the incident energy are shown in certain array locations. The phenomenon is analysed using: (i) band diagrams for doubly-periodic arrays (ii) numerical simulations for infinite and finite arrays and (iii) eigenvalue analysis of transfer matrices operating over in idual columns of the array. It is shown that the locations of the large lifications are predicted by propagation cut-offs in the modes associated with the transfer-matrix eigenvalues. For the infinite array, the eigenvalues form a countable set, and for the low frequencies considered, only a single propagating mode exists for a given incident wave, which cuts off within the array, leading to predictive capabilities for the lification location. For the finite array, it is shown that (in addition to a continuous spectrum of modes) multiple discrete propagating modes can be excited, with the grading generating new modes, as well as cutting others off, leading to complicated lification patterns. The numerical simulations reveal that the largest lifications are achieved for a single row array, with lifications an order of magnitude smaller for the corresponding infinite array. This article is part of the theme issue ‘Modelling of dynamic phenomena and localization in structured media (part 1)’.
Publisher: Copernicus GmbH
Date: 03-05-2017
Abstract: Abstract. Impacts of wave-induced breakup of Antarctic sea ice on ice concentration and volume are investigated using a modified version of the CICE sea-ice model, run in stand-alone mode from 1979–2010. Model outputs show that during summer wave-induced breakup reduces local ice concentration by up to 0.3–0.4 in a vicinity of the ice edge and total ice volume by up to a factor of 0.1–0.2.
Publisher: The Royal Society
Date: 2015
Abstract: An experimental validation of theoretical models of regular-water-wave transmission through arrays of floating discs is presented. The experiments were conducted in a wave basin. The models are based on combined potential-flow and thin-plate theories, and the assumption of linear motions. A low-concentration array, in which discs are separated by approximately a disc diameter in equilibrium, and a high-concentration array, in which adjacent discs are almost touching in equilibrium, were used for the experiments. The proportion of incident-wave energy transmitted by the discs is presented as a function of wave period, and for different wave litudes. Results indicate the models predict wave-energy transmission accurately for small- litude waves and low-concentration arrays. Discrepancies for large- litude waves and high-concentration arrays are attributed to wave overwash of the discs and collisions between discs. Validation of model predictions of a solitary disc's rigid-body motions are also presented.
Publisher: Springer Science and Business Media LLC
Date: 05-04-2019
Publisher: Elsevier BV
Date: 08-2020
Publisher: Society for Industrial & Applied Mathematics (SIAM)
Date: 2013
DOI: 10.1137/120903439
Publisher: Copernicus GmbH
Date: 17-10-2020
Abstract: Abstract. The Southern Ocean has a profound impact on the Earth's climate system. Its strong winds, intense currents, and fierce waves are critical components of the air-sea interface and contribute to absorbing, storing, and releasing heat, moisture, gasses, and momentum. Owing to its remoteness and harsh environment, this region is significantly under s led, h ering the validation of prediction models and large scale observations from satellite sensors. Here, an unprecedented data set of simultaneous observations of winds, surface currents, and ocean waves is presented, to address the scarcity of in situ observations in the region – 0.26179/5ed0a30aaf764 (Alberello et al., 2020c), and 0.26179/5e9d038c396f2 (Derkani et al., 2020). Records were acquired underway during the Antarctic Circumnavigation Expedition (ACE), which went around the Southern Ocean from December 2016 to March 2017 (Austral summer). Observations were obtained with the wave and surface current monitoring system WaMoS-II, which scanned the ocean surface around the vessel using marine radars. Measurements were assessed for quality control and compared against available satellite observations. The data set is the most extensive and comprehensive collection of observations of surface process for the Southern Ocean and has the potential to support further theoretical and numerical research on lower atmosphere, air-sea interface and upper ocean processes.
Publisher: American Meteorological Society
Date: 07-2022
Abstract: Irregular, unidirectional surface water waves incident on model ice in an ice tank are used as a physical model of ocean surface wave interactions with sea ice. Results are given for an experiment consisting of three tests, starting with a continuous ice cover and in which the incident wave steepness increases between tests. The incident waves range from causing no breakup of the ice cover to breakup of the full length of ice cover. Temporal evolution of the ice edge, breaking front, and mean floe sizes are reported. Floe size distributions in the different tests are analyzed. The evolution of the wave spectrum with distance into the ice-covered water is analyzed in terms of changes of energy content, mean wave period, and spectral bandwidth relative to their incident counterparts, and pronounced differences are found between the tests. Further, an empirical attenuation coefficient is derived from the measurements and shown to have a power-law dependence on frequency comparable to that found in field measurements. Links between wave properties and ice breakup are discussed.
Publisher: The Royal Society
Date: 12-09-2022
Abstract: A summary is given on the utility of laboratory experiments for gaining understanding of wave attenuation in the marginal ice zone, as a complement to field observations, theory and numerical models. It is noted that most results to date are for regular incident waves, which, combined with the highly nonlinear wave–floe interaction phenomena observed and measured during experimental tests, implies that the attenuation of regular waves cannot necessarily be used to infer the attenuation of irregular waves. Two experiments are revisited in which irregular wave tests were conducted but not previously reported, one involving a single floe and the other a large number of floes, and the transmission coefficients for the irregular and regular wave tests are compared. The transmission spectra derived from the irregular wave tests agree with the regular wave data but are overpredicted by linear models due to nonlinear dissipative processes, regardless of floe configuration. This article is part of the theme issue ‘Theory, modelling and observations of marginal ice zone dynamics: multidisciplinary perspectives and outlooks’.
Publisher: Copernicus GmbH
Date: 27-03-2022
DOI: 10.5194/EGUSPHERE-EGU22-2294
Abstract: & & & & & span& Overwash is an important aspect of the dynamics in the marginal ice zone where sea ice and ocean waves interact. Overwash dissipates wave energy, and the presence of water on top of sea ice can drive growth or melting, depending on the local thermodynamic conditions. The presence of water on floes is also important for biologic and chemical processes. While overwash has been observed and investigated under experimental conditions, it has not yet been studied in the marginal ice zone. One reason for this lack of in-situ measurements and observations is due to the marginal ice zone being highly dynamic, and the onset of overwash only occurring under specific and sensitive conditions. To facilitate future observations we have produced a model of the extent of overwash into fields of sea ice by combining a new model of the onset of overwash and a standard attenuation model. This model of overwash extent is validated against experimental observations and is used to provide the extent of overwash for realistic ice and wave field conditions observed during the July 2017 voyage of the South African icebreaker S.A. Agulhas II.& /span& & span& & & /span& & & & / & & & & & & span& & & /span& & & & / &
Publisher: American Geophysical Union (AGU)
Date: 25-10-2015
DOI: 10.1002/2015GL065937
Publisher: Elsevier BV
Date: 08-2019
Publisher: AIP Publishing
Date: 10-2023
DOI: 10.1063/5.0165305
Publisher: Cambridge University Press (CUP)
Date: 12-04-2022
DOI: 10.1017/JFM.2022.247
Abstract: Extensions of Rayleigh–Bloch waves above the cutoff frequency are studied via the discrete spectrum of a transfer operator for a channel containing a single cylinder with quasi-periodic side-wall conditions. Above the cutoff, the Rayleigh–Bloch wavenumber becomes complex valued and an additional wavenumber appears. For small- to intermediate-radius values, the extended Rayleigh–Bloch waves are shown to connect the Neumann and Dirichlet trapped modes before embedding in the continuous spectrum. A homotopy method involving an artificial d ing term is proposed to identify the discrete spectrum close to the embedding. Moreover, Rayleigh–Bloch waves vanish beyond some frequency but reappear at higher frequencies for small and large cylinders. The existence and properties of the Rayleigh–Bloch waves are connected with finite-array resonances.
Publisher: Society for Industrial & Applied Mathematics (SIAM)
Date: 2021
DOI: 10.1137/20M1386979
Publisher: Elsevier BV
Date: 09-2019
Publisher: Cambridge University Press (CUP)
Date: 09-10-2009
DOI: 10.1017/S0022112009991017
Abstract: A three-dimensional model of ocean-wave scattering in the marginal ice zone is constructed using linear theory under time-harmonic conditions. In idual floes are represented by circular elastic plates and are permitted to have a physically realistic draught. These floes are arranged into a finite number of parallel rows, and each row possesses an infinite number of identical floes that are evenly spaced. The floe properties may differ between rows, and the spacing between the rows is arbitrary. The vertical dependence of the solution is expanded in a finite number of modes, and through the use of a variational principle, a finite set of two-dimensional equations is generated from which the full-linear solution may be retrieved to any desired accuracy. By dictating the periodicity in each row to be identical, the scattering properties of the in idual rows are combined using transfer matrices that take account of interactions between both propagating and evanescent waves. Numerical results are presented that investigate the differences between using the three-dimensional model and using a two-dimensional model in which the rows are replaced with strips of ice. Furthermore, Bragg resonance is identified when the rows are identical and equi-spaced, and its reduction when the inhomogeneities, that are accommodated by the model, are introduced is shown.
Publisher: American Geophysical Union (AGU)
Date: 09-11-2022
DOI: 10.1029/2022GL100868
Abstract: An efficient mathematical model is presented for predicting the transfer of ocean waves to ice shelf flexure along two‐dimensional transects. The model incorporates varying ice shelf thickness and seabed bathymetry profiles, and is able to predict responses of large ice shelves over a broad frequency spectrum. The model is used to generate displacement and strain transfer functions for the Ross Ice Shelf (RIS) using geometries from the Bedmap2 data set. The transfer functions are validated against recent observations and used to study the influence of geometrical variations on strain transfer close to the shelf front. Predictions of RIS strain in response to ex le irregular incident swell and infragravity waves are generated over a wide region, and show similar maximum strains but contrasting spatial strain patterns. The model and results provide a basis for studying destabilizing impacts of ocean waves on the RIS.
Publisher: Elsevier BV
Date: 04-2017
Publisher: Copernicus GmbH
Date: 22-03-2021
DOI: 10.5194/ESSD-13-1189-2021
Abstract: Abstract. The Southern Ocean has a profound impact on the Earth's climate system. Its strong winds, intense currents, and fierce waves are critical components of the air–sea interface and contribute to absorbing, storing, and releasing heat, moisture, gases, and momentum. Owing to its remoteness and harsh environment, this region is significantly unders led, h ering the validation of prediction models and large-scale observations from satellite sensors. Here, an unprecedented data set of simultaneous observations of winds, surface currents, and ocean waves is presented, to address the scarcity of in situ observations in the region – 0.26179/5ed0a30aaf764 (Alberello et al., 2020c) and 0.26179/5e9d038c396f2 (Derkani et al., 2020). Records were acquired underway during the Antarctic Circumnavigation Expedition (ACE), which went around the Southern Ocean from December 2016 to March 2017 (Austral summer). Observations were obtained with the wave and surface current monitoring system WaMoS-II, which scanned the ocean surface around the vessel using marine radars. Measurements were assessed for quality control and compared against available satellite observations. The data set is the most extensive and comprehensive collection of observations of surface processes for the Southern Ocean and is intended to underpin improvements of wave prediction models around Antarctica and research of air–sea interaction processes, including gas exchange and dynamics of sea spray aerosol particles. The data set has further potentials to support theoretical and numerical research on lower atmosphere, air–sea interface, and upper-ocean processes.
Publisher: Cambridge University Press (CUP)
Date: 20-07-2015
DOI: 10.1017/JFM.2015.378
Abstract: A theoretical model of water wave overwash of a thin floating plate is proposed. The nonlinear shallow-water equations are used to model the overwash, and the linear potential-flow/thin-plate model to force it. Model predictions are compared with overwash depths measured during a series of laboratory wave basin experiments. The model is shown to be accurate for incident waves of low steepness or short length.
Location: United Kingdom of Great Britain and Northern Ireland
Start Date: 2020
End Date: 2024
Funder: Australian Research Council
View Funded ActivityStart Date: 2021
End Date: 2024
Funder: Australian Research Council
View Funded ActivityStart Date: 2015
End Date: 2022
Funder: United States Department of the Navy
View Funded ActivityStart Date: 2020
End Date: 2023
Funder: Australian Research Council
View Funded ActivityStart Date: 2013
End Date: 2015
Funder: Australian Antarctic Division
View Funded ActivityStart Date: 2019
End Date: 2022
Funder: Australian Antarctic Division
View Funded ActivityStart Date: 2017
End Date: 2019
Funder: Australian Antarctic Division
View Funded ActivityStart Date: 2021
End Date: 2021
Funder: Australian Research Council
View Funded ActivityStart Date: 2022
End Date: 2022
Funder: Australian Research Council
View Funded ActivityStart Date: 2014
End Date: 12-2016
Amount: $200,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 07-2022
End Date: 12-2023
Amount: $328,389.00
Funder: Australian Research Council
View Funded ActivityStart Date: 06-2013
End Date: 12-2017
Amount: $375,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 06-2021
End Date: 06-2025
Amount: $1,161,512.00
Funder: Australian Research Council
View Funded ActivityStart Date: 07-2021
End Date: 06-2024
Amount: $427,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 07-2020
End Date: 07-2024
Amount: $884,063.00
Funder: Australian Research Council
View Funded ActivityStart Date: 06-2020
End Date: 06-2024
Amount: $349,000.00
Funder: Australian Research Council
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