Frazil-ice growth rate and dynamics in mixed layers and sub-ice-shelf plumes

Jones, David Rees; Wells, Andrew

doi:10.5194/tc-12-25-2018

Cited by 27 publications

(18 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These laboratory measurements of the properties of frazil ice particles and flocs in saline water can be applied to oceanic frazil ice production models (Galton-Fenzi et al, 2012;Wells, 2015 and2018). Due to the complexity of the processes involved in the frazil ice production, all these models rely on the parameterization of small-scale phenomena and on the introduction of empirical constants (De Santi and Olla, 2017).…”

Section: Discussionmentioning

confidence: 99%

“…Due to the complexity of the processes involved in the frazil ice production, all these models rely on the parameterization of small-scale phenomena and on the introduction of empirical constants (De Santi and Olla, 2017). Rees Jones and Wells (2018) noted that it is difficult to discriminate between models that use different crystal growth rate parameterizations because they can predict the same experimentally observed supercooling time series using different size distributions of initial seed crystals. They concluded that what was needed to discriminate between different models was for experiments to be conducted to measure crystal sizes as well as supercooling, which is precisely what we have done in this study.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Laboratory Study of the Properties of Frazil Ice Particles and Flocs in Water of Different Salinities

Schneck¹,

Ghobrial²,

Loewen³

2019

Preprint

View full text Add to dashboard Cite

Abstract. Measurements of the size and shape of frazil ice particles and flocs in saline water and of frazil ice flocs in freshwater are limited. This study consisted of a series of laboratory experiments producing frazil ice at salinities of 0 ‰, 15 ‰, 25 ‰, and 35 ‰ to address this lack of data. The experiments were conducted in a large tank in a cold room with bottom mounted propellers to create turbulence. A high-resolution camera system was used to capture images of frazil ice particles and flocs passing through cross polarizing lenses. The high-resolution images of the frazil ice were processed using a computer algorithm to differentiate particles from flocs and determine key properties including size, shape, and volume. The size and volume distributions of particles and flocs at all four salinities were found to fit lognormal distributions closely. The concentration, mean size, and standard deviation of flocs and particles were assessed at different times during the supercooling process to determine how these properties evolve with time. Comparisons were made to determine the effect of salinity on the properties of frazil ice particles and flocs. The overall mean size of frazil ice particles in saline water and freshwater was found to range between 0.52 and 0.45 mm with particles sizes in freshwater ~ 13 % larger than in saline water. However qualitative observations showed that frazil ice particles in saline water tend to be more irregularly shaped. The overall mean size of frazil ice flocs in freshwater was 2.57 mm compared to a mean size of 1.47 mm for flocs in saline water. Estimates for the porosity of frazil ice flocs were made by equating the estimated volume of ice produced based on thermodynamic conditions to the estimated volume of ice determined from the digital images. The estimated porosities of frazil ice flocs were determined to be 0.86, 0.82, 0.80, and 0.75 for 0 ‰, 15 ‰, 25 ‰, 35 ‰ saline water, respectively.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Laboratory Study of the Properties of Frazil Ice Particles and Flocs in Water of Different Salinities

Schneck¹,

Ghobrial²,

Loewen³

2019

Preprint

View full text Add to dashboard Cite

show abstract

“…where the one-to-one equivalence has no dynamic significance). Rees Jones and Wells (2018) use one of the faster rise rates from the same set of results which is applicable to smaller crystal sizes (e.g. none of which conforms to the drag based estimates described in Daly, 1984) whereas Matsumura and 305 Oshima (2015) use a fixed rise rate of 1 mm s -1 , again for small crystals.…”

Section: Is There Evidence Of Large Pelagic Crystals?mentioning

confidence: 99%

Dynamics of Large Pelagic Ice Crystals in an Antarctic Ice Shelf Water Plume Flowing Beneath Land-Fast Sea Ice

Stevens

Robinson

O'Connor

et al. 2020

Preprint

View full text Add to dashboard Cite

Abstract. Observations of boundary-layer processes and ice crystal behaviour in an outflow region from the Ross/McMurdo Ice Shelves are presented. From a fast ice field camp, we captured the kinematics of free-floating relatively large (many 10s of mm in scale) ice crystals that were advecting as well as aggregating in a depositional layer on the sea ice underside (SIPL, sub-ice platelet layer). Simultaneously, we measured the background oceanic temperature, salinity, currents and turbulence structure. At the camp location the total water depth was 536 m, with the uppermost 50 m being in-situ super-cooled. Tidal flow speeds had an amplitude of around 0.1 m s−1 and the resulting under-ice boundary layer sustained turbulent dissipation rates as large as &varepsilon; = 10−6 W kg−1. Acoustic sampling (200 kHz) identified three classes of backscatter (1) large individual highly mobile targets, (2) echoes from large, individually identifiable suspended crystals and (3) a varying background, presumably of very small (frazil) crystals. This second class of backscatter was associated with crystal sizes far larger than typical, certainly larger than anything normally described as frazil, and some individuals at least were depositing close to fully grown. Measurement indicated crystal scales of the range 30–80 mm. The existence and settlement of this scale of crystal has implications for understanding SIPL evolution and the processes controlling the fate of Ice Shelf Water.

show abstract

“…Inclusion of suspended frazil in ocean modeling is well developed (e.g., Jenkins & Bombosch, 1995; Svensson & Omstedt, 1998). Plume models include a range of frazil crystal size classes (e.g., Holland & Feltham, 2005; Hughes et al, 2014; Rees Jones & Wells, 2018; Smedsrud & Jenkins, 2004). Frazil crystal size distribution is also now included in three‐dimensional ocean circulation models (Galton‐Fenzi et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Observations of the Size Distribution of Frazil Ice in an Ice Shelf Water Plume

Frazer

Langhorne

Leonard

et al. 2020

Geophysical Research Letters

View full text Add to dashboard Cite

The size distribution of frazil ice is currently unconstrained in ice shelf cavity modeling. Here we observe the time-dependent behavior of the number and size of frazil ice particles in an Ice Shelf Water plume. A novel acoustic scattering inversion was used to infer frazil ice crystal diameters, assuming a log-normal distribution. Observation sites were on land-fast sea ice approximately 13 and 33 km from the front of the McMurdo Ice Shelf, Antarctica. The water column from the ice-water interface to 30 m below mean sea level was monitored over 3 weeks in November of 2016 and 2017. At 15 m below sea level the mean frazil crystal diameter was ∼1 mm. Fractional ice volume, derived from frazil crystal size and number density, correlates with in situ supercooling (up to 50 mK at 15 m below sea level). The data presented here provide valuable input for model initiation and evaluation. Plain Language Summary For the first time we have observed the number and sizes of tiny, disc-like, crystals that appear beneath the springtime sea ice of McMurdo Sound, Antarctica. They are generated by melting at the base of gigantic floating glaciers that surround the Antarctic continent, and are carried out beneath the sea ice in water that is just below its freezing point. From sonar measurements we have found that at 15 m below sea level, there is about one disc-shaped ice crystal with an average diameter of approximately 1 mm in each 10 cm 3 of sea water. Previously, there have been no observed sizes of these ice crystals to guide modeling of the interaction between glaciers and the ocean, and our new results provide valuable input for model initiation and evaluation.

show abstract

Frazil-ice growth rate and dynamics in mixed layers and sub-ice-shelf plumes

Cited by 27 publications

References 34 publications

Laboratory Study of the Properties of Frazil Ice Particles and Flocs in Water of Different Salinities

Laboratory Study of the Properties of Frazil Ice Particles and Flocs in Water of Different Salinities

Dynamics of Large Pelagic Ice Crystals in an Antarctic Ice Shelf Water Plume Flowing Beneath Land-Fast Sea Ice

Observations of the Size Distribution of Frazil Ice in an Ice Shelf Water Plume

Contact Info

Product

Resources

About