Winter snow cover at Austre Okstindbreen is influenced strongly by patterns of atmospheric circulation, and by air temperatures during precipitation. Differences of circulation over the North Atlantic and Scandinavia during the winters of 1988–89 and 1989–90 were reflected in the ionic and isotopic composition of snow that accumulated at the glacier. Early summer ablation did not remove, or smooth out, all the initial stratigraphic differences. In the first half of the 1988–89 winter, most air masses took a relatively short route between a marine source and Okstindan; late winter snowfalls were from air masses which had taken a longer continental route. The snow that accumulated in the first half of the 1989–90 winter was associated with air masses which had followed longer continental routes, and so brought higher concentrations of impurities from forests, lakes and crustal material. The ablation season began earlier in 1990 than in 1989, and summer winds and rain supplied more impurities to the snowpack surface.

An intensive snow-cover survey at Lake Laflamme, Quebec, during the spring of 1983 showed that wet deposition in the form of rain, which was a dominant phenomenon during the 1983 melt season, gave rise, according to the intensity and chemical quality of the precipitation, to both losses and gains of ion loads (meq m−2) in the snowpack. Mean values for the daily wet deposition loadings (meq m−2 d−1) of ionic species associated with atmospheric aerosols (H+, , ) were of approximately the same magnitude as the daily changes in gains recorded in the snow cover during the melt period. In contrast, the mean value for the contribution by wet deposition to the total loads of K+ and in the snow cover was far outweighed by the gains which were observed at the same time. The expected losses for the snowpack, calculated from the sum of the total loads stocked in the pack at the beginning of the melt period and the total loads in precipitation during the melt period, were lower than the sum of the actual losses observed for all ionic species except H+. The increases (%) in the loads for the major anions Cl−, and were comparable (25 to 32%). The results suggested that dry deposition either directly by aerosol interaction with the snow cover or indirectly by adsorption on organic material followed by leaching during the melt period, or by a combination of both, was a major factor in the increases observed. The values for the increases in loads for Ca2+, , Mg2+ and Na+ (50 to 287%) probably represented, in addition to leaching of local debris, the exudates of cellular material from the cell plasmolysis of detrital organic debris. High rates of in-pack production, however, were characteristic of Al3+. Mn2+, K+ and which showed substantial increases in pack loads (480 to 750%). These increases cannot be accounted for by any local phenomena other than the dissolution or microbiological degradation of organic debris. It is suggested that ion exchange capacity of both particulate and soluble organic material led to a decrease in pack acidity; this phenomenon should thus be considered as a major factor in all attempts to model acid rain fluxes through boreal forest systems.

Landsat photographic products on the Space Oblique Mercator (SOM) projection are used to construct a map of Nordaustlandet (Svalbard), of known accuracy. The map includes ice divides. Accurately enlarged Landsat images were digitized. Combined digitizer and operator errors were 64 m, at the enlargement scale. Fifteen ground control points rixed the two scenes. RMS errors in control point identification were <123 m. Geographical coordinates were extracted by: 1) converting digitizer coordinates to SOM cartesian coordinates and 2) transforming these coordinates to latitude and longitude. This map production method is applicable to any imagery of known projection. The digitally stored map may be plotted on a variety of map projections and scales. Two problems in image interpretation were: I) shadows obscuring detail on NNE-facing coasts and 2) summer snow cover obscuring parts of the terrestrial ice cap margins, The map is similar to an east coast map produced from Landsat computer compatible tapes. Differences between the Landsat map and a 1:50 000-scale aerial photograph were <100 m.

Late Holocene sediment deposits in Pine Island Bay, West Antarctica, are hypothesized to be linked to intensive meltwater drainage during the retreat of the paleo-Pine Island Ice Stream after the Last Glacial Maximum. The uppermost sediment units show an abrupt transition from ice-proximal debris to a draped silt during the late Holocene, which is interpreted to coincide with rapid deglaciation. The small scale and fine sorting of the upper unit could be attributed to origins in subglacial meltwater; however the thickness and deposition rate for this unit imply punctuated- rather than continuous-deposition. This, combined with the deposit's location seaward of large, bedrock basins, has led to the interpretation of this unit as the result of subglacial lake outbursts in these basins. However, the fine-scale sorting of the silt unit is problematic for this energetic interpretation, which should mobilize and deposit a wider range of sediment sizes. To resolve this discrepancy, we present an alternative mechanism in which the silt was sorted by a distributed subglacial water system, stored in bedrock basins far inland of the grounding line, and subsequently eroded at higher flow speeds during retreat. We demonstrate that this mechanism is physically plausible given the subglacial conditions during the late Holocene. We hypothesize that similar silt units observed elsewhere in Antarctica downstream of bedrock basins could be the result of the same mechanism.

Glide-snow avalanches release due to a loss of friction at the snow–ground interface, which can result in large avalanches that endanger infrastructure in alpine regions. The underlying processes are still relatively poorly understood, in part due to the limited data available on glide processes. Here, we introduce a pixel-based algorithm to detect glide cracks in time-lapse photographs under changing illumination and shadow conditions. The algorithm was applied to 14 years of time-lapse images at Dorfberg (Davos, Switzerland). We analysed 947 glide-snow events at a high-spatial (0.5 m) and temporal (2–15 min) resolution. Avalanche activity and glide-crack opening dynamics were investigated across timescales ranging from seasonally to hourly. Events were separated into surface (meltwater percolation) and interface events (no meltwater percolation). The results show that glide activity is highly variable between and within seasons. Most avalanches released without crack formation or within 24 h after crack opening, and release was favoured in the afternoon hours. Glide rates often showed a stick–slip behaviour. The acceleration of glide rates and non-constant increases in glide crack aspect ratio were indicators for avalanche release. This comprehensive dataset provides the basis for further investigations into glide-snow avalanche drivers.

Based on recent studies on sea ice and newly developed technologies, this paper examines the requirements and environmental factors for exploitation of sea ice as a freshwater resource. Considering the ‘mining’ of sea ice, the suitability of locations in the Bohai Sea, China, for exploitation was analysed and evaluated using GIS technology. The ice must be >10 cm thick, the intertidal zone must be narrow and the ‘mining’ area must have a water depth of at least 2 m. The sea areas with feasible resources are located mainly in the nearshore area of northern Liaodong Bay and in a narrow and long area along the coast of Bohai Bay. Most coastal areas of northern Liaodong Bay have favourable conditions, while Bohai Bay is widely constrained by unsuitable conditions. According to the status of the resources and the coastal environment conditions, the eastern and western coasts of northern Liaodong Bay are the most suitable areas for exploitation at the current technological level.

In order to investigate the temperature dependence of vibrational spectra of ice, we measured the Raman spectra of artificial ice Ih in the temperature range 198–270 K. The frequency of translational lattice vibrations decreases with increases in the measurement temperature, and the rate of decrease discontinuously changes at 237 K. The discontinuous change of the rate of decrease is consistent with the phase transition from a proton-disordered arrangement to a proton-ordered arrangement at the ice temperature Ti = 237 K in polar ice sheets, as proposed by Fukazawa and others (1998b). We then compared the Raman spectra of translational lattice vibrations in ice Ih and Antarctic ice and examined the possible effects of the phase transition on the geophysical properties of Antarctic ice. We also report preliminary results of the neutron powder diffraction of Dome Fuji (DF) Antarctic ice, and discuss arrangements of protons in DF ice.

A new visibility-range measuring system has been developed which uses a video camera, and with which visibility can be estimated by measuring the brightness contrast of a black target against a standardized background. This principle has been applied to development of the new visibility-range monitor described in this paper. In this monitor, a charge-coupled device (CCD) video camera measures the brightness of an arbitrary area in its range of vision, and visibility range measured by the video camera in blowing snow can be compared with that measured by the transmissometer-type visibility-range monitor and can also be calculated by direct observation using optical targets.

The new sytem can monitor visibility and record information about traffic on highways at 1 s intervals for a maximum of six separate positions. The vertical distribution of visibilities over a snow surface has been observed, and it has been found that the fluctuation in visibility is greatest at lower levels above the ground in blowing snow.

Passive microwave brightness temperatures from the Special Sensor Microwave Imager (SSMI) are studied together with surface air temperatures from two Automatic Weather Stations (AWS) for the year 1989. One station is located on the East Antarctic plateau (Dome C) and the other on the Ross lee Shelf (Lettau).The satellite data for frequencies 19, 22 and 37 GHz with vertical polarization,centered on the two AWS stations, are studied. A simple thermodynamic model and asimple radiative-transfer model, that takes into account the snow temperature profile and assumes a constant annual emissivity, are proposed. The combination of these two models enables us to compute extinction coefficients, penetration depths and toretrieve the measured brightness temperature variations from the AWS surface temperatures. Afterwards, this model is reversed in order to retrieve the snow-surface temperatures from the satellite data. Results are promising but strong approximationsand a priori knowledge of the extinction coefficient are still needed at this point.

One of the main aims of the Snow and Ice Hydrology Project, a joint Canada-Pakistan endeavour, is to estimate ice loss in the ablation areas of glaciers in order to predict with greater confidence stream flow in the headwaters of the Indus River. To this end, Miar Glacier, located in the central Karakoram Range, north of Gilgit, was intensively studied during the summers of 1986 and 1987.

Measurements of glacier mass balance by the monitoring of accumulation and ablation at stake locations is very difficult in the Himalyan environment. It is usually almost impossible to reach elevations above the equilibrium line without major effort, and always very difficult once there to make meaningful measurements; the ablation areas are often heavily crevassed and/or debris-covered, and this poses difficult sampling problems.

The method used in this study was to monitor annual surface movement on a cross-profile as near as possible to the equilibrium line. The measurements, obtained in conjunction with depth soundings made on the same profile, allow the annual ice flux through the cross-profile to be calculated. If an approximately steady-state glacier is assumed, it would be expected that this flux would be roughly equivalent to the rate of ice loss below the profile.

The movements of wooden stakes drilled into the glacier were monitored throughout each of the summers and, since two of the stakes survived the intervening winter, this allowed calculation of annual movement. Distances between the crests of ogives were also surveyed, providing an independent assessment of glacier movement. Depth measurements by radio-echo sounder were successfully made in the summer of 1987, showing maximum ice depths of 550 m. The annual ice flux through the transverse profile was estimated as 5.67 × 107 m3, which corresponds to a mean annual ice loss from the glacier surface below the profile of 8.10 m of ice.

In order to clarify the process of snow accretion, which occurs at a temperature below the melting point of ice, experimental studies were made on the microscopic process of ice Adhesion as well as the tensile adhesive strength of snow onto various kinds of materials.

For this purpose, direct observations were made of the formation of an ice bond developed at the interface between an ice particle and a plate made of a transparent material such as glass, acrylic plastic (polymethyl methacrylate (PMMA)), or ice, and measurements made of the growth rate of the real contact area.

The growth rate of an ice bond formed at the interface between an ice particle and the plate of a hydrophilic material such as glass was equal to or slightly larger than that of ice sintering, while an ice bond was not formed at the interface between an ice particle and the plate of a hydrophobic material such as teflon.

As for adhesive strength, with the lapse of time it increased rapidly at the former interface and slowly at the latter interface. Examinations of fracture planes revealed that at or near the interface a pure adhesive break did not take place with the exception of teflon and vinyl, and that what took place there was a cohesive break or a mixture of cohesive and adhesive breaks.

This paper deals with the influence of the vertical and horizontal variation of Aeolian snow flux on estimations of snow-storm duration and on snowdrift patterns simulated in a wind tunnel.

First of all, we shall review recent developments, including our own simulations, concerning the horizontal increase of mass flux until drifting-snow saturation has been reached.

Next, after a critical examination of various snowdrift-modelling criteria, we present the results of an experiment undertaken in our wind tunnel: We studied cross-section drill-area changes behind a small-scale snow fence as a function of time for different fetches but for the same mean wind speed at the beginning of the testing section. For each fetch, we carried out vertical profiles of sand particles using image processing and we studied the geometrical parameters of the drift. We conclude dial changes in the cross-section drift area depend on the ablation length and if particle saturation is not reached, the use of a storm-duration scale leads to Overevaluation of prototype storm duration. Moreover, we point out that drift pattern vary as a function of the concentration profiles.

In 1980 the new advance of Glacier Blanc covered a trail leading to a mountain hut and threatened the footbridge that crosses its melt-water stream. This event prompted the Laboratoire de Glaciologie et Géophysique de l’Environnement (LGGE) to undertake a new study of the glacier. With the old Eaux et Forêts measurements, and the more recent LGGE ones, it has been possible to forecast the probable fluctuations in glacier length by two different methods: a statistical method based on a correlation between the variations in length and mass balance, and a one-dimensional numerical ice-flow model. Both methods show that a substantial glacier retreat is unlikely during the 1985–90 period.

Lake Arsine, a pro-glacial lake in the French Alps, first appeared 30 years ago and has since been growing steadily. In 1985, it reached an area of 5.9 ha, a maximum depth of 39 m, and a volume of 0.8 × 106 m3. This lake is dammed partially by a glacial moraine and partially by a tongue of dead ice covered by a moraine 1–2 m thick. The glacier calves into the lake, which collects all the melt water from the surrounding glacial area of 250 ha. No open outlet exists and seepage reaches a value of 5 × 106 m3 year−1. A 1 year water balance shows that seepage increases rapidly with water level, from less than 0.03 m3 s−1to more than 0.75 m3 s−l for a rise in water level of 10 m. The seasonal lake-volume fluctuations of 0.5 × 106 m3 are small compared with the inflow volume of 5 × 106 m3.

Progressive clogging of the bottom by glacial flour has led to a gradual rise of 8 m in 16 years in the summer level, while at the same time the height of the dam has decreased by 10 m due to the melting of dead ice. Consequently, by the end of July 1985 the freeboard was only 2 m and overflow on to the dead ice was thought likely to occur in the very near future. To eliminate this flood hazard, a 250 m long channel was dug in an ice-free zone which had been profiled by geophysical prospecting. This work was carried out between 14 April and 13 June 1986, in order to benefit from the low winter water level.

Geotechnical studies of the moraine have shown that no large landslide is to be feared. A crude model of the waves created by calving shows that the new water level is safe and the channel is capable of handling the maximum likely discharge of 15 m3 s−1 resulting from the highest possible wave of 3.5 m.

The internal structure of powder-snow avalanches was investigated at Kurobe Canyon in the Shiai-dani area of Japan in 1988. Internal velocity was derived for avalanches of this kind by frequency analysis of impact-force data, and was found to undergo a remarkable change with time. The shear of the avalanche flow was estimated to range from 1 to 7 s−1. The front region of the avalanche wind was observed to precede the front of the avalanche by a distance of 17.3 m. The maximum wind velocity was comparable with the internal velocity of the front region of the avalanche.

Data obtained from tests of uniaxial and multi-axial compressive strength on saline ice have been used to determine the coefficients of the Smith yield function, which uses seven parameters, and of the Pariseau yield function, which uses five. Both functions describe orthotropic materials and have been reduced for transverse isotropy. The tests of compressive strength were carried out over the past few years in the ice laboratory of the Hamburgische Schiffbau-Versuchsanstalt (HSVA) on a closed-loop controlled triaxial loading frame with brush-type loading platens. The values for tensile strength have been obtained from data published by other researchers.

The ice-strength values computed by means of the two yield functions were compared with measured ice strengths; the seven-parameter Smith yield function provides reliable results over the whole stress space, while the simpler Pariseau yield function is only applicable within a restricted area of the stress space.

We present a simple parameterization of the effect of open leads in a general circulation model of the atmosphere. We consider only the case where the sea ice distribution is prescribed (i.e., not interactive) and the fraction of open water in the ice is also prescribed and set at the same value at all points in the Southern Hemisphere and a different value in the Northern Hemisphere. We approximate the distribution of sea ice over a model “grid box” as a part of the box being covered by solid ice of uniform thickness and the complement of the box consisting of open water at a fixed -1.8 C. Because of the nonlinearity in the flux computations, separate calculations are performed over the solid sea ice and over the open leads. The net fluxes conveyed to the atmosphere over the grid box are determined by performing the appropriate area-weighted average over the two surface types.

We report on an experiment designed to assess the sensitivity of the modelled climate to the imposition of a 50% concentration in the winter Antarctic sea ice. Significant warming of up to 6°C takes place in the vicinity of and above the Antarctic sea ice and is associated with significant changes in the zonal wind structure. Pressure reductions are simulated over the sea ice, being particularly marked in the Weddell Sea region, and an anomalous east-west aligned ridge is simulated at about 60°S. Very large changes in the sensible heat flux (in excess of 200 Wm−2) are simulated near the coast of Antarctica.

Seasonal mean changes in the surface elevation of the ablation zone of West Greenland to 72°N between spring 1985 and summer 1986 are measured using radar altimeter data from the 18-month Geosat Geodetic Mission. Semi-variograms are used to estimate the noise in the data as a function of position on the ice sheet. Mean elevation changes are computed by averaging the elevation differences measured at points where orbits ascending in latitude are later crossed by orbits descending in latitude (or the reverse), with each cross-over difference weighted in proportion to the inverse square of the noise level in the neighborhood of the cross-over point. The mean surface elevation of the ablation zone, relative to spring 1985, ranged from 1.5 ± 0.6 m lower during summer 1985 to 1.7 ± 0.4 m higher during spring 1986.

Shallow corings and pit studies were carried out in 1987 on the Chongce Ice Cap in the West Kunlun Mountains which lie along the southern edge of the Taklamakan Desert. Stratigraphic observations, as well as measurements of insoluble particles, chemical constituents and liquid conductivity, on the core and pit samples allowed identification of annual layers, although visible dirt layers are not always annual signals. A vertical profile of stable isotope content showed a periodic variation near the surface, strongly attenuated with depth.

A satellite radar altimeter can be used to monitor surface elevation change over polar ice sheets. Thirty-five months of Geosat Exact Repeat Mission (ERM) data from November 1986 to September 1989 over a section of East Antarctica (69–72.1 ∘S, 80–140∘ E) have been used in this study. A model that considers both surface and volume scattering was used to retrack the altimeter waveforms. Surface elevations for each month after the first three were compared to the average elevations for the first 3 months through a crossover method. The averaged crossover elevation difference changed with time in a way that suggests a yearly cycle in surface elevation. The average amplitude of the cycle is about 0.6 m. We have been unable to find any satisfactory explanation for the observed changes, in terms of either sources of error or contributors to real surface-height changes. We strongly suspect that orbit error plays a major role in producing the variations, although we know of no quantitatively satisfactory source of a quasi-seasonal variation in orbit error. Other possible contributors include a real seasonal variation in accumulation rate, seasonal changes in the delay of the radar signal as it propagates through the atmosphere, unmodeled variations in the depth of penetration of the radar pulse into the firn, changes in the thickness of the ice and the firn zone in response to seasonal variations in pressure and temperature, and the inverted barometer effect. Even though we do not know the cause of the variations, the results show the importance of comparing elevations at the same time of year for observations that are not continuous, while at the same time showing that even annually spaced measurements may not be free of substantial errors associated with interannual variability. The quasi-periodic variations obscure any evidence of a moderate secular change in surface height, if there is one, but a dramatic lowering at rates approaching 1 ma–1, such as are known elsewhere in Antarctica, can definitely be ruled out.