A nuclear magnetic resonance study of Antarctic sea ice brine diffusivity

Callaghan, Paul T.; Dykstra, Robin; Eccles, C.D.; Haskell, T. G.; Seymour, Joseph D.

doi:10.1016/s0165-232x(99)00024-5

Cited by 59 publications

(51 citation statements)

References 24 publications

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“…A novel, entirely different approach to overcome the problems related to sample extraction has Ž . been taken by Callaghan et al 1999 . Utilizing the earth's magnetic field to observe nuclear precession, Callaghan et al were able to determine the brine volume fraction directly at the site or even in situ and furthermore extended the method to measurements of brine diffusivities.…”

Section: Introductionmentioning

confidence: 99%

Magnetic resonance imaging of sea-ice pore fluids: methods and thermal evolution of pore microstructure

Eicken

Bock

Wittig

et al. 2000

Cold Regions Science and Technology

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Microstructure and thermal evolution of sea-ice brine inclusions were investigated with magnetic resonance imaging Ž . 1MRI techniques. Ice samples were kept at temperatures between y28C and y258C during H imaging in a 4.7-T magnet Ž at 200 MHz. Measurements were completed in a 20-cm diameter cylindrical probe and actively shielded gradient coils max. y1. 50 mT m , pixel dimensions ) 0.2 mm, slice thicknesses ) 1 mm , and for higher resolution in a mini-imaging unit with y1 Ž . a 9-cm diameter probe with gradient coils of 200 mT m pixel dimensions -0.1 mm, slice thickness -0.4 mm . Ž . Absorption of radio-frequency RF signals in the dielectrically lossy brine resulted in degraded signals and was alleviated Ž . Ž by use of a contrast agent decane . MRI data and sea-ice thin section images agree very well -5% deviation for pore . microstructural parameters . Analysis of ice grown under different current speeds indicates that pores are smaller and pore number densities larger at higher current speeds. The thermal evolution of fluid inclusions was studied on cold first-year ice samples, maintained at close to in-situ temperatures prior to experiments. Warming from y218C to y108C to y68C is Ž . associated with a distinct increase in pore size from 1.5 to 1.7 to 2.6 mm for the upper 10-percentile in the vertical and Ž . Ž elongation 4.0 to 4.2 to 6.2 for ratio of major to minor pore axes in the vertical and a decrease in number densities 0.75 to y3 . Ž . 0.62 to 0.58 mm in the vertical . Aspect ratios increased from 4:2:1 to 6:2:1 upper 10-percentile , indicating expansion and merging of pores in the vertical, possibly promoted by microscopic residual brine inclusions. q

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Section: Introductionmentioning

confidence: 99%

Magnetic resonance imaging of sea-ice pore fluids: methods and thermal evolution of pore microstructure

Eicken

Bock

Wittig

et al. 2000

Cold Regions Science and Technology

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“…Using Nuclear Magnetic Resonance (NMR), Mercier et al (2005) showed isotropy and anisotropy in sea ice diffusion coefficients. Callaghan et al (1999) and Hunter et al (2009) showed the NMR technique well-replicated calculated brine volume fractions in sections of Antarctic sea ice up to 220 cm thick and 180 cm thick respectively. However, the NMR technique is unable to determine pore sizes, shapes, or distribution within the sea ice, highlighting the need for a greater library of physical observations of liquid inclusions in sea ice under a variety of sea ice types/environments (e.g.…”

Section: Introductionmentioning

confidence: 89%

“…We define this relationship as linear based on the work of Callaghan et al (1999), who made a linear regression analysis of NMR-derived brine volume and brine volume calculated using the equation of Cox and Weeks (1983) yielding a correlation coefficient of 0.952. We calculated the liquid water fraction for every voxel to create a liquid volume profile analogous to a brine volume profile derived using temperature and bulk salinity measurements from a traditionally sectioned core, but at a much higher (0.623 mm) vertical (Y) resolution.…”

Section: Methodsmentioning

confidence: 99%

Imaged brine inclusions in young sea ice—Shape, distribution and formation timing

Galley

Else

Geilfus

et al. 2015

Cold Regions Science and Technology

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a b s t r a c t a r t i c l e i n f oLiquid inclusions in sea ice are variable and dependent on the myriad of physical conditions of the atmospheresea ice environment in which the sea ice was grown, and whether or not melting processes affected the sea ice. In that light, there exist relatively few observations and resultant quantification of the morphology and vertical distribution of brine inclusions in sea ice. Using a magnetic (3.0 T) resonance (MR) imager using constructive interference steady state gradient echo sequence, we show that it is possible to image brine channels and pockets in an 18.5 cm young sea ice core in three-dimensions in only four and a half minutes following core storage at −20°C. We present a three-dimensional image of a brine drainage channel feature in a young sea ice core, give the physical context for its formation by presenting the physical conditions of the atmosphere and water/sea ice prior to sea ice growth through the sampling date, and observe its physical characteristics. We illustrate that brine drainage channels may be established concurrently with ice growth, and indicate the amount and location of vertical and horizontal fluid connectivity in the young sea ice sample in the context of the environment in which it grew. Finally, we show that a vertical brine volume distribution profile can be calculated using MR image data, extending the (non-imaging) nuclear magnetic resonance work of others in this vein.

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“…SNMR is an emerging geophysical technique, specifically developed for hydrogeological investigations Hertrich, 2008;Knight et al, 2012). Selective sensitivity to groundwater is the main advantage of SNMR in comparison with other geophysical tools, and the magnetic resonance phenomenon can also be used for investigating brine and water inclusions in ice (Callaghan et al, 1999). Note that cold ice with negligible interstitial water does not produce an SNMR response and will be interpreted as a dry material.…”

Section: Introductionmentioning

confidence: 99%

Monitoring water accumulation in a glacier using magnetic resonance imaging

et al. 2014

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Abstract. Tête Rousse is a small polythermal glacier located in the Mont Blanc area (French Alps) at an altitude of 3100 to 3300 m. In 1892, an outburst flood from this glacier released about 200 000 m 3 of water mixed with ice, causing much damage. A new accumulation of melt water in the glacier was not excluded. The uncertainty related to such glacier conditions initiated an extensive geophysical study for evaluating the hazard. Using three-dimensional surface nuclear magnetic resonance imaging (3-D-SNMR), we showed that the temperate part of the Tête Rousse glacier contains two separate water-filled caverns (central and upper caverns). In 2009, the central cavern contained about 55 000 m 3 of water. Since 2010, the cavern is drained every year. We monitored the changes caused by this pumping in the water distribution within the glacier body. Twice a year, we carried out magnetic resonance imaging of the entire glacier and estimated the volume of water accumulated in the central cavern. Our results show changes in cavern geometry and recharge rate: in two years, the central cavern lost about 73 % of its initial volume, but 65 % was lost in one year after the first pumping. We also observed that, after being drained, the cavern was recharged at an average rate of 20 to 25 m 3 d −1 during the winter months and 120 to 180 m 3 d −1 in summer. These observations illustrate how ice, water and air may refill englacial volume being emptied by artificial draining. Comparison of the 3-D-SNMR results with those obtained by drilling and pumping showed a very good correspondence, confirming the high reliability of 3-D-SNMR imaging.

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A nuclear magnetic resonance study of Antarctic sea ice brine diffusivity

Cited by 59 publications

References 24 publications

Magnetic resonance imaging of sea-ice pore fluids: methods and thermal evolution of pore microstructure

Magnetic resonance imaging of sea-ice pore fluids: methods and thermal evolution of pore microstructure

Imaged brine inclusions in young sea ice—Shape, distribution and formation timing

Monitoring water accumulation in a glacier using magnetic resonance imaging

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