bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Field Test to Assess Snow-Slope Stability
Authors: Conway H. , Abrahamson J. , Young R. 
Published: September 2017

AbstractA simple field test of snow-slope stability is proposed, which allows decisions about a number of factors recently described by Conway and Abrahamson (1984). These include spatial variation of snow strength along a slope, and progression of failure from a localized initial failure. Strength within the snow slab is considered as well as that at its base. A snow saw is required for the test and, because a number of tests can be made in a few minutes, much information on the state of the slope can be obtained in a practical time.
Short Notes: Note on the “Arikaree Stade” of the Rocky Mountains Neoglacial
Authors: Mahaney William 
Published: September 2017

AbstractNeoglacial deposits in the Indian Peaks section of the Colorado Front Range have been dated lichenometrically by recourse to a growth-rate curve developed for Rhizocarpon geographicum and three glacial fluctuations of the Temple Lake (4500–2700 B.P. ), “Arikaree” (1900–1000 B.P.) and Gannett Peak (300–50 B.P.) have been recognized and identified by Benedict (1968). Recent soil investigations on neoglacial deposits suggest the need to define an alternative type “Arikaree” in the Indian Peaks.
Note On Correlation Coefficients Derived from Cumulative Distributions with Reference to Glaciological Studies
Authors: Andrews J.T. , Faiiey B.D. , Alford D. 
Published: September 2017

AbstractIn many areas of glaciology, cumulative degree days, either positive or negative, are regressed against another cumulative value, such as ablation or lake-ice growth. Very strong functional relationships are frequently found with high correlation coefficients. This note shows that, if pairs of random numbers are cumulated, the resulting correlation coefficients are extremely high with a Fisher transformed mean of r = 0.986 and standard error of ±0.001 (based on 50 individual computations of r which in turn were based on 20 cumulated pairs of random numbers between 0 and 99). These results indicate that caution must be exercised in the physical interpretation of data of this kind.
Ice-Cored Moraines in South-Western Ellesmere Island, N.W.T., Canada
Authors: Souchez R. A. 
Published: September 2017

AbstractThe north-west margin of the main ice cap in south-western Ellesmere Island is fringed by ice-cored moraines. The formation of these moraines seems to be more complex than simple upwarping of the foliation bands at the margin of the ice cap. At one locality, where outer and inner zones can be distinguished on the basis of lithological composition, debris in the outer zone is composed of material from farther back under the ice cap than debris in the inner zone. In another locality, localized ridges cross each other independently of the trend of the main ridge.The time required to obtain the quantity of debris forming the moraine at the ice surface is estimated to be between 65 and 300 years.
The Effect of Impurities on the Surface Structure of Evaporating Ice
Authors: Cross J.D. 
Published: September 2017

AbstractMicrographs of the surface of evaporating polycrystalline ice containing impurities are presented. The micrographs show that impurities that enter the ice lattice substitutionally enhance the fine structure on the surface, but impurities rejected by the lattice suppress the fine structure. It is concluded that the observed fine structure is not an artifact of the machine but a real property of evaporating ice dependent upon the defects at the surface.
Short Notes: New Data on the Thermal Conductivity of Natural Snow
Authors: Weller Gunter E. , Schwkkdtfecjer Peter 
Published: September 2017

AbstractThe thermal conductivity and diffusivity of natural snow computed from Fourier-type analyses of annual snow temperature variations are shown to be strongly temperature dependent. The computed temperature coefficients of-0.007 and -0.012 deg-1 respectively, agree well with older laboratory experiments carried out on polycrystalline ice.
The Crystallization Pressure of Ice—A Simple Experiment
Authors: Connell D.C. , Tombs J.M.C. 
Published: September 2017

AbstractPolycrystalline ice, growing from the melt, can exert a pressure against an extended obstacle, even though it is free to grow in other directions. Pressures of over 0.2 bar (20kN m-2) have been measured with simple apparatus. This phenomenon may be important in explaining the frost-shattering of rocks.
Quaternary Glaciations in the Andes of North-Central Chile
Authors: Caviedes Cesar N. , Paskoff Roland 
Published: September 2017

The extension of the Quaternary glaciations has been studied in the semi-arid Andes of north-central Chile, where the glacial modelling is striking. In the Elqui valley (lat. 30°S.), two glacial advances were identified reaching down to 3 100 m (Laguna glaciation) and 2 500 m (Tapado glaciation). In the Aconcagua valley (lat. 33°S.), moraines from three major glacial advances were found, at 2 800 m (Portillo glaciation), 1 600 m (Guardia Vieja glaciation) and 1 300 m (Salto del Soldado glaciation).The Quaternary glaciations were linked with a decrease of temperature, but more significantly with a marked increase of precipitation probably related to an equatorward shift of 5–6 degrees of the austral polar front. The results obtained in the semi-arid Chilean Andes are correlated with those recently reported from other sectors of the southern Andes.
Snow Pressure on Rigid Obstacles
Authors: McClung David 
Published: September 2017

Abstract
In this paper a continuum mechanical formulation of snow pressure is given. The snow
pressure against retaining structures on slopes is considered in two separate parts: (1) the
static component due to the regression of transverse expansion as discussed by Haefeli, and
(2) the dynamic component due to the interruption of the creep (internal deformation) and
glide (slip of the entire snow cover over the ground). Snow-pressure calculations made using
the non-linear viscous constitutive equations given by McClung (in press) are given for the
plane strain-rate problem of a rigid barrier on a snow-covered slope. These calculations are
compared with the previous formulation of snow pressure given by Haefeli for the expected
range of boundary conditions for the structure and for the snow-earth interface. The results
show that the original formulation by Haefeli gives a dynamic component of similar magnitude
to the present calculations. Substantial differences are apparent when the up-slope distances
for interruption of the creep and glide processes are compared.
Glacier Sliding Down an Inclined Wavy Bed With Friction
Authors: Morland L. W. 
Published: September 2017

The effects of frictional tangential traction combined with regelation on the basal sliding of a temperate glacier down an inclined wavy bed are examined. Two friction models are treated. First, a Coulomb law model having the assumptions that sliding occurs everywhere and that the tangential traction is proportional to the normal pressure. Secondly, a velocity power law in which the tangential traction is proportional to a power of the slip velocity. The ice motion is approximated by steady slow Newtonian flow and the bed undulation about a mean bed-line has a maximum slope ∊ ≪I. Flow solutions are constructed as perturbations (in powers off ∈) of the plane laminar flow corresponding to non-slip on the mean bed-line assuming that the ice remains everywhere in contact with the bed; that is, no cavitation takes place. If the normal traction is predicted to be tensile over part of the bed, implying that cavitation has occurred, then a new solution is needed in which the ice base over cavities is traction-free. Since the cavity sections and profile of the free ice base are then part of the overall solution, an intricate mixed boundary-value problem is set up for the flow and the present analysis is inadequate.For a sinusoidal bed the perfect-slip (zero tangential traction) solution predicts compressive normal traction everywhere on the bed provided that the mean bed-line inclination α (to the horizontal) is less than a critical value αe which is of order ε. For greater values of α including a range of order ∊, the normal traction is tensile on some parts of the bed, and a solution with cavitation is needed. If the tensile sections are relatively small it is expected that the resulting cavitation will not change the overall solution significantly. However, the Coulomb friction solution has extensive zones of tensile traction for all values of α, so that extensive cavitation would occur. In contrast, the velocity-power friction solution has compressive traction everywhere on the bed for α ⩽αe=0(I) provided that the ice depth is not too large, and also for deep glaciers for α ⩽αe=O∊ Furthermore, the predicted basal sliding velocity varies much less with the length scale of the bed undulation than in the perfect-slip solution, and is smaller.
Thermal Stresses near the Surface of a Glacier
Authors: Sanderson T. J. O. 
Published: September 2017

AbstractStresses occur in the uppermost 10 m of a glacier as a result of temperature fluctuations at the surface. A model is set up of a typical year's surface temperature variation, and the progress of temperature waves through the glacier is calculated using Fourier theory of heat conduction. Short-period fluctuations are rapidly attenuated, and at 10 m depth the annual cycle is reduced to 5% of its surface amplitude. As the temperature of the ice varies it undergoes small volume changes; stresses are calculated on the assumption that any tendency of the ice to expand or contract laterally results in the creation of just enough stress to cause the ice to remain unstrained. It is found that in the top 2 or 3 m stresses of thermal origin are generally in excess of those due to gross deformation or overburden pressure. For the case of high-density ice Glen's flow law is used, and conditions are found to be favourable for the formation of surface rumples of wavelength about 10 m. For the case of firm or snow a Newtonian flow law is assumed, and it is found that under cold conditions fracture under tension can occur. Cracks of thermal origin may be responsible for the initial formation of crevasses, and they also provide an explanation for background noise encountered when seismic shooting at low temperatures. Calculations are made of the strain-rate field surrounding a crack and it is found that thermal effects can lead to appreciable Strain-rate anomalies for strain-rate measurements near cracks. The magnitude of the effect is easily sufficient to account for anomalous fluctuating strain-rates found by workers using wire strainmeters on the Barnes Ice Cap.
Early Discoverers XXXII: P. A. Tutkovskiy and the Glacial Theory of Loess Formation
Authors: Smalley I. J. 
Published: September 2017

AbstractIn 1899 P. A. Tutkovskiy published a theory of loess formation which depended on the presence of large continental glaciers. Unfortunately there was no glacial requirement in the theories of Berg and Richthofen and these have survived better than that of Tutkovskiy with the result that the close relationship between glacial action and loess formation is sometimes overlooked.
A Mechanical Test Procedure for Avalanche Snow
Authors: Mccabe S. L. , Smith F. W. 
Published: September 2017

AbstractThe design, construction, and testing of a portable constant strain-rate testing machine for determining the mechanical behavior of avalanche snow is described. The machine is intended for use in determining the stress strain time behavior of low-density natural snows in the field. A technique for making direct measurements of strain in the snow sample is described and stress-strain curves are presented for strain-rates ranging from 0.5 to 5.0 x 10-5 s-1. The densities of the snow samples tested range from 186 to 335 kg m-3 Ultimate-strength data and relaxation curves arc also presented.
Grain Coarsening of Water-Saturated Snow
Authors: Raymond Charles F. , Tusima Katsutosi 
Published: September 2017

AbstractExperimental measurements were made of changes in grain-size distribution with time in snow saturated with solutions of various impurity contents. Qualitatively, the changes in grain-size distribution occur by shrinkage and eventual disappearance of the relatively small particles and growth of the relatively large particles by a solid mass-exchange process which conserves the total solid mass. The distribution of relative grain size is found to be essentially time independent except for transient effects lasting only several to several tens of hours after the time of initial saturation. Mean grain volume increases at a constant rate, which for solutions of impurity concentration less than about 0.01 mol 1–1 is (5 to 6) X 10–3 mm3 h–1. In pure solutions the smallest particles shrink at a characteristic rate of about 1 x 10–2 mm3 h–1. Once the steady relative-size distribution is established, the rate of volume change of typical grains varies linearly with grain volume from the characteristic negative rate for the smallest particles through zero for particles of mean volume to positive values for particles of larger volume. The basic features of the changes that take place are explained in terms of heat-flow controlled melting and freezing determined by temperature differences associated with the effect of particle surface curvature on melting temperature. The constant rate of increase of mean grain volume is a consequence of conservation of total ice volume. The expectation that particles of intermediate size would be neither shrinking or growing leads to the conclusion that the actual rate of increase in mean grain volume is about one-half the characteristic melting rate of the smallest particles, which fits the observations. The process of grain growth is slowed by impurities in a way which can be predicted from the melting-temperature depression caused by the impurity and its diffusion coefficient. The transport of heat between grain surfaces is largely through the liquid-filled gaps between them, but about 19% is conducted through the solid.
Cryoconite Holes on Sermikavsak, West Greenland
Authors: Gribbon P. W. F. 
Published: September 2017

AbstractThe depths and diameters of 158 cryoconite holes were measured at ten positions in the ablation zone of Sermikavsak, West Greenland. It was found that the depths increased on going up the glacier in agreement with other measurements made earlier on polar glaciers. There was no significant correlation of depth with diameter. The relative importance of the combined short- and long-wavelength radiation balances and the transfer of heat by convectional mixing in water-filled holes is discussed. The variations in depth are attributed to changes in the albedo and the bulk extinction coefficient of the surface ice layers on the glacier.
Equilibrium Profile of Ice Shelves
Authors: Sanderson T. J. O. 
Published: September 2017

AbstractUsing expressions for ice-shelf creep derived by Weertman (1957) and Thomas (1973[b]) a general method is developed for calculating equilibrium thickness profiles, velocities, and strain-rates for any ice shelf. This is done first for an unconfined glacier tongue and the result agrees well with data for Erebus Glacier tongue (Holdsworth, 1974). Anomalies occur within the first 3 km after the hinge zone and these are too great to be the result of local bottom freezing; they are probably due to disturbance of the velocity field. Secondly, profiles are calculated for bay ice shelves. Thickness gradients are largely independent of melt-rate or flow parameters but are inversely proportional to the width of the bay. Data from Antarctic ice shelves agree with this result both qualitatively and quantitatively. The theory is readily extended to ice shelves in diverging and converging bays. An ice shelf in a diverging bay can only remain intact if it is thick enough and slow enough to creep sufficiently rapidly in the transverse direction. If it cannot, it will develop major rifts or will come adrift from the bay walls. It is then likely to break up. The presence of ice rises or areas of grounding towards the seaward margin can radically alter the size of the ice shelf which can form. The theory could be used as a starting point to study non-equilibrium behaviour.
“Saw-Tooth” Moraines in Front of Bødalsbreen, Southern Norway
Authors: Matthews John A. , Cornish Roger , Shakesby Richard A. 
Published: September 2017

AbstractA series of end moraines, with a remarkable saw-tooth pattern, is reported from the glacier foreland of Bødalsbreen, a northern outlet of the ice cap Jostedalsbreen. The three-dimensional morphology of the moraines is described and analysed. Historical records and lichenometric measurements indicate that they were deposited after the “Little Ice Age” glacier maximum of the mid-eighteenth century. It is inferred that the local topography of Bødalen was conducive to the formation of a heavily crevassed pecten at the snout of Bødalsbreen, which produced the end moraines by a push mechanism during minor glacier advances. The observations suggest that pushing may be an underestimated mechanism in moraine ridge formation generally.
An Analysis Of Ice Profiles Obtained By Submarine Sonar In The Beaufort Sea
Authors: Wadhams P. , Horne R. J. 
Published: September 2017

AbstractA profile of the ice cover in the southern Beaufort Sea was obtained by the submarine U.S.S. Gurnard in April 1976, using a narrow-beam upward-looking sonar. The 1 400 km profile consisted of three legs, of which the long south-north and east-west legs intersected near the Caribou camp of the AIDJEX experiment. A statistical analysis was carried out over contiguous 50 km sections to yield probability-density functions of the drafts of ice and of level ice, the distributions of keel spacings and drafts, and the frequencies and widths of leads. Two distinct types of ice cover were found in the profile. The first, nearest the coast in the south and west of the experimental area, consisted of heavily ridged ice with mean drafts of up to 5.1 m. The rest of the track (1 200 km) consisted of a homogeneous ice cover with a mean draft of 3.7 m. The percentage of thin ice varied greatly from section to section, with a range of 0.4 to 12.3% for ice of 0–1 m draft. Level ice, defined as ice with a local gradient of less than 1 in 40, made up 56% of the homogeneous cover, with a preferred draft of 2.7 to 2.9 m. Keel spacings obeyed a negative exponential distribution, with a deficit at small spacings due to a keel shadowing effect and a surfeit at very large spacings due to the contribution of polynyas. The draft distribution of keels was a negative exponential of form , with B and b as parameters. This differs from the distribution of Hibler and others (1972), probably because the narrow beam records a complex structure for every keel. The homogeneous cover had a lower keel frequency and mean draft than the ice nearest the coast. Maximum keel draft was 31.12 m. The average separation of leads was 212 m, with almost all leads being less than 50 m in width.
Applications of Satellite Thermal Infrared Images for Monitoring North Water during the Periods of Polar Darkness
Authors: Dey B. 
Published: September 2017

AbstractThe study reported here illustrates the unique value of NOAA thermal infrared (TIR) images for monitoring the North Water area in Smith Sound and northern Baffin Bay during the periods of polar darkness. Wintertime satellite images reveal that, during the months of December through February, open water and thin ice occur in a few leads and polynyas. However, in March, the areas of open water and thin ice decrease to a minimum with a consequent higher concentration of ice. Two ice dams, in northern Kennedy Channel and in northern Smith Sound, regulate the flow of ice into northern Baffin Bay and also determine the areal variations of open water and thin ice in Smith Sound.
Growth Rate and Salinity Profile of First-Year Sea Ice in the High Arctic
Authors: Nakawo M. , Sinha N. K 
Published: September 2017

AbstractThis paper describes the growth of sea ice and the salinity profiles observed in Eclipse Sound near Pond Inlet, Baffin Island, Canada, during the winter of 1977–78. A numerical method of calculation has been developed to incorporate the variations in snow conditions and physical properties of ice and snow during the growth season. It is shown that the growth rate can be predicted reasonably well. It is also shown that the vertical salinity profile in the ice towards the end of the season, provides a record of previous climatological conditions. A dependence has been shown between the predicted growth rate and the measured salinity.
A Numerical Study of Plane Ice-Sheet Flow
Authors: Hutter K. , Yakowitz S. , Szidarovszky F. 
Published: September 2017

AbstractThe plane steady flow of a grounded ice sheet is numerically analysed using the approximate model of Morland or Hutter. In this, the ice behaves as a non-linear viscous fluid with a strongly temperature-dependent rate factor, and ice sheets are assumed to be long and shallow. The climate is assumed to be prescribed via the accumulation/ablation distribution and the surface temperature, both of which are functions of position and unknown height. The rigid base exerts external forcings via the normal heat flow, the geothermal heat, and a given basal sliding condition connecting the tangential velocity, tangential traction, and normal traction. The functional relations are those of Morland (1984) or motivated by his work. We use equations in his notation.The governing equations and boundary conditions in dimensionless form are briefly stated and dimensionless variables are related to their physical counterparts. The thermo-mechanical parabolic boundary-value problem, found to depend on physical scales, constitutive properties, and external forcing functions, has been numerically solved. For reasons of stability, the numerical integration must proceed from the ice divide towards the margin, which requires a special analysis of the ice divide. We present this analysis and then describe the versatility and limitations of the constructed computer code.Results of extensive computations are shown. In particular, we prove that the Morland–Hutter model for ice sheets is only applicable when sliding is sufficiently large (satisfying inequality (30)). In the range of the validity of this inequality, it is then demonstrated that of all physical scaling parameters only a single π-product influences the geometry and the flow within the ice sheet. We analyse the role played by advection, diffusion, and dissipation in the temperature distribution, and discuss the significance of the rheological non-linearities. Variations of the external forcings, such as accumulation/ablation conditions, free surface temperature, and geothermal heat, demonstrate the sensitivity of the ice-sheet geometry to accumulation conditions and the robustness of the flow to variations in the thermal state. We end with a summary of results and a critical review of the model.
Some Observations on Subglacial Ground-Water flow
Authors: Smart C. C. 
Published: September 2017

AbstractConduit and regelation water are inferred to drain as ground water from up to 130 km2 of Columbia Icefield. Subglacial conduits appear to be generally occupied by free surface streams. Ground-water flow will allow exchange between the regelation film and conduits. Present-day discharge from beneath the accumulation zone carries little sediment, and past injections of sediment appear to correspond to ancient interglacials. Transport of sediment through cave passages may be analogous to transport through basal conduits.