Analyses of total β and γ radioactivity have been carried out on ten shallow ice cores collected in 1989 and 1990 on Kongsvegen and Sveabreen, Spitsbergen. No peak of total β radioactivity, corresponding to the Chernobyl accident (1986), can be identified. Chernobyl layers were identified by 137Cs and 134Cs activities, and a signal from the nuclear tests in Novaya Zemlya (1961–62), was detected at one location by 137Cs activity. The mean net accumulation for the periods 1986–89 and 1962–88 was estimated for both glaciers. Using topographic data, the mean net ablation on Kongsvegen was estimated for the period 1964–90 and the mean net balances were calculated. The results agree with recent direct glaciological balance measurements. For the period 1986–89, the net accumulation was higher on Sveabreen than on Kongsvegen, and the equilibrium-line altitudes (ELA) were around 450 and 520 m a.s.l., respectively. Kongsvegen had a positive balance of 0.11 m w.eq. and Sveabreen was in equilibrium, whereas for the last 26 years the balance of Kongsvegen was slightly negative (−0.10 m w.eq.) and the ELA was around 560 m a.s.l.

The tensile force required to break bonds between ice grains after short contact times (1–500 s) is measured as a function of temperature and contact pressure. The results indicate a sharp increase of the tensile load capacity of bonds alter short contact times near the melting point and a maximum rate of increase of the load capacity at −5 °C. The initial state or sintering is modelled, assuming viscous surface flow and plastic deformation as the main mechanisms.

Laboratory pH analyses of glacial melt waters are unrepresentative of in situ values, due primarily to CO2 gas exchange between the sample and the atmosphere, and solute enrichment from chemical reaction with sediment and colloidal particles. A method is presented which enables field pH measurements that are reproducible within ±0.04 pH units to be made in glacial melt waters, using commonly available digital pH meters with combination electrodes.

During initial spring snow melt in May 1981 at Gornergletscher, Switzerland, melt waters in the proglacial stream leaving the glacier terminus were oversaturated with respect to atmospheric p(CO2), and rapidly increased pH during CO2 outgassing at in situ temperature and pressure. Summer ice melt from glaciers which are temperate in the ablation zone are usually undersaturated by about ten times with respect to atmospheric p(CO2), and rapidly lower their pH values to achieve equilibrium upon encountering the atmosphere, as observed at Gornergletscher during July and August 1981. Gornergletscher summer proglacial stream waters, sometimes show pH increases from rock weathering, with the rate limited by the transfer rate of CO2 across the air-water interface to drive the weathering reactions. Throughout the year, any water parcel at equilibrium with atmospheric CO2 is generally at an equilibrium pH value, if filtration prohibits solute enrichment. For these reasons, laboratory pH measurements are unacceptable for quantitative studies of melt-water chemistry and should be discontinued.

Attempts are made to test the relation predicted by Brace (1960) between strain-rates and the ice-fabric patterns obtained at Mawson station, east Antarctica. These orientation fabrics not only are hardly related to the prediction by Brace (1960) or Kamb (1959) but also change easily within a strain grid with 100m diagonals.

Stable patterns of two- and three-maximum fabrics are confirmed. The latter is common and stable in the coarse ice at the surface of the ice sheet. It is apparent that the fabric patterns are generally related to the grain-size. The single-maximum fabric always occurs in fine-grained ice, then more maxima are formed in the course of grain growth.

It appears that syntectonic-secondary recrystallization is effective in producing the orientation fabrics with two, three and multiple maxima. Also, the maxima always shift away from the pole of foliation as grain-size increases and there are several stable positions of maximum such as 0°, 17°, 23° and 30°. It is expected that further stable angles would occur with coarser crystals as found in temperate glaciers.

The glacier sliding theory of Nye is modified to include the effect of solutes in subglacial regelation waters on the sliding process. Motivation for this development stems from studies of subglacially formed chemical deposits that appear to be widespread on rock surfaces recently exposed by retreating temperate glaciers. These deposits indicate clearly that considerable local concentration of solutes commonly occurs subglacially as a result of the selective rejection of solutes into the melt during the freezing associated with regelation sliding. Because solutes accumulate where regelation waters refreeze, they tend to lower the temperature there and hence inhibit the heat transport away from these areas that is essential for regelation sliding. For a simple sinusoidal bed and solute distribution in the regelation water film, the modified theory shows that a maximum excess of solutes of, for example, several millimoles/1 of dissolved CaCO3 along lee surfaces relative to stoss surfaces impedes basal sliding significantly, especially if the bed roughness wavelength does not exceed about one meter.

Observations and measurements made on the Ross Ice Shelf during 1974 suggest that rime and surface hoar deposited on the surface during fogs may contribute 5-10% of the annual accumulation. Layers formed during such fogs may be mistaken for depth hoar layers in the snow-pack.

Wave ogives arise in a solution of the continuity equation by the method of characteristics. Steady ice flow is assumed. Ice velocity, channel width, and mass-balance functions combine to form a wave-excitation potential that yields the forcing function for wave ogives. This linear-systems formulation extends the ogive theory of Nye. Convolution of the temporal cumulative mass balance and spatial forcing functions gives the total wave pattern below an ice fall. Many ice falls do not generate ogives because the wave amplitude is modulated by a factor related to ice-fall length. The wave ogives at Austerdalsbreen, Norway, are due almost entirely to ice acceleration at the top of the ice-fall, i.e. the same zone that King and Lewis showed was responsible for forming Forbes bands.

A numerical avalanche-prediction scheme was developed for highway applications at Kootenay Pass, British Columbia. The model features parametric discriminant analysis using Bayesian statistics to predict avalanche occurrences. Cluster techniques are then employed in discriminant space to analyze avalanche occurrences by the method of nearest neighbours. Extensive numerical testing of the model using an historical data base indicates that prediction accuracy may be 70% or better for both avalanche and non-avalanche time intervals.

We interpreted flow dynamics of the Kahiltna Pass Basin accumulation zone on Mount McKinley, Alaska, USA, using 40,100 and 900 MHz ground-penetrating radar profiles and GPS surface velocity measurements. We found dipping, englacial surface-conformable strata that experienced vertical thickening as the glacier flowed westward from a steep, higher-velocity (60 m a-1) region into flat terrain associated with a 90° bend in the glacier and lower velocities (15 m a-1) to the south. Stratigraphy near the western side of the basin was surface-conformable to ˜170m depth and thinned as flow diverged southward, down-glacier. We found complex strata beneath the conformable stratigraphy and interpret these features as buried crevasses, avalanche debris and deformed ice caused by up-glacier events. We also suggest that basin dimensions, bed topography and the sharp bend each cause flow extension and compression, significantly contributing to conformable and complex strata thickness variations. Our findings show that surface-conformable stratigraphy continuous with depth and consistent strata thicknesses cannot be assumed in accumulation basins, because local and up- glacier terrain and flow dynamics can cause structural complexities to occur under and within surface- conformable layers.

During Cook's 1772–75 Antarctic circumnavigation on the HMS Resolution, he recorded the positions of hundreds of icebergs. This paper compares Cook's observations and those of Halley in 1700, Bouvet in 1739 and Riou in 1789, with the Brigham Young University/National Ice Center (BYU/NIC) and the Alfred Wegener Institute datasets. Cook's description of the iceberg plume east of the Amery Ice Shelf and the iceberg distributions in the Weddell, Ross and Amundsen Seas agree with modern data. In January 1774, Cook reached his farthest south on the shelf of the Amundsen Sea Embayment, the site of the current International Thwaites Glacier Collaboration field study. Cook's largest iceberg had a 2.5 km diameter, where power-law models show that icebergs of this size or smaller comprise 92% of their total number. In the eastern Weddell, Cook's observation of a sea-ice tongue with a much greater extent than in satellite imagery remains unexplained. Although Riou's icebergs lie 1000 km east of the BYU/NIC trajectories, application of the England and others (2020) fracture and drift model to the trajectories removes the discrepancy and means that all the ship observations are consistent with modern observations and theory.

The turbulent flux of sensible heat in the energy balance of a glacier surface is assumed to be proportional to the temperature difference between the glacier surface and the atmosphere at the same level but outside the thermal influence of the glacier. The factor of proportionality between them is first explained in terms of friction velocity, roughness height, and stability function of the logarithmic wind and temperature profile. It is then derived from climatological records and measurements of the energy balance and its altitudinal gradients at Hintereisferner. Examples of the energy-balance components and their change with altitude are given for the entire ablation season as well as for short periods. The heat transfer coefficients derived have a mean value of 1.7±0.2 MJ m−2 d−1 K−1 (40 ± 5 ly d−1 K−1).

Radio echo-sounding equipment has been designed, and used for depth sounding on temperate glaciers in Iceland. Two devices have been built. Mark I operates in the frequency band 2 to 5 MHz. The overall range is 100 to 1000 m. The arrival of the echo can be timed with an accuracy which corresponds to 20 m resolution. The equipment has been used for routine soundings on Mýrdalsjökull and Vatnajökull for the last two years. Mark II operates at 2 to 10 MHz. The range is from 30 to 400 m and the range resolution is 8 m. The equipment has been used for successful soundings on valley glaciers.

The power consumption of the whole system is 18 W plus 72 W for the oscilloscope (Tektronix Model 465). The voltage is supplied from 12 V car batteries. The total weight of the equipment is about 35 kg plus the weight of batteries. The antennae are contained in 16 mm plastic tubes. The equipment is placed on two sledges and towed behind a snowmobile or a skidoo. A continuous sounding record is photographed from the oscilloscope.

Thermal conductivity of snow has been investigated experimentally using the thermal-probe method, which is a transient method of measurement. The measurements have been made over a wide range of snow density (for fresh and dense snow), for varying temperatures and for different conditions of water content, snow-grain type, etc., both in the field and in the laboratory. The results are presented along with detailed sample descriptions. Thermal conductivity of snow increases with density and water content. It also increases with temperature, and the effect is more pronounced for temperatures between –15° and 0°C.

We studied the diffusion rate of stable isotopes of water ice in a controlled laboratory experiment, where isotopically different layers of fabricated firn were stacked. This experiment was done in order to study the diffusion rate between the isotopically different layers and to compare the measurements with forward-calculated diffusion rates of the fabricated firn stack, using three different analytical and numerical methods. The layers varied in thickness within the stack, and the studied period includes variations in firn temperature. We sampled the firn stack on five different dates along the 144 day long experiment. We obtained a quantitatively good match between the calculated and measured diffusion rates, with a root-mean-square similarity of 67–80% in the depth-averaged diffusion rates. Despite the good average match, we found some qualitative discrepancy between our calculations and our measurements. The calculated diffusion rates predict >5% faster isotopic decay of thinner layers and 13% slower decay of thicker layers than our measurements show. We speculate that grain size and grain fabric may influence the tortuosity of the firn pack, and that the current generalization of tortuosity, being a function of firn density as the only free parameter, is an oversimplification.

Previous research has documented a close association between high-resolution snow-pit profiles of hydrogen and oxygen stable-isotope ratios and multi-year Special Sensor Microwave/lmager (SSM/I) 37 GHz brightness temperature data in central Greenland. Comparison of the SSM/I data to profiles obtained during the 1989-91 field seasons indicated that δD and δ18O data from the near-surface snow at the Greenland summit are a reliable, high-resolution temperature proxy. To test this new technique further, additional stable-isotope data were obtained from a 2 m snow pit constructed during late-June 1995 near the GISP2 site.

This new profile, supported by pit stratigraphy and chemistry data, confirms the utility of comparing stable-isotope records with SSM/I brightness temperatures. The sub-annual variation of the δD record at the GISP2 site was determined using 15 match points, from approximately December 1991 through June 1995 and was guided in part by time-constrained hoar layers. The close association of these temperature proxies supports the assertion that snow accumulation occurs frequently through the year and that the isotope record initially contains temperature information from many times of the year. This is also independently confirmed by analysis of H2O2 data. The slope of the multi-year T vs δ correlation was evaluated along with the sub-annual variation in the amount, rate and timing of accumulation. These new results are consistent with those from the previous study and they also demonstrate that the snow in this area initially contains temperature and chemical records with sub-annual resolution. This encourages confident interpretation of the paleoclimatic signal variations in the GISP2 and GRIP deep cores.

In order to avoid problems stemming from the accumulation of rock fragments at the bottom of the hole during conventional thermal drilling in ice, a new type of probe has been developed. In this system, the water is warmed electrically inside the probe itself and propelled by a micro-pump. In this way, the hot water sprayed towards the ice scatters the insulating layer of debris and drilling continues normally, as shown by tests on several glaciers over the past 4 years.

In an earlier study on the variations in micro-structure during large volumetric deformations of snow, the authors observed that, contrary to expectations, the length of necked regions connecting adjacent grains did not necessarily decrease during compression. Rather, there was no discernible or predictable change in neck length, in some cases increasing and in others decreasing. Further evaluations of the data and an analysis of the mechanics of neck deformation determined that the process is complicated by three different effects: (1) increase in coordination number (number of bonds per grain), (ii) plastic deformation of the neck, and (iii) a geometric effect determined by bond growth and grain geometry. It is found that the first two effects tend to decrease the neck length and that the third produces an increase in mean neck length. A set of coupled differential equations is developed describing the variation of neck length and bond radius, and solved numerically for conditions consistent with the experimental data. Calculated results agree well with the data for the bond radius but the results for the neck length are less satisfactory. Reasons for this lie with difficulty in making accurate measurements of mean neck length from two-dimensional surface-section data and in the criteria for the definition of necks.

Black Rapids Glacier, a surge-type glacier in the Alaska Range, most recently surged in 1936–37 and is currently in its quiescent phase. Mass balance, ice velocity and thickness change have been measured at three to ten sites from 1972 to 1994. The annual speed has undergone cyclical fluctuations of as much as 45% about the mean speed. Ice thickness and surface slope did not change enough to cause the speed fluctuations through changes in ice deformation, which indicates that they are being drinven by changes in basal motion. The behavior of Black Rapids Glacier during this quiescent phase is significantly different from that of Variegated Glacier, another well-studied surge-type glacier in Alaska. The present medial-moraine configuration of Black Rapids Glacier indicates that a surge could occur at any time. However, ice velocity data indicate that the next surge may not be imminent. We belive that there is little chance that the next surge will cross and dam the Delta River.