The radiant surface temperature imaged by thermal infrared line-scanning equipment is a product of both surface temperature and emissivity. In detail it is the integrated product of the evolutionary development of the near-surface energy transfer regime. The variation of surface radiant temperature spatially and temporally contains information about the structure, composition, and thermal state of near surface materials. It is suggested that the study of ground ice, sea/lake ice, and the thermal regimes of mountain snow and ice bodies, are reasonable targets for the quantitative application of thermal mapping technology, and that considerable technical development effort be expended on spectral, spatial, and temporal operators for use in computer processing of pictures for glaciological data.

Seismic observations on the Salmon Glacier have shown that the glacier bed has a general V-shape with a depth-to-width ratio of about 1:2. These studies also indicate that the north terminus of the glacier effectively dams Summit Lake. Several reflections were recorded from surfaces transverse to the glacier length that curve from near tangency with the bottom surface of the glacier to a vertical attitude at the upper surface. These reflections are restricted to the part of the glacier near the source area.

The annual mass of snow moved by avalanches was observed at 45 avalanche paths over a period of 19 years by measuring the volume and density of each individual avalanche. Several other methods to estimate the total annual avalanche mass were applied but they were found less efficient owing to inaccuracy and difficulties in timing.

For the data set, the yield ratio, i.e. the percentage of snow removed annually by avalanches, had a mean value of 11.2% and a 30 year maximum of 30.9%. The yield ratio varied strongly among avalanche paths and yearly, and could not be explained satisfactorily. The exposure to wind, inclination of the avalanche track, control by artillery, and the winter weather can all have an influence on the value of the parameter.

The temporal variability of avalanche yield is erratic but weather patterns frequently associated with high or low yield ratios could be identified. High values are usually associated with large avalanches triggered by major weather events in the late part of the winter.

The annual layering in the Greenland and Antarctic ice sheets revealed by the b 0 record becomes less distinct with depth because of self-diffusion. However, the calculated diffusion rates are loo slow to explain die observations. It is suggested that the presence of veins of liquid water increases the effective diffusion constant by a factor of about 20.

The formation of superimposed ice in the accumulation area of sub-polar glaciers plays an important role in the heat and mass balance of the glaciers. In order to study the process of superimposed ice formation in detail, field observations were conducted on McCall Glacier, a sub-polar glacier in Arctic Alaska. It was found that the approximate thickness of superimposed ice formed in a whole summer was 20 cm in the upper region and 30—40 cm in the lower region of the accumulation area of the glacier. This difference in thickness may be attributed to the difference in the temperature of the underlying ice and the rate of supply of melt water. The ratio of the amount of superimposed ice formed in the accumulation area from May to July in 1972 to the total amount of melt was determined. Approximately 50% of the total melt water was discharged from the glacier as run-off water, and the remainder contributed to the formation of superimposed ice.

An experimental study on the artificial formation of superimposed ice was conducted in the cold laboratory to obtain the ratio of superimposed ice, that of run-off water, and that of free water suspended between snow grains, to the total amount of melt water produced in the snow. The ratios obtained in the laboratory experiment agree fairly well with those derived from the observational data on McCall Glacier.

Numerical calculations were conducted to examine the relationship between the growth rate of superimposed ice, the rale of snow melting, the rate of discharge of excess melt-water, and the temperature of the underlying ice. Calculations were made in reference to both the laboratory experiment and the field observations on McCall Glacier. It was found that the predominant factors controlling the growth rate or the total amount of superimposed ice in a sub-polar glacier are the rate of supply of melt water to the snow-ice interface and the initial temperature distribution in the underlying ice. By using the present calculation, it may be possible to estimate the growth rate, the total amount of superimposed ice, and the ratio of superimposed ice to the total amount of melting in the accumulation area of any sub-polar glacier, if observational data on the initial temperature distribution in ice and the rate of snow melting at the snow surface are available.

A description is given of two tunnels, each 60–70 m. long, one directly above the other, at 4,000 and 4,020 m, a.s.l. excavated through cold firn and ice of the Breithorn in the Alps. The temperature rose from −5.5° C. at the portal to −0.5° C. at the rock interface 70 m, from the portal in the upper tunnel, and from −5.5° C. to 0° C. at a water reservoir 60 m. from the portal in the lower tunnel. In both cases cracks or minute sealed crevasses, cut by the tunnel, operated to cool the ice locally below the temperature to be expected from a smooth curve. Possible. origins of the water reservoir are discussed.

Small amounts of air at a moderate pressure, enclosed in small, sealed cracks and hollows, were punctured between 60 and 70 m. from the portal in the upper tunnel. The pungent odor of the air thus released was identified as ozone (a) by its characteristic odor, (b) by its reaction on rubber, and (c) by potassium iodide starch paper tests. The source of such ozone is suspected to be minute electric sparks resulting from static electric charges built up in cold ice when it is subjected under pressure to cracking or deformation; Photographs taken with exposures of 8 hr. in the upper tunnel at night apparently show such sparks.

A description is given of the appearance of cold ice, frozen to the bedrock, being forcibly tortured into streamers and bands by the movement of the entire ice body at 0.6 m./yr.

With the aid of an atomic absorption spectrophotometer (Perkin Elmer 303), chemical analyses were performed on different types of ice collected in an enclosed natural subglacial cavity of the Glacier d’Argentière (French Alps). Contamination was reduced to background noise level of the instrument at each step of the procedure which was developed. One of the main problems encountered during the processing was the desorption of cations adsorbed on the surface of particles dispersed in the ice.

The mean composition in Na, K, Ca and Mg was established for glacier ice and for ice accretions hanging from the ceiling of the cavity or at the bedrock–glacier contact. The mean composition and the ratio (Na+K)/(Ca + Mg) of the ice accretions are higher than those of the glacier ice. This implies a refreezing of interstitial water which was enriched by desorption when, before refreezing, it was forced through the mud layer plastered at the base of the glacier.

The long-term refrigerated storage of melted snow and/or ice samples for analyses of insoluble microparticles (hereafter, microparticles) may be limited by increases in the biological particle concentration caused by microbial growth after ~1–2 weeks. In this study, we examined an ultraviolet (UV) disinfection method for the storage of melted snow and/or ice samples and determined the effects of this method on microparticles. Surface snow obtained from Glacier No. 31 in the Suntar-Khayata Range, eastern Siberia, Russia was divided into two portions for UV treatment and untreated controls. Microparticle concentrations and size distributions (in the range of 0.52–12.0 μm) in the samples were measured using a Coulter counter. Whereas the microparticle concentration in untreated samples increased, no obvious increase was observed over 53 d in the samples subjected to UV treatment. Microbial growth was detected in only untreated samples using a viable particle counter. In addition, the original microparticle concentrations and size distributions were unaffected by UV treatment. Our results demonstrated that the microparticle size distribution in untreated melted water samples reflects the growth, decomposition and succession of microorganisms over time and further indicate that UV irradiation is effective for long-term storage for microparticle analysis.

The ability to perform microbial detection and characterization in-field at extreme environments, rather than on returned samples, has the potential to improve the efficiency, relevance and quantity of data from field campaigns. To date, few examples of this approach have been reported. Therefore, we demonstrate that the approach is feasible in subglacial environments by deploying four techniques for microbial detection: real-time polymerase chain reaction; microscopic fluorescence cell counts, adenosine triphosphate bioluminescence assay and recombinant Factor C assay (to detect lipopolysaccharide). Each technique was applied to 12 subglacial ice samples, 12 meltwater samples and two snow samples from Engabreen, Northern Norway. Using this multi-technique approach, the detected biomarker levels were as expected, being highest in debris-rich subglacial ice, moderate in glacial meltwater and low in clean ice (debris-poor) and snow. Principal component analysis was applied to the resulting dataset and could be performed in-field to rapidly aid the allocation of resources for further sample analysis. We anticipate that in-field data collection will allow for multiple rounds of sampling, analysis, interpretation and refinement within a single field campaign, resulting in the collection of larger and more appropriate datasets, ultimately with more efficient science return.

Penetration tests in snow show that the Rammsonde number R as a measure of force resisting penetration may be in error by a factor of two depending on the ratio of hammer to probe weight and the coefficient of restitution. It is suggested that the Hiley pile driving formula is applicable to the problem and gives more accurate values for the force of penetration. This formula accounts for the influence of different hammer weights, is in agreement with the conservation laws to the first approximation, and has been in general use for some time as one of the best simple equations for determining the dynamic resistance of piles.

The Rammsonde equation is notable for its simplicity. The Hiley equation, using the same factors does not detract from this virtue. Further research is suggested to find ways of replacing the coefficient of restitution with more fundamental parameters in impact problems.

Digital airborne-radar data were collected during the 1988–89 Antarctic field season in six gridded blocks covering the upstream parts of Ice Streams A, Β and C. An automated processing procedure was developed for picking onset times, converting travel times, interpolating missing data, converting pressure-transducer readings, correcting navigational drift, performing cross-over analysis and zeroing remanent cross-over errors. Cross-over analysis was used to remove the effects of temporal variations in atmospheric pressure and to estimate errors. Interpolation between flight lines was carried out using the Kriging method. Surface elevation was referred to the Rapp Set A geoid by tying the gridded surface to satellite-surveyed ground stations, using a planar-model fit.

Maps of surface elevation, ice thickness and bottom topography with standard-error estimates of 4–9 m for surface elevation and 30–60 m for ice thickness and bottom topography were produced. These maps show that the locations of the ice streams are not clearly reflected in either the surface or basal topography, so are presumably controled by basal or internal conditions, that there is no clearly demarcated transition zone between sheet flow and streaming flow, that there is no clear cut evidence for the capture of the catchment of Ice Stream C by Ice Stream B, but that Ice Stream Β does drain virtually the entire region between the lateral boundaries of Ice Streams A and C.

Snow-avalanche speeds, run-out distances, and the concepts from dense granular flows are combined in a model for prediction of speeds along the incline. Field measurements indicate that speeds and run-out distances are nearly independent of path steepness once a length is chosen to scale them. Application of granular-flow concepts explains these results. The most important feature of the model (and the speed data) is the steep gradient of speeds in the run-out zone. These results emphasize the need for high precision in run-out prediction when construction or defences are contemplated.

A new model of dislocations glide in ire Ih is proposed. In developing this model certain assumptions are made: (i) dislocations have a non-crystalline extended core, and (ii) transitions occur through cooperative movements of ?2? molecules in the core of dislocations. A relation between the velocity νd of linear defects and shear stress τ or temperature T is obtained. This relation shows that νd varies linearly with τ at low values of τ and (or) T but varies more rapidly at higher stresses; this non-linearity is more pronounced the higher the temperature. Such results are in agreement with experimental data.

Creep tests provide invaluable data to better understand the physical properties of ice under various conditions. We describe here a simple, updated pneumatic apparatus for experimental studies of ice rheological properties. The apparatus is designed to perform two simultaneous compression creep tests either in a cold room or in atmospheric conditions when coupled to an external cooling circulator. We present results from calibration tests of the apparatus and provide new data from creep tests performed on temperate glacier ice samples. These calibration and creep results show that the apparatus is able to provide fast and reliable mechanical ice characterization. The secondary creep rates measured in this study range between 1.59 × 10−8 s−1 (at 0.21 MPa) and 4.38 × 10−7 s−1 (at 0.71 MPa) at −10°C for quasi-isotropic ice, which is consistent with former standard published data. The corresponding mean parameter, A, is 5.20 × 10−16 s−1 kPa−3, which also compares well with the range of reported other studies.

Studies of radar reflection characteristics can indicate much about the bed of an ice sheet and the associated ice motion. This contribution analyzes the relative significance to the ice flow of rough ice-rock, rough ice-water-rock, and flat ice-water-rock interfaces, and establishes criteria for distinguishing among these interface types under ice sheets using radar equipment of the type developed by the Technical University of Denmark.

Down-wasting has affected southern glaciers in New Zealand later than northern glaciers under the influence of a southward rising snow line which is attributed to a southerly shift in prevailing wind belts. Evidence from the Hooker Glacier indicates that the present period of wasting is the fourth of a series which began about 200 years ago.

As the firn line rises a glacier is planed in the ablation zone so that successive surfaces are parallel to the original surface, which shows that ablation is more active for a short distance below the fern line than near the terminal face. A period of accelerated terminal retreat can result from parallel down-wasting without a correlative acceleration in the rate of climatic change.