Determination of the Water Content of Snow by Dielectric Measurements

Camp, Paul R.; LaBrecque, David

doi:10.21236/ada256299

Cited by 7 publications

(10 citation statements)

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“…An alternate design uses an aluminum pipe. The snow sample is placed inside of the pipe [Camp and LaBrecque, 1992;Perla and Banner, 1988]. A parallel plate capacitor sensor can be placed on the end of a rod, and the rod used to penetrate the snow surface to obtain snow profile measurements [Louge et al, 1998].…”

Section: Reviews Of Geophysicsmentioning

confidence: 99%

Measurement of the physical properties of the snowpack

Kinar

Pomeroy

2015

Reviews of Geophysics

196

202

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This paper reviews measurement techniques and corresponding devices used to determine the physical properties of the seasonal snowpack from distances close to the ground surface. The review is placed in the context of the need for scientific observations of snowpack variables that provide inputs for predictive hydrological models that help to advance scientific understanding of geophysical processes related to snow in the near-surface cryosphere. Many of these devices used to measure snow are invasive and require the snowpack to be disrupted, thereby precluding the possibility for multiple measurements to be made at the same sampling location. Moreover, many devices rely on the use of empirical calibration equations that may not be valid at all geographic locations. The spatial density of observations with most snow measurement devices is often inadequate. There is a need for improved automation of snowpack measurement instrumentation with an emphasis on field-based feedback of measurement validity in lieu of postprocessing of samples or data at a lab or office location. The scientific future of snow measurement instrumentation thereby requires a synthesis between science and engineering principles that takes into consideration geophysics and the physics of device operation.

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Section: Reviews Of Geophysicsmentioning

confidence: 99%

Measurement of the physical properties of the snowpack

Kinar

Pomeroy

2015

Reviews of Geophysics

196

202

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“…Another way to induce a homogeneous liquid-water content into the snow without destroying the snow sample is microwave heating (Brun, 1989;Camp and LaBrecque, 1992). In this case, the water retention curve of snow (Yamaguchi et al, 2010) is approached from the left site.…”

Section: Introductionmentioning

confidence: 99%

“…In this case, the water retention curve of snow (Yamaguchi et al, 2010) is approached from the left site. A uniform electric field oscillating at an appropriate frequency excites the dielectric properties of ice enabling heat to be dissipated through the whole volume of snow (Mellor, 1977;Brun, 1989;Camp and LaBrecque, 1992).…”

Section: Introductionmentioning

confidence: 99%

“…However, the relaxation frequency of dry snow lies between 10 and 100 kHz depending on the snow density and temperature (Bader and Kuroiwa, 1962;Polder and Van Santen, 1946;Evans, 1965). The presence of liquid water strongly affects the dielectric properties of the wet snow sample (Sweeny and Colbeck, 1974;Denoth, 1980, Camp andLaBrecque, 1992). A wide spectrum of frequencies has been explored to determine the free water content of water in snow (Ambach and Denoth, 1975;Boyne and Fisk, 1987;Brun, 1989;Denoth et al, 1984;Denoth and Foglar, 1986;Perla, 1990;Camp and LaBrecque, 1992).…”

Section: Introductionmentioning

confidence: 99%

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Liquid-water content and water distribution of wet snow using electrical monitoring

Ebner¹,

Coulin²,

Borner³

et al. 2020

Preprint

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Abstract. Snow exists in a wide range of temperatures and around its melting point snow becomes a three-phase material. A better understanding of wet snow and the first starting point of water percolation in the seasonal snowpack is essential for snow pack stability, snow melt run-off and remote sensing. In order to induce and measure precisely the liquid water and the corresponding dielectric properties inside a snow sample, an experimental setup was developed. Using microwave heating at 18 kHz allows the use of dielectric properties of ice to enable heat to be dissipated homogeneously through the entire volume of snow. A desired liquid water content inside the snow sample could then be created and analysed in a micro-computer tomography. Based on the electrical monitoring a promising perspective for retrieving water content and water distribution in the snowpack is given. The heating process and extraction of water content are mainly dependent on the morphological properties of snow, the temperature and the liquid water content. The experimental observation can be divided in three different heating processes affecting the dielectric properties of snow for different densities: (1) dry snow heating process up to 0 °C indicating a temperature and snow structure dependency of the dielectric property of snow; (2) wet snow heating at stagnating temperature of 0 °C and the presence of uniformed distributed liquid water changes the dielectric properties. The presence of liquid water decreases the impedance of the snow sample until water starts to percolate; and (3) the start of water percolation is between 5–12 water volume fraction depending on the snow density and confirms the literature findings. The onset of water percolation initiated an inhomogeneity in snow and water distribution, strongly affecting the dielectric properties of the snow. These findings are pertinent to the interpretation of the snow melt run-off of spring snow. These laboratory measurements allow to find the narrow range of the starting point of water percolation in coarse-grained snow and to extract the corresponding dielectric properties which is important for remote sensing.

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“…Kawashima and others (1998) made a portable calorimeter to measure this quantity, and Denoth (1994) designed a moisture meter, based on change in the dielectric constant of snow due to variations in the the liquid-water content. Time-domain reflectometry (TDR), based on the interaction of a microwave pulse with liquid water, is yet another method used to measure liquid-water content (Stein and Kane, 1983; Camp and Labrecque, 1992; Schneebeli and others, 1995; Spaans and Baker, 1995; Lundberg, 1996; Stein and others, 1997; Schneebeli and others, 1998). A flat-cable TDR system was used by Stähli and others (2004) to estimate the liquid-water content and water equivalent of snow from a spatially distributed snow cover at a fixed installation.…”

Section: Introductionmentioning

confidence: 99%

A parallel-probe saturation profiler: a new technique for fast profiling of meltwater saturation in a seasonal snowpack

et al. 2009

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We describe a parallel-probe saturation profiler (PPSP) for accurate and fast profiling of liquid-water saturations in a snowpack. This device utilizes the absorption of electrical energy, by water molecules under the action of an external electric field, due to instantaneous rotations from initially random orientations to the orientation of the applied electric field. Our observations show that the height of first peak signal (HFPS), i.e. the difference between the maxima and minima in the PPSP signal-response time series, is proportional to the liquid-water content and the water saturation of snow. The HFPS corresponding to different liquid-water contents were obtained from various naturally occurring snow types and were observed to be proportional to the water saturation of the snow, irrespective of snow types. For simultaneous measurements at corresponding depths in a snowpack, a position encoder supports the PPSP. This device was calibrated for various types of snow samples and was then tested on the snow covers under different climatic zones of the Himalaya. The operation of the PPSP is easy and fast. The distribution of liquid water within a large snow cover can be estimated speedily using the PPSP, with a vertical resolution of 7 mm.

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Determination of the Water Content of Snow by Dielectric Measurements

Cited by 7 publications

References 0 publications

Measurement of the physical properties of the snowpack

Measurement of the physical properties of the snowpack

Liquid-water content and water distribution of wet snow using electrical monitoring

A parallel-probe saturation profiler: a new technique for fast profiling of meltwater saturation in a seasonal snowpack

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