Glaciar Pio XI (or Glaciar Brüggen) may be the only glacier in the world currently at its Neoglacial maximum. During the 20th century, most glaciers in Patagonia have consistently retreated, whereas Glaciar Pio XI has advanced almost 10 km, most recently at rates of ≤ 1.5 m d−1. This advance cannot be explained with reference to climate alone. An explanatory model combining calving dynamics, sediment budget and fjord topography explains the main features of recent behaviour. This case-study exemplifies the climatically out-of-phase behaviour so typical of calving glaciers, and illustrates the spatial and temporal scale over which they may behave asynchronously in the southern Andes.

Changes in planimetric area, elevation and volume were calculated for Athabasca Glacier, Alberta, Canada, below 2400 m elevation for the period 1919–79 from maps produced using aerial or terrestrial photogrammetry. Map contours were digitized and converted into raster digital elevation models (DEMs). Comparison of the models allowed changes in volume and elevation to be estimated. In the time of record, the glacier lost 2.344 × 108 m3 of volume and downwasted significantly.

There are several sources of error associated with DEM generation and construction: source maps have spatially variable uncertainty in vertical estimation, associated with the photogrammetric process used; small errors are introduced in the creation of raster DEMs as a result of fitting surfaces to digitized contours; errors of registration, leading to errors in estimation of vertical change over time, can be of significance, especially when comparing maps produced by different photogrammetric techniques.

These errors are quantified and displayed in transect and map form. Especially with maps only 2 years apart in time, errors are often greater than actual changes in surface elevation. The magnitude of the errors involved in the comparison of maps made with a 2 year interval would suggest that 5 or 10 years between successive mappings might have been more scientifically justifiable and more cost effective.

The volume of debris in the left-lateral, Little Ice Age (LIA: AD 1550–1850) moraine of the Feegletscher, Valais, Switzerland was compared with the actual volume being transported currently by the glacier. The latter is smaller by a factor of about two. In Tröllaskagi, north Iceland, a surface cover of debris on top of a very slow moving glacier ice mass (glacier noir, rock glacier) has been dated by lichenometry. The age of the oldest part is commensurate with LIA moraines in the area. Knowing the volume of debris of a given age allows an estimate of the debris supply to the glacier in a given time. Again, there appears to have been a significant reduction in debris to the glacier since the turn of the 19th century. Debris input in the early LIA seems to have been particularly copious and this may be important in the formation of some glacier depositional forms such as rock glaciers.

In April 2004 the Royal Navy submarine HMS Tireless became the first UK submarine to conduct environmental monitoring in the Arctic Ocean since 1996. As the last US SCICEX (Scientific Ice Expeditions) cruise was in 2000, this has been the only opportunity for a civilian scientist to carry out measurement of ice draft and oceanography over a wide area of the Arctic. This paper presents preliminary results and compares them with similar investigations in the 1970s–90s. The route of Tireless covered a large area of the European sector of the Arctic from 5˚E to 62˚W. Transects were carried out from the marginal ice zone in Fram Strait up to the North Pole and along the 85˚N parallel north of Greenland. As part of work for the European Commission IRIS project, image intensity from the advanced synthetic aperture radar instrument on the European Space Agency’s Envisat satellite has been compared with ice draft from the submarine. The raw data were found to be highly variable, so a moving average was applied, producing a correlation of 0.79. Tireless carried a full oceanographic sensor suite and expendable probes for investigation into changes in the Arctic Ocean. The results from these show further erosion of the Arctic cold halocline layer by advancing Atlantic Water compared to previous climatologies and fieldwork expeditions. Preliminary ice-draft data from 85˚N show deeper ice keels than those encountered by a submarine on the same route in 1987.

An extreme value (Gumbel) distribution was evaluated as a model of maximum run-out distances of avalanches in southwest Montana defined in terms of dimensionless ratios. The run-out ratios are defined relative to an arbitrarily defined reference point. The development and analysis of the statistical model were based on data taken from surveys of 24 avalanche paths. The technique bears promise as a user-friendly tool; however, due to the small vertical drop of avalanches in southwest Montana, the model appears to be quite sensitive to measurement errors in the field. This sensitivity also seems to depend on the definition of the reference point. Comparison with models developed for other mountain ranges indicates that models developed for one range cannot be used to estimate accurately maximum avalanche run-out distances in other mountain ranges until influencing factors are better understood.

A digital radar system comprising multiple microprocessors, for use with 50 MHz radar units modified from the Scott Polar Research Institute Mark IV design, is described. The major features of the system include coherent integration of radar traces, storage of data in raw digitized form without demodulation, real-time play-back of digitized information, and high system performance resulting in good spatial sampling with integration even in airborne operations. Unfocused synthetic beam shaping also results from the integration of echoes, thus reducing clutter or incoherent scattering from the sides of the beam pattern along the profiling track.

Examples of data collected during the austral summer of 1985–86 in the Antarctic on ice stream B, in both ground and airborne programs, illustrate both the flexibility in data presentation and features present in the records.

Daily weather measurements, snow stability assessments and recorded weak layers of 23 stations covering an observation area of approximately 40 000 km2 in western Canada were analyzed. The study area includes three major mountain ranges with different snow climates. All stations included assess the stability of the snow cover. However, the focus of the avalanche safety program of the different types of operation (heli-ski operation, ski resorts and parks) varies significantly. The three stations in the Coast Mountains show the highest snow stability, followed by the South Columbia Mountains and then the North Columbia and Rocky Mountains. The weather data were analyzed to try to explain some of these differences. Intensive snowfall at relatively high temperatures proved to be important for the higher snow stability over the season in the Coast Mountains. Theweak-layer data were used to complement the snow stability assessments. Most persistent weak layers were reported in the Columbia Mountains, followed by the three stations in the Coast Mountains and trailed by the Rocky Mountains. Although some weather observations indicate climatic reasons for the smaller number of weak layers in the Rocky Mountains, it cannot be excluded that these differences are also related to the different type of operations.

A one-dimensional numerical thermodynamic model is used to study the effects of strain heating on temperature profiles along the flowline of two outlet glaciers in Dronning Maud Land, Antarctica, flowing down a steep escarpment. Measurements of ice surface velocities on the glaciers show higher speeds than surface speeds calculated using Glen’s flow law. These calculations are based on ice-temperature distributions excluding strain heating in the general heat equation. The incorporation of strain heating in the general heat equation produces higher ice temperatures, and calculated ice surface speeds that are close to the measured values. It is found that relatively short-scale temporal and spatial steps in basal topography are enough to drive the ice flow into a positive feedback loop as long as the bedrock step produces a stress that overcomes the advection of cool ice from the surface. In this case, where surface temperatures are –25°C, stresses of 0.4 MPa are enough to drive the base of the ice to the melting point within 102 years.

How landscapes respond to, and evolve from, large jökulhlaups (glacial outburst floods) is poorly constrained due to limited observations and detailed monitoring. We investigate how melt of glacier ice transported and deposited by multiple jökulhlaups during the 2010 eruption of Eyjafjallajökull, Iceland, modified the volume and surface elevation of jökulhlaup deposits. Jökulhlaups generated by the eruption deposited large volumes of sediment and ice, causing significant geomorphic change in the Gígjökull proglacial basin over a 4-week period. Observation of these events enabled robust constraints on the physical properties of the floods which informs our understanding of the deposits. Using ground-based LiDAR, GPS observations and the satellite-image-derived ArcticDEMs, we quantify the post-depositional response of the 60 m-thick Gígjökull sediment package to the meltout of buried ice and other geomorphic processes. Between 2010 and 2016, total deposit volume reduced by −0.95 × 106 m3 a−1, with significant surface lowering of up to 1.88 m a−1. Surface lowering and volumetric loss of the deposits is attributed to three factors: (i) meltout of ice deposited by the jökulhlaups; (ii) rapid melting of the buried Gígjökull glacier snout; and (iii) incision of the proglacial meltwater system into the jökulhlaup deposits.

Experiments were performed to determine the forces required to buckle a floating ice sheet pushing against structures of different widths. The characteristic length of each ice sheet was determined to enable a comparison to be made between the theoretical and experimental results.

Most of the experimental data points are within the range of the theoretical values of normalized buckling loads for frictionless and hinged boundary conditions, which represent the extreme situations for ice-structure contact. Thus, the agreement between the theoretical and experimental buckling loads is considered to be good. Photographs of the buckled ice sheets show a resemblance to the theoretical mode of buckling.

A repeated compression and annealing experiment was conducted using polycrystalline ice samples. The sample was compressed in steps of 10% at a constant low deformation rate at 272 K., and annealed at the same temperature, thus allowing the sample to recrystallize. As a result, the ice gradually changed to a fabric pattern of the 4-maximum or 3-maximum type. The result indicates that repetitive recrystallization plays an important role in forming the preferred orientation of ice in glaciers.

Through comparison of snow-pit NO3– profiles from central East Antarctica and the northern Qinghai-Tibetan Plateau (QTP), we conclude that NO3– peaks in the uppermost surface snow layers in central East Antarctica are not related to an atmospheric signal and that they need to be accounted for by post-depositional effects. Such effects, however, are not found in the snow-pit NO3– profiles from the northern QTP. NO3– can be deposited as a gas (HNO3–) or as a neutral salt, particularly by reaction with ammonia to form NH4NO3, or fixed by sea salt or terrestrial dust (Mulvaney and others, 1998). Thus, a difference in speciation between NO3– in snow layers in East Antarctica and at the northern QTP is suggested as the reason for the different post-depositional processes of NO3– in the two areas.

The Japanese Antarctic Research Expedition (JARE) has set up automatic weather stations at six sites on a 1000 km long traverse route between Syowa station (21 ma.s.l..) and Dome Fuji station (3810 ma.s.l.) since 1993. Large temperature rises in winter were observed several times in this area. There were two patterns of time delay of the temperature rises. One was that the temperature rise at Mizuho station preceded that at other stations, and the other was that the temperature rise at Dome Fuji station preceded the others. The former occurred when a disturbance came from the coast between east Enderby Land and the Amery Ice Shelf and strong winds destroyed the stable inversion layer. The latter occurred when the low-pressure center was near the coast of west Wilkes Land. in this case, temperature rise was caused by adveclion of warm air. The atmospheric pressure at Dome Fuji station and Relay Point oscillated with a period of 0.5 year and amplitude of about 15hPa. The pressure was higher in July and December, and was accompanied by a temperature rise. Fluctuations of hourly air temperature at Dome Fuji station were approximately twice as large as fluctuations at the other sites. The lapse rale of the annual mean temperature increased with elevation, while the monthly lapse rate was largest in April.

Construction of an iceberg processing plant at Saldanha Bay, Republic, of South Africa, is proposed. A reservoir would be constructed at Rieibaai for ice storage. Tidal forces would be harnessed to pump the warm water of Saldanha Lagoon over heat exchangers (using ammonia or propane gas as a heat exchange medium), thus providing power for electrical generators and for melting ice. A functional analysis of operations is presented, together with proposed costs. It is suggested that the fresh water and electricity produced by this system will cost 6¢/m3 and 3¢/kwH, respectively.

The French 870 m deep temperature profile gives us temperature differences with an accuracy of 0.01 deg (to obtain such an accuracy, the sensors must be applied against the walls of the bore hole). The error on the vertical gradient T' cannot be lessened by weighted running means. Thus, only a mean value of its derivative T" can be reached.

Data have been analysed by assuming a two-dimensional flow over a plane horizontal bedrock. As a first step, the steady state at an ice divide has been calculated by solving the complete set of equations. The vertical strain-rate is a constant over two-thirds of the ice sheet. It appears that, at Dome C, sliding and no-sliding solutions are plausible, as well as cyclic oscillations between them. Next, the temperature response of the ice sheet to an impulse for the surface temperature has been computed, and convolved with surface palaeotemperatures deduced from the 180 profile, to obtain the time derivative Ṫ.

Mean values of T', T" and Ṫ allow an estimation of the vertical velocity, which is much smaller than the balance one. Therefore, the ice sheet has thickened by 200 to 280 m during the last 10 ka.

It is proposed that an ice shelf disintegrates when its calving front retreats faster than its grounding line. This paper examines the role of ice thinning in grounding-line retreat. Thinning occurs as a result of creep spreading and ice melting. Thinning by creep is examined for the general regime of bending converging flow in an ice shelf lying in a confined embayment, and at the grounding lines of ice streams that supply the ice shelf and ice rises where the ice shelf is grounded on bedrock. Thinning by melting is examined at these grounding lines for tidal pumping and for descent of surface melt water into strandline crevasses, where concentrated melting is focused at the supposed weak links that connect the ice shelf to its embayment, its ice streams, and its ice rises. Applications are made to the Ross Ice Shelf.

A global collection of high temporally resolved ice-core-derived δ18O records is examined to assess whether the proxy records are consistent with contemporaneous observed temperature variations in their respective regions. This is prerequisite to using the older parts of the proxy (δ18O) records to assess whether 20th-century temperatures remain within the range of longer-term natural variability. Excluding the high plateaus in East and West Antarctica where 20th-century temperatures show modest cooling, the ice-core records from other regions suggest modest to strong 20th-century warming. The recent warming over Greenland has been modest and spatially variable. The 20th-century warming over both the Barents Sea region and the Tibetan Plateau now falls well outside the range of prior longer-term temperature variability. Similarly, over the South American Andes and the Antarctic Peninsula the recent warming exceeds the long-term mean for the last 1000 and 500 years, respectively. The ice fields in these regions are in danger of being compromised or lost if the present warming trend in these regions persists.

Ice cores contribute important records of past climate changes. As one of the thickest ice caps in central Asia, the Guliya ice cap (35°17′ N, 81°29′ E) provides valuable information for this critical region about the past climate and environment changes. We used wavelet analysis to examine periodic temperature and precipitation oscillations over the past 1700 years recorded in the Guliya ice core. The results show non-linear oscillations in the ice-core records, with multiple timescales. Temperature records indicate persistent oscillations with periodicities of approximately 200, 150 and 70 years. Precipitation records show significant periodicities at 200, 100, 150 and 60 years. However, the amplitude modulation and frequency vary with time. Wavelet analysis can explore these time series in greater detail and furnish additional useful information.

Many ice-core drilling projects expect to reach depths greater than 1000 m. At such depths it is necessary to fill the borehole with a fluid to compensate the ice pressure and avoid the resulting significant hole closure. Knowledge of the ice-chips and drilling-fluid circulation parameters (e.g. flow rate, pressure drop, velocity) is essential for understanding the behaviour of the fluid around the drill and will support drill design through a better parameterization in models. A characterization of the dynamic viscosity and of the density of the ice-chips and drilling-fluid mixture is required to calculate these circulation parameters. The goal of this study is to propose a method to calculate, to a first approximation, both these physical properties. The relationships presented here have been established after experimentation, building on prior assumptions taken from the literature.