For the observation of areal snow-depth distribution over a wide area, such as the Ishikari Plain in Hokkaido, Japan, existing telephone poles were used in place of the snow scales. Telephone pole number plates (telephone poles in Japan have number plates) were photographed by a 35 mm camera with zoom lens ranging from 80 mm to 200 mm through the window of the observation vehicle. The snow depth was calculated by the ratios of the length of the number plates to the distance between the lower edge of the number plates and the snow surface. Since measurements by direct sounding using a rod as compared with the values by the above method showed a good coincidence with an accuracy of ± 10 cm, it was considered satisfactory for snow depth observation over a wide area.

A linear model was used to investigate the behaviour of the Italian Western Tauri glaciers as a result of temperature changes projected for the 21st century. The model estimates the temperature variations once the glacier snout length variations are known and vice versa: it estimates the glacier snout length variations once the air temperature variations are known or predicted. The 46 glaciers of the Italian Western Tauri, 35 (76%) of which have areas smaller than 0.5 km2 and only 7 (15%) larger than 1 km2, are mostly mountain type glaciers and only three are presently valley glaciers. The model has been forced by the air temperature projections of the A1B emission scenario, which indicates an increase in temperature of 2.7°C from 2015 to 2100. The results show a shortening of more than 35% for mountain glaciers by 2100 with a surface loss of more than 60% and smaller reductions for valley glaciers. The consequent fragmentation into smaller units would lead to the extinction of 95% of the existing glaciers by the end of the century, possibly leaving only the valley glaciers surviving.

Remote-sensing methods are the primary ones used for ice mapping in the Baltic Sea. A major methodological improvement is now being introduced by satellite radars due to their weather independency and high resolution. To learn how to use ERS-1 synthetic aperture radar (SAR) data, an extensive field programme BEPERS (Bothnian Experiment in Preparation for ERS-1) with airborne SARs has been arranged. The BEPERS pilot study was undertaken in 1987 using the French VARAN-S X-band SAR. The SAR was flown on 1 day over four study areas of size approximately 10 km x 50 km, and intensive validation observations were made. The data were most useful for the education they provided on how to work with SAR in sea-ice mapping. They have been used for developing SAR image-analysis methods, back-scatter modelling investigations and geophysical validation of SAR imagery. Cleaning-up of images consisted of speckle reduction and segmentation. Back-scatter characteristics of undeformed ice and ridges were examined. Ice-type classification was based on the box-classification method. Eight ice types were defined but basically only two types, undeformed ice/open water and deformed ice, could be discriminated. Two basic problems of high practical importance remained: how to discriminate between (1) open water and undeformed ice, and (2) ridged ice and brash ice. The data further showed illustrative examples of SAR imagery over sea ice.

Stable isotope ratios and salinities of ice samples obtained from a submarine ice cliff at Explorers Cove demonstrate that the upper parts of the ice cliff have frozen directly from sea-water and are an underwater expression of permafrost, whereas the lower parts appear to be partially glacial in origin. These results indicate that there may be ice cores in the moraines of Explorers Cove, in which case the coastline of McMurdo Sound is more extensively ice-cored than previously known.

The orientations of individual crystals within a polycrystalline aggregate subjected to stress have a strong influence on its bulk strain rate and flow behavior. The ability to include the effect of crystal fabric and recrystallization processes in an ice flow law, especially at the bottom of glaciers and ice sheets where temperature is close to the pressure-melting point, is important because the stratigraphy of the ice body may be affected and the paleoclimate reconstruction hampered. We present herein three newly developed deformation apparatuses offering the possibility, from single experiments, of investigating different finite strain stages and their corresponding c-axis fabric and grain texture patterns in various confined, shear flow configurations (simple shear, pure shear and compression/extension bending). The technical set-ups and major advantages compared to classical methods are explained, and results from experiments are discussed in order to illustrate the functioning and purposes of the methods. In all experiments, significant variations in the microstructural development have been observed that reflect the varying orientations of the anisotropy and its relationship to the stress pattern. In monocrystalline ice-bending experiments, the pre-existing c-axis fabric is shown to have a profound influence on the response to stress and possibly to the type of slip system activated.

The literature reporting scientific and engineering investigations on ice has grown rapidly in the past 50 years, and increased by a factor of at least ten in the past 20 years. A review is presented of advances in engineering for ice problems during this period, including ice formation in rivers, lakes, and oceans; ice forces on structures; bearing capacity of ice covers; and atmospheric icing. The difficulties faced by engineers due to the unique physical and mechanical properties of ice and its normal thermal state are emphasized.

Diethyl phthalate, dimethyl phthalate, ethyl anisate, and α-tetralone are examples of liquids that can be used to fill the pore space of snow specimens. After the pore space is filled, the specimen is frozen solid. A section plane is microtomed and polished. Photomicrographic contrast of the section plane is improved by gently rubbing on to the plane a water–insoluble powder, such as carbon powder, or by rubbing on a water–soluble stain such as powder of acid fuchsin. Photomicrographic contrast is also improved by adding a water–insoluble dye such as oil blue N or oil red O to the pore–space filler.

The practical analysis of the growth of a sea-ice cover is discussed with initial reference to the classical work of Stefan, whose basic equation connecting surface temperature with the growth of a uniform ice cover of negligible specific heat and hence infinite diffusivity is extended to cover “real” cases. The separate effects of a finite heat content and thermal diffusivity are derived theoretically and semi-empirically respectively, and combined in a more general ice-growth equation which is then tested in the analysis of annual sea-ice growth on Hudson Bay.

Mountain glaciers have response times that govern retreat due to anthropogenic climate change. We use geometric attributes to estimate individual response times for 383 glaciers in the Cascade mountain range of Washington State, USA. Approximately 90% of estimated response times are between 10 and 60 years, with many large glaciers on the short end of this distribution. A simple model of glacier dynamics shows that this range of response times entails consequential differences in recent and ongoing glacier changes: glaciers with decadal response times have nearly kept pace with anthropogenic warming, but those with multi-decadal response times are far from equilibrium, and their additional committed retreat stands well beyond natural variability. These differences have implications for changes in glacier runoff. A simple calculation highlights that transient peaks in area-integrated melt, either at the onset of forcing or due to variations in forcing, depend on the glacier's response time and degree of disequilibrium. We conclude that differences in individual response times should be considered when assessing the state of a population of glaciers and modeling their future response. These differences in response can arise simply from a range of different glacier geometries, and the same basic principles can be expected in other regions as well.

A small ice-dammed glacial lake beside the Casement Glacier in south-eastern Alaska was observed to drain in two separate pulses during the summer of 1965. The initial discharge appears to have resulted when the ice lobe damming the lake was floated by the increasing depth of water. There is no good explanation for the second rapid discharge but it may have been due to the sudden opening of crevasses.

The 2037 m deep bore hole at Dye 3 in south Greenland was surveyed in 1981, 1983, 1985, and 1986. The directional surveys show the ice flow is planar with a surface velocity of 12.2m/year at an azimuth of 060°, which agrees with surface velocity measured by navigation satellites. Measurements of hole diameter and inclination are highly correlated with dust content in the ice. The temperature measurements show strong convection in the hole fluid with a cell height of about 20 m and an amplitude of 0.1 K. The calculated mean in-situ ice density is 921.3 ± 1.5kg/m3. Due to ice deformation, the lowest 4 m of the hole were not accessible in 1985 and the lowest 180 m were not accessible in 1986.

Spatially variable basal conditions are thought to govern how ice sheets behave at glacial time scales (>1000 years) and responsible for changes in dynamics between the core and peripheral regions of the Laurentide and Fennoscandian ice sheets. Basal motion is accomplished via the deformation of unconsolidated sediments, or via sliding of the ice over an undeformable bed. We present an ice sheet sliding module for the Parallel Ice Sheet Model (PISM) that takes into account changes in sediment cover and incorporates surface meltwater. This model routes meltwater, produced at the surface and base of the ice sheet, toward the margin of the ice sheet. Basal sliding is accomplished through the deformation of water saturated sediments, or sliding at the ice-bed interface. In areas with continuous, water saturated sediments, sliding is almost always accomplished through sediment deformation. In areas with incomplete cover, sliding has a stronger dependence on the supply of water. We find that the addition of surface meltwater to the base is a more important factor for ice sheet evolution than the style of sliding. In a glacial cycle simulation, our model causes a more rapid buildup of the Laurentide Ice Sheet.

A snow crystal has been successfully collected on to a scanning electron microscope (SEM) stub in central Greenland. It was preserved at liquid-nitrogen temperature for 5 months, prior to examination in the SEM. This is believed to be the first time a snow crystal has been observed directly in the SEM and offers some new experimental methods for understanding crystals and their chemistry.

The cross-sectional profile of a glacial valley can be obtained with a variational principle in which the friction against the valley walls and the glacier bed is extremized, subject to a Lagrangian constraint. We show that the actual valley profile maximizes the friction, thus settling an old debate.

The towing of unprotected icebergs from the Antarctic continent (66° S.) to latitude 38° S. has been simulated using an explicit hydrodynamic model and an extended two-dimensional melting model. It was found that nominal towing accelerations in excess of 2 × 10-5 m s-2 were required to deliver ice over this route in most circumstances, and minimum energy consumptions were obtained at accelerations around 10-4 m s-2. Unprotected icebergs could be delivered with about 50% yield to latitude 38° S., but the rate of deterioration in the warm waters indicates that protection would be required for longer journeys. The towing simulation was most sensitive to north-south current components, the total towing distance and the rate of iceberg deterioration. Efforts directed towards locating suitable icebergs in the region 50° S. to 60° S., and towards increasing knowledge of the changing current patterns in the Southern Ocean would be most valuable, as would a knowledge of the mechanisms and rates of deterioration of icebergs in warm seas.

To develop new strategies for global mass-balance monitoring, data for the period 1961–90 have been compiled for 80 glaciers with a variety of mass-balance and morphological parameters. This dataset is significantly larger than that used in previous studies. This allows us to check the mass-balance data for both strong and weak correlations with different glacier parameters. In many cases, the strong correlations suggest new approaches to monitoring glaciers on a global scale. For example, the mass balance at the terminus is strongly correlated with the difference in elevation between the terminus and the glacier’s mean elevation. These easily measured parameters could be particularly useful in assessing maximum ablation and meltwater potential based on altitudes derived from maps and photographs. Good correlations also exist between differences in mass-balance parameters (e.g. net balance minus terminus balance) and several other morphological properties (e.g. elevation range and length). Equally important, the weak correlations demonstrate that some relationships commonly used on individual glaciers are not appropriate when considering global monitoring strategies. For example, the correlation between net mass balance and terminus balance is very poor. Likewise, the correlation between the net mass balance and equilibrium-line altitude is weak, and the correlation between the net mass balance and activity index is almost non-existent. This suggests that although these climatically sensitive parameters may be closely related on individual glaciers, these same relationships are not reliable as tools for monitoring glaciers on a global scale.

An outdoor sea-ice tank system for measuring the microwave properties of sea ice has been developed. With the natural cooling and the help of a cooling unit in the movable roof attached to the tank, the system can grow sea ice to about 50 cm thickness continuously without the effects of snowfall and/or melting. Portable microwave radiometers are attached beside the tank to measure the brightness temperature of the ice. As sea ice grows, the system can measure microwave brightness temperature, and seawater/ice temperature at each depth and thickness of sea ice. The bulk salinity of sea ice is measured by sampling. The following results were obtained from experiments conducted during two winters. (1) Rapid desalination was observed during the early stages of growth with ice thicknesses of 0–5 cm. (2) A new relational expression between ice thickness and bulk salinity at this thickness was obtained. (3) The rapid rise in microwave brightness temperature associated with the increase in sea-ice thickness during the early stages of sea-ice growth was captured in each frequency band. The microwave measurements from the sea-ice tank system are expected to provide new insights into the microwave properties of sea ice.