scholarly journals A Possible Relation Between Grain Size, Density, and Light Attenuation in Natural Snow Cover

1970 ◽  
Vol 9 (55) ◽  
pp. 154-156
Author(s):  
James D. Bergen
Keyword(s):  
Grain Size ◽  
Porous Medium ◽  
Specific Surface ◽  
Snow Cover ◽  
Extinction Coefficient ◽  
Light Attenuation ◽  
Empirical Relation ◽  
Air Permeability ◽  
Fair Agreement ◽  
Natural Snow

AbstractThe extinction coefficient for the transmission of light through snow cover is related to the grain size and density of the snow cover. The connection is made by means of an empirical relation between the latter parameters and the air permeability and by the Carmen–Kozney relation between the air permeability and specific surface of a porous medium. The results are compared with a set of measurements found in the literature with fair agreement between the predicted and measured values of the extinction coefficient.

scholarly journals A Possible Relation Between Grain Size, Density, and Light Attenuation in Natural Snow Cover

1970 ◽  
Vol 9 (55) ◽  
pp. 154-156 ◽  
Author(s):  
James D. Bergen
Keyword(s):  
Grain Size ◽  
Porous Medium ◽  
Specific Surface ◽  
Snow Cover ◽  
Extinction Coefficient ◽  
Light Attenuation ◽  
Empirical Relation ◽  
Air Permeability ◽  
Fair Agreement ◽  
Natural Snow

Abstract The extinction coefficient for the transmission of light through snow cover is related to the grain size and density of the snow cover. The connection is made by means of an empirical relation between the latter parameters and the air permeability and by the Carmen–Kozney relation between the air permeability and specific surface of a porous medium. The results are compared with a set of measurements found in the literature with fair agreement between the predicted and measured values of the extinction coefficient.

scholarly journals Some Measurements of Settlement in a Rocky Mountains Snow Cover

1978 ◽  
Vol 20 (82) ◽  
pp. 141-148 ◽  
Author(s):  
James D. Bergen
Keyword(s):  
Grain Size ◽  
Snow Cover ◽  
Rocky Mountains ◽  
Early Spring ◽  
Fair Agreement ◽  
Snow Density ◽  
Density Measurements ◽  
Colorado Rockies ◽  
Precipitation Records ◽  
Snow Temperature

AbstractSnow-cover settlement was measured in a dry, annual sub-alpine snow cover in the Colorado Rockies with settlement gages. Settlement viscosities were calculated from the change in gage heights over various periods during the winter and early spring, and the associated overburden over the gages as estimated from density measurements and precipitation records. When adjustments are made for local snow temperature, viscosities are in fair agreement with values found in the literature from similar snow covers, although considerable scatter for a given snow density is found in all sets compared. The viscosity for a given density does not appear to vary systematically with grain size.

scholarly journals The Extinction and Absorption of Solar Radiation Within a Snow Cover

1985 ◽  
Vol 6 ◽  
pp. 118-122
Author(s):  
Hiroshi Fukami ◽  
Kenji Kojima ◽  
Hideaki Aburakawa
Keyword(s):  
Heat Conduction ◽  
Solar Radiation ◽  
Snow Cover ◽  
Extinction Coefficient ◽  
Temperature Increase ◽  
Radiative Energy ◽  
Wet Snow ◽  
Equation Of Heat Conduction ◽  
Natural Snow ◽  
Local Temperature Increase

A device capable of measuring the extinction coefficient of solar radiation within the snow cover was developed, using small silicone photocells as sensors. Extinction coefficient measured for natural snow covers in the field was 37-97 m-1 for dry snow of density 90-470 kg m-3. It decreased in the process of metamorphism from new snow to slightly compacted snow, and increased in the process of settlement from slightly compacted to compacted snow. It was 23-58 m-1 for wet snow of density 430-530 kg m-3 and in water content from 5-15%, being smaller than that for dry snow of the same density. The authors also determined local temperature increase of snow cover related to absorption of solar radiation. The temperature profile within the snow cover was calculated by solving the equation of heat conduction including the term of absorption of radiative energy. Measured and calculated snow temperatures agreed well, indicating the accuracy of the extinction measurements.

scholarly journals The Extinction and Absorption of Solar Radiation Within a Snow Cover

1985 ◽  
Vol 6 ◽  
pp. 118-122 ◽  
Author(s):  
Hiroshi Fukami ◽  
Kenji Kojima ◽  
Hideaki Aburakawa
Keyword(s):  
Heat Conduction ◽  
Solar Radiation ◽  
Snow Cover ◽  
Extinction Coefficient ◽  
Temperature Increase ◽  
Radiative Energy ◽  
Wet Snow ◽  
Equation Of Heat Conduction ◽  
Natural Snow ◽  
Local Temperature Increase

A device capable of measuring the extinction coefficient of solar radiation within the snow cover was developed, using small silicone photocells as sensors. Extinction coefficient measured for natural snow covers in the field was 37-97 m-1 for dry snow of density 90-470 kg m-3. It decreased in the process of metamorphism from new snow to slightly compacted snow, and increased in the process of settlement from slightly compacted to compacted snow. It was 23-58 m-1 for wet snow of density 430-530 kg m-3 and in water content from 5-15%, being smaller than that for dry snow of the same density. The authors also determined local temperature increase of snow cover related to absorption of solar radiation. The temperature profile within the snow cover was calculated by solving the equation of heat conduction including the term of absorption of radiative energy. Measured and calculated snow temperatures agreed well, indicating the accuracy of the extinction measurements.

scholarly journals Retrieval of snow grain size and albedo of Western Himalayan snow cover using satellite data

2011 ◽  
Vol 5 (1) ◽  
pp. 605-653 ◽  
Author(s):  
H. S. Negi ◽  
A. Kokhanovsky
Keyword(s):  
Grain Size ◽  
Snow Cover ◽  
Western Himalaya ◽  
Sensor Data ◽  
Art Theory ◽  
Grain Sizes ◽  
Spectral Bands ◽  
Steep Slopes ◽  
Different Parts ◽  
Good Agreement

Abstract. In the present study we describe the retrievals of snow grain size and spectral albedo (plane and spherical albedo) for Western Himalayan snow cover using Hyperion sensor data. The asymptotic radiative transfer (ART) theory was explored for the snow retrievals. To make the methodology operational only five spectral bands (440, 500, 1050, 1240 and 1650 nm) of Hyperion were used for snow parameters retrieval. The bi-spectral method (440 nm in the visible and 1050/1240 nm in the NIR region) was used to retrieve snow grain size. Spectral albedos were retrieved using satellite reflectances and estimated grain size. A good agreement was observed between retrieved snow parameters and ground observed snow-meteorological conditions. The satellite retrieved grain sizes were compared with field spectroradiometer retrieved grain sizes and close results were found for Lower Himalayan snow. The wavelength 1240 nm was found to be more suitable compared to 1050 nm for grain size retrieval along the steep slopes. The methodology was able to retrieve the spatial variations in snow parameters in different parts of Western Himalaya which are due to snow climatic and terrain conditions of Himalaya. This methodology is of importance for operational snow cover and glacier monitoring in Himalayan region using space-borne and air-borne sensors.

scholarly journals The referential grain size and effective porosity in the Kozeny–Carman model

2016 ◽  
Author(s):  
K. Urumović ◽  
K. Urumović Sr.
Keyword(s):  
Grain Size ◽  
Hydraulic Conductivity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Effective Porosity ◽  
Critical Conditions ◽  
Saturated Porous Media ◽  
New Developments ◽  
Mean Grain Size

Abstract. In this paper, the results of permeability and specific surface area analyses as functions of granulometric composition of various sediments (from silty clays to very well-graded gravels) are presented. The effective porosity and the referential grain size are presented as fundamental granulometric parameters expressing an effect of the forces operating on fluid movement through the saturated porous media. This paper suggests procedures for calculating referential grain size and determining effective (flow) porosity, which result in parameters that reliably determine the specific surface area and permeability. These procedures ensure the successful application of the Kozeny–Carman model up to the limits of validity of Darcy’s law. The value of effective porosity in the referential mean grain size function was calibrated within the range of 1.5 μm to 6.0 mm. The reliability of the parameters applied in the KC model was confirmed by a very high correlation between the predicted and tested hydraulic conductivity values (R2=0.99 for sandy and gravelly materials; R2=0.70 for clayey-silty materials). The group representation of hydraulic conductivity (ranging from 10–12 m/s up to 10–2 m/s) presents a coefficient of correlation of R2=0.97 for a total of 175 samples of various deposits. These results present new developments in the research of the effective porosity, the permeability and the specific surface area distributions of porous materials. This is important because these three parameters are critical conditions for successful groundwater flow modeling and contaminant transport. Additionally, from a practical viewpoint, it is very important to identify these parameters swiftly and very accurately.

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