bluuebunny/crossref_metadata_2025_split huggingface dataset:
Deep Drilling at Base Roi Baudouin, Dronning Maud Land, Antarctica
Authors: Tongiorgi E. , Picciotto E. , Breuck W. de , Norling T. , Giot J. , Pantanetti F. 
Published: September 2017

AbstractA drilling operation and core investigations at Base Roi. Baudouin (lat. 70° 25′ 5″ S., long. 24° 18′ 38″ E.) in January 1961 are discussed. The drilling, undertaken with light equipment, attained a depth of 115.72 m. From the start serious difficulties were encountered so that it was decided to use a SIPRE auger driven by the mechanism of the drilling machine. Core recovery was close to 100 per cent. Below a depth of 43.70 m., since the drill had reached the zone of high ice density (0.85 g./cm.3), a 3 m. double core barrel was used with air circulation. A depth of 79.33 m. was reached with a core yield close to 100 per cent. From this level downwards to the final depth of 115.72 in. the core yield was only 55 per cent.Preliminary observations were made at the site. A stratigraphie profile of the first 43 m. showed an al terna-ion of coarse-grained summer layers with ice formation and fine-grained winter deposits. From the seasonal alternations of the last six years, an average annual accumulation of 38.3 cm. of water was calculated. No coloured or dust layers were observed. Between 9 and 16 m. and between 41 and 44 m. an intense formation of ice was noticed. The depth-density curve is similar to those found by the. Norwegian-British-Swedish Antarctic Expedition at Maudheim and by the Americans at Little America V. If an average annual accumulation of 38 cm. of water is assumed, the whole depth drilled corresponds to approximately 240 yr. Temperature measurements could not he carried out b;rcause of the limited time available.Detailed stratigraphie and morphological studies of the cores, which are stored at −15°C. in Brussels, are planned, as well as chemical and isotopic investigations.
The Settling of Firn at Little America III, Antarctica, 1940–58
Authors: Hoinkes Herfried C. 
Published: September 2017

AbstractObservations in the glaciological pit of Little America III (1939–41), carried out in March 1957 and in January 1958, are discussed. Of particular interest is the analysis of the settling of firn over a period of 17.6 years. The observed data, including those of Wade taken in 1940 and of Howard in 1947, were fitted best by a logarithmic expression, which proved useful as an interpolation formula. From the computed values of the rate of settling, and the observed density-depth relation, the average accumulation is calculated, using Sorge’s law. For the undisturbed period 1947–58 an average annual accumulation of 19 g./cm.2 is found for Little America III (position in 1958 about lat. 78° 26′ S., long. 163° 52′ W.).
Aspects of the Glaciology of Meighen Island, Northwest Territories, Canada
Authors: Arnold K. C. 
Published: September 2017

AbstractMeighen Island lies in the centre of the north coast of the Queen Elizabeth Islands and fronts on the Arctic Ocean. An ice cap of about 76 km.2 covers about one-tenth of the island. Its greatest thickness of 150 m. occurs under the summit, near the south end, which was 268 m. above sea-level in 1960. The northern half of the ice cap is less than 30 m. thick; and the total volume is of the order of 2,000 × 106 m.3.Precipitation is low in the northern Queen Elizabeth Islands, and Meighen Island lies in an area where summer temperatures are lowest. In the winters of 1959–60, 1960–61 and 1961–62, the snow accumulation was 12.6, 18.2 and 14.1 cm. of water equivalent. Some snowfall remained on the higher part of the ice cap in the cold summer of 1961; but the ice cap diminished in volume in each year; by 36 × 106, 72 × 106, 22 × 106 and 91 × 106 m.3 in the 1959, 1960, 1961 and 1962 ablation seasons.If the conditions of these four seasons were maintained the ice cap would disappear in about 100 yr. However, a radio-carbon dating of a saxifrage exposed by the retreat of the ice from a small nunatak near the northern edge gave a date of less than 100 yr., and it appears that the existence of the ice cap might be sensitively related to recent climatic change.Careful surveys were made in 1959, 1960 and 1961 in an attempt to detect movement in the ice cap. Unequivocal evidence is not available from these surveys; but the stake network has been maintained and another survey has recently been completed.
Densification of Snow on the Ice Sheet of Ellsworth Land and the Southern Antarctic Peninsula
Authors: Behrendt John C. 
Published: September 2017

AbstractDensity-depth curves constructed from seismic travel-time data observed at 25 locations, show a large variation over an essentially isothermal area (T = −22±2.6° C). This is correlated with the wide range of mean annual accumulation values. (A = 20 to 50g./cm.2yr). Quantitative estimates of mean annual accumulation can be obtained from seismic refraction data in this area by the expression A = 23.5+0.049(3500−V200) where V200 is the compressional wave velocity (m./sec.) observed at 200 m. from the shot point. The density-depth curves can be used to give estimates of accumulation by the expression:where ρ40 is the density (g./cm.3) at 40 m. depth. The internal consistency of these methods is indicated by the standard deviation of ±2.9./cm.2 yr. for comparisons of accumulation estimates. The theoretical basis for these results is discussed.
On the Accumulation and Seasonal Stratification Of Snow at the South Pole
Authors: Gow Anthony J. 
Published: September 2017

AbstractThe seasonal distribution of snow at the South Pole and its relationship to stratigraphy was investigated to pits dug beside a number of four-year-old accumulation stakes. Results show that conventional stratigraphic methods yield thoroughly reliable values of accumulation rates. Even hiatuses in accumulation can be identified from the intensity of sublimation of layers of depth hoar in the stratigraphic section. Such hiatuses are due almost invariably to the prolonged absence of accumulation rather than to widespread scouring of pre-existing layers of snow. The bulk of the year’s accumulation is deposited as dunes during winter. The majority of dunes are subsequently transformed into linear sastrugi by wind with the result that the amplitude of surface relief observed at the end of winter frequently exceeds the average thickness of snow accumulated annually. Such gross relief does not persist to the end of summer, however. Instead the dunes and sastrugi arc gradually worn down by a process of sublimation-deflation. It is this leveling of the surface relief in summer and the resultant redistribution of snow more uniformly over the surface that are believed to be the significant factors in the formation of the systematic stratigraphy observed in pits at the South Pole.
Gravity Measurements on the Devon Island Ice cap and an Adjoining Glacier
Authors: Hyndman R. D. 
Published: September 2017

AbstractGravity measurements have been used to determine ice thicknesses across the western part of the Devon Island ice cap in the Canadian Arctic. A detailed profile of the ice-cap edge and a profile across an adjoining glacier are also given. The ice cap has been found to have a largely rock core with ice thicknesses generally less than 500 m. A deep valley has been found in the bedrock beneath the ice cap some 15 km. from the start of a draining glacier. The measured depths on the ice cap should be within 15 per cent and those on the glacier within 20 per cent of the true values.
Net Budget and Flow of South Cascade Glacier, Washington
Authors: Meier Mark F. , Tangborn W. V. 
Published: September 2017

AbstractIce velocity, net mass budget and surface elevation change data were collected over the length and width of a small (3.4 km. long) valley glacier from 1957 to 1964. Ice velocities range up to about 20 m./yr.; three prominent velocity maxima along the length of the glacier correspond to maxima in surface slope. Net mass budgets averaged over the glacier surface range between − 3.3 m. of water equivalent (1957–58) and +1.2 m. (1963–64). Except for the year 1960–61, curves of net budget versus altitude are parallel. During the period 1958–61 the glacier became thinner at a rate averaging 0.93 m./yr. The net budget and thinning data are internally consistent. Relations between emergence velocity, net budget and surface elevation change are examined at four specific points on the glacier surface and as functions of distance along the length of the glacier. Emergence velocity averages about −0.5 m. in the upper part of the glacier and about +1.0 m. in the lower part. Ice discharge and ice thickness are also calculated as functions of distance. The discharge reaches a peak of 8.8 × 105 m.3 of ice per year 2.2 km. from the head of the glacier. The mean thickness of the glacier is about 83 m. A steady-state distribution of net budget is used to calculate a steady-state discharge, which is 2.2 times larger than the present discharge.
The Frequency Response of Glaciers
Authors: Nye J. F. 
Published: September 2017

AbstractThe theory developed in previous papers to represent the response of a glacier to changes in the rate of accumulation and ablation has been used for a number of applications. A method of integrating the differential equations for a fixed frequency was programmed for a high-speed digital computer. This provides a better way of finding the frequency response than the earlier method which used series approximations or high and low frequencies. Results are given for (a) an artificial glacier showing varying amounts of diffusion of the kinematic waves, (b) South Cascade Glacier, Washington, U.S.A., as a check on previous results, and (c) Storglaciären, Kebrekaise, Sweden. The response curves of Storglaciären are very similar in shape In those of South Cascade Glacier but, since. Storglaciären moves more slowly, the curves are shifted in frequency (by a factor of two). The phase of the response at the terminus of Storglaciären plotted against frequency shows a double peak.Certain mathematical results for the artificial case of no diffusion are given in an Appendix.A computer programme was also written for calculating λ and μ coefficients and applied to South Cascade Glacier and Storglaciären.
Accumulation of Snow in Alpine Areas of Central Colorado and Means of Influencing it
Authors: Martinelli M. 
Published: September 2017

AbstractThe accumulation of snow in terrain depressions was studied in an alpine basin in central Colorado. Snow fences and a jet roof were built up-wind of several natural catchments to see if such barriers could be used in combination with terrain features to produce snow fields that would persist until late summer. At three of the six test sites, fences increased snow depths appreciably and the snow fields persisted longer than usual. At the other test sites snow depths were increased close behind the fences but were decreased farther down-wind with no net increase in the amount of snow caught.
Thickness and Basal Configuration of Lower Blue Glacier, Washington, Determined by Gravimetry
Authors: Corbató Charles E. 
Published: September 2017

AbstractGravity measurements at 146 stations on lower Blue Glacier were used to determine the subglacial bedrock configuration. The gravity values, station elevations and density contrast were carefully measured, and terrain corrections thoroughly evaluated to insure accuracy of the Bottguer anomalies. A series of successive approximations results in evaluation of the regional gravity field and a three-dimensional model of the glacier whose gravimetric effects fit the range of the observational and computational errors. Comparison with bore holes and seismic reflections indicates no significant errors in the model and accuracies of 5–10 per cent in the calculated thicknesses of the glacier.
The Bottom Topography of Gulkana Glacier, Alaska Range, Alaska
Authors: Ostenso N. A. , Sellmann P. V. , Péwé T. L. 
Published: September 2017

AbstractAs an extension of an intensive study of Gulkana Glacier a 42 station gravimeter survey was made to gain some insight into its third dimension. This survey showed that the glacier’s main tongue occupies a complex valley composed essentially of two parallel channels separated by a medial ridge which extends southward from rock bastions in the accumulation zone. At mid-glacier the ice thickness in the larger eastern channel is 225 m., in contrast to 130 m. in the western channel. The medial ridge degenerates down-glacier probably disappearing within 2 km. of the glacier terminus. The basic surface flow pattern of the glacier described by Moores can be adequately explained by this basal topography. Seasonal velocity variations are possibly caused by melt-water basal lubrication with one channel being favored over the other at different times of the year, in agreement with observations by Elliston on the Gorner-Gletscher, Switzerland, and with the glacier sliding theory of Weertman.
Foliation Pattern of Gulkana Glacier, Alaska Range, Alaska
Authors: Rutter Nathaniel W. 
Published: September 2017

AbstractGulkana Glacier, consisting of three major ice streams and two prominent ice falls, displays a complex foliation pattern. In the western ice stream, below Gabriel Ice Fall, the foliation is transverse, developing gradually down-glacier into a distinct series of nested arcs. The arcs are concave up-glacier with the foliation dipping steeply toward the inside of the arc. A similar pattern is displayed in the eastern ice stream but there the pattern is less distinct with the arcs evolving into a series of nested semi-arcs. The central ice stream is characterized by vertical layers of foliation with a longitudinal strike. Apparently, longitudinal foliation will form in areas with strong compression and shear caused by differential flow velocity such as where two ice streams unite. The foliation that ultimately displays arcuate (or semi-arcuate) patterns originates principally at the base of an ice fall where strong longitudinal compression is present due to the decrease of gradient.
Névé-Capped Snow Pillars Resulting from Ablation on Teton Glacier, Wyoming
Authors: Fryxell Roald 
Published: September 2017

AbstractNévé-capped snow pillars found on Teton Glacier in August 1956 were formed in the same manner as the ice cones of glacier tables, the névé acting in this instance as the protective cover usually provided by slabs of rock. Measurements of the largest pillar indicate a minimum ablation of 6.5 ft. (1.98 m.) of snow on the surface of Teton Glacier for that summer up to 7 August, and suggest an average rate of snow wastage of 1.5 in. (3.8 cm.) per day during this time. The pillars appear to have been produced by ablation through melting due primarily to direct radiation but supplemented by indirect radiation and conduction-convection influenced by air currents moving across the surface of the glacier.
Dielectric Properties of Ice and Snow–a Review
Authors: Evans S. 
Published: September 2017

AbstractThe permittivity and loss tangent of naturally occurring ice and snow are considered. The direct-current conductivity is considered only when it is of importance to the alternating-current and radio-frequency properties. Laboratory measurements on pure ice, and deliberately contaminated ice, are included to help in explaining and extrapolating the behaviour of natural ice and snow. The lower band of frequencies from 10 c./sec. to 1 Mc./sec. is occupied by a relaxation spectrum in which the relative permittivity falls from approximately 100 to 3. The loss tangent reaches a maximum at a frequency which varies from 50 c./sec. to 50 kc./sec. as the temperature increases from −60°C. to 0°C. We are interested in the effect of snow density, impurities, stress, crystal size, and orientation. For frequencies much greater than 1 Mc./sec., the relative permittivity is 3.17±0.07. The loss tangent reaches a minimum value at approximately 1,000 Mc./sec. beyond which the dominant influence is infrared absorption. The minimum is 10−3at 0°C or 2×10−5at −60°C. These values are greatly increased by impurities or free water. Some possible applications to glaciological field measurements are mentioned.
Seasonal Weather Trends in Relation to Fluctuations of the Jan Mayen Glaciers Since 1920
Authors: Sheard J. W. 
Published: September 2017

AbstractThe meteorological records for Jan Mayen have been examined on a seasonal basis in order to obtain a clearer understanding of the fluctuations of the Beerenberg glaciers from 1920 to the present day. Summer and winter have been arbitrarily defined as including those months with mean monthly temperatures, at sea-level, above and below 0°C., respectively. The results indicate that the retreat of Sørbreen prior to 1940 was associated with high summer temperatures and high summer precipitation, and relatively low winter precipitation. A rapid rise in winter precipitation followed, which culminated about 1950. The advance of Sørbreen since about 1954 is thought to have been caused by this rapid rise of precipitation and has also been associated with a slight drop in summer temperature, which is considered to be of secondary importance. The most recent trends of rising summer temperature since 1956 and falling winter precipitation since 1958, if they continue, must lead to a renewed retreat of the glaciers. Studies on Sørbreen in the summer of 1963, which show that the recent advance has ceased, support this view.
The Formation of Drainage Wind on a Snow-Dome
Authors: Businger J.A. , Ramana Rao K. 
Published: September 2017

AbstractDirect measurements of the horizontal divergence of the air flow close to the snow surface have been made. The mean vertical wind component has been derived from these observations. The temperature profile has been analyzed near the center of the snow-dome and a method to determine the sensible heat flux independent from the energy budget has been developed.
Long-Term Glacier Variations Measured by Photogrammetry. A Re-Survey of Tunsbergdalsbreen after 24 Years
Authors: Kick W. 
Published: September 2017

AbstractThe relations between geodetic measurements of the surface level variations Δh and net budget measurements by stakes arc discussed. In 1961, 24 yr. after Finsterwalder’s survey, Tunsbergdalsbreen, the largest and most regular of the 26 outlet glaciers of Jostedalsbreen, was re-surveyed. The variations in the length, area, ice thickness, and volume of its tongue are shown. The lake Brimkjelen was 99 m. deep in 1937; it disappeared in 1949. From 1900–40 the whole Jostedalsbre lost 0.4 m./yr., about the same amount as the glaciers of the eastern Alps. The ice thickness of the Tunsbergdalsbre tongue diminished by −ΔhA = 0.46+0.0022 (1500−A) m./yr. from 1937–61; for the eastern Alps from 1920–50 −ΔhA ≈ 0.53+0.0021 (2850−A) m./yr. where A is the altitude. The change of Δh with altitude is much the same. The amounts of the retreat of the Alpine glaciers, of Tunsbergdalshreen, and at Werenskioldbreen, Vestspitsbergen, were the greater the higher the latitude. The numerical relations between Δh, net budget, and ice movement are shown. The temporary velocity transverse profile of 1937 served as a prototype for the streaming mode of flow, but in 1961 the glacier partially showed Blockschollen movement, although the velocity had decreased by more than 30 per cent. The article is accompanied by a map showing ice surface contours in 1937 and 1961.
A Theory of the Consolidation of Snow
Authors: Feldt E. D. , Ballard G. E. H. 
Published: September 2017

AbstractA consolidation theory is developed for an age-hardened snow under uniaxial stress in the porosity range of 35 to 55 per cent by considering one mechanism, viz. viscous flow of interparticle bonds. For a uniaxial stress σ the differential equation for porosity n in terms of time t is shown to be
where a and ν are structural parameters and η is the coefficient of viscosity of ice. Comparison of this equation and the integrated form with existing data predicts consistent and reasonable values for a. The predicted values of η/ν range from 10−2 to 102 times the published values for, η which may indicate that ν, and hence the consolidation rate, is greatly affected by the diagenetic history of the snow and the conditions of experimentation.
Instruments and Methods Snow Density Profiling by Nuclear Means
Authors: Leighty Robert D. 
Published: September 2017

AbstractDuring the period 8–19 May 1963 a preliminary field investigation was conducted in Greenland to determine the feasibility of using a nuclear technique to determine snow and ice density profiles. A standard nuclear soil-moisture depth probe was used with two modes of processing and recording the nuclear pulses. Example data are compared with snow densities obtained by the standard weighing technique. The nuclear method was found to be feasible; however, deficiencies related to poor resolution render the probe unusable for detailed profiling of snow stratigraphy in its present form, but expected progress in nucleonics should enable improved resolution and accuracy to be achieved by improvement of nuclear detectors.
Effect of a Basal Water Layer on the Dimensions of Ice Sheets
Authors: Weertman J. 
Published: September 2017

AbstractThe effect of a basal water layer on the equilibrium dimensions of an ice sheet is examined. A thick water layer can decrease the equilibrium thickness of an ice sheet such as covers Antarctica (which contains no significant ablational areas) by a factor of the order of 2. Similar large changes in the equilibrium dimensions occur for ice-age ice sheets (which have extensive ablation areas). The extent of the ablation area of an ice-age ice sheet which may be covered with morainal debris is also calculated.
A Seismic Reconnaissance in the Mcmurdo Sound Region, Antarctica
Authors: Bell Robin A. I. 
Published: September 2017

AbstractA portable first-arrival seismic refraction instrument was used to measure seismic P-wave velocities in ice, frozen ground, till and shattered rock at various places in the McMurdo Sound region, Antarctica. It was found that some frozen ground exhibits the same seismic velocity as ice, so that buried ice cannot be idengified by seismic velocity measurements.The depth of exfoliation of a granite outcrop in Taylor Valley was successfully measured, as was the depth of an ice-free moraine in Wright Valley. From this latter depth, and from reasonable assumptions about the diffusion of water vapour through till, a minimum age of 75,000 yr. has been deduced for the moraine. This age implies that no through-glacier occupied Wright Valley during the last Northern Hemisphere glaciation.
Some Observations on the Climate of Lewis Glacier, Mount Kenya, During the Rainy Season
Authors: Platt C. M. 
Published: September 2017

AbstractMeteorological observations were made on Lewis Glacier, Mount Kenya, during the “long rains” in April 1960. General meteorological observations indicated rather similar conditions to those found in other months. Ablation occurred on each day but amounts were generally small. Rather more accumulation occurred than is expected during the dry season, but again amounts were small. The net accumulation over a to day period was only 0.38 cm. water-equivalent, although about 30 cm. new snow (about 10 cm. water-equivalent) was lying when the expedition arrived. Detailed observations of short-wave radiation, temperature, wind and humidity with estimates of long-wave radiation were used to calculate the heat balance at the surface of the upper ablation region. Agreement between calculated and measured ablation was reasonably good. Over the periods considered, radiation accounted for 89.5 per cent of ablation, turbulent exchange from the air for 8.0 per cent and evaporation for 2.5 per cent. Subsurface melting was taken into account and the formation of ice bands in terms of such melting is discussed.