bluuebunny/crossref_metadata_2025_split huggingface dataset:
Geometry and flow conditions of subglacial water at South Cascade Glacier, Washington State, U.S.A.; an analysis of tracer injections
Authors: Fountain Andrew G. 
Published: September 2017

AbstractTracers were injected into South Cascade Glacier to determine the flow condition and geometry of the subglacial water system. Results indicate that two distinct drainage basins on the glacier feed the two main streams flowing from the glacier. In the largest basin, two parallel drainage networks exist, one englacial and the other subglacial. The englacial system is an arboresecent network of conduits, whereas the subglacial system is a distributed flow system. Both systems connect to a single subglacial conduit which appears as a stream at the glacier’s terminus. The comparison between the travel time of the tracers and stream discharge indicated that the single conduit was pressurized in July and partly filled in August and September.To estimate the flow geometry (e.g. path length, flow depth and velocity), the advection-diffusion equation was formulated to express the water velocity as a function of water depth. Longitudinal dispersion of the tracer was calculated from the shear in longitudinal water velocity. Results indicate that the flow is very wide compared to its depth and that the path is sinuous. The estimated flow speed in the conduits is an order of magnitude larger than the measured speed through the glacier, indicating that other flow processes, probably englacial, route the water much more slowly.The other, smaller, basin drains the water from the surface to the subglacial distributed flow system. Based on the travel time of the individual concentration peaks, the water could be flowing through a linked-cavity system or interconnected bands of highly permeable debris separated by zones of less permeability.
Basal ice accretion and debris entrainment within the coastal ice margin, Law Dome, Antarctica
Authors: Goodwin Ian D. 
Published: September 2017

AbstractBasal ice stratigraphy in coastal ice cliffs at the Law Dome margin has revealed the basal accretion of clean and debris-bearing ice, marine congelation ice and granular marine ice inland of the margin. Co-isotopic analysis of δ18O and δD isotopes together with solute chemistry were applied to determine the modes of accretion and debris entrainment. The marine congelation ice and the granular marine ice were formed from the basal freezing of desalinated sea water and the episodic mixture of basal meltwater and sea water, respectively. Two different debris-entrainment mechanisms were identified. Debris-band ice with debris concentrations of 6.3–33% (by volume) was formed from proglacial raised beach and shallow marine sediment incorporated by an over-riding advance of the margin. Two other debris-bearing ice types, dispersed debris-poor ice with debris concentrations <0.3% (by volume) and laminated debris ice with debris concentrations 0.9–1.9% (by volume) were accreted further inland from the margin by basal regelation processes associated with the Robin (1976) heat-pump effect.
Automated image analysis of ice thin sections — instrumentation, methods and extraction of stereological and textural parameters
Authors: Eicken Hajo 
Published: September 2017

AbstractImage-analysis procedures have been developed for a simple PC-based system to evaluate the textural features of ice thin sections automatically. The method yields parameters that describe both ice crystals and pores in an objective, reproducible manner. Specimens are recorded in linearly and circularly polarized light (ice grains) as well as in transmitted and incident plain light (pores) under standardized conditions. After preparative filtering, images are segmented through union of two Sobel-filtered images (ice crystals/grain boundaries) or through thresholding (ice crystals/pores). The quantification of texture is based on the evaluation of image contrast as well as on linear analysis and non-linear transforms to obtain information on grain-sizes and their distribution. In the study of ice pores, stereological effects of finite section thickness have to be corrected. The discussion focuses on errors involved in automated textural analysis and the glaciological yield of measured and derived parameters.
Velocity of radio waves in glaciers as an indicator of their hydrothermal state, structure and regime
Authors: Macheret Yu. Ya. , Moskalevsky M. Yu. , Vasilenko E.V. 
Published: September 2017

AbstractThe results of measurements of radio-wave velocities (RWV) by wide-angle reflection (WAR) methods in the temperate Abramov Glacier in the Alai Mountain Ridge and the “two-layered” sub-polar Fridtjovbreen and Hansbreen on Svalbard using a low-frequency (2–13 MHz) radar are considered and discussed. The experimental data obtained and the data from the literature show that the values of RWV could be a good indicator of the hydrothermal state of glaciers. As such, these data enable the identification of cold, temperate and transitional (two-layered) glaciers, and can be used for estimation of the water content in glaciers and changes in the hydrothermal state.
Snow Crystals Observed at Mauna Loa
Authors: Nakaya Ukichiro 
Published: September 2017

AbstractThe expedition to Mauna Loa in Hawaii was undertaken in the winter of 1956–57 in order to study the nature of snow crystals in the district where the fewest aerosol particles are present. 170 photomicrographs of snow crystals were taken at the summit—13,450 ft. (4000 m.). The varieties of snow crystals were abundant and almost all types hitherto known were observed. The characteristic of the snowfall was the abrupt transition of one type to the other. Many single needles were observed, which were very rare in Hokkaido. Two new types were found; one was a needle composed of many hexagonal columns, and the other an elongated column which is the intermediate state of needle and column. Several photographs were obtained which show the mechanism of formation of ice pellets.
The Deformation of a Glacier Below an Ice Fall
Authors: Nye J. F. 
Published: September 2017

AbstractMeasurements have been made on Austerdalsbreen, Norway, to test the theory that wave ogives at the foot of an ice fall are formed by pressure. The pattern of deformation over the first three waves from the Odinsbre ice fall was studied by measuring the absolute and relative motions of 35 stakes during August 1956. There are large variations of longitudinal compression through the wave pattern, but no simple correlation exists between the compression and the crests; nor are the crests consistently rising with respect to the average surface. We conclude that the waves are not forming by pressure in this area. A detailed quantitative explanation of the observed pattern of deformation is found by improving the existing theory of glacier flow. The deformations taking place are explained as essentially independent of the presence of the waves; they are primarily due (a) to the compression that must occur in the ice as its slope decreases and it becomes thicker, and (b) to the bending and unbending to which the ice is subjected as it passes over a bed of changing curvature. Additional contributions to the deformation arise from the widening of the glacier channel, which is important at the immediate foot of the ice fall, and from the annual ablation.The theory explains quantitatively the rotation and bending of the tunnel excavated in 1955; it was also used to make a prediction, which was successfully verified in a further experiment on the glacier in July and August 1957.A pressure mechanism of wave formation can be reconciled with the observations if it is supposed that the compression in the lower two-thirds of the ice fall, which was measured photogrammetrically in August 1956, varies significantly with the seasons. However, the positions and amplitudes of the observed waves are fully accounted for by the combined plastic deformation and ablation mechanism recently described in another paper. There is therefore no longer any need for the pressure hypothesis as a primary cause of the waves.
Geothermal Heat and Glacial Growth
Authors: Wexler H. 
Published: September 2017

AbstractIn a 300 m. deep hole drilled in the 3000 m. thick ice at Byrd Station (lat. 80° S. long. 120° W., 1513 m. above sea-level), the temperature was observed to decline with depth below 45 m. This profile was extended to the bottom of the ice with the aid of heat conduction theory under these assumptions:
i.that as the ice was deposited the climate became warmer at the rate of 045° C. per 1000 years;ii.The conduction of geothermal heat is 31.6 cal. cm.−2 yr.−1.It is estimated that the first 2000 years of geothermal heat conducted to this ice, whose annual accumulation is 30 cm., is dissipated to the atmosphere and space. When the ice becomes thicker, it retains all the geothermal heat given to it for a long time.An alternative, non-climatic change explanation of the decreasing temperature in the Byrd Station hole is based on colder ice from higher elevations moving under the warmer ice accumulated locally. However, an examination of the topography of the Marie Byrd Land ice does not appear to support this explanation.
Mass Balance Studies in Antarctica
Authors: Mellor Malcolm 
Published: September 2017

AbstractThe general characteristics of the coastal regions between long. 45° E. and long. 80° E. are described. The features and conditions are similar to those found along the coasts of the Australian sector further to the east. Measurements of accumulation, snow transport, ice flow and ablation are described and results are given.Accumulation, measured from stakes and pits, is 1.0 × 1014 gm./yr. in a 1 km. wide strip running 850 km. inland from the coast of MacRobertson Land. The methods of gauging drifting snow and extrapolating the results are given and a meridional mass transport of 0.16 × 1014 gm./km. yr. is deduced. Iceberg calving rates given in a previous paper are again quoted, although they are now felt to be too low. Net ablation is 0.053 × 1014 gm./km. yr. and additional evaporation above the firn limit accounts for 0.045 x 1014 gm./km. yr. The estimates are compared with old and new observations from other parts of Antarctica and the problem of bottom melting beneath ice shelves is discussed.A distinction is made between the meteorological water budget for Antarctica and the glaciological mass balance for the ice sheet. Mass budgets for the sector between long. 45° E. and long. 80° E. and for the whole of Antarctica are drawn up. In each case a surplus of accumulation over losses appears, but it is felt that the data are insufficient to claim that the ice sheet is growing at the present time. The drift snow and ablation losses are added to the net accumulation to give a figure of 14 cm. of water as the mean annual precipitation over Antarctica, a value lying between the estimates of Meinardus and Kosack.
Equilibrium Profile of Ice Caps
Authors: Weertman J. 
Published: September 2017

AbstractNye’s theory of the equilibrium profile of two-dimensional ice caps is modified to include longitudinal stress and creep rate effects. A more generalized law for the sliding velocity of a glacier over its bed is introduced into the analysis in order to permit the inclusion of these additional complications. It is found that in the case of small ice caps (of the order of 30 km. in width), it is important to include the longitudinal stress. A somewhat “flatter” profile than that calculated by Nye is obtained. For ice sheets of the dimensions of the Greenland or Antarctic Ice Sheets, the additional stress causes essentially no modification in Nye’s theory. Nye’s theory also has been extended to include an isostatic sinking under the weight of the ice of the bedrock below an ice cap.
Mechanism for the Formation of Inner Moraines Found Near the Edge of Cold Ice Caps and Ice sheets
Authors: Weertman J. 
Published: September 2017

AbstractA new mechanism is described which explains the formation of moraines in the ablation areas of cold ice sheets. The mechanism involves the freezing of water onto the bottom surface of an ice sheet. This water comes from regions of the bottom surface where the combination of the geothermal heat and the heat produced by the sliding of ice over the bed is sufficient to melt ice. A number of criticisms are made of the shear hypothesis, which has been advanced to explain moraines occurring on Baffin Island and near Thule, Greenland. It is concluded that this older hypothesis may be inadequate to account for these moraines.Although in theory the mechanism proposed in this paper undoubtedly will lead to the formation of moraines, the existing field data are insufficient to prove conclusively that actual moraines have originated by means of this mechanism.
Glaciological Work of the 1959–60 U.S. Victoria Land Traverse
Authors: Stuart A. W. , Heine A. J. 
Published: September 2017

AbstractAccumulation along the route of the 1959–60 Victoria Land traverse, derived from 19 snow pits, was found to be 16 cm. of water equivalent. Sastrugi, reflecting prevailing surface wind directions, indicate that the surface winds in Victoria Land are katabatic. Movement points on the Ross Ice Shelf show a maximum rate of about 844 m./yr. with Iesser rates obtaining in more marginal areas. Stake measurements of accumulation on the Ross Ice Shelf indicate an average of 20 cm. of water equivalent/yr. A large glacier, about 300 km. long and up to 30 km. wide and draining into Rennick Bay, was discovered.
The Bara Shigri Glacier, Kangra District, East Punjab, India
Authors: Dutt G. N. 
Published: September 2017

AbstractDuring the monsoon of 1956 the Geological Survey of India sponsored an expedition to the Bara Shigri Glacier (lat. 32° 16′N., long. 77° 40′E), Kangra District, in the great Himalayan ranges of the Punjab, as part of the Indian programme for the International Geophysical Year 1956–57. Topographical maps of the terminal 3 miles of the glacier, on scales of 1:63.360 and 1:10,000, were prepared for comparison of morphological changes since it was last surveyed 50 years ago. The glacier appears to have shrunk considerably but its full extent could not be assessed because of insufficient earlier data. The Shigri Stream now emerges from a different part of the glacier snout. In order to assist future surveys three photographic stations were established.
Formation of “Blue” Glacier Ice by Horizontal Compressive Forces
Authors: Crary A. P. , Charles R. Wilson 
Published: September 2017

AbstractData are supplied to show that the “blue” surface ice zone encountered in the Skelton Glacier, Antarctica, results from horizontal compressive forces. Examples of the densification of surface snows of the Ross Ice Shelf by this means are also given. Such density changes should be expected in any area where either of the principal horizontal strain-rates is negative.
Glaciological Observations in Trinity Peninsula, Graham Land, Antarctica
Authors: Koerner R. M. 
Published: September 2017

AbstractThis paper is a summary of the more important results of glaciological investigations carried out in Trinity Peninsula, Graham Land during 1958–60, and which will be published at length in Falkland Islands Dependencies Survey Scientific Report No. 42. The budgets for Depot Glacier and the ice piedmont between Hope Bay and Trepassey Bay are given and it is concluded that in a normal year they are in a state of near equilibrium. The state of the glaciers of southern Trinity Peninsula is discussed in a consideration of the importance of rime ice formation on the west coast of the peninsula. Movement and accumulation studies in Trinity Peninsula and the islands of the James Ross Island group demonstrate a decrease in glacierization south-eastwards from the central plateau area. The recent glacial history of the area is also briefly reviewed.
Measurements of Side-slip at Austerdalsbreen, 1959
Authors: Glen J. W. , Lewis W. V. 
Published: September 2017

AbstractMeasurements have been made using two different methods of the rate at which the glacier Austerdalsbreen is slipping past its side wall at four sites. The rate of slipping varies from site to site in a way which seems to be connected with the details of glacier flow in the neighbourhood, and in all cases is less than the slip previously measured further up-glacier at the foot of one of the ice falls, and is also a smaller fraction (about one sixth) of the flow rate in the centre of the glacier. One of the methods measured the velocity of the last metre of ice, and this method gave movements which were more erratic than the other method, which measured velocity a few metres from the edge. This suggests that protuberances of rock and boulders lodged between the ice and the rock wall cause local variations in flow which are smoothed out in a few metres. The results are discussed in connection with the process of glacial erosion.
Contribution to the Movement and the form of Ice Sheets in the Arctic and Antarctic
Authors: Haefeli R. 
Published: September 2017

AbstractStarting from Glen’s flow law for ice and from a series of assumptions based in part on observations in Greenland and in the Jungfraujoch, the velocity distribution (horizontal velocity component) and surface configuration is derived for a strip-shaped ice sheet in a stationary state. For the choice n = 3 − 4 of the exponent in the power-law flow relation, there is extensive agreement between the theoretically calculated surface profile and the east-west profile measured through “Station Centrale” by Expéditions Polaires Françaises. The corresponding theoretical solution for a circular ice sheet is also given. As a first application of this theory, an attempt is made to calculate the average rate of accumulation in Antarctica from its surface profile (assumed circular in plan) and from the flow-law parameters derived from the Greenland Ice Sheet. It is also shown that a change in accumulation has only a small influence on the total ice thickness of an ice sheet. A method of calculating approximately the age of ice in an ice sheet, based on the foregoing theory, is illustrated by applying it to the Greenland Ice Sheet. After comparing the present theory with that of Nye, a general expression for the surface profile of an ice sheet with constant accumulation is set up and discussed by means of comparison with two profiles through Antarctica.
Early Discoverers XIII: The First Glaciologists in Central Asia
Authors: Kick W. 
Published: September 2017

AbstractContributions to the glaciology of the Himalaya, Karakoram, and Turkestan areas are contained in the hitherto unpublished records of the Schlagintweit brothers. These should be of considerable value for future research since the records include paintings, sketch maps, descriptions, and also measurements of glacier speed, which give details of the state of the glaciers in 1855–56. These records were used recently to great advantage on Nanga Parbat.
Notes on the Recent Advance and Retreat of Sefströmbreen in Ekmanfjorden, Vestspitsbergen
Authors: Dineley D.L. , Waters R.S. 
Published: September 2017

AbstractThese notes are based on observations made in 1958 while the writers were members of the Birmingham and Exeter Universities Spitsbergen Expedition. The position of the ice front in 1958 is compared with that recorded on five previous occasions between 1882 and 1936. A rapid 6 km. advance at the end of the nineteenth century has been followed by a slower but equally extensive retreat. A revision of the limit of maximum advance is based on geomorphological evidence. Reasons are suggested for the relatively small changes in the outline of the ice front since 1927, and the effects of spells of moderately high atmospheric pressure are noted.
Crystal Growth and the Formation of Spikes in the Surface of Supercooled Water
Authors: Hallett J. 
Published: September 2017

AbstractObservations made of ice crystals growing on the surface of supercooled water show that they take the form of a composite structure, called surface needles, each of which consists of dendrites growing into the liquid, and of ribs growing in the liquid surface. Each needle is a single crystal. The precise form of the needle is determined by the orientation of the initial nucleus. If its optic axis is near normal to the surface, growth occurs rapidly in two dimensions and covers a much larger proportion of the surface than is covered by the narrow surface needles, so that ice forming this way appears to have its optic axis vertical. Hollow ice spikes observed on pools are shown to have been formed by the freezing of water forced from beneath the surface at the intersection of two or three surface needles, the shape of the spike depending on their orientation.
An Historical Survey of the Late-Season Snow-Bed in Tuckerman, Ravine, Mount Washington, U.S.A.
Authors: Havens James M. 
Published: September 2017

AbstractAs a result of an historical sketch of scientific activity on Mount Washington, New Hampshire, it is shown that the late-season snow-bed that annually forms in Tuckerman Ravine disappeared, on the average, during the first week in August for the period 1922–58 as compared with an average date of 11 August for the period 1878–1906. This appears to correspond to a rise in spring (April to May) and summer (June to September) mean temperatures of 0.9° F. (0.5° C.) for each season from 1872–87 to 1933–58. The snow-bed probably has persisted through only one ablation season during recent years, that of 1926, although some evidence exists that it may have lasted through an occasional summer during the early and middle nineteenth century.
Ogives of the Forbes Type on Alpine Glaciers and a Study of their Origins
Authors: Fisher Joel E. 
Published: September 2017

AbstractOgives form beneath active ice falls whose heads are situated near or below the firn line. They consist of curved bands of alternating white, bubbly, less dense ice and darker, denser ice with fewer bubbles, extending throughout the thickness of the glacier. The difference in character is held to be due to the different conditions in the upper ice fall, through which the ice passes in one year at high speed. In summer the thin and shattered ice is exposed to high temperatures and melt water, while in winter the conditions are of Arctic-type throughout the thickness of the attenuated ice. A lane of ice on the Gornergletscher, originating as cold, dry snow with no melt water present, illustrates the character and origin of the white bubbly ice. The greater elevation of this cold-snow ice and the waves formed beneath the ice falls are considered to be the result of the lesser thermal conductivity and greater albedo of the white bubbly ice.
Contribution to the Knowledge of the Antarctic Ice Sheet: A Synthesis of Glaciological Measurements in Terre Adélie
Authors: Lorius C. 
Published: September 2017

AbstractThis paper is a synthesis of glaciological investigations conducted in Terre Adélie, mainly during the LG.Y. The surface and bedrock profiles have been obtained along a 500 km. line roughly perpendicular to the coast; the mean annual temperature has been studied as a finnction of altitude, and mean accumulation has been related to distance from the coast and surface slope. Stratigraphic studies made at Station Charcot again raise the problem of the determination of mean accumulation in certain parts of the Antarctic plateau; they provide a quadratic relationship between density and depth. The snow-drift studies lead to the Mowing conclusions: wind velocity and density of drifting snow are functions of height above the surface, and the total transport depends on wind velocity. Lastly, measurements have been made of glacier flow near the coast. The paper ends with a schematic study of the mass balance in Terre Adélie; accumulation seems to be slightly larger than ablation, a result that is to be contrasted with the obtervrd coastal retreat near Dumont d’Urille base.