Differences in compaction behavior of three climate classes of snow

Sturm, Matthew; Holmgren, Jon

doi:10.3189/1998aog26-1-125-130

Cited by 30 publications

(14 citation statements)

References 11 publications

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“…For example, the relatively low density of the snow during 2001-02 can be explained by the complete absence of flooding and the retention of larger amounts of low-density depth hoar than in those winters when flooding occurred and removed some depth hoar from the snow cover. The snow density-time curves at MST Pond (Figure 2a-f) have slopes and intercepts similar to those reported for snow on land in this region (Sturm and Holmgren, 1998). This suggests, for the moment, that the compaction of snow on lake ice is determined by the same factors as for snow on land, i.e.…”

Section: Mst Pond Poker Flatsupporting

confidence: 79%

“…Although occasional wind erosion occurs, none of the sites displayed any evidence of wind slab, which, coupled with temperature-gradient metamorphism and depth hoar formation meant that, over the course of the six winters, all density values were low (relative to those at the ALISON locations; see next section), ranging from 70 kg m 3 to 250 kg m 3 (Figure 2a-f), which are typical for this region (Sturm and Holmgren, 1998). Moderate differences in the range of density values each winter can be explained by variations in the frequency and magnitude of precipitation events and by the occurrence of flooding and snow ice formation.…”

Section: Mst Pond Poker Flatmentioning

confidence: 97%

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Instantaneous daytime conductive heat flow through snow on lake ice in Alaska

Jeffries

Morris

2006

Hydrological Processes

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Abstract:The instantaneous daytime conductive heat flow through the snow on lake ice was derived from snow depth, temperature and density measurements made during the course of six winters at MST Pond in central Alaska. The MST Pond data for winter 2003-04 are compared with results for the same period at six other sites (Barrow, Nome, Amos Lakes, Fairbanks, Wasilla, Seward) in Alaska. The maximum heat flow at MST Pond has varied between 19Ð5 and 8Ð8 W m 2 . Each winter, the heat flow decreases as the total thickness of snow and ice increases with time. Superimposed on this trend are variations due to fluctuating air temperatures. The comparison of the MST Pond data with the other locations in Alaska reveals heat flow differences that reflect different weather conditions, particularly air temperature and wind, and the latter's effect on snow depth and density. Notwithstanding the regional differences, the heat flow values are of the same order of magnitude as those obtained for sea ice in the Arctic and Antarctica. The implications for the total winter conductive heat loss at large lakes and for regions where many small lakes cover a large proportion of the land are discussed.

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Section: Mst Pond Poker Flatsupporting

confidence: 79%

Section: Mst Pond Poker Flatmentioning

confidence: 97%

Instantaneous daytime conductive heat flow through snow on lake ice in Alaska

Jeffries

Morris

2006

Hydrological Processes

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“…The snow density, ρ snow , due to metamorphosis is computed using Sturm and Holmgren (1998), that is,…”

Section: The Snow and Sea Ice Thermodynamic And Mass Modelmentioning

confidence: 99%

Simulations of the snow covered sea ice surface temperature and microwave effective temperature

Tonboe

Dybkjær

Høyer

2011

Tellus A: Dynamic Meteorology and Oceanography

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A B S T R A C TThe snow surface on thick multiyear sea ice in winter is on average colder than the air because of the negative radiation balance. Beneath the snow surface there is a strong temperature gradient in winter with increasing temperatures towards the ice-water interface temperature at the freezing point around -1.8 • C. The sea ice surface temperature and the thermal microwave brightness temperature were simulated using a combination of thermodynamic and microwave emission models.The simulations indicate that the physical snow-ice interface temperature or alternatively the 6 GHz effective temperature have a good correlation with the effective temperature at the temperature sounding channels near 50 GHz. The complete correlation matrix based on the simulations for physical and effective temperatures is given.The physical snow-ice interface temperature is related to the brightness temperature at 6 GHz vertical polarization as expected. However, the emissivity factor normally used when converting brightness temperature to the ice temperature is dependent on the ice temperature. The simulations indicate that a simple model may be used to derive the snow-ice interface temperature from satellite AMSR 6 GHz measurements.

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“…Different grain and bond characteristics can lead to larger differences in snow compaction than different loads and load histories (Sturm and Holmgren, 1998). Several field observations confirm large differences in viscosity between different snow types at equal density, as rounded well-sintered snow settles faster than depth hoar (Kojima, 1967; Armstrong, 1980; Shapiro and others, 1997; Sturm and Benson, 1997; Sturm and Holmgren, 1998). There is clear evidence from the field that the snow microstructure affects viscosity, but experimental data under controlled conditions are lacking, making modeling difficult.…”

Section: Introductionmentioning

confidence: 99%

Early-stage interaction between settlement and temperature-gradient metamorphism

Wiese

Schneebeli

2017

J. Glaciol.

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Snow metamorphism and settlement change the microstructure of a snowpack simultaneously. Past experiments investigated snow deformation under isothermal conditions. In nature, temperature gradient metamorphism and settlement often occur together. We investigated snow settlement in the first days after the onset of temperature-gradient metamorphism in laboratory experiments by means of in-situ time-lapse micro-computed tomography. We imposed temperature gradients of up to 95 K m−1 on samples of rounded snow with a density of ~230 kg m−3 and induced settlement by applying 1.7 kPa stress with a passive load on the samples simultaneously. We found that snow settled about half as fast when a temperature gradient was present, compared with isothermal conditions. The change in specific surface area after 4 days caused by temperature-gradient metamorphism was only a few percent. The viscosity evolution correlated with the amount of the temperature gradient. Finite element simulations of the snow samples revealed that stress-bearing chains had developed in the snow structure, causing the large increase in viscosity. We could show that a small change in microstructure caused a large change in the mechanical properties. This explains the difficulty of predicting snow mechanical properties in applications such as firn compaction or snow avalanche formation.

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Differences in compaction behavior of three climate classes of snow

Cited by 30 publications

References 11 publications

Instantaneous daytime conductive heat flow through snow on lake ice in Alaska

Instantaneous daytime conductive heat flow through snow on lake ice in Alaska

Simulations of the snow covered sea ice surface temperature and microwave effective temperature

Early-stage interaction between settlement and temperature-gradient metamorphism

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