Innovations in geodesy enable widespread analysis of glacier surface elevation change and geodetic mass balance. However, coincident glacier area data are less widely available, causing inconsistent handling of glacier area change. Here we quantify the bias introduced into meters water equivalent (m w.e.) specific geodetic mass balance results when using a fixed, maximum glacier area, and illustrate the bias for five North American glaciers. Sites span latitudes from the northern U.S. Rocky Mountains (48°N) to the Central Alaska Range (63°N) between 1948 and 2021. Results show that fixed (maximum) area treatment subdues the m w.e. mass change signal, underestimating mass balance by up to 19% in our test cases. This bias scales with relative glacier area change and the mass balance magnitude. Thus, the bias for specific geodetic mass balances will be most pronounced across rapidly deglaciating regions. Our analysis underscores the need for temporally resolved glacier area in geodetic mass balance studies.

The first successful radar echo soundings through glacier ice in Canada were carried out by the Dominion Observatory in 1965 on an outlet glacier of the Penny Ice Cap in Baffin Island. An unmodified 440 MHz SCR-718 radar altimeter was used, of the type that is readily and inexpensively available on the surplus market. The radar soundings were generally in agreement, within the range of the reading accuracy of the oscilloscope (± 15 m), with depths obtained seismically, gravimetrically, and by the electrical resistivity method. The minimum and maximum recorded depths were 45 m and 550 m, respectively. The pip positions on the standard oscilloscope were recorded visually. This recording method was not satisfactory, but for future use the instrument could easily be modified to incorporate a larger oscilloscope with continuous photographic recording. Use of the relatively high carrier frequency of 440 MHz (compared with the more customary frequency of about 35 MHz) allows the use of smaller antennas and results in better resolution of the bedrock surface.

Supraglacial lakes on Antarctic ice shelves can have far-reaching implications for ice-sheet stability, highlighting the need to understand their dynamics, controls and role in the ice-sheet mass budget. We combine a detailed satellite-based record of seasonal lake evolution in Dronning Maud Land with a high-resolution simulation from the regional climate model Modèle Atmosphérique Régional to identify drivers of lake variability between 2014 and 2021. Correlations between summer lake extents and climate parameters reveal complex relationships that vary both in space and time. Shortwave radiation contributes positively to the energy budget during summer melt seasons, but summers with enhanced longwave radiation are more prone to surface melting and ponding, which is further enhanced by advected heat from summer precipitation. In contrast, previous winter precipitation has a negative effect on summer lake extents, presumably by increasing albedo and pore space, delaying the accumulation of meltwater. Downslope katabatic or föhn winds promote ponding around the grounding zones of some ice shelves. At a larger scale, we find that summers during periods of negative southern annular mode are associated with increased ponding in Dronning Maud Land. The high variability in seasonal lake extents indicates that these ice shelves are highly sensitive to future warming or intensified extreme events.

The Pindari Glacier is situated in the heart of the Kumaon Hills in lat. 30° 17′ N. and long. 80° 0′ E. This glacier was visited by the authors in October 1959 when morphological and other observations were made. On the basis of these observations, it appears that during the last hundred years the rate of retreat of this glacier has been phenomenal, and it may be as much as 132 ft. (40.2 m.)/yr. There is also evidence that in the past the Pindari valley suffered at least two glacial advances.

This paper is a summary of the more important results of glaciological investigations carried out in Trinity Peninsula, Graham Land during 1958–60, and which will be published at length in Falkland Islands Dependencies Survey Scientific Report No. 42. The budgets for Depot Glacier and the ice piedmont between Hope Bay and Trepassey Bay are given and it is concluded that in a normal year they are in a state of near equilibrium. The state of the glaciers of southern Trinity Peninsula is discussed in a consideration of the importance of rime ice formation on the west coast of the peninsula. Movement and accumulation studies in Trinity Peninsula and the islands of the James Ross Island group demonstrate a decrease in glacierization south-eastwards from the central plateau area. The recent glacial history of the area is also briefly reviewed.

During a full-scale iceberg-impact study conducted in July 1995 on the Labrador coast, Canada, a sample of ice was retrieved from the impacted surface of an iceberg. The sample was thin-sectioned and the observations of the contact-zone microstructure are presented in this paper.

Thin sections were prepared from two slabs cut parallel to the impacted surface. In each of the thin sections taken from the impacted-surface slab, fine-grained material was found to surround parent-size grains (as observed in the second slab). A boundary between the parent grains and the grains of modified microstructure was found running approximately parallel to the impacted surface in each of the thin sections taken from the impacted-surface slab. This boundary was pronounced towards the edges of the contact zone. Lateral movement of grains outward along this boundary was observed in thin sections near the edges but not near the centre of the contact zone.

The thin sections were compared to the results of medium-scale indentation tests in 1989 and 1990 from the Arctic Ocean. The same type of fine-grained material and layer formation of modified microstructure was found in the contact zones.

Temperatures have been measured at two sites in a temperate glacier (Blue Glacier, Washington, U.S.A.) to depths of 192 and 76 m. The accuracy, which varies between about 0.002 and 0.005 deg, is about an order of magnitude better than previously obtained. Except near the surface, temperatures vary linearly with depth but are in disagreement with the simplest model of a temperate glacier, being about 0.02 deg colder near the surface and 0.04 deg colder at 192 m depth.

A new method for high-resolution (3 mm) dielectric profiling of ice cores is described. The method measures the capacitance and conductance of the ice at a single frequency (chosen to be 50 kHz in this case). The technique requires only a few minutes per metre of core, and no sophisticated data analysis. The system is designed to operate on ice cores that have been cut longitudinally, providing one flat and one curved surface. The 50 kHz conductance is dependent on the acid and neutral-salt concentrations in the ice. The new method was tested successfully on the GRIP core from Summit, Greenland, in 1991. It is useful for detecting seasonal variations in impurities in both acidic Holocene ice and in normally alkaline Wisconsin ice.

Ice skates are remarkably slippery across a wide range of conditions. We propose, based on earlier observations and new modeling, that an ice-rich slurry forms rapidly beneath a skate blade during each stride to lubricate the interface. Crushing from normal load and abrasion from sliding provide ice particles and heat to the slurry, with average contact pressures approaching melting pressures for the bulk ice. Shearing of the slurry by forward motion generates additional heat to melt the ice particles at the pressure-reduced temperature. We model these mechanics and link the viscosity of the resulting slurry to its ice fraction, which controls slurry-film thickness via lateral squeeze-flow. The slurry properties quickly converge to establish a highly efficient lubricating film that provides the characteristically low skate friction across a wide range of conditions. Although our 1D model greatly simplifies the complex interaction mechanics, its predictions are insensitive to most assumptions other than the average contact pressure. The presence of ice-rich slurries supporting skates merges pressure-melting, crushing, abrasion and lubricating films as a unified hypothesis for why skates are so slippery across broad ranges of speeds, temperatures and normal loads.

We report on the radiative transfer process and optical properties of sea ice in the thermal infrared (TIR) band, presenting two new linear kernel driver models (Relative Emissivity Distribution Function, REDF) that describe TIR emission characteristics of smooth and rough ice. In order to test the models and determine the necessary coefficients, in situ measurements from the Bohai Sea were carried out during the 2011/12 and 2012/13 boreal winters. The results show that the relative emissivity of smooth sea ice decreases along with increasing viewing zenith angle, and the shape of the relative emissivity curve is similar to that of an ideal plane. Affected by parameters such as roughness and surface temperature distribution, the anisotropy of relative emissivity of sea ice with a high degree of roughness is stronger relative to the cosine emitter. The model coefficients were also obtained using a robust regression method based on the measured data. The presented models are more practical than the numerical radiative transfer model and can be used for multi-angular TIR remote sensing.

The Gorge du Guil (Hautes-Alpes) might be regarded as a typical example of a post-glacial gorge. In fact, this is not the case. Systematic and very detailed observations based on maps of the scale of 1 : 5,000 have revealed that the greatest part of the excavation of the defiles, cut across the bands of massive rocks, was accomplished by subglacial melt waters. Remnants of glacial deposits containing well-rounded pebbles, but whose finer constituents have been largely removed, occur a few metres above the present valley floor in each of these defiles. The down-cutting was very powerful, being facilitated by the crevassing of the ice, which was at the most 300 m. thick, over the ridges and in the constricted sections of the valley, and by the load carried in the englacial melt water. The sheltered and sunny climate, and the situation of the area below the limit of permanent snow also favoured erosion by melt water. By comparison, post-glacial down-cutting has been slight, not exceeding some ten metres in the massive strata, and appears to have been far less rapid than the subglacial erosion.

Two flood waves from the terminus of Peyto Glacier occurred as a result of very high precipitation in early July 1983 and a landslide which exposed a large section of ice-cored moraine. The flood waves induced erosion, and subsequent melt, of the moraine and deposited an estimated 6000 m3 of gravel in the valley. The majority of the deposition occurred in an area approximately 200 m × 20 m to depths of 3 m at the site of the National Hydrology Research Institute gauging station 1 km from the glacier terminus. The initial flood washed away most of the equipment from the site and the gravel deposition totally destroyed the rest of the installation. These events appear to be unique in the period that hydrological records have been maintained for Peyto Creek.

Surface strain-rate is best observed by fitting a strain-rate ellipsoid to the measured movement of a stake network, or other collection of surface features, using a least-squares procedure. Error of the resulting fit varies as (LΔt√n)-1 where L is the stake separation, Δt is the time period between initial and final stake survey, and n is the number of stakes in the network. This relation suggests that, if n is sufficiently high, the traditional practice of re-visiting stake-network sites on successive field seasons may be replaced by a less costly single-year operation. A demonstration using Ross Ice Shelf data shows that reasonably accurate measurements can be obtained from 12 stakes after only four days of deformation. The least-squares procedure may also aid airborne photogrammetric surveys in that reducing the time interval between survey and re-survey could permit better surface-feature recognition.

The wave of cold temperature, which begins to propagate into a snow field during the winter, may be considerably enhanced by the thermal blanketing of snow accumulating on the surface. This effect is discussed theoretically by means of calculations based on the mathematical theory of the conduction of heat in solids. The results of these calculations show that for an assumed steady velocity of accumulation at the rate of 4 meters/year or 8 meters/year, the winter cold wave should assume significantly larger proportions than in the absence of accumulation.

The velocity of flow of a glacier was measured at two places where the ice margin had no moraine debris between clear ice and unfragmented rock. In one of these places the point at which the measurement was made was only about 1 m. from the solid rock. It was found that at both sites the ice was flowing past the rock at a velocity of the same order of magnitude as the velocity of flow in the centre of the glacier in this region. Although conditions at the side of a glacier are not the same as at the bed, this large amount of slip is evidence for a high rate of slip all along the ice-rock interface, and this is in accordance with current ideas of the flow of ice below ice falls.