Ice sheets consist of several disjoint regions, each with physically distinct behavior. Parts are cold; others are temperate and either partly or completely saturated. Varying dust content, impurities, debris content, etc., may affect the ice flow. Usually, these regions are separated by material or non-material surfaces or boundaries. We use mixture concepts, involving the balances of mass, momentum, energy and entropy. When applied to regular domain points these concepts and appropriate constitutive postulates yield the field equations for the evolution of the constituents. When formulated in terms of singular surfaces, boundary and transition conditions emerge. Our presentation takes the form of an extended abstract of work that is presently under consideration (Hutter and Engelhardt 1988; Hutter and Engelhardt, in preparation).

Radiation budget measurements were made at Mizuho station (70°42'S, 44"20'E, 2 230 m a. s.1.), East Antarctica, in 1979, within the framework of the Japanese POLEX-South programme. Global, and reflected short-wave and downward and upward long-wave radiat i on fluxes were measured at the snow surface and at the top of a 30 m tower. Direct solar radiation was also measured at the snow surface.

Seasonal variations of net radiation and net short-wave and net long-wave radiation are presented. Daily variation of net radiation is also presented with the daily value of meteorological elements. The monthly amounts of net radiation in winter months had very large negative values of about -80 MJ m−2 month−1. (-2 kly month−1). Daily totals of net radiation for clear skies were negative even i n summer, and were always smaller than those for cloudy skies. Monthly amounts of net radiation in summer months (about -1 MJ m−2 month−1 in December) were the smallest among the several Antarctic stations compared, and whether the balance was negative or positive depended on the ratio of clear and cloudy days. Comparison of seasonal variations of radiation components was made and the dominant cause of the radiation balance was discussed.

Good hydrological knowledge is necessary for the planning of a hydro-electric power installation. Observations of daily discharge in Norwegian streams are available for several decades, but for glacierized basins there is a lack of information. Either the observation period is too short or it comprises mainly years when glaciers retreated and thus produced extra amounts of melt water – a direct result of negative mass balance. Consequently, many discharge figures are too ‘optimistic” — they indicate larger average run-off than would be the case if glaciers were in a steady state, or, even worse, if they started to grow and then started to reduce their melt-water contribution to rivers.

Our means of correcting actually observed discharge figures for glacier influence is to perform annual mass-balance measurements. This has been done since 1948 for one glacier and since 1962 for several glaciers and results have been used in the planning of power stations. The method is, however, relatively costly.

Another method is now being developed. Repeated glacier mapping makes it possible to calculate the average change (decrease) in glacier volume between the years when air photographs were taken. Therefore, several glacier maps have been produced based upon older vertical photographs and new maps are constructed from repeated air photography of the same glaciers. By subtraction, the total decrease in ice volume can be calculated and, hence, corrections of observed discharge be made.

This method is quicker and cheaper than conventional mass-balance measurements. Large potentials for this method lie in future digital maps.

Almost all the detailed (1:10 000) Norwegian glacier maps are printed in four colours and they have a standard UTM coordinate grid and 10 m contours. An example of a recent map is enclosed in the map pocket on the rear cover of this volume.

The spatial pattern of accumulation rate for eastern Kemp Land in the elevation range 1850-2700 m is presented together with observations of the physical parameters of snow temperature, average microwave emissivity (19 GHz, H polarization), distribution of depth hoar and firn-crystal diameter. The broad accumulation pattern in the region was found to be significantly low when compared to other coastal areas of East Antarctica such as Wilkes Land. The low accumulation regime is attributed to low atmospheric moisture transport and low penetration of synoptic cyclonic systems on to the coastal slopes. In the absence of high coastal precipitation, the accumulation rate is determined predominantly by surface snow redistribution processes. Attempts to determine accumulation-rate time series using visible layer, δ18O isotope and electrical conductivity stratigraphies were unsuccessful due to the relatively low coastal accumulation rates (less than 280 kg m-2a-1) and the complex modification of precipitation by redistribution processes.δ18O variations of seemingly cyclic nature observed throughout the cores were interpreted as a product of the snow-dune building and erosion processes, together with general redistribution of snows by the surface wind field, under the influence of mesoscale topographic roughness

Intense deformation within an extensive englacial debris layer appears to be a dominant flow mechanism for glaciers on Mount St Helens, Washington. Observations of this phenomenon have been made on Shoestring Glacier and more recently on other glaciers on the volcano. Transverse velocity profiles on Shoestring Glacier have shown a marked plug flow behavior occurring between narrow marginal zones of crevassing. Both longitudinal and transverse velocity profiles on Shoestring Glacier were measured during the year before and the two years after the cataclysmic eruption of the volcano on 18 May 1980.

The geometry and regime of every glacier on Mount St Helens dramatically changed during the eruption. The entire accumulation area of Shoestring Glacier was removed by a volcanic landslide and blast, and the glacier surface was deeply incised through the action of pyroclastic flows and mudflows. Surface velocity measurements were supplemented by vertical profiles taken along the newly exposed ice cliffs. Large velocity gradients seen in the transverse, longitudinal and vertical profiles coincided with the mapped location of a recently exposed englacial debris layer. Further detailed measurements on the vertical profiles show that the intense shear occurs by deformation internal to the debris layer, A study of the properties of debris-laden ice was undertaken to determine the mechanism for localization of deformation to the debris layer and for the associated response of the glacier to a sudden change in stress.

Temperature measurements taken in young, landfast Antarctic sea ice show daily oscillations consistent with heating by solar radiation. We present and solve a heat conduction model for the temperature with a non-linear thermal capacity and a distributed source term for solar power absorption based on Monte Carlo scattering simulations of penetrating photons. We observe two characteristic modes for solar heating in sea ice, one dominated by travelling thermal waves or conduction in the upper half, and the other dominated by in-place solar heating in the lower half. We note that deep thermal responses to solar radiation are larger by a factor of ∼ 10 than predicted by scattering measurements, due possibly to the presence of algae and/or dissolved organic material.

Knowledge of frontal ablation from marine-terminating glaciers (i.e., mass lost at the calving face) is critical for constraining glacier mass balance, improving projections of mass change, and identifying the processes that govern frontal mass loss. Here, we discuss the challenges involved in computing frontal ablation and the unique issues pertaining to both glaciers and ice sheets. Frontal ablation estimates require numerous datasets, including glacier terminus area change, thickness, surface velocity, density, and climatic mass balance. Observations and models of these variables have improved over the past decade, but significant gaps and regional discrepancies remain, and better quantification of temporal variability in frontal ablation is needed. Despite major advances in satellite-derived large-scale datasets, large uncertainties remain with respect to ice thickness, depth-averaged velocities, and the bulk density of glacier ice close to calving termini or grounding lines. We suggest ways in which we can move toward globally complete frontal ablation estimates, highlighting areas where we need improved datasets and increased collaboration.

Blue Glacier was subject to 5 to 10% increase in thickness during the period 1958 to 1978. A surface velocity increase of 15 to 50% has accompanied this change in ice thickness. A non-uniform distribution of thickening over the glacier produced a general decrease in surface slope. The flow law parameters in a power-law relation for ice can be obtained from the resulting increase in velocity.

In 1957–58 the surface velocities and surface elevation along several transverse profiles were determined by others. During the period 1977 to 1980 similar measurements were made of surface velocity, elevation, and ice thickness along profiles spatially equivalent to those of the 1957–58 survey. Using these results a detailed study of the flow response has been made. Preliminary results indicate that the controlling surface slope a is one that is averaged over approximately ten times the glacier thickness and also indicate a relatively high stress exponent n = 4 to 5.

Blue Glacier flows in a complex channel and any detailed interpretation of the flow response requires the inclusion of this geometry in a model. For this reason multi-dimensional finite-element methods using a non-linear constitutive relation were employed. Various degrees of model sophistication allowed for the specification of different parameters governing the flow of the glacier. Variations in the flow law parameters and the curvature of the channel were found to have significant effects on the velocity and stress fields, as well as on the characteristics of the flow response to the thickness perturbation. Fully three-dimensional models of the flow of Blue Glacier and its response to the thickness increase were developed. Important effects such as those arising from longitudinal thickness and surface slope variations were included in three-dimensional modeling. The three-dimensional effects were seen to play an important role in flow of a rheologically non-linear fluid such as ice.

We performed X-ray diffraction measurements on eight ice samples taken between 3200 and 3611 m depth of the Vostok (Antarctica) ice core to observe lattice distortions of ice crystals. Selected samples represent three distinct sections of the core: (i) glacier (meteoric) ice with well-preserved climatic record (down to 3310 m), (ii) ‘shear zone’ at the base of the glacier ice (3450– 3537 m) within which the climatic record is disturbed by ice deformation, and (iii) accretion ice formed by freezing of subglacial Vostok lake waters at the base of the ice sheet (from about 3537 m depth to the bottom of the core). The dislocation density decreases from 1012 to 108m–2 with increasing depth. In the accretion ice, lattice distortion tends to decrease with depth. However, the dislocation density does not reach a level typical for laboratory-grown columnar ice even at 3610 m. This reflects plastic deformation which accretion ice has undergone after its formation.

Laboratory results are presented concerning ice creep at minimum creep rate (at ~1% strain) for fine-grained, initially isotropic, polycrystalline samples. The effect on the creep rate of ice density, sample shape (aspect ratio) and size, grain-size and ratio of grain-size to sample size is examined. Provided sample density is above ~0.83 Mg m−3 (i.e. the close-off density), there is no effect of density on ice-creep rate. Results provide no evidence of a creep rate dependence on test sample length for cylindrical samples. Sample diameter, however, does affect creep rate. Over the range of sample diameters studied (16.2 to 90 mm) creep rate decreases monotonically by a factor of ~4. This effect is independent of sample aspect ratio. Experiments examining size effects in simple shear indicate no dependence of minimum flow rate on shape or size in this stress configuration. Two grain-sizes were represented within the samples tested for the effect of sample size. As expected from earlier work, no grain-size effect on minimum creep rate is evident. In addition, there was no evidence of an effect on creep rate of the ratio of grain-size to sample size.

Citizen science and related engagement programmes have proliferated in recent years throughout the sciences but have been reasonably limited in the cryospheric sciences. In the semiarid Andes we at the Centro de Estudios Avanzados en Zonas Áridas have developed a range of initiatives together with the wider community and stakeholder institutions to improve our understanding of the role snow and ice play in headwater catchments. In this paper we reflect on ongoing engagement with communities living and working in and near study sites of cryospheric science in northern Chile as a strategy that can both strengthen the research being done and empower local communities.

This paper presents a model of snow structure (model of regular grain packing) that is based on experimental determination of various geometrical characteristics of fine-, medium- and large-grained granular snow. Data analysis supports the possibility of approximating the ice-matrix configuration as a regular lattice of nearly spherical ice grains connected by rigid ice bonds. The model was successfully used for relating microstructural parameters of snow to snow density, compaction behavior and evolution of mechanical properties.

The Tianger area in the Tien Shan preserves many glacial landforms to which several methods of estimating ancient equilibrium-line altitudes (ELAs) can be applied. Thus it provides the opportunity to compare different methods and evaluate the correlation between the methods and their errors. This comparison provides guidance in the application of these methods in other mid-latitude alpine glaciated areas. In this paper we calculate characteristic ratios relating to the ELAs, including accumulation–area ratio (AAR), toe–headwall altitude ratio (THAR), terminus–summit altitude method (TSAM) and Höfer value, and their correlations with each other and the geomorphological characteristics. The AAR of a glacier is small when the slope of the bedrock beneath it is small and the area is large, and the AAR of a glacier with such characteristics is better correlated with its THAR, TSAM and Höfer value. Paleoclimate information derived from these characteristic ratios relating to ELAs is discussed. The glaciers and the glacial climate of the early and middle stage of the last glacial are more continental than those of the Last Glacial Maximum (LGM). Compared with those of the LGM on the Qinghai–Tibetan Plateau and surrounding mountains, the ELA characteristics of the early and middle stage of the last glacial in the Tianger area show more continental features.

In the 1979–80 field season, a site survey was carried out in the southern Weddell Sea for the construction of a wintering station. The survey comprised glaciological investigations on the Filchner and Ronne ice shelves, such as ice movement, deformation, ice thickness, calving, accumulation, and snow temperature measurements which are relevant to mass-balance studies. Along with the investigations on the ice, oceanographical and bathymetrical observations were carried out along the ice front. The field data and observations lead to assumptions about the advance of the ice shelf as well as about the mass loss at the frontal zone due to calving and bottom melting. The ice-front velocity at 50°W is about 1 070 m a−1 and the bottom melting is estimated to be 3.2 m a−1 at 20 km south-west of the ice front.

The meltwater percolation process through the snowpack greatly influences its physical and mechanical properties. The percolation process is important for understanding the spring avalanche phenomenon as well as the meltwater runoff for basin hydrology studies. The permeability of individual snow layers depends on parameters such as porosity, pore connectivity and the geometrical shape of the pores. Snowpack equivalent permeability plays an important role in governing the transmission of meltwater through the different layers of the snowpack. In this paper, we present the design, fabrication and installation of a snowmelt lysimeter at Patsio field research station, Himachal Pradesh, India, and determine the snowpack equivalent permeability using lysimeter discharge data. The snowmelt lysimeter, having a collector area of 6.25 m2 and a high-capacity snowmelt measuring tipping bucket, was installed on flat ground near the observatory with a data acquisition system. Snowmelt discharge measurements were made for two melt seasons, 2006/07 and 2007/08. Snow and meteorological data were collected at 15 min intervals using a semi-automatic weather station. The hourly surface snowmelt was estimated using an energy-balance approach. The maximum daily discharge was >2 mm w.e.h−1 for most of the observation period. The daily mean wave speed of the meltwater front varied from 109 to 285 mm h−1 for a daily mean discharge range of 0.6–1.8 mm w.e.h−1, while wave speeds for a particular melt flux of 2 mm w.e.h−1 varied between 113 and 486 mm h−1. The pore-size distribution index was estimated using the power-fit relation between wave speed and discharge. The equivalent permeability of the snowpack was found to vary between 3.4 × 10−8 and 9.9 × 10−12 m2.

A mathematical model makes it possible to estimate the stability of soils in permafrost, the origin of different forms of underground ice, and pingo formation in several parts of the surface in the permafrost. The cryogenic formation of pingos, which is very widespread in permafrost areas, is investigated in the paper. The velocity and height of pingo growth depend on the total moisture content in soil, the type of soil, the initial salinity and the climate conditions. This problem is addressed using equations of Stefan’s heat problem, filtration and salt diffusion and equations for water pressure, with water moving to the phase boundary under different hydrostatic and osmotic pressures.

The Polar Sea Ice Topography REconstruction System, or PSITRES, is a 3D camera system designed to continuously monitor an area of ice and water adjacent to an ice-going vessel. Camera systems aboard ships in the polar regions are common; however, the application of computer vision techniques to extract high-level information from the imagery is infrequent. Many of the existing systems are built for human involvement throughout the process and lack automation necessary for round the clock use. The PSITRES was designed with computer vision in mind. It can capture images continuously for days on end with limited oversight. We have applied the system in different ice observing scenarios. The PSITRES was deployed on three research expeditions in the Arctic and Subarctic, and we present applications in measuring ice concentration, melt pond fraction and presence of algae. Systems like PSITRES and the computer vision algorithms applied represent steps toward automatically observing, evaluating and analyzing ice and the environment around ships in ice-covered waters.

Using significant technological breakthroughs and unconventional approaches, the goal of the in situ probing of glacier ice for a better understanding of the orbital response of climate (SUBGLACIOR) project is to advance ice core research by inventing, constructing and testing an in situ probe to evaluate if a target site is suitable for recovering ice as old as 1.5 million years. Embedding a laser spectrometer, the probe is intended to make its own way down into the ice and to measure, in real time and down to the bedrock, the depth profiles of the ice δD water isotopes as well as the trapped CH4 gas concentration and dust concentration. The probe descent is achieved through electromechanical drilling combined with continuous meltwater sample production using a central melting finger in the drill head. A key aspect of the project lies in the design and implementation of an efficient method to continuously transfer to the surface the ice chips being produced by the drill head and from the refreezed water expulsed downstream from the melting finger, into the borehole. This paper presents a detailed calculation and analysis of the flow rates and pressure conditions required to overcome friction losses of the drilling fluid and to effectively transport ice chips to the surface.

Measurements of a sample from ~580 m depth in the WAIS Divide (WDC06A) ice core reveal that bubbles are preferentially elongated in the basal plane of their parent grain, as expected if bubble shape preserves the record of dominant basal glide. This suggests that a method using bubbles as strain gauges could provide insights to grain-scale ice deformation. We introduce a technique using fabric and image analyses of paired thin and thick sections. Comparison of the crystallographic orientations of 148 grains and the shape orientations of 2377 intragrain bubbles reveals a strongly preferred elongation of bubbles in the grain basal planes (R2 = 0.96). Elongation magnitudes are consistent with a balance between ice flow deformation and diffusive restoration, with larger bubbles more elongated. Assuming bubbles record ice strain, grains with greater resolved stress on their basal planes from the far-field ice flow stresses show greater deformation, but with large variability suggesting that heterogeneity of the local stress field causes deformation even in unfavorably oriented grains. A correlation is also observed among bubble elongation, grain size, and bubble size, explaining a small but significant fraction of the variance ( P< 0.05), with implications for controls on ice deformation, as discussed here.