Characterizing suspended frazil ice in rivers using upward looking sonars

Ghobrial, Tadros; Loewen, Mark; Hicks, Faye

doi:10.1016/j.coldregions.2012.10.002

Cited by 32 publications

(32 citation statements)

References 27 publications

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“…We focus on solidification controlled by the long range diffusive transport of heat and salt, and how this couples with anisotropic kinetic attachment in determining bulk crystal growth from the melt. Frazil ice is observed to form axisymmetric disk-shaped crystals, at least for fairly weak supercooling [12][13][14]. Slow attachment kinetics limit growth perpendicular to the basal plane of the crystal while growth in the basal plane is limited by diffusion [2,15].…”

Section: Introductionmentioning

confidence: 99%

“…Consider an isolated axisymmetric disk-shaped crystal, as shown in figure 1, of radius R and half-thickness H, such that the aspect ratio α = H/R, which we expect to be small. To aid progress with modelling, we make the simplifying assumption that crystal growth maintains the disk like geometry observed in experiments [12][13][14] with uniform growth rates across each individual crystal face. This is a reasonable approxima- tion for radial growth of the thin disk edges provided that the disk remains morphologically stable (discussed further in section V D).…”

Section: A Governing Equationsmentioning

confidence: 99%

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Solidification of a disk-shaped crystal from a weakly supercooled binary melt

Jones

Wells

2015

Phys. Rev. E

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The physics of ice crystal growth from the liquid phase, especially in the presence of salt, has received much less attention than the growth of snow crystals from the vapour phase. The growth of so-called frazil ice by solidification of a supercooled aqueous salt solution is consistent with crystal growth in the basal plane being limited by the diffusive removal of the latent heat of solidification from the solid-liquid interface, while being limited by attachment kinetics in the perpendicular direction. This leads to the formation of approximately disk-shaped crystals with a low aspect ratio of thickness compared to radius, because radial growth is much faster than axial growth. We calculate numerically how fast disk-shaped crystals grow in both pure and binary melts, accounting for the comparatively slow axial growth, the effect of dissolved solute in the fluid phase and the difference in thermal properties between solid and fluid phases. We identify the main physical mechanisms that control crystal growth and show that the diffusive removal of both the latent heat released and also the salt rejected at the growing interface are significant. Our calculations demonstrate that certain previous parameterizations, based on scaling arguments, substantially underestimate crystal growth rates by a factor of order 10-100 for low aspect ratio disks, and provide a parameterization for use in models of ice crystal growth in environmental settings.

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Section: Introductionmentioning

confidence: 99%

Section: A Governing Equationsmentioning

confidence: 99%

Solidification of a disk-shaped crystal from a weakly supercooled binary melt

Jones

Wells

2015

Phys. Rev. E

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“…Recent river ice research efforts have included several studies (Jasek et al, 2005;Morse and Richard, 2009;Marko and Jasek, 2010a,b,c;Richard et al, 2011and Ghobrial et al, 2012, 2013 directed at quantifying frazil suspensions from acoustic backscattering (ABS) data. Although the reported results offered previously unavailable insights into frazil dynamics and properties, underlying simplifications and approximations left considerable interpretative uncertainties.…”

Section: Introductionmentioning

confidence: 99%

“…It has been applied to St. Lawrence River frazil data (Richard et al, 2011) gathered at a single acoustic frequency (1.229 MHz) to identify possible compatible combinations of particle size and concentration. North Saskatchewan River frazil data (Ghobrial et al, 2013) were also interpreted using a different single frequency method based upon laboratory-derived regression relationships between S v and fractional volume (F) (Ghobrial et al, 2012). Given the strong dependences of cross sections on particle size and shape, applications of the latter relationships were limited to situations in which particle size and shape distributions could be assumed to be very similar to those associated with the laboratory measurements.…”

Section: Introductionmentioning

confidence: 99%

Laboratory measurements of acoustic backscattering from polystyrene pseudo-ice particles as a basis for quantitative characterization of frazil ice

Marko

Topham

2015

Cold Regions Science and Technology

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“…Detection and measurement of frazil ice in rivers and lakes is difficult because frazil ice is very sensitive to handling (it cannot be sampled easily) and it evolves and transforms rapidly. Recent studies have shown that underwater acoustic sonars might offer advantages over other methods to detect and to potentially estimate the sizes and concentration of suspended frazil ice particles (Ghobrial 2012;Ghobrial et al 2012aGhobrial et al , 2012bJasek 2010a, 2010b;Richard 2009, 2010). Underwater acoustics methods have been successfully applied to other kinds of suspended particles such as sediment particles (e.g., Gartner 2004;Tessier et al 2007) and biomass (e.g., Greenlaw 1979;Medwin 2005;Brierley et al 2006).…”

Section: Introductionmentioning

confidence: 99%

Modeling frazil ice growth in the St. Lawrence River

2015

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Abstract:The paper presents a complete energy balance model of suspended frazil ice formation in the tidal water column of the St. Lawrence River. The model estimates of suspended frazil ice concentration are compared to in situ observations of an analogue of suspended frazil ice crystals, with good results. A time series of observed acoustic backscattering from suspended frazil serves as the analogue of the suspended frazil concentration. The model of frazil ice growth is used to estimate the rate of increase in mass of the suspended frazil ice by balancing the net rate of energy exchange with the atmosphere with the observed changes in water temperature and in anchor ice thickness. The positive results are achieved despite a number of difficulties with analysis. These difficulties include the bias resulting from the inability of the sonar to detect across the complete size range of suspended ice, the unknown impacts of advection, the unknown impact of anchor ice build-up on temperature and sonar readings, and the lack of knowledge regarding the accuracy of sonar estimation of anchor ice thickness. These results highlight the promise of models, suitably applied, and sonar to quantitatively estimate suspended frazil ice concentration.

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Characterizing suspended frazil ice in rivers using upward looking sonars

Cited by 32 publications

References 27 publications

Solidification of a disk-shaped crystal from a weakly supercooled binary melt

Solidification of a disk-shaped crystal from a weakly supercooled binary melt

Laboratory measurements of acoustic backscattering from polystyrene pseudo-ice particles as a basis for quantitative characterization of frazil ice

Modeling frazil ice growth in the St. Lawrence River

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