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The instrumented sample holder Snowbreeder 5 is used to investigate the simultaneous influence of settlement on temperature-gradient snow metamorphism in time-lapse micro-computed tomography experiments. So far, experiments have only been done on temperature-gradient snow metamorphism without settlement or settlement under isothermal conditions. With the new device we can impose a constant temperature gradient on a snow sample and induce settlement by placing a passive load on top of the snow sample. The weight of the load can be varied, simulating various snow heights on top of the snow sample. Snow-temperature measurements on the passive load are possible due to wireless data transfer via Bluetooth. The temperature gradient is set by controlling the air temperature inside the computer tomograph and by a Peltier element at the bottom of the snow sample. First experiments under isothermal conditions and a constant temperature gradient of 43 K m−1 showed that the settlement was reduced to almost half as soon as a temperature gradient was applied under otherwise almost equal snow conditions. The compactive viscosity in the isothermal experiment was in the range of literature values. [ABSTRACT FROM AUTHOR]

Particle size, particle speed and airflow speed have been measured in the powder snow clouds of avalanches to investigate the suspension and transportation processes of snow particles. The avalanches were artificially triggered at the Lautaret full-scale avalanche test-site (French Alps) where an ultrasonic anemometer and a snow particle counter were setup in an avalanche track for measurements. Relatively large particles were observed during passage of the avalanche head and then the size of the particles slightly decreased as the core of the avalanche passed the measurement station. The particle size distribution was well fitted by a gamma distribution function. A condition for suspension of particles within the cloud based on the ratio of vertical velocity fluctuation to particle settling velocity suggests that the large particles near the avalanche head are not lifted up by turbulent diffusion, but rather ejected by a process involving collisions between the avalanche flow and the rough snow surface. Particle speeds were lower than the airflow speed when large particles were present in the powder cloud. [ABSTRACT FROM AUTHOR]

We present a set of new volume scaling relationships specific to Svalbard glaciers, derived from a sample of 60 volume-area pairs. Glacier volumes are computed from ground-penetrating radar (GR)-retrieved ice thickness measurements, which have been compiled from different sources for this study. The most precise scaling models, in terms of lowest cross-validation errors, are obtained using a multivariate approach where, in addition to glacier area, glacier length and elevation range are also used as predictors. Using this multivariate scaling approach, together with the Randolph Glacier Inventory V3.2 for Svalbard and Jan Mayen, we obtain a regional volume estimate of 6700±835km3, or 17±2 mm of sea-level equivalent (SLE). This result lies in the mid- to low range of recently published estimates, which show values as varied as 13 and 24 mm SLE. We assess the sensitivity of the scaling exponents to glacier characteristics such as size, aspect ratio and average slope, and find that the volume of steep-slope and cirque-type glaciers is not very sensitive to changes in glacier area. [ABSTRACT FROM AUTHOR]

In the simulation of skiing the force between ski and snow is a decisive factor. We decompose the reaction force into a penetration force normal to the snow surface, a shear force and friction. Two portable measurement devices were developed to study the penetration and shear forces for compacted snow on groomed ski slopes. The penetration force was assessed by measuring the penetration depth of a ski-tool loaded normal to the snow surface. For the shear force the tangential load was measured when the snow began to fail. Overall 236 penetration and 108 shear experiments were conducted on different types of snow. The penetration force was proportional to the volume of snow displaced by the ski-tool. The failure shear force was proportional to the penetration depth multiplied by the length of the tool. The constants of proportionality, Hy and Sf, are material parameters of snow. The snow hardness, Hv, varied between 0.04 and 90 N mm-3 and the failure shear stress, Sf, between 0.04 and 0.40 N mm-2. In another investigation, skiing turns were simulated using the presented snow reaction forces. Maximum deviations between computed and real trajectories were <1 % of the overall length of the runs. [ABSTRACT FROM AUTHOR]

The article discusses a study which describes the characteristics, instrument design, and performance of an ultra-wideband and microwave radar for measuring snow thickness on sea ice. It says that the radar is developed by the Center for Remote Sensing of Ice Sheets (CReSIS) which is capable of operation on long-endurance aircraft to characterize the thickness of snow. It adds that the radar was capable of snow depth retrievals ranging from 10 centimeters (cm) to >one meter (m). Furthermore, the radar is used to map near-surface internal layers in polar firn with fine range resolution.

The article discusses a study which introduces the design, ability, and performance of the Crocus-DEB model to explore relationships between meteorological conditions, model parameters, and the critical debris thickness. It says that the model was developed as an adaptation of Crocus, the detailed snowpack model, to stimulate the mass balance and energy of debris-covered glaciers. It adds that the model was evaluated using field data from the debris-covered glaciers in Changri Nup in Nepal, Himalaya. Furthermore, the application of empirical methods is discussed.

Temporal and spatial variations of the seasonal snow cover at 40 sites in Nordland county, Norway, since the last decade of the 19th century are examined. Nordland lies across the Arctic Circle. Annual maximum snow depths there have varied, reflecting the interaction of synoptic conditions, temperature and terrain. North/south and coastal/inland differences are evident, but common temporal trends are identified. Maximum snow depths are strongly related to the winter North Atlantic Oscillation index. Early in the 20th century, the index was positive and the associated stormy conditions resulted in a deep, prolonged snow cover. As the index declined in the 1920s, snow depths decreased sharply. Through much of the second half of the 20th century they increased as the index tended to become more positive. The start and duration of the period of continuous snow cover is influenced by the autumn NAO index. A decrease of duration around 1990 was particularly evident at low-lying stations and those in northern Nordland. The NAO has varied considerably over the past 120 years. Because of its influence, forecasting future trends of snow depth and snow-cover duration is not a simple task. [ABSTRACT FROM AUTHOR]

This study presents results from an Airborne Laser Scanning (ALS) mapping survey of snow depth on the mountain plateau Hardangervidda, Norway, in 2008 and 2009 at the approximate time of maximum snow accumulation during the winter. The spatial extent of the survey area is >240 km². Large variability is found for snow depth at a local scale (2m²), and similar spatial patterns in accumulation are found between 2008 and 2009. The local snow-depth measurements were aggregated by averaging to produce new datasets at 10, 50, 100, 250 and 500m² and 1 km² resolution. The measured values at 1km² were compared with simulated snow depth from the seNorge snow model (www.senorge.no), which is run on a 1 km² grid resolution. Results show that the spatial variability decreases as the scale increases. At a scale of about 500m² to 1 km² the variability of snow depth is somewhat larger than that modeled by seNorge. This analysis shows that (1) the regional-scale spatial pattern of snow distribution is well captured by the seNorge model and (2) relatively large differences in snow depth between the measured and modeled values are present. [ABSTRACT FROM AUTHOR]

The article discusses a study which reported density profiles gathered at 46 survey sites, from coastal to inland plateau regions in East Antarctica. Research groups from Japan and Sweden carried out a traverse expedition in East Antarctica, between the Japanese inland base S16 and the Swedish Wasa station, from November 2007 to January 2008. Snow measurements were conducted on a side-wall of a snow pit excavated at each survey site. The snow structure was classified into fresh snow, compacted snow, faceted crystals or depth hoar, and a crust layer.

The article presents a study on the use of thin-blade snow hardness gauge. The tool measures the average penetration resistance over a length scale to describe snow properties related to avalanches. Description of the apparatus is presented, including its advantages for field and laboratory use. It discusses the methodology to measure the blade hardness index in comparison to the hand hardness test. It explores the importance of the research in evaluating the parameters in the dynamics of slab avalanches and snow slope stability.

The article presents a study which developed a parallel-probe saturation profiler (PPSP) device for a more accurate and efficient recording of meltwater saturations in a snowpack. The device is used to utilize the absorption of energy during the rotation of the water molecules on the action of an external electric field. The heights of first peak signal (HFPS) corresponding to various liquid-water contents were obtained from several snow types. The HFPS were then observed and revealed its proportionality to the water saturation of the snow regardless of the snow type. The instrument is regarded as a useful tool for scientist involved in snow physics, hydrology, or glaciology. It can also be used with a data logger to monitor the liquid-water saturations or contents in field studies.

The article examines the composition, structure and deformation of amber ice as well as its influence on Rhone Glacier's behaviour in the McMurdo Dry Valleys in Antarctica. The basal ice sequence of the cold-based glacier was investigated using isotopic and solute chemistry data. The study identifies three different ice facies including englacial, amber and stratified. The analysis of stratified facies shows an isotopic signature which indicates melt then refreeze processes and is most likely associated with apron entrainment. It was found out that impurities in the amber ice has prolonged contact with the bed and that depleted isotopic signature is consistent with ice formed during a cooler period.

The article presents a research on the estimation of glacier runoff and future trends in the Yangtze River source region (YRSR) in China from 1961-2000. Research uses streamflow simulation modelling to quantify the possible effects of the runoff. Study shows that glacier runoff accounts 11.0% of the total river runoff during this period, while its contribution to river runoff increases to 17.0%. It notes that the effect of glacier runoff on river runoff increased in the source region due to the rate of glacier decrease. It was found out that the annual glacier runoff shows a significant increase due to the heightened ice melting in all climate-change scenarios.

The article focuses on the chemistry of deposited snow during the summer monsoon and in the winter season at Baishui glacier No. 1 in Yulong mountain in China. Baishui glacier No. 1 is considered as the largest with up to 90% annual precipitation falls in summer. This is the time when warm moisture-rich air masses linked to southwest monsoon reach the area from the Indian Ocean. The snow it accumulates includes marine aerosols associated with the summer monsoon, and dust from central/west Asia, Africa or the Thar Desert area.

The article reports on the derivation of melt factors for snow and ice from altered daily air-temperature series and particular mass-balance data at nine glaciers in the western Cordillera of Canada. The interannual variability of melt factors was examined for two long-term datasets. Computed yearly, snow- and ice-melt factors were comparatively stable from year to year, 1.17 and 0.81 were standard deviations for ice-melt factors while 0.48 and 0.42 were standard deviations for snowmelt factors at Peyto and Place Glaciers.