bluuebunny/crossref_metadata_2025 huggingface dataset:
Microwave Emissivity and Accumulation Rate of Polar Firn
Authors: Jay Zwally H.
Published: September 2017

Radiative transfer theory is formulated to permit a meaningful definition of emissivity for bulk emitting media such as snow. The emissivity in the Rayleigh-Jeans approximation is then the microwave brightness temperature TB divided by an effective physical temperature 〈T〉. The 〈T〉 is an average of the physical temperature, T(z), weighted by a radiative transfer function ƒ(z). Similarly,

where e(z) is the local emittance. An approximate ƒ(z) is used to determine analytically the effects of various absorption coefficients, of scattering coefficients that vary with depth, and of the seasonal variation of T(z). It is shown that a mean emissivity, which is equal to the mean annual TB divided by the mean annual surface temperature Tm, is a useful quantity for comparing theory and observations. Snow-crystal size measurements, r(z), at seven locations in Greenland and Antarctica are used to determine the Mie/Rayleigh scattering coefficient γs(z) and to calculate the mean emissivities. The observed mean emissivities are determined by a which is the average of 12 monthly Nimbus-5 (1.55 cm) microwave observations, and the Tm measured at the same locations. The calculated emissivities are about one-half of the observed values. The assumption that each snow crystal is an independent and equally effective scatterer, and the use of an approximation to ƒ(z), tend to over-estimate the effect of scattering. Therefore, a parameter multiplying γs(z) is used. The emissivities calculated with a single value of this empirical parameter for all seven locations agree well with the observed emissivities, showing that the microwave emissivity variations of dry polar urn can be characterised as a function of the crystal sizes. One optical depth corresponds to a typical fini depth of 5 m, but significant radiation emanates from up to 30 m. Since r(z) depends on the snow accumulation rate A and Tm. the sensitivity of the emissivity to changes in Tm or A are estimated using this semi-empirical theory. The results show that a one degree change or uncertainty in Tm is approximately equivalent to a 10% change in A, and that such a change will affect the emissivity by 0.003 to 0.014 or the TB by about 0.6 K to 3 K, depending on the location.
Phase-Sensitive Radio-Echo Sounding at the Devon Island Ice Cap, Canada
Authors: Walford M.E.R. , Holdorf P.C. , Oakberg R.G.
Published: September 2017

A radio-echo sounder has been built with which both the amplitude and phase of radio echoes can be measured. In experiments with this instrument at the Devon Island ice cap, in the Canadian Northern Territories, precise amplitude and phase measurements have been made upon radio echoes from the bed of the ice cap. If these measurements are repeated after a number of years, the results, considered in conjunction with snow accumulation and compaction data, will be interpretable as a long-term change in the thickness of the ice cap. Wave dislocations and bend points have been observed in radio echoes reflected from the bed, It is suggested that amplitude and phase measurements from a network of sites may be synthesized in order to explore the geometry of the reflecting surface on a fine scale.
Glaciological Problems Set by the Control of Dangerous Lakes in Cordillera Blanca, Peru. III. Study of Moraines and Mass Balances at Safuna
Authors: Lliboutry Louis , Arnao Benjamín Morales , Schneider Bernard
Published: September 2017

We explain how preliminary results concerning the internal constitution of the big push moraine at Safuna were obtained in 1967. Cross-sections which were obtained later through electrical and seismic exploration and arduous borings are given. Under the lake Safuna Alta there exists a layer of dead ice which is probably a remnant from an old glacier advance and over which the active glacier slides, but this dead ice does not extend into the push moraine. Since 1950 Safuna Alta has formed, the glacier tongue has lowered by 0.8 m per year on average, and the big push moraine has moved and settled.

The annual balance on the glacier tongue was measured in 1968. It increases by 3.9 m of ice per 100 m in altitude. The discharge of ice near the lake and the annual balance further up-valley allow an estimate of the mean annual balance in the accumulation zone (between 4850 and 6020 m) at 2.30 m of water per year. Until now no annual precipitation higher than 1 m/year had been measured in Cordillera Blanca, but this Cordillera includes many meso-climates.

Eight successive moraines are found at Safuna. They are tentatively correlated with the eight existing between Huaraz and Laguna Llaca. Clapperton's (1972) “group 4” was not formed during the 20th, but during the 17th century. His “group 3” is not from A.D. 1750-1800, but is rather 5 000 to 7 000 years old, according to the offset of Cordillera Blanca great fault.
Penetration Depth of Closely Spaced Water-free Crevasses
Authors: Weertman J.
Published: September 2017

An approximate, analytic solution is found for the profile of a water-free crevasse in a field of closely spaced crevasses. The depth of penetration of the crevasses into the glacier is found. If the fracture strength of ice is taken to be zero, the penetration depth is equal to the value found by Nye and is independent of the crevasse spacing. This conclusion is in disagreement with results reported recently by R.A. Smith. If the fracture strength of ice is taken to be finite, the penetration depth is reduced if the spacing between crevasses is reduced.

The results of the analysis can be applied to other crack problems. In particular, it can be applied to thermal, secondary cracking that it is hoped occurs when cooling fluid flows through the cracks created by hydraulic fracture for the purpose of extracting geothermal heat from hot, dry rock masses.
A Method For Cutting And Preparing Thin-Sections Of Frozen Soil
Authors: Osterkamp T.E.
Published: September 2017

A diamond wire saw was modified for cutting thin sections of frozen soil and suitable operating conditions were determined experimentally. It was found that a lubricated wire, 0.34 mm in diameter, operaied at cutting velocities of 100-300 mm s-1 and cutting forces 0.02-0.1 kg produced smooth cut surfaces un thin sections 0.4-0.5 mm in thickness. The; temperature and wire size were not critical operating parameters and the wire tensions recommended by the manufacturer were satisfactory. A method of mounting the thin sections is also described.
Wind Erosion By Snow
Authors: Dietrich R.V.
Published: September 2017

Calcite (Mohs hardness 3), fluorite (hardness 4) and periclase (hardness 5 1/2) have been eroded by snow blown at moderate wind velocities, at temperatures between —10 and —25°C. Future interpretations involving ventifacts and apparently wind-blasted rock exposures must take this information into account.
Orientation of Soil Stripes Caused by Needle Ice
Authors: Mackay J. R. , Mathews W. H.
Published: September 2017

Orientation of striping caused by needle ice has been ascribed in the past to (1) wind direction during soil freezing, and (2) azimuth of the sun during thawing. Recent evidence supports the latter concept.
Boudinage in Glacier Ice — Some Examples
Authors: Hambrey M. J. , Milnes A. G.
Published: September 2017

Boudinage structures have only rarely been reported in glacier ice, yet they seem to be widespread in Swiss glaciers. They form in debris-free, strongly foliated ice by the stretching, necking and rupture of layers or groups of layers, when the principal compressive strain axis lies at a high angle to the layering. Two main types of boudinage are distinguished. The first results from the difference in competence between fine-grained and coarse-grained ice, and indicates that the former is more resistant to flow than the latter. The second occurs in more equigranular ice which shows a strong planar anisotropy; associated with the necking of such ice is the development of shear planes, along which the layers are displaced. As in deformed rocks, it is not possible to determine the directions of the finite principal strain axes from the boudinage structures alone. Although the boudins described here all occur in longitudinal foliation, it is suggested that they are likely to form in other situations also.
The Specific Heat of Saline Ice
Authors: Dixit Bharat , Pounder E. R.
Published: September 2017

A calorimetric experiment was performed to determine empirically the dependence of the specific heat of ice with salinity 0-10‰ over the temperature range from –23° C to the melting point The experimental results agree with the theoretical model determined by Schwerdtfeger (1963) for calculating the specific heat except within several degrees of the melting point and for very pure ice.
Quantitative Stereological Analysis of Grain Bonds in Snow
Authors: Kry P. R.
Published: September 2017

A section-plane preparation technique and an operational definition of a snow grain bond are developed to allow the quantitative analysis of bonding in snow structure. Values for three-dimensional grain size, grain-bond size and number density, and related bonding measurements are presented for equi-temperature metamorphosed snow. These results from mutually orthogonal planes within a given snow block show that the assumptions of randomness and isotropy of grain and grain-bond location and orientation, necessary for stereological analysis from one plane, are satisfied to within ± 10% even after 30% uniaxial plastic deformation of the snow block. The idealization of a grain bond as a circular plane disk yields self-consistent results. The number of bonds per grain cannot be accurately determined from two-dimensional studies due to variations in the shape and size of snow grains within a given sample.
Electromagnetic Reflection from Multi-Layered Snow Models
Authors: Linlor William I. , Jiracek George R.
Published: September 2017

The remote sensing of snow-pack characteristics with surface installations or an airborne system could have important applications in water-resource management and flood prediction. To derive some insight into such applications, the electromagnetic response of multi-layered snow models is analyzed in this paper. Normally incident plane waves at frequencies ranging from 106 to 1010 Hz are assumed, and amplitude reflection coefficients are calculated for models having various snow-layer combinations, including ice layers. Layers are defined by a thickness, permittivity, and conductivity; the electrical parameters are constant or prescribed functions of frequency. To illustrate the effect of various layering combinations, results are given in the form of curves of amplitude reflection coefficients versus frequency for a variety of models. Under simplifying assumptions, the snow thickness and effective dielectric constant can be estimated from the variations of reflection coefficient as a function of frequency.
Boulder Polygons and Stripes in the Cairngorm Mountains, Scotland
Authors: King R. Bruce
Published: September 2017

Measurements of widths, diameters and boulder sizes of patterned ground in the Cairngorm Mountains indicate two sorts of stripes and polygons (fine and coarse). Pipkrake and boulder-inclination observations and measurements suggest that fine polygons are produced by heave and their sizes are dependent upon the frequency of boulders large enough to be resistant to heave, which in turn depends upon climatic severity. The lack of orientation, angle of boulder inclination, hemispherical shape, high relative size dispersion and lithological dependence of coarse polygons indicate a selective weathering origin. The frequency of low inclination of boulders in stripes suggests an origin due to solifluction, whereby large immobile or relatively slower-moving boulders impede soil (and smaller boulder) movements and control stripe spacing. Movement observation and lichenometry indicate that fine polygons and stripes and bare coarse polygons are active at the present time and that coarse stripes and vegetated coarse polygons probably date from the Little Ice Age.
Short Note: Finite-Element Stress Analysis of Avalanche Snowpacks
Authors: Smith F. W. , Sommerfeld R. A. , Bailey R. O.
Published: September 2017

The elastic stresses have been determined, in a single-layer homogeneous snowpack on a realistic avalanche slope, by a two-dimensional finite-element analysis. Calculation of the state of stress throughout the 0.96 m snow layer on a slope approximately that of the Lift Gully at Berthoud Pass, Colorado, resulted in reasonable stress values. In particular, both field experience and the calculated shear stresses predict avalanching in the lower-density snows. Also, tensile stresses were present only in the area of the observed fracture line.
Analysis of Glacier Run-Off and Meteorological Observations
Authors: Gudmundsson Gudmundur , Sigbjarnarson Guttormur
Published: September 2017

Linear models of the relationships between meteorological observations and the flow of river Tungnaá at the western margin of glacier Vatnajökull were investigated by means of spectral analysis and estimation of the impulse response. Most of the variation of Tungnaá is confined to the lowest frequencies and the diurnal variations. The temperature has most effect on the rapid variations around 1 cycle/day whereas the largest coherences with the precipitation are in the lowest frequencies. The wind explains over 20% of the variations in the frequency range from 0–1 cycle/day, but this is partly due to its coherence with the precipitation. The time lag between changes in the temperature and the river is about 2 h, but the time lag between precipitation and the river is longer. Analysis of longer records of daily observations from Ϸjórsá shows that the coherence of the run-off and temperature increases at frequencies too low to be estimated from these data. At frequencies over 1 cycle/day most of the observed variations of the river cannot be explained by means of a linear relationship with the meteorological series.
Creep of Ice Containing Dispersed Fine Sand
Authors: Hooke Roger LeB. , Dahlin Brian B. , Kauper Michael T.
Published: September 2017

Cylindrical samples of ice with 0.0 to 0.35 volume fraction fine sand were tested in unconfined uniaxial compression at stresses between 5.3 and 6.4 bar and at temperatures between −7.4 and −9.4° C. Secondary creep rates were obtained from the slope of the total strain vs. time curve and were normalized to 5.6 bar and −9.1° C. Creep rates in ice with low sand concentrations were in some cases higher and in other cases lower than in clean ice. However at higher sand concentrations the creep rate decreases exponentially with increasing volume fraction sand. The latter results are in general agreement with theories developed to explain dispersion hardening of metals, and suggest that each sand grain is surrounded by a tangled network of secondary dislocations which impede passage of primary glide dislocations.
Power Spectrum Analysis of Undersea and Surface Sea-Ice Profiles
Authors: Hiblek William D. , LeSchack Leonard A.
Published: September 2017

Under-ice sonar profiles and surface laser profiles of the Arctic pack ice have been analyzed using power-spectrum techniques to extract significant spectral peaks corresponding to spatial periodicies in the ice. The analysis suggests that, for a section of ice sampled by two intersecting under-ice profiles, the ridges are not randomly oriented. Moreover, the lineation or directionality of the ridges may be approximately determined from the two intersecting profiles. Also the spectra from surface profiles of multi-year ice and from surface profiles of first-year ice are of a much different nature, thus suggesting a technique for determining ice types from laser profiles.
Elastic Stresses in Layered Snow Packs
Authors: Smith F. W.
Published: September 2017

A two-dimensional finite element computer program has been used to compute the elastic stress distribution in realistic multi-layered snow packs. Computations have been done on three-layered and five-layered snow packs intended to simulate conditions on the Lift Gully at Berthoud Pass, Colorado. Calculations have been performed to determine the effect of a layer of new snow and the effect of a weak sub-layer. Stress levels were obtained which are reasonable compared with available snow strength data.
Temperature Distribution in the Upper Layers of the Ablation Area of Athabasca Glacier, Alberta, Canada
Authors: Paterson W. S. B.
Published: September 2017

Ten-meter temperature measurements show that Athabasca Glacier is temperate in the accumulation area but not in the ablation area. An important factor in determining whether all the ice will reach a temperature of 0° C by the end of summer is how much of the layer of ice, cooled during the previous winter, is removed by ablation. However, calculations show that, even when allowance is made for ablation, not enough heat is conducted into the ice to bring it all to the melting point. As recent work suggests that ice at 0° C is permeable to water, latent heat released by refreezing of percolating melt water is considered; it appears likely that this process is an insignificant heat source in the ablation area. Available data show that the penetration of solar radiation can probably also be neglected. The question of how widespread temperate glaciers are is discussed; it is predicted that in most, if not all, glaciers there is a region below the equilibrium line where, because ablation is low, the glacier is not strictly temperate.
Measurements of Water Pressure in Moulins as Part of a Movement Study of the White Glacier, Axel Heiberg Island, Northwest Territories, Canada
Authors: Iken Almut
Published: September 2017

In 1970 water pressure was measured in several moulins on the White Glacier. Pressure variations in some moulin channels extended over the full measuring range of the instruments (0–1 and 0–2 bar above atmospheric pressure), even at depths of less than 50 m below the surface. Measurements at different depths showed that total pressure variations were sometimes greater than this. The pressure data are compared with variations in the surface velocity of the glacier.
Snow Accumulation at “Byrd” Station, Antarctica
Authors: Gow A. J. , de Blander F. , Crozaz G. , Picciotto E.
Published: September 2017

The rate of snow accumulation at “Byrd” station, Antarctica, was measured by various methods. Surface measurements yield a mean accumulation of 117 kg m−2 year−1 for the time interval 1962–70, within a 10 m radius of the station. The distribution of fission products with depth indicates a rate of 67 ± 4 kg m−2 year−1 for the period 1955–68 and of 100 ± 10 kg m−2 year−1 for the period 1965–68. The 210Pb method yields a 60 year average of 110 ± 10 kg m−2 year−1.
Seismic Refraction and Reflection Measurements at “Byrd” Station, Antarctica
Authors: Kohnen Heinz , Bentley Charles R.
Published: September 2017

Seismic refraction and reflection shooting was carried out along three profiles about 10 km long, angled 60° to one another, near “Byrd” station, Antarctica, during the 1970–71 field season. No dependence of velocity upon azimuth was found, but velocities at 200 or 300 m depth were slightly greater than at a site 30 km away where measurements were made in 1958. The difference can probably be attributed to different ice fabrics arising from a 50% difference in snow accumulation rates at the two sites. The velocity depth and density–velocity functions at the two sites are also significantly different, but close agreement was found at each site between the depths to significant changes in the velocity gradient and the depths of fundamental change in the densification process. Such agreement may permit density–depth curves, and consequently accumulation rates, to be measured by seismic refraction shooting alone.

The reflection shooting on a common reflection-point profile led to a good determination of mean velocity through the ice as a function of angle of incidence. The results agree closely with similar measurements at the 1958 site, and with an anisotropic model based on glaciological and sonic logging observations in the deep drill hole. The mean vertical velocity of 3.90–3.93 km/s through the solid ice is about 2% higher than has commonly been used for determinations of ice thickness from seismic reflection shooting.
A Photogrammetric Survey of Hoseason Glacier, Kemp Coast, Antarctica
Authors: Morgan Peter J.
Published: September 2017

A study of Hoseason Glacier was made to test whether photogrammetry could yield meaningful glaciological information from repeated series of air photographs without ground control. Three maps indicate that large time differences, different camera systems, and the use of sea ice as a level datum do not present insurmountable difficulties in photogrammetric reduction. Surface horizontal movement was determined and level profiles were compiled. Hoseason Glacier is probably in equilibrium.
Morphology of the Ice-sheet Margin Near Thule, Greenland
Authors: Hooke Roger Leb.
Published: September 2017

Three types of glacier margin are found along the edge of the Greenland ice sheet near Thule: ice cliffs, ramps and ice-cored moraines. Where the glacier margin is perpendicular to prevailing katabatic winds, drifting snow accumulates along it in stagnant wind-drill ice wedges. Upward flow of active ice behind these wedges causes ice originally near the base of the glacier to rise to the surface. Where this basal ice is free of debris, a gently sloping ramp develops. However, where the basal ice contains sufficient debris, a layer of till accumulates on the glacier surface. Ice beneath the till is insulated and a debris-capped ice ridge or ice-cored moraine forms, Ice cliffs occur where the ice-sheet margin is parallel to prevailing winds and is thus swept clear of drifting snow. Although the ice sheet in the Thule area appears to have had a negative mass balance for many years, all three types of glacier margin are believed to be equilibrium forms that can develop and persist on a glacier with a balanced mass budget.

Foliation in wind-drift ice wedges generally dips down-glacier but foliation in active ice dips up-glacier. It is inferred that foliation in the wedges was once sedimentary stratification that has been tipped upward and locally overturned.
The Mass Balance of the Devon Island Ice Cap, Northwest Territories, Canada, 1961-66
Authors: Koerner R.M.
Published: September 2017

Methods used in measuring the mass balance of the Devon Island ice cap are described. The use of dyes and melt trays is recommended in the superimposed-ice and firn zones of sub-polar glaciers. The north-west part of the ice cap was studied in most detail and has had a slightly negative net balance for the period 1961-66. An inverse relationship between mean net balance (bn) and elevation of the equilibrium line in the north-west part of the ice cap indicates that the mean net balance there would be zero with an equilibrium line at 920 m (±80 m) elevation. Accumulation on the ice cap is greatest in the south-east but the measurements suggest that the mean net balance there is similar to the mean net balance on the rest of the ice cap. It is concluded that the present accumulation pattern must have existed for several hundreds, and possibly thousands of years. A study of firn stratigraphy and of variations in the elevation of the firn and equilibrium lines indicates that between 1961 and 1966 only 1962 had a more negative mean net balance than the average value for the period 1934-60. During the same 26 year period the net balance at 1 787 m elevation has varied, but summer conditions do not appear to have changed significantly.
The Possible Importance of Electrical Forces in the Development of Snow Cornices
Authors: Latham J. , Montagne J.
Published: September 2017

Measurements were made of the vertical electric field Strength around snow cornices on Bridger Ridge (2 590 m a.s.l.) in the Bridger Range, South-western Montana. The fields were considerably enhanced, owing to the exposed position of the cornices, but were nevertheless appreciably lower than those shown by Latham and Saunders (1970[b]) to be necessary in order to provide significant additional bonding when ice crystals collide with an ice surface. However, measurements made on Bridger Ridge and neighbouring Bangtail Ridge showed that the charges carried on snow crystals saltating over the surface of cornices were close to their limiting values.

Rough calculations indicated that pressure melting is unlikely to be of importance in the development of snow cornices formed from granular crystals, that frictional melting is probably significant only at fairly low temperatures and moderately high wind velocities, and that strong electrostatic forces between highly charged snow crystals saltating over the surface of a cornice may be sufficient to provide bonding where the crystal velocities are comparatively low.
The capillary effects on water percolation in homogeneous snow
Authors: Colbeck S. C.
Published: September 2017

A theoretical basis for introducing capillary effects into the theory of water percolation through snow is given. A capillary pressure-liquid saturation relationship found in the laboratory is used together with the theory to make a quantitative examination of capillary effects. It is shown that capillarity accounts for less than 10% of the total force when water flux is 10–8m s–1although the percentage rapidly increases for smaller fluxes. The experiments suggest that the irreducible water content of dense snow is 7% of the pore volume. It is concluded that the wave-front diffusion seen in lysimeter studies is not the result of capillary action. Other possible causes are suggested.
Observations on the Drainage of a Glacier-Dammed Lake in Norway
Authors: Aitkenhead N.
Published: September 2017

The behaviour of a Norwegian glacier-dammed lake, before, during and after drainage in 1957 is described. The evidence of former shoreline terraces is interpreted and possible drainage mechanisms are discussed.
Studies of the Shrinkage After a Sudden Advance, Blue Bands and Wave Ogives on Glaciar Universidad (Central Chilean Andes)
Authors: Lliboutry Louis
Published: September 2017

The recently discovered Glaciar Universidad is the second largest glacier in central Chile. Aerial photographs taken in 1945 show that just before that date it had undergone a “glacier flood” or sudden advance, similar to those suffered by four other great glaciers of central Chile between 1927 and 1947. The cause of these floods is sought. Surface features (firn line, absence of penitentes but presence of “pocket-penitents”, glacier mills, dirt cones, water-filled holes with submerged ice crystals in them) prove that Glaciar Universidad is the most northerly glacier in the Andes of an Alpine type. The disposition of blue bands, crevasses, closed crevasses and shear planes is reported. Wave ogives are studied and an explanation is given of why dark Forbes’ bands form subsequently on these waves. A kind of unstratified esker of a form similar to a deposit observed by Mr. W. H. Ward in Baffin Island, has been studied, as also has the shearing of the frontal cliff along dirt strata; a theory of both phenomena according to which shear transfers material from the bed to the surface is questioned.
On the Formation of Snow Penitentes
Authors: Amstutz G. C.
Published: September 2017

An attempt is made to throw some light on the physical processes in the development of penitentes as a result of new observations in Peru and a study of the literature. This paper offers a variety of approaches to the problem rather than any final view or theory, and is therefore mostly suggestive and intended to be a program for further, more detailed research.
The Summer Climate in the Accumulation Area of the Salmon Glacier
Authors: Adkins C. J.
Published: September 2017

During the summer of 1957 a party visited the Salmon Glacier in British Columbia. A meteorological station was established in the accumulation area at an altitude of 1700 m. From 12 June to 16 August pressure, temperature and humidity were recorded continuously and the daily totals of precipitation, ablation and percolation were obtained. Periodic measurements of snow density were made; on the first occasion to a depth of 4.7 m. and later near the surface only. Occasional observations of snow temperatures to a depth of 12 m. were also made. Towards the end of the season the heat balance of the snow surface was examined in detail. The various contributions to the melting are evaluated for several short periods and their relative magnitudes compared.
The Knife Creek Glaciers of Katmai National Monument, Alaska
Authors: Muller Ernest H. , Coulter Henry W.
Published: September 2017

A group of previously unmapped glaciers on the slopes of Trident and Katmai Volcanoes, southwestern Alaska, was studied for information on the abnormal regimen produced by effects of the 1912 eruption of Mount Katmai. During the eruption an area of 5 square miles (13 km.2) of the summit above regional snow line was destroyed, and the beheaded glaciers were buried under a blanket of pumice and ash. Field data are presented to indicate that the terminus of Fourth Glacier has been essentially stationary since the 1912 eruption. Upper portions of the glacier have thinned, exposing the rim of the caldera which 40 years ago was partly ringed with fringing ice cliffs. Permafrost has developed to within a few feet of the surface of the pumice mantle. Under prevailing climatic conditions Fourth Glacier may be preserved in its present static condition for an indefinite period.
Deformation of Floating Ice Shelves
Authors: Weertman J.
Published: September 2017

The problem of the creep deformation of floating ice shelves is considered. The problem is solved using Glen’s creep law for ice and Nye’s relation of steady-state creep (the analogue of the Lévy-Miles relation in plasticity theory). Good agreement is obtained between an observed creep rate at Maudheim in the Antarctic and that predicted from the results of creep tests made by Glen.
Temperature Measurements at a Cirque Bergschrund in Baffin Island: Some Results of W. R. B. Battle’s Work in 1953
Authors: Thompson H. R. , Bonnlander B. H.
Published: September 2017

Thermograph, thermistor, and thermometer readings at a 30 m. deep bergschrund from June 6 to July 22, 1953, showed that there was little direct relationship between air temperatures outside and at the bottom of the Schrund. The air temperature inside ranged from −3.7° C. (253° F.) to +0.5° C. (32.9° F.), but from July 2 onwards it oscillated between –0.5° C. and +0.5° C., with a 3–4 day periodicity. The ice temperature at the bottom of the schrund behaved similarly, though it was about 0.5° C. colder. The oscillations may have been caused by the interplay of flowing melt water (source of heat) and air drainage in quiet weather (source of cold). The granite-gneiss headwall, where not sheathed by refrozen melt water, appeared to be chemically and mechanically unweathered, which supported the conclusions of Battle’s earlier tests in deep bergschrunds and in the laboratory.
Sorge’s Law of Densification of Snow on High Polar Glaciers
Authors: Bader Henri
Published: September 2017

Ernst Sorge, a member of Wegener’s Greenland Expedition 1930–31, discovered an important law on the densification of snow in high polar glaciers. It is here given a simple mathematical form and some of its implications are formulated and discussed. Apart from its significance to glaciology and snow mechanics, Sorge’s law should also be useful in the study of consolidation of accumulating fine-grained lacustrian and oceanic sediments.
The Glaciological Studies of The Baffin Island Expedition, 1950: Part V: On The Variation of The Shear Stress on The Bed of An Ice Cap
Authors: Orvig Svenn
Published: September 2017

Some recent work by Dr. J. F. Nye on the calculation of the thickness of ice sheets has prompted the author to apply Nye’s formula to the Barnes Ice Cap in Baffin Island. A gravimetric survey of the southern lobe was carried out in 1950, and the data from four of the traverses have been used to calculate the variation of the shear stress on the bed. Some of the values obtained are exceptionally low, possibly explained by the fact that the lines of travel over the surface do not necessarily correspond to the lines of greatest slope or lines of flow. Only in one direction are the values relatively high, and it is concluded that there is a considerably greater movement of the ice in this direction. This conclusion is in agreement with observations on the ground.
Local Pleistocene Glaciation and the Level of the Snow Line of Croaghaun Mountain in Achill Island, Co. Mayo, Ireland
Authors: Farrington A.
Published: September 2017

The group of corries on Croaghaun Mountain on Achill Island is described. The existence of these corries and the absence of any extraneous drift from the mountain is taken as evidence that the inland ice of Co. Mayo did not extend far beyond the present coast. The relation of the corries to the local topography is described, and the effect of the topography on the apparent snow line is discussed. The probable snow line of the main glaciation of the west of Ireland is shown to be in the neighbourhood of 1250 ft. O.D. (384 m.) but may have been as low as 1000 ft. O.D. (305 m.) and that of the Late-glacial period in the neighbourhood of 1750 ft. O.D. (533 m.).
More About Advancing and Retreating Glaciers in Patagonia
Authors: Lliboutry Louis
Published: September 2017

Contrary to prevailing opinions, the glaciers of south Patagonia have normally been stationary or have advanced during the last twenty years. Exceptions can be accounted for by a lag due to a long travel through narrow passes or by the lowering of waters in the terminal lake at the foot of a rocky cliff.
On the Causes of Palaeoclimatic Variations and of the Ice Ages in Particular
Authors: Öpik E. J.
Published: September 2017

A method of quantitative climatological analysis is developed by applying the principle of geometric similarity to the convective heat transport, which is assumed to vary with the 1.5 power of temperature difference. The method makes possible the calculation of the change in the mean annual, or seasonal temperature, produced by a variation in insolation, cloudiness, snow cover, etc.

It is shown that the variations in the orbital elements of the earth cannot account for the phenomena of the ice ages; the chronology of the Quaternary, based on these variations, has no real foundation.

Palaeoclimatic variations are most probably due to variations of solar luminosity. These can be traced to periodical re-adjustments in the interior of the sun, produced by an interplay between nuclear reactions and gas diffusion, repeating themselves after some 250 million years. Complications from the outer envelope of the sun lead to additional fluctuations of a shorter period, of the order of 100,000 years to be identified with the periodical advance and retreat of the glaciers during the Quaternary.

Calculations of the variations of luminosity in a star of solar mass substantiate this hypothesis.
Thermal Regimen of Firn on Upper Seward Glacier, Yukon Territory, Canada
Authors: Sharp Robert P.
Published: September 2017

Temperatures were measured within the firn and ice of the upper reaches of the Seward Glacier (referred to in this paper as the “upper Seward Glacier”) to a depth of 204 ft. (62.2 m.) by means of thermohms and a Wheatstone bridge. Thermal boring proved a feasible means of penetrating this glacier. The winter’s chilled layer here develops a thickness of 40–50 ft. (12.2–15.2 m.) and attains temperatures of at least −13° C. Deterioration of the chilled Iayer is rapid and irregular in the final phase and is attributed largely to freezing of percolating melt water. Melt water exerts such a powerful influence on thermal regimen that bodies of firn in environments with mean annual temperatures below freezing may, nonetheless, be geophyaically temperate because of extensive warming by melt water in summer. In both 1948 and 1949, the annual chilled layer on the upper Seward Glacier disappeared within the first 10 days of July. The slow development and rapid deterioration of diurnal crusts on firn and the lag effects at depth reproduce in miniature the behavior of the annual chilled layer. On the basis of its thermal regimen the upper Seward Glacier is geophysically temperate.
Pot-Holes and Glacier Mills
Authors: Streiff-Becker R.
Published: September 2017

Such pot-holes as are caused by glacial action are in the main not due to cascades of melt water falling direct to the glacier bed, but are formed by the subglacial stream when conditions are favourable.
The Dwindling Glaciers of the Upper Rakaia Valley, Canterbury, New Zealand
Authors: Gage Maxwell
Published: September 2017

These glaciers are in a district that was seldom visited before the great expansion of recreational tramping and mountaineering in New Zealand during the past twenty years, but the record extends back for eighty-five years. During this time the chief glaciers have receded considerably but irregularly, and for one of them the records indicate a vertical downwasting and thinning. Although this glacier shows no sign yet of recovery it is fed from the same snowfield as that which supplies another glacier descending west from the main divide and which may have begun to advance. An appreciable re-advance of the Franz Josef Glacier has already been given notice in the, Journal of Glaciology, and it may be that the steep gradients of the west-flowing glaciers of the Southern Alps enable them to respond to short-term climatic fluctuations, whereas the flatter east-flowing streams continue to shrink, in keeping with the world-wide trend.
Further Observations on Stress-generated Ice in the Blue Glacier, Washington, U.S.A.
Authors: Knight Charles A. , LaChapelle E.
Published: September 2017

A more detailed examination is made of the stress-generated ice crystallization features already discussed by LaChapelle (1968), using mainly thin-section techniques. The crystallization features on the walls of a tunnel within the Blue Glacier are localized at fine-grained layers and are fed by liquid water traveling along grain boundaries within the wall and within the deposits themselves. The water filling the crevasse encountered at the end of the tunnel was freezing uniformly to the crevasse walls as well as forming Thomson crystals within the water, and the evidence points to an important role for constitutional super-cooling in the Thomson crystal formation. The forms of most of the Thomson crystals are explainable qualitatively by beat flow effects.
Attenuation of Sound in Sea Ice, 10–500 kHz
Authors: Langleben M. P.
Published: September 2017

Measurements of the attenuation of acoustic waves in sea ice at frequencies f between 10 kHz and 500 kHz have been made on the ice cover at Tanquary Fiord, Ellesmere Island (lat. 81° 25′ N., long 76°50′ W.). A horizontal transmission path at a depth of 4 ft (1.3 m), mid-way between the top and bottom surfaces of the ice cover, was used at ranges varying from 25 ft (7.6 m) to 4 ft (1.3 m) between piezoelectric transducers immersed in oil-filled bore holes. The attenuation coefficient α was found to fit the equation a α = c1f+c2f4 with c1 = 4·45 × 10−2 db m−1 kHz−1, and c2 = 2·18 × 10−10 db m−1 kHz−4. Over the frequency band covered, the linear term was predominant and the Rayleigh scattering term relatively insignificant.
Observations on a Collapsing Kame Terrace In Glacier Bay National Monument, South-Eastern Alaska
Authors: Mckenzie Garry D.
Published: September 2017

Detailed observations on a collapsing kame terrace indicate that the terrace is being reshaped by: slumping and sliding of debris into depressions, melt-water erosion on the side of the terrace, debris flows in the gullies, and stagnant-ice bursts, a phenomenon analogous to a glacier burst except in the mode of formation of the water. Temperatures in the gravel over the ice, where the gravel is about 4 m thick, indicate that the rate of melting of the upper surface of the ice due to conduction may be as high as 24 cm year−1. Highest temperatures in the gravel were recorded during periods of heavy rainfall.
Kettle Holes
Authors: Clark R. P. K.
Published: September 2017

An alternative origin and significance for kettle holes is considered. Kettles among some kame tracts may be due not to melt of buried ice but rather represent the location of ice pillars or roof pendants among stratified subglacial deposits.
Glaciological Observations around Mount Atter, West Greenland
Authors: Holland Michael
Published: September 2017

In an uncompleted paper, the glaciological observations made by the late Michael Holland and his party in the mountainous Sukkertoppen region of West Greenland (lat. 66° N.) during the summer of 1956 are described. Notes on the features of this region and of the present state of the glaciers were fairly complete; it is felt that these should be put on record as likely to be of use to future workers. It is concluded that in recent years retreat of the main glaciers appears to have been very slight. Pit measurements were made and tabulated and comparisons were made with the earlier findings by Etienne in the same area. No notable difference in the annual accumulation is yet apparent; it is tentatively concluded that there may have been a small increase, but caution is heeded in interpretation as the nearest meteorological stations lie at some distance.
Composition of Gas Bubbles In Greenland Icebergs
Authors: Scholander P. F. , Hemmingsen E. A. , Coachman L. K. , Nutt D. C.
Published: September 2017

An investigation has been made on the amounts and composition of gases enclosed in West Greenland glaciers ranging from the Thule area near lat. 77° N. to Brede Fjord at lat. 62° N. In general, the gas composition deviated appreciably from that of air, and also varied within each piece of ice. Presumably these variations are caused by melting either in the firn area, or, more often, at the outlet sites.13C analyses indicate that organic contamination of the snow may be another factor. Undisturbed ancient atmospheric air was therefore not encountered in our Greenland samples, but indications are that it might be found in the much colder Antarctic ice sheet. Gas bubbles analyzed from crack fills in icebergs had high oxygen concentrations, sometimes almost matching that of air-equilibrated ice-cold water, from which they undoubtedly originated. Blue icebergs, which often were seen floating up from the bottom of glacier fronts, also tended toward high oxygen concentration and very likely, therefore, are caused by freezing of melt water seeping down and collecting underneath the glacier.
Ice Budgets for Antarctica and Changes in Sea-Level
Authors: Wexler H.
Published: September 2017

Eight different ice budgets for the Antarctic Ice Sheet are examined. Five of these budgets call for rates of increase of the ice which are in surprisingly good agreement considering the wide dispersion of individual components of the budgets. The observed rise in sea-level of the world’s oceans would appear to contradict the removal of water required to nourish the Antarctic Ice Sheet at the claimed rates. The thermal expansion of oceanic columns, caused by “climatic” warming of the oceans, has been invoked to resolve this contradiction but it appears that this is not large enough judging from the 30 yr. difference in water temperatures measured by theMeteorand theCrawfordin two profiles across the tropical Atlantic Ocean.
On the Iceberg Severity off Newfoundland and its Prediction
Authors: Schell Irving I.
Published: September 2017

An analysis of the iceberg count off Newfoundland for the period 1880–1925 shows that stronger than usual north-westerly winds off the Labrador and Newfoundland coasts and relatively low temperatures over Newfoundland during the months from December to March lead to greater than average berg counts off Newfoundland in the following months, mainly April to June. Conversely, lighter than usual north-westerly winds and relatively high temperatures lead to lower than average berg counts in the following months. The relative strength of winds can be measured by the pressure difference between Belle Isle and Ivigtut. The relationship investigated provides a basis for predicting the berg count each year at the end of March. A comparison of the computed values of the berg count with the actual values on scale 0 to 10 for the following period 1927–61 shows marked agreement.

It is further indicated that a more detailed representation of the winds, temperatures and other elements during the winter and early spring in that general area would lead to a closer relationship with the berg count and a broader basis for its prediction.
Assessing Glacier Mass Budgets by Reconnaissance Aerial Photography
Authors: LaChapelle E.
Published: September 2017

Glacier reconnaissance in North America depends largely on aerial photography. Qualitative interpretation of such photography presently yields information on extent and yearly variations of existing glaciers, vigor of their activity, formation of kinematic waves, snow-line altitudes, residual annual snow accumulation, and recent climatic changes. Methods are proposed whereby such data can be combined with limited ground observations to obtain quantitative mass budget data.
Seismic Depth Study of the Salmon Glacier, British Columbia
Authors: Doell Richard R.
Published: September 2017

Seismic observations on the Salmon Glacier have shown that the glacier bed has a general V-shape with a depth-to-width ratio of about 1:2. These studies also indicate that the north terminus of the glacier effectively dams Summit Lake. Several reflections were recorded from surfaces transverse to the glacier length that curve from near tangency with the bottom surface of the glacier to a vertical attitude at the upper surface. These reflections are restricted to the part of the glacier near the source area.
Thermoluminescence Techniques in Determination of the Stress and Crystallization History of Ice
Authors: Zeller E. J. , Ronca L. B.
Published: September 2017

A series of glow-curve measurements were made to determine the general nature of the thermoluminescence of natural ice. The curves were made by subjecting the samples to ultraviolet radiation from a quartz-envelope mercury arc lamp while keeping the samples at liquid air temperature. The samples were then heated by passing a stream of air over the sample container. The resultant rise in temperature is non-linear but is nearly uniform from run to run. The light emitted was measured by the microphotometric portion of the standard apparatus for determination of mineral thermoluminescence.

Curves were obtained on samples collected from the ice tunnel in the ice cap at Jungfraujoch and from freshly fallen and old snow at Bern in Switzerland. A systematic variation in glow-curve shape was found. This variation appears to be directly related to the stress history of the ice. Ice which has been subjected to high shearing stress can he readily distinguished from ice which has not.
Lake Ice Investigation at Peters Lake, Alaska
Authors: Muguruma Jiro , Kikuchi Katsuhiro
Published: September 2017

In this paper a study of lake ice at Peters Lake with respect to crystallographic nature and impurity in crystal grain boundaries is described. The appearance of the ice structure in 1962 was quite uniform over the whole area of the lake; it showed predominantly horizontal c-axes. Another type of ice with predominantly vertical c-axes could not be found even in the surface layer of the ice. The cause of these two types of ice is explained as being due to wind action. A correlation between the grain-size and the depth of ice is expressed in exponential form down to a depth of 100 cm. A linear relationship between the thickness of ice and the depth of snow cover was obtained. Impurity in grain boundaries measured as specific electrical conductivity was hard to detect in such a pure ice as that at the lake whose purity was about 1 micromho/cm. Supplementary data from Lake Nukabira, Hokkaido, are summarized and compared with the data from Peters Lake.