bluuebunny/crossref_metadata_2025 huggingface dataset:
A Flow Law for Temperate Glacier Ice
Authors: Colbeck S. C. , Evans R. J.
Published: September 2017

Uniaxial compressive creep tests were performed on polycrystalline samples of glacier ice at stresses ranging from 0.06 bar to 1.0 bar under conditions similar to those actually occurring in a temperate glacier. Tests were conducted in an ice tunnel on the Blue Glacier, Mt Olympus, Washington, U.S.A., thus ensuring that the temperature remained at the pressure melting point.

The flow law proposed as an appropriate one-dimensional flow law for temperate glacier ice is a polynomial expression containing linear, cubic and fifth-order terms. This law provides a good fit to the data and is also consistent with the quasi-viscous creep data of Glen (1955).
Radio Echo Sounding on a Valley Glacier in East Greenland
Authors: Davis J. L. , Halliday J. S. , Miller K. J.
Published: September 2017

Although radio echo sounding equipment has been used with success for measuring the thickness of ice sheets in the Arctic and Antarctic, a valley glacier poses the additional problems of echoes from the valley walls, which may obscure the bottom echoes, and a high attenuation of radio waves in the ice. During July and August 1970, a study was carried out on Roslin Gletscher in Stauning Alper, East Greenland, to investigate the problems of radio echo sounding on a valley glacier. Results show that reflections from the valley walls are minimized by using sufficiently directional antennae, but attenuation of the signal in the ice is higher than that in polar ice at the same temperature. Water in and on the ice probably accounts for much of the attenuation, and the use of a lower frequency or measurements before the melt commences should give improved performance.
Glacial History of Kolahoi Glacier, Kashmir, India
Authors: Ahmad N. , Hashimi N. H.
Published: September 2017

Kolahoi Glacier is one of the longest glaciers in Kashmir and in the past it extended for at least 35 km. In the Pleistocene there were three advances of Kolahoi Glacier and the last one of them was a major advance when the glacier extended as far as Pahalgam.
Froude Criterion for Ice-Block Stability
Authors: Ashton George D.
Published: September 2017

The conditions under which a floating fragment of ice is either entrained under the upstream edge of a down-stream ice cover or accumulated up-stream are examined by means of dimensional analysis and a simplified analysis of the moments acting on an idealized ice fragment. The significant parameter descriptive of the critical conditions is found to be a Froude number based on block thickness. The influence of the ratio of thickness to flow depth is shown to be due to the effect of the block constricting the flow cross-section, thus amplifying the velocity in accordance with simple continuity. Under-turning instability occurs at a lower critical velocity than required for vertical submergence. Comparison of experimental data with the theoretical results show good agreement and demonstrates the vital dependence on fragment thickness as well as providing a criterion readily applicable to special flow conditions where a Froude number based on flow depth is illogical.
Subglagial Geomorphology Surrounding the Ice-Free Valleys of Southern Victoria Land, Antarctica
Authors: Calkin Parker E.
Published: September 2017

The results of airborne radio-echo (R/E) depth sounding over Wilson Piedmont Glacier, Mackay, Ferrar and Taylor outlet glaciers, and over the ice sheet bordering the mountains, provide ice thicknesses and subglacial topography accurate to 20 m and to 1 km areally. The R/E records show that flours of the Debenham, Wright and Victoria Valleys occur beneath the Wilson Piedmont at elevations of –260 m, and up to 260 and 670 m, respectively. The 670 m “threshold” may have blocked easterly marine and glacial invasions experienced by lower valleys. Profiles along the outlet glaciers display large depressions, some below sea-level. These are associated with erosion by tributaries and with glacial erosion through thick dolerite sills. Elevated ridges thought to be sills submerged beneath the heads of these glaciers also limit nourishment from the adjacent part of the ice sheet. The subglacial west flank of the mountains is formed by a series of high steep-sided plateaux with gentle west-sloping surfaces. Block faulting, west-dipping dolerite and sandstone units, and glacial erosion must explain this topography.
Differential Sea-Ice Drift. II. Comparison of Mesoscale Strain Measurements to Linear Drift Theory Predictions
Authors: Hibler W. D.
Published: September 2017

A comparison of mesoscale strain measurements with the atmospheric pressure field and the wind velocity field indicate that the ice divergence rate and vorticity follow the local pressure and wind divergence with significant correlation. For low atmospheric pressures and converging winds the divergence rate was found to be negative with the vorticity being counter-clockwise. The inverse behavior was observed for high pressures and diverging winds. This behavior was shown to agree with predictions based upon the infinite boundary solution of a linearized drift theory in the absence of gradient current effects and using the constitutive law proposed by Glen (1970) for pack ice. The best least-squares values of the constitutive law parameters η and ζ were found to be ≈ 1012 kg/s. Using typical divergence rates these values yield compressive stresses of the magnitude of 105 N/m which are similar to values suggested by the Parmerter and Coon (1972) ridge model. In general, the infinite boundary solution of the linear drift equation indicates that in a low-pressure region that is reasonably localized in space, the ice would be expected to converge for high compactness (winter) and diverge for low compactness (summer).

Calculations were also carried out using a more general linear visco-elastic constitutive law that includes memory effects and which includes a generalized Hooke’s law as well as the Glen law as special cases. A best fit of this more general calculation with strain measurements indicates overall a better agreement with viscous behavior than with elastic behavior, with the frequency behavior of the estimated “viscosities” similar to the Glen law behavior at temporal frequencies less than ≈ 0.01 h−1.
Autumn, Winter and Spring Soil Temperatures in Okstindan, Norway
Authors: Harris Charles
Published: September 2017

Soil temperatures were recorded over periods of several weeks in the years 1909 and 1970 in two sites to a depth of 100 cm. It was found that snow depth was of major importance in the rate of freezing of the soil in winter; where snow cover was less than 5 cm in depth freezing rates were almost double those where snow depth was over 1 m. Snow cover also insulated the soil surface from above-zero air temperatures during spring, and soil thawing commenced from the surface only following the clearance of snow. Similarly, insulation of the soil surface by snow prevented short-term freezing and thawing cycles penetrating the soil, although even where snow cover was absent such short-term cycles were not observed to penetrate the soil to depths in excess of 5 cm. This surficial freezing and thawing of the soil took place more readily in spring than in the autumn. It was concluded that the annual cycle of soil freezing and thawing was the dominant factor in the thermal regime of these soils, short-term freezing cycles affecting only the immediate surface soil layers.
Early Discoverers XXXI: Descartes’ Observations on the Amsterdam Snowfalls of 4, 5, 6 and 9 February 1635
Authors: Frank F.C.
Published: September 2017

In Les météores (1637), in the midst of a father far-fetched theory of their origin, Descartes incorporated a detailed description, from actual observation, of a variety or kinds of snow crystals and hail particles. These even include the tsuzumi crystals, described as “wheels joined two by two by an axle” or as “little crystal columns decorated at each end with a six-petalled rose”, and such exceptional forms as twelve-rayed and eight-rayed stars. The accompanying diagrams, which have been reproduced a number of times, are distinctly inferior to his verbal description.
Material property and boundary condition effects on stresses in avalanche snow-packs
Authors: Curtis J. O. , Smith F. W.
Published: September 2017

A linear elastic finite element computer program was applied to determine the stress distributions in multi-layered snow-packs typical of those found at Berthoud Pass, Colorado. The effect on stress distribution of wide variations in elastic material properties was examined. Also, an attempt was made to model the shear failure of a weak sub-layer in the snow-pack by relaxing the condition that the bottom snow layer be firmly attached to the ground.
Salinity Variations in Sea Ice
Authors: Cox G. F. N. , Weeks W. F.
Published: September 2017

The salinity distribution in multi-year sea ice is dependent on the ice topography and cannot be adequately represented by a single average profile. The cores collected from areas beneath surface hummocks generally showed a systematic increase in salinity with depth from 0‰ at the surface to about 4‰ at the base. The cores collected from areas beneath surface depressions were much more saline and displayed large salinity fluctuations.

Salinity observations from sea ice of varying thicknesses and ages collected at various Arctic and sub-Arctic locations revealed a strong correlation between the average salinity of the ice and the ice thickness h. For salinity samples collected from cold sea ice at the end of the growth season, this relationship can be represented by two linear equations: ; . It is suggested that the pronounced break in slope at 0.4 m is due to a change in the dominant brine drainage mechanism from brine expulsion to gravity drainage. A linear regression for the data collected during the melt season gives . An annual cyclic variation of the mean salinity exists for multi-year sea ice. The mean salinity reaches a maximum at the end of the growth season and a minimum at the end of the melt season.
Mass Balance of the Ward Hunt Ice Rise and Ice Shelf: A 10 Year Record
Authors: Hattersley-Smith G. , Serson H.
Published: September 2017

The results of 10 years' (1958–68) record of accumulation and ablation from the Ward Hunt ice rise and of 3 years' (1965–68) record from the Ward Hunt Ice Shelf are presented. The net mass balances on the ice rise for the 3 years 1962–65 are positive, while the net mass balances measured in the other years on both ice rise and ice shelf are all negative.
Crystal Orientation in Glacier and in Experimentally Deformed Ice
Authors: Rigsby George P.
Published: September 2017

More than 8,000 ice crystals have been oriented and measured for crystal fabric studies from widely separated temperate and polar glaciers, using a large universal stage and thin-section techniques. Very strong fabrics have been found and a number of laboratory experiments on deformation and recrystallization of ice were conducted in an attempt to solve some of the perplexing problems raised concerning glacier flow.

In polar glaciers the c or optic axes of the ice crystals tend to be perpendicular to the foliation plane (alternating planar structures of bubbly and clear ice). In areas of high shearing stress the preferred orientation of the axes reached 39 per cent in 1 per cent of the area when plotted on a Schmidt equal-area projection. In temperate glaciers the optic axes tend to form three or four strong maxima which also appear related to the foliation.

Patterns from ice deformed in the laboratory resemble some of the fabric patterns found in polar glaciers. During deformation of laboratory specimens, large crystals have been observed recrystallizing into many smaller ones, while fine-grained ice, after completion of deformation (both glacier ice and laboratory deformed ice), has been annealed at melting temperature into a few large crystals with different orientations from the original pattern.
An Esker-Like Ridge in Process of Formation, Flatisen, Norway
Authors: Stokes J. C.
Published: September 2017

A ridge of drift emerging from the snout of Flatisen resembles a small esker. It originates in a subglacial tunnel. The source of the material forming the ridge was a number of thrust planes exposed in the sides and roof of the tunnel. The main features of the tunnel and the ridge are described and the mode of formation of the ridge suggested.
Sea Ice Thrust Structures
Authors: Weeks W. F. , Anderson D. L.
Published: September 2017

Unusual thrust structures in thin sea ice sheets were observed in Labrador and Greenland. These structures are the result of thin ice sheets being of wind and waves. When thicker pack ice is subjected to these same forces pressure ridges result.
The Surface Velocity of The Yakataga Glacier Alaska
Authors: Miller Don J.
Published: September 2017

The Yakataga Glacier occupies a steep-walled valley in the Robinson Mountains on the north coast of the Gulf of Alaska. The main trunk of the glacier descends from 1130 to 150 m. in a distance of 21 km. A rock fall at the head of the glacier formed a moraine of distinctive shape which advanced at an average rate of 114 m./yr. from 1938 to 1954. The surface velocity of the glacier at fifteen stations below the firn line was calculated from the displacement of the rock-fall moraine and other less conspicuous features that are shown in two sets of vertical aerial photographs, taken in 1948 and 1954. For this time interval the average surface velocity along the medial line of the glacier ranged from a maximum of about 90 m./yr. at a station 14 km. above the terminus to zero at a station 2.3 km. above the terminus. The technique of photogrammetric measurement of surface velocity by using natural features on the surface of a glacier has wide application in Alaska, where many glaciers have been rephotographed from the air after intervals of a few years to as many as thirty years.
Observations on Break-Up in the Mackenzie River and its Delta in 1954
Authors: Brown R. J. E.
Published: September 2017

Winter conditions on the Mackenzie River and Delta in North-west Canada are discussed. Daily observations during the break-up period of the Mackenzie River for 1954 are recorded, as well as a general record of the break-up of ice in the delta and detailed observations of the break-up in one of the main channels.
Incipient Glacier Development within Katmai Caldera, Alaska
Authors: Muller E. H. , Coulter H. W.
Published: September 2017

An unusual opportunity for the study of glaciers in the process of development is afforded in Katmaicaldera in south-western Alaska. A violent eruption in 1912 destroyed the summit of glacier-clad Mount Katmai, creating a caldera 4 km. wide and 800 m. deep. Ice cliffs produced by beheading of the glaciers have since thinned and shrunk away from the rim of the caldera, except in the south-west. There, local reversal of direction of movement has resulted in an ice fall which descends part way down the crater wall. In the past thirty years two small glaciers have formed, near 1525 m. above sea level, within the caldera on large masses of slumped wall-rock below the north and south rims respectively. Elsewhere the sheer walls of the crater descend so steeply to the level of the caldera lake that permanent snowbanks cannot accumulate. The lake, which continues to rise at a rate of more than five meters per year, is at present the primary deterring factor in glacier development in the caldera.
Glaciological and Geomorphological Reconnaissance in the Antarctic in 1956
Authors: Shumskiy P. A.
Published: September 2017

This paper presents a preliminary account of the glaciological observations made by the Antarctic Expedition of the U.S.S.R. Academy of Sciences in Kaiser Wilhelm II Land, Queen Mary Land and Knox Coast in 1956. The topography of the edge of the ice sheet is described, and the ice regime is discussed, particularly in relation to the existence of ice-free areas such as “Bunger’s oasis”.
The Strength of Snow in Compression
Authors: Gold Lorne W.
Published: September 2017

The hardness observations taken in the Canadian Snow Survey are analysed and found to depend on snow density, temperature, and crystal size. This strength property of the snow is found to be highly variable and the variability is attributed to unstable bonding between individual snow grains.
The Disappearance of the Last Ice Sheet from Central Norway
Authors: Strøm Kaare
Published: September 2017

The lecture was a review of the research work carried out by the author and his collaborators, as well as by J. Gjessing and students working for their final degree. Attention is called to the existence of local centres in western regions even during the maximum of the last glaciation, as well as the transition from down-wasting of dead ice near the ice divide to backward melting of partly active glacier tongues in the high mountains near the sea. Regional reconstructions of the waning of the glacier ice are attempted.
Some New Aspects of the Grímsvötn Problem
Authors: Thorarinsson Sigurdur
Published: September 2017

Grfmsvötn (The Lakes of Grünur) is the name of a volcanic centre in Vatnajökull, the eruptions of which accompany the gigantic glacier bursts on Skeidarársandur which occur normally about every tenth year. Recent expeditions to Grimsvötn and reconnoitring flights have led to the view that between glacier bursts the Grlmsvötn depression is gradually filled with water, forming a lake with a maximum area of about 35–40 sq. km. This accumulation of water is partly due to ablation and partly to continuous solfatara and fumarolic activity.

The close resemblance between the discharge graphs of glacier bursts from Grimsvötn and graphs of drainage of normal ice-dammed lakes such as Lake Graenalón is stressed. It is also pointed out that ten years’ accumulation, about 7 cu. km., in the area drained into the Grfmsvötn depression, corresponds roughly with the total discharge of a normal glacier burst from Grfmavötn. It is suggested that the glacier bursts determine the moment of eruption and not vice versa. This might explain the usually very regular intervals between these eruptions. The irregularities occurring since 1934 might be due to the present climatic amelioration.
The Castner Glacier Region, Alaska
Authors: Nielsen Lawrence E. , Post Austin S.
Published: September 2017

Three valley glaciers of the eastern Alaska Range are described. On one of these, the Castner Glacier, an unusual medial moraine was discovered, which has its beginning from an outcrop in the center of a cirque-like basin. This large moraine extends down the glacier for 4 miles (6.4 km.) and ends abruptly several miles from the end of the glacier. The advances and recessional behavior as deduced from end moraines, lateral moraines and the limits of forest destruction (forest trimlines) are briefly discussed.
The Initiation of Dirt Cones on Snow
Authors: Wilson J. Warren
Published: September 2017

Dirt cones develop where debris has been blown on to snow and has become concentrated into numerous small patches thick enough to protect the underlying snow from ablation. These striking accumulations of dirt, separated by virtually dirt-free snow, are produced by movement (both contraction and expansion) of the snow surface during ablation. Factors controlling this movement operate in such a way that local concentrations of dirt will be produced even when initial deposition of the dirt is almost uniform. The significance of these processes in relation to the development and structure of dirt cone fields is discussed, and certain experiments and observations on dirt cones are described.
The Glaciological Studies of the Baffin Island Expedition, 1950: Part IV: The Heat Exchange at the Surface of the Barnes Ice Cap During the Ablation Period
Authors: Ward W. H. , Orvig S.
Published: September 2017

The heat exchange takes place in two stages: (i) the atmospheric heat causes melting of the whole of the annual snow accumulation and leads to the formation of slush rivers; (ii) some of the melt water refreezes to form a new layer of ice superimposed on the original ice, which is warmed by the latent heat yielded to it. A theoretical estimate of the rate of formation of the superimposed ice, and of the temperature change in the original ice, is given, which agrees reasonably with the actual measurements. A rough measurement of the melt water run-off checks with the observations of ablation and superimposed ice. The total energy available for melting is estimated approximately from the meteorological observations; it underestimates the actual ablation. About 70 per cent of the total ablation energy (47 cm. water, total ablation) is disposed of as melt water that is discharged from the ice cap surface; the remainder goes as sensible heat to the low temperature ice.
An Electron Microscope Study of Snow Crystal Nuclei
Authors: Nakaya Ukichiro
Published: September 2017

Snow crystals were received on the collodion film of the holder of an electron microscope, and made to sublimate without melting. These specimens were investigated under an electron microscope. One solid nucleus was always observed in the central portion of a snow crystal. These centre nuclei were of sizes between 0.5 and 8μ. Most of them were presumed to be kaolin, clay or carbon particles; some were considered to be micro-organisms. In the other parts of snow crystals numerous smaller nuclei were observed, whose dimensions were of the order of those of condensation nuclei. These condensation nuclei were found to be of two kinds, the larger ones most frequently having a diameter of about 0.15μ, the smaller ones of about 0.05μ. A new theory was proposed from the data of the electron microscopic studies and those of the conditions of formation of snow crystals. In this theory it is proposed that minute water droplets of 1μ or so play an important rôls in the process of snow crystal growth.
Part II: The Physics of Deglaciation in Central Baffin Island
Authors: Ward W. H. , Hale Mason E.
Published: September 2017

The shearing and ablation of “cold” ice that leads to the formation of ablation and end moraines and the characteristic form of the S.E. edge of the Barnes ice cap are discussed. Some evidence suggests the existence of considerable areas of dead glacier ice extending well beyond the current moraines and completely insulated from melting by glacial debris. This debris consists of old moraines whose relief has been inverted and subdued. An appendix by Mason E. Hale on the current moraine plant succession suggests that the last stable position of the S.E. edge of the ice cap occurred about 1860 and has been followed by retreat at an average rate of about 3 m. per year.
The Longitudinal Stress and Strain-rate Gradients in Ice Masses
Authors: Budd W.F.
Published: September 2017

The fundamental equation for the longitudinal stress and strain-rate gradient For ice masses with small slope (Budd, (1968)) has been derived exactly for any slope by Nye (1969) who shows that by using a variable longitudinal axis inclination, parallel to the surface, this equation takes on its simplest form. However for the integration of this equation along the ice mass to obtain stress and strain-rates it is necessary to use a fixed axis direction. Here the equation is derived generally for a longitudinal axis of arbitrary inclination, from which the relation between the expressions for the fundamental equation with respect to any longitudinal axis inclination such as parallel to the surface, parallel to the base or horizontal is readily discerned.

An expression for the longitudinal strain-rate is derived to obtain the flow law from longitudinal stress and strain-rate measurements. A single “generalized viscosity function” is introduced to avoid the complication of both the power flow-law parameters varying with stress.
A Note on the Surface Profile of the Greenland Ice Sheet
Authors: Philberth K. , Federer B.
Published: September 2017

This paper deals with the influence on the surface profile of the Greenland ice sheet, of an accumulation which increases between the ice divide and the coast, and of the thermal softening of the lowermost layers. It is concluded that the form of the surface of the profile measured by E.G.I.G. can be described by Glen's law with the exponent n = 3.5. The assumption is made that the bottom differs everywhere from the pressure melting point by a constant amount. This assumption is dropped in the second part of the paper. On the basis of the measured surface profile it is shown that the maximum increase of the bottom temperature is a few degrees within a range of 300 km. In view of the increasing surface temperature and heat of friction towards the outer edge it is concluded that, relatively close to the ice divide, that ice at the bottom must be temperate. Therefore we concluded that friction forces are preventing the ice from slipping on the bedrocks.
Fabric Analysis of Surface Ice near Casey Range, East Antarctica
Authors: Kizaki Koshiro
Published: September 2017

Forbes Glacier, one of the outlet ice streams from the Antarctic ice sheet, is located 20 km west of Mawson, Mac.Robertson Land, east Antarctica. In the uppermost part of the glacier near Casey Range, the velocity at the centre of the glacier is 59 m year−1 and the strain-rate at seven strain grids ranges from −6.7 to 6.7×10−3 year−1 on the surface of the glacier. The fabric types of this area are characterized by single-maximum and small-girdle fabrics. It is confirmed that the single-maximum fabric is an original pattern which changes gradually to a small girdle fabric about the maximum compressive axis in association with grain growth. The patterns predicted by Brace (1960) can be adapted to the small-girdle fabrics of this area.
Albedo and Degree of Puddling of a Melting Cover of Sea Ice
Authors: Langleben M. P.
Published: September 2017

Continuous measurements of incident and reflected short-wave radiation have been obtained from 12 May to 17 June 1968 on the ice cover at Tanquary Fiord, Ellesmere Island (lat. 81° 25′ N., long. 76° 50′ W.). The observations were made with radiometers suspended between two towers at a height of 50 ft (15 m) to sample an area large enough to be representative of the surface of the ice cover. From the start of surface melting, time-lapse photographs were taken at intervals of 3 h with a camera mounted on one of the towers at a height of 20 ft (6 m) and slanted below the horizontal.

Values are presented, for the observation period, of incident short-wave radiation, albedo, air temperature at screen height and percentage of surface covered with melt pools. It is shown that the albedo decreases linearly with increasing area of water puddles.
Surface Topography of Etched Ice Crystals Observed by a Scanning Electron Microscope
Authors: Kuroiwa Daisuke
Published: September 2017

Surface topography of etched ice crystals was examined by a scanning electron microscope in combination with a Formvar replica method. The deep focus of the scanning electron microscope allowed observation of the sharply three-dimensional topography of ice surfaces. Various useful information was obtained from microphotographs of etched basal and prismatic planes, fractured surfaces, and grain boundaries formed between microcrystals of ice.
Glacial and Subglacial Topography of West Antarctica
Authors: Bentley Charles R. , Ostenso Ned A.
Published: September 2017

A summary of the techniques used and results obtained from three oversnow traverses in Marie Byrd Land and the Ellsworth Highland between January 1957 and January 1959 is presented. Seismic reflection shooting at 30 nautical mile (55.5 km.) intervals was combined with gravity, magnetic and altimetric measurements to determine the glacial and subglacial topography. It was found that a vast portion of West Antarctica has an ice–rock interface well below sea-level. A major connecting channel with a maximum depth of more than 2,500 m. below sea-level exists between the Ross and Bellingshausen–Amundsen Seas, whereas there is no major topographic connection between the Ross and Weddell Seas. This channel divides West Antarctica into two provinces with granite and rocks of sedimentary origin to the east and south, and a volcanic region to the north-west. Present ice flow is outward from two high areas, centred over mountainous regions on either side of the channel. It is concluded that the present ice sheet has grown from the convergence of the two smaller ice sheets which formed in the mountainous areas and joined across the intervening open water.
Studies on the Density of Naturally and Artificially Formed Fresh-Water Ice
Authors: Ager B. H:son
Published: September 2017

Observations were made on the density of naturally and artificially formed lake and river ice. The effect of initial snow density, size and shape of snow crystals, rate of water spread and rate of freezing on the density of snow-ice obtained was studied in the laboratory and is presented in graphical form. The observations indicate that snow-ice formed under natural conditions will probably have a density between 0.85 and 0.90 g./cm.3. The classification of snow-ice is discussed briefly.
Proposed Definitions for Glacier Mass Budget Terms
Authors: Meier Mark F.
Published: September 2017

A set of internally consistent mass budget terms is proposed for consideration. Vertically measured, water-equivalent components of accumulation, ablation, and net budget are defined for points on a glacier (specific quantities) or as area-integrated totals for the whole glacier (total quantities). The budget year is defined as the time between two minima of net budget. Additional terms involving specific and total rates of accumulation, ablation, net budget, and various subdivisions of the glacier area are developed. Mass budget quantities can be separated into steady-state and budget imbalance terms. Net budgets can be calculated by simplified means when the variation of budget with altitude is known. It is suggested that the term “firn” be applied to layers which have survived one summer’s ablation season.
Studies of Arctic Lake Ice
Authors: Knight Charles A.
Published: September 2017

Discussions of possible causes of preferred crystal orientations in fresh-water ice are presented, with data on ice orientations from several Arctic lakes. Evidently, initial ice orientations are determined by wind conditions. Orientation selection during growth at the bottom of the ice also takes place, but in the lake ice examined it is apparently largely unsystematic. Constitutional supercooling can cause c-axis-horizontal orientations, but it is not of sufficient magnitude in the lakes examined to have much effect. Striations are locally significant but erratic.
Ice Mounds and Melt Phenomena in the Sør-Rondane, Antarctica
Authors: Van Autenboer T.
Published: September 2017

The occurrence of ice mounds, which were observed in the western part of the Sør-Rondane by a geological and gravity reconnaissance party of the 1960 Expédition Antarctique Belge, is described. An explanation of the origin of these mounds could be the refreezing of an accumulated pocket of melt water within the ice. The possibility of the formation of pockets of melt water, despite the severity of the climate, is discussed in relation to several examples of the melting of snow and ice. It seems that such a pocket could form above the higher mounds of the underlying moraine by the hot-house effect.
On the Transfer of Visible Radiation through Sea Ice and Snow
Authors: W. Thomas Charles
Published: September 2017

Coefficients of absorption of visible radiation are determined for sea ice and snow as a function of porosity of the medium and wave-length of energy refracted into it. A comparison is made between the values derived and those obtained by other investigators under similar snow conditions. A difference in results suggests a significant rôle of crystal size and orientation in the absorption properties of sea ice and snow.
Age Hardening of Snow at the South Pole
Authors: Gow Anthony J. , Ramseier René O.
Published: September 2017

The age hardening of artificially and naturally compacted snow has been investigated at the South Pole. Results show that the age-hardening process is greatly retarded at low temperatures. Artificially compacted samples of density 0.55 g./cm.3 attained a compressive strength of less than 3.0 kg./cm.2 after one year’s ageing at −49° C. Exposure to solar radiation accelerated the age hardening. Irradiated samples attained a strength of 6.0 kg./cm.2 after 100 hr., increasing to a virtual maximum of 8.0 kg./cm.2 at the end of 600 hr. Compressive strengths increased with decrease in snow-particle size and with increasing angularity of the particles. Below 3 m. the strength of naturally compacted snow was found to increase rapidly with increase in density. Naturally compacted snow of density 0.55 g./cm.3 possessed considerably greater strength than any of the age-hardened samples of artificially compacted snow of the same density. Thin-section studies show that age hardening can be correlated with the formation and growth of intergranular bonds, and that bond growth falls off rapidly with decreasing temperature. In view of the low strengths found in both naturally compacted snows near the surface and in artificially compacted snow at the South Pole, “cut-and-cover” under-snow camp construction may not prove too practical at the South Pole.
Comparisons of Ogive Systems Under Various Regimes
Authors: Atherton David
Published: September 2017

It is suggested that the dark and light bands associated with a wave ogive system are the result of preferential adsorption of wind-blown dust by interstitial water held in narrow coarsely crystalline bands, which are more frequent in the dark bands. These narrow bands are presumed to be produced by regelation on the closure of extensive crevasses in the cwm zone above the ice fall and that, although originally uniformly distributed, there is a bunching effect caused by velocity fluctuations in the glacier at the top of the ice fall. These velocity fluctuations, which are attenuated by irregularities in the glacier’s bed, produce waves at these points, multiple irregularities producing multiple wave systems.
Glaciation of Observation Hill, Hut Point Peninsula, Ross Island, Antarctica
Authors: Forbes Robert B. , Ester Donald W.
Published: September 2017

East-west glacial striations and grooves were discovered on the summit ridge of Observation Hill, which parallel the present direction of shelf ice movement to the east and south-east of the Hut Point peninsula. This evidence suggests that Observation Hill may have been glaciated by a thickened McMurdo lobe of the adjacent Ross Ice Shelf, moving west, as it does today.
Some Photogrammetric and Geodetic Aspects of Measurement of Glacier Surface Movement as Function of Time
Authors: Adler Ron K. H.
Published: September 2017

The ice movement on the Byrd Glacier, Antarctica, was measured as function of time, on the basis of aerial photography. The method of aero-levelling strip triangulation with a minimum of geodetic control was applied. The methods and procedures were verified over Laufen-Bauma test area.
Water Pressure under a Glacier
Authors: Mathews W. H.
Published: September 2017

Observations in a deep mine working which reached the base of a valley glacier some 150 m. below the ice surface indicated an initial cold and impervious condition at and near the ice–rock contact. Later, however, an excellent hydraulic connection with free water in the upper layers of the glacier was established, perhaps by the thawing of a passage upward through the ice by warm water escaping from the mine. Subsequent records of water levels, or of water pressures, within the mine, reflecting conditions in the upper part of the glacier, show periods of moderately steady conditions, at times showing slight diurnal fluctuations, interrupted by irregular and catastrophic surges, particularly during periods of rapid snow melt and heavy rains. A seasonal cycle in pressure is suggested by the record.
Non-Basal Slip as a Major Deformation Process in the Creep of Polycrystalline Ice
Authors: Tegart W. J. McG.
Published: September 2017

Published data on the creep of polycrystalline ice and crystals oriented for non-basal slip are discussed in terms of theories of prismatic slip in hexagonal metals. It is concluded that creep of polycrystalline ice near the melting point is controlled by non-basal slip but a decision on the exact mechanism of slip cannot be made on the basis of available data.
Net Balance, Surface Lowering, and Ice-Flow Pattern in the Interior of Lewis Glacier, Mount Kenya, Kenya
Authors: Hastenrath Stefan
Published: September 2017

Observations obtained in a long-term monitoring program on Lewis Glacier, Mount Kenya, include measurements of net balance and velocity at a stake network over the period 1978–82, and airborne mapping of the glacier surface topography at the beginning and end of this interval. Horizontal and vertical flow components and mass continuity are evaluated along the longitudinal axis of the glacier.

The largest horizontal velocity at the surface is about 5 m a−1, while the submergent vertical velocity at the surface in the upper, and the emergent component in the lower glacier are of the order of 1–2 m a−1. Horizontal and vertical flow components in the interior of the glacier are calculated from the surface observations under plausible assumptions. Isotachs and streamlines plotted in a longitudinal–vertical cross-section permit the estimation of representative residence times of ice within Lewis Glacier. The largest values for the longest trajectories with submergence at the surface in the uppermost area of the glacier and emergence near the snout are of the order of a few centuries. However, such estimates are compromised, in particular, by the continuing non-equilibrium conditions of Lewis Glacier.

Mass continuity is directly related to the vertical motion field. In the upper area of the glacier the submergence velocity exceeds the rise of glacier surface observed with respect to the stake network, while in the lower glacier the emergent flow component falls short of the local negative net balance. This differing behavior of altitudinal zones is consistent with the fact that actual lowering of the glacier surface topography documented by the repeated airborne mappings is larger than expected from the stake network in the upper but less in the lower glacier. This differing behavior of altitude zones appears mitigated by the tendency for confluence in the upper and diffluence in the lower glacier.
Thermal Expansion of Saline Ice
Authors: Cox Gordon F. N.
Published: September 2017

The coefficient of thermal expansion of NaCl ice and natural sea ice is theoretically shown to be equal to the coefficient of thermal expansion of pure ice.
Elastic Constants of Artificial and Natural Ice Samples by Brillouin Spectroscopy
Authors: Gammon P. H. , Kiefte H. , Clouter M. J. , Denner W. W.
Published: September 2017

The method of Brillouin spectroscopy has been used to measure the dynamic elastic moduli of local homogeneous regions in ice samples representing four different environments of formation. These included artificial ice frozen from distilled water, clear monocrystalline glacial ice, bubbly lake ice, and sea ice. The samples studied were found to have identical local elastic properties. Accordingly the elastic properties of homogeneous monocrystalline ice have been found not to vary with sample age, with impurities present at the time of freezing, or with crystal quality. The bulk elastic properties of ice remain, of course, subject to modification by different crystal grain textures and the presence of inclusions of various sorts. Because the elastic constants obtained in the present work are subject to smaller overall uncertainty than values measured previously, it is believed that they are the most reliable obtained to date. The values at −16 °C were determined to be c11 = 139.29 ± 0.41, c12 = 70.82 ± 0.39, c13 = 57.65 ± 0.23, c33 = 150.10 ± 0.46, c44 = 30.14 ± 0.11 (units of 108 N m− 2 or kbar). A full range of derived elastic parameters for monocrystalline ice and for homogeneous isotropic polycrystalline ice has been calculated.
Annual net balance of North Cascade glaciers, 1984-94
Authors: Pelto Mauri S.
Published: September 2017

Annual net balance eight North Cascade glaciers during the 1984-94 period has been determined by measurement of total mass loss firn and ice melt and ice melt and, residual snow depth at the end of the Summer season. Overall spatial density of measurment points is 200 points km−2. Mean annual balance of North Clascade glaciers from 1984 to 1994 has been −0.38 ma−1. The resulting 4.2 m loss in water-equivalent thickness is significant, since North Cascade glaciers have an average thickness of 30–50 m.

Cross-correlation of annual net balance Ior eight glaciers ranges from 0.83 to 0.97. This indicates the mass balances of the eight glaciers have been responding similarly to elimate conditions despite their range of topographic and geographic characteristics. Annual net balance of individual glaciers was correlated with climate records. The highest ablation-season correlation coefficient is mean May–August temperature, ranging from 0.63 to 0.84. The highest accumulation-season correlation coefficient is total accumulation-season precipitation, ranging from 0.35 to 0.59.
Measurement of ice-sheet topography using satellite-radar interferometry
Authors: Joughin Ian , Winebrenner Dale , Fahnestock Mark , Kwok Ron , Krabill William
Published: September 2017

Detailed digital elevation models (DEMs) do not exist for much of the Greenland and Antartic ice sheets. Radar altimetry is at present the primary, in many cases the only, source of topographic data over the ice sheets, but the horizontal resolution of such data is coarse. Satellite-radar interferometry uses the phase difference between pairs of synthetic aperture radar (SAR) images to measure both ice-sheet topography and surface displacement. We have applied this technique using ERS-1 SAR data to make detailed (i.e. 80 m horizontal resolution) maps of surface topography in a 100 km by 300 km strip in West Greenland, extending northward from just above Jakobshavns Isbræ. Comparison with а 76 km long line of airborne laser-altimeter data shows that We have achieved a relative accuracy of 2.5 m along the profile. These observations provide a detailed view of dynamically Supported topography near the margin of an ice sheet. In the final section We compare our estimate of topography with phase contours due to motion, and confirm our earlier analysis concerning vertical ice-sheet motion and complexity in ERS-1 SAR interferograms.
Instruments and methods: Submersible remotely operated vehicles (ROVs) for investigations of the glacier-ocean-sediment interface
Authors: Dowdeswell Julian A. , Powell Ross D.
Published: September 2017

Submersible remotely operated vehicles (ROVs) are valuable research tools for data collection in dangerous or inaccessible environments associated with glaciers terminating in the sea. At tide-water ice cliffs, iceberg calving makes close approaches for extended time periods In manned vessels dangerous. ROVs can be operated from relatively safe distances (hundreds of metres); they can also descend to considerably greater depths (hundreds rather than tens of metres) than scuba diving permits. They can provide data on glacier grounding-line and sea-floor morphology and water-column characteristics (e.g. salinity, turbidity, current velocity). They are also used for. diving under floating glacier tongues and ice shelves where no other access is possible. They can be fitted with a variety of oceanographic sensors, imaging sensors, tracking devices and water and sediment samplers, making them versatile research instruments that can supply qualitative and quantitative data for process studies in logistically difficult environments.
Pleistocene Ice at the Base of the Barnes Ice Cap, Baffin Island, N.W.T., Canada
Authors: Leb. Hooke Roger
Published: September 2017

Oxygen-isotope ratios indicate that a distinctive band of white ice along the margin of the Barnes Ice Cap is of Pleistocene age. It is estimated freom a flow mogerl that beneath the center of the ice cap the thickness of the band shuuld be abont 0.6 times its thickness at the margin, or about 8 m. However, an ingerpengernt estimate, based on calculated vertical strain-rates and explicitly assuming no basal melting, predicts a thickness of about 22 m beneath the center of the ice cap. The discrepancy between the two thickness estimates is interpreted as indicating that basal melting has occurred. Calculated basal temperatures support this conclusion.
Ridges on Antarctic Ice Rises
Authors: Martin P. J.
Published: September 2017

Satellite pictures have revealed the presence of ridges on the summits of ice rises in Antarctica. Because ice does not exhibit a critical stress it is conclugerd that these ridges must be produced by a snow accumulation process rather than by ice gerformation. A sand-mogerl analogue has been used to simulate this behaviour.
The Effect of Longitudinal Stress on the Shear Stress at the Base of an Ice Sheet
Authors: Nye J. F.
Published: September 2017

Robin (1967) and Budd (1968, unpublished) have succeeded in connecting the variations in surface slope of an ice sheet with variations in the gradient of the longitudinal strain-rate. This paper tries to improve the theoretical basis of their work. By choice of a suitable coordinate system and suitable redefinition of the variables, Budd’s formula for the basal shear stress is derived with a minimum of restrictive assumptions. The resulting formula, containing the gradient of a longitudinal stress, is thought to be of high accuracy for the two-dimensional flow of cold ice sheets, and is valid for slopes of any magnitude.
On the Hypothesis of Ice Ages Suggested by Captain E. S. Gernet
Authors: Chizhov O. P.
Published: September 2017

This paper is devoted to the causes of initiation and development of the Quaternary glaciation and climatic fluctuations connected with it. There are many hypotheses on this problem. The most interesting of them are those suggesting the evolution of glaciers and ice sheets, and variation of climate as a self-regulating process.

The first person to offer a definite mechanism for such self-regulation was the Russian sailor, Captain E. S. Gernet, whose book about this was published in 1930. The book is of great scientific importance, but so far few people appear to have known anything about it. This paper gives a brief summary of the book, shows the similarity between the main ideas of Captain Gernet and the American geologists, W. L. Stokes, M. Ewing and W. L. Donn (the theory of the two latter authors has become well known recently), and justifies naming this concept after Gernet and Stokes in honour of the men who first proposed it.
The Effect of Glacial Cross-Section on Vertical Resistivity Depth Soundings
Authors: Taylor R. W. , Greenfield R. J.
Published: September 2017

The determination of glacial ice thickness by vertical resistivity depth soundings relies upon the use of theoretical curves which neglect the effect of valley walls. To improve the utility of glacial resistivity measurements an analytical expression is derived for the apparent resistivity determined by a Wenner array oriented parallel to the strike of a layered trough embedded in a perfectly conducting half space. Numerical evaluation of this expression allows the effects of glacial cross-section to be determined. It is shown that the presence of valley walls and layering within the glacier can strongly effect the determination of total ice thickness, and a criterion for the reliable use of plane-layered master curves in the interpretation of field data is established. An apparent resistivity curve calculated for a layered trough is shown to give an excellent fit to field data published by Röthlisberger and Vögtli (1967).