The time decay of surface undulations is modeled analytically. The particular application is the decay of flow stripes on the Ross Ice Shelf that emanate from Byrd Glacier. The model predicts two extreme undulation types. One extreme, which we term the buckle solution, has a decay time of only 13 years. The other, the pinch-and-swell case, can persist much longer (700 years), because each surface ridge is underlain by deep roots. Flow stripes may originate as a combination of both the buckle and pinch-and-swell extremes, but only the pinch-and-swell aspect is predicted to survive in the ice shelf The predicted decay time and that measured from satellite imagery are in close agreement.

The manner in which inelastic Shockwaves propagate through snow is evaluated. The volumetric material behavior of snow is represented as an inelastic rate sensitive relationship. The constitutive equation has incorporated into it such crystalline properties as grain size, bond length, bond radius, pore size, and average number of bonds per grain. As a consequence, this constitutive formulation can be used to describe how Shockwave behavior is affected by different physical properties. The governing equations, i.e. the momentum and continuity equations, are solved by integrating them to put these equations in terms of jumps in pressure, density, and particle velocity.

Results are obtained for a wide variety of snow properties. First, the effect of density is evaluated by considering densities ranging from 150 to 300 kg m−3. Then the effect of intergranular bonding is considered by varying the bond radius/grain radius ratio from 0.15 to 0.40. Finally, the Shockwave frequency is varied parametrically to determine the effect of these parameters on wave attenuation rates.

The results are then compared to experimental data. The theoretical results are shown to agree well with the test data. The degree of intergranular bonding was also found to have a very significant effect on attenuation rates.

Finally the importance of the air phase on the propagation of Shockwaves in snow is investigated. The governing equations for each phase are developed by using a mixture theory formulation. An order of magnitude analysis is made in order to assess the importance of the air phase on attenuation rates.

A high-precision, self-operating storage precipitation gauge was designed and field-tested. It consists of a cylinder-shaped container that incorporates antifreeze solution to melt snow and a quartz-crystal pressure sensor to detect mass of the contained liquid. Field trials showed performance to be at least equivalent to the Japanese standard gauge. A novel feature of the developed instrument is that it also measures a parameter related to wind speed, which is the basis for a catch correction. The instrument is simple, robust and can be battery-operated, therefore making it useful for winter precipitation measurements at sites where electric power supply is unavailable.

In this study we investigate the relationship of the atmospheric circulation and the sea-ice distribution in the Laptev Sea, Arctic Ocean, in the summers 1979−96. Sea-ice data from passive-microwave radiometers, global atmospheric data analyses, cyclone statistics and simulations of the regional climate model HIRHAM4 were analyzed to find out if periods of reduced or increased sea-ice concentrations are linked to synoptic patterns (circulation anomalies, cyclone activity). A canonical correlation analysis between Arctic sea-level pressure and sea-ice concentration anomalies confirms large-scale relationships among these variables. We did not find a simple relationship between sea-ice area anomalies and cyclone activity in the Laptev Sea area

Local ice strains and in situ ice stresses were simultaneously measured on the Coordinated Eastern Arctic Experiment (CEAREX). The experiment took place in the fall of 1988 and was centered about an ice-strengthened ship moored to a multi-year floe in the pack ice northeast of Spitsbergen. During the period of data collection, which extended from early October to late November, the ship and the ice surrounding it drifted from 82°40′N, 32°32′E to 78°54′N, 31°27′E.

As soon as ice temperatures were low enough to permit installation, stress sensors were placed at four sites, two sites on each of two adjacent multi-year floes. Principal stress components and the principal stress direction were determined at each sensor. At the same time, microwave transponders, capable of measuring ice deformation to accuracies better than 1 m, were positioned within 1 km of the stress sensors and provided an approximation of the local strain field.

What makes this joint dataset particularly interesting is that it includes some large ridging events and a particularly large event which terminated the experiment when the multi-year floes in the local area were broken into small fragments. A wide range of ice stresses was measured during the period. The largest compressive stresses, about 250 kPa, were measured by the near-surface sensors. Although sensors in different locations responded differently to ice movement, the large events were common to all shallow sensors.

Fifteen 1: 250000 and one 1: 1000 000 scale Landsat Thematic Mapper (TM) image mosaic maps are currently being produced of the West Antarctic ice streams on the Shirase and Siple Coasts. Landsat TM images were acquired between 1984 and 1990 in an area bounded approximately by 78°-82.5°S and 120°- 160° W. Landsat TM bands 2, 3 and 4 were combined to produce a single band, thereby maximizing data content and improving the signal-to-noise ratio. The summed single band was processed with a combination of high- and low-pass filters to remove longitudinal striping and normalize solar elevation-angle effects. The images were mosaicked and transformed to a Lambert conformal conic projection using a cubic-convolution algorithm. The projection transformation was controled with ten weighted geodetic ground-control points and internal image-to-image pass points with annotation of major glaciological features. The image maps are being published in two formats: conventional printed map sheets and on a CD-ROM.

A major concern of the cryospheric community is the availability of reliable data for use with various types of models. The National Science Foundation’s Arctic System Science program (ARCSS) integrates specific Arctic investigations ranging from the Greenland Ice Sheet Project, the Land-Almosphere-Ice Interactions, the Ocean-Atmosphere-Ice Interactions and its associated Surface Heat Energy Budget of the Arctic program to the recently initiated Human Dimensions of the Arctic System project. All data collected from these investigations are archived at the ARCSS Data Coordination Center and the National Snow and Ice Data Center at the University of Colorado, U.S.A. A primary goal of the ARCSS Data Coordination Center is to facilitate better use of observed data within cryospheric modeling efforts. Working with the ARCSS Data Management Group and the Modeling Working Group, we are developing data appropriate for the cryospheric modeling community. This paper summarizes the data currently available at the ARCSS Data Coordination Center, and details the mechanisms by which Arctic researchers can access these data.

We analyze the internal structure of two polythermal glaciers, Hurd and Johnsons, located on Livingston Island, Antarctica, using 200 and 750 MHz GPR data collected in 2003/04, 2008/09 and 2016/17 field campaigns. Based on the different permittivities of snow and ice, we determined the thickness distribution of the end-of winter snow cover and of the cold ice layer. Their knowledge is fundamental for mass balance and glacier dynamics studies due to the different densities and rheological properties of such media. The average measured thicknesses for the snow and cold ice layers (the latter including the snow layer) were of 1.44 ± 0.09 and 29.1 ± 1.5 m, and their corresponding maxima were of 2.45 ± 0.21 and 80.8 ± 2.5 m. GPR snow profiling allowed for extension of the coverage of the snow thickness survey, but added little information to that supplied by snow pits, stake readings and manual snow probing, because of the multiplicity of reflections within the seasonal snowpack caused by internal ice layers and lenses. The polythermal structure determined for Hurd Glacier fits into the so-called Scandinavian type, seldom reported for the Antarctic region.

Melting is a fundamental process in glacier mass balance as well as in other glacial processes such as ice movement, ice avalanches and snow metamorphism. At Terra Nova Bay, Antarctica, the annual mean temperature is <0˚C but melting is not negligible. Our data show that melting is present up to 1300ma.s.l. The distribution and relative importance of melting change with elevation and exposure. At low elevation and with a southerly exposure, melting is one of the major summer ablation processes, synergetic with dry calving and katabatic wind. Meltwater seepage reaches the glacier substrate. Discharge appears to be linked to irradiation, offset by a few hours relative to it. The frontal area of the glaciers therefore behaves like an aquifer, and its characteristics depend on the morphology of the front. As elevation increases, melting at first becomes limited to the snowpack, then to low-albedo cases, for example when dust is brought in from the areas surrounding the glacier. In this case, melting limits ablation, providing the snow with increased resistance to wind erosion.

The images of NOAA/TIROS-N APT, AVHRR and a few Landsat MSS obtained from 1980 to 1985 are analysed in this paper. It is found that the snow-cover distribution in Qilian Mountains is above 3700 m a.s.l. during winter to spring every year. There are two concentrations of snow cover. One is on Mount Leng Longling in the upper reaches of the Shiyang River and the other is located between Hala Lake and Mount Danghe Nanshan.

Based on preliminary investigations, it is known that the surface water resource in the Hexi region is 68 8 × 108 m3, of which about 24.8% is from glaciers and melting, and the snow-melt run-off is 7.63 × 108 m3, equal to 62.6% of the total amount of spring run-off.

The average value of Cv for spring run-off in the Shiyang River, Heihe River, and Shule River is 0 32 and the Cv value of snow-melt run-off in spring is 0.41, about three times as much as that of the annual run-off in the Hexi, region. A prediction model of spring snow-melt run-off at the Ying Louxia Hydrometric station in the Heihe River area can be constructed by using hydrometeorological data and snow-cover percentage for the Heihe River basin obtained from NOAA/TIROS-N APT, and AVHRR images. The prediction models (2) and (3) have been tested by the Water Resources Management Office of the Heihe River basin in the Zhangye and Flood Prevention Office of Gansu Province. The prediction accuracy is suitable for demands.

A box model combining the different physical components of the coupled ocean, atmosphere, sea-ice and land-ice climate system is used to study the possible role of sea ice in the glacial-interglacial oscillations. In this paper we investigate the teleconnection between the two hemispheres, and suggest a mechanism which can explain the observed Southern Ocean sea-ice variability during glacial-interglacial cycles. The teleconnection mechanism involves changes in the temperature of the water transported from the Northern to the Southern Hemisphere by the thermohaline circulation (THC), rather than the amplitude of the THC as has often been suggested. The sequence of events proposed by this model indicates that it would be especially interesting to obtain accurate information on the relative timing of sea-ice and land-ice variations. Fuller general circulation models and new sea-ice proxy data are needed to quantify the relative role of the proposed teleconnection mechanism.

A key measure of our understanding of polar glaciation is the ability to model the initiation, maintenance, and elimination of glaciation over Antarctica and high-latitude land masses in the Northern Hemisphere. Studies that address questions of Cenozoic Antarctic glaciation, as well as studies that address questions of Pleistocene glaciation in the Northern Hemisphere, are described in some detail. The intention is to emphasize and discuss issues that are important in modeling these types of glacial events as much as to present specific results.

Uniaxial compression tests (UCT) under constant cross-head speed and simple shear tests (SST) under constant load have been carried out in a snow cave at -16°C on ice cores within at most one month of extraction from depths of 235, 504, 708, and 896 m at Dye-3, Greenland, as part of the Greenland Ice Sheet Program (GISP), in order to improve understanding of flow behavior. UCT specimens had their stress axis at 45° from the core axis and SST specimens had their shear parallel to the horizontal plane of the core, so that in both cases maximum resolved shear stress was in the horizontal plane of the ice sheet.

Fracture stresses in UCT had characteristic values for each depth corresponding to core quality. When effective strain-rate was plotted against effective shear stress on a double logarithmic plot, (1) data from the same depth fell on the same straight line for both tests, (2) for a given stress, strainrate varied with core-depth by less than half an order of magnitude, and (3) the stress exponent lay between 2 and 2.5, significantly less than the 3 to 4 reported for polycrystalline ice.

Values extrapolated from the present data agree quite well with those deduced from bore-hole tilting measurements at Byrd station, Antarctica, and Camp Century, Greenland.

Avalanche defence structures such as retarding dams and breaking mounds are widely used to protect residential areas and other kinds of infrastructure. The effect of the defence structures depends largely on their effective height relative to the velocity, volume and flow depth of the avalanche. Snow depositions from earlier avalanches as well as from drifting snow can significantly alter the effective height of defence structures. Different designs of avalanche-breaking mounds and retarding dams were tested in the Cemagref (Grenoble, France) wind tunnel for their effect on drifting snow. Examples included dams and mounds of different sizes and heights. The models were tested in a wind tunnel with sand particles subjected to different wind directions. The resulting depositions were scanned with a laser system to obtain a three-dimensional picture of the accumulation pattern. The results show that the accumulated snow varies widely with the design of the structure for a given wind direction. Most snow is accumulated around narrow mounds, with least accumulation observed around mounds covering a smaller relative area of the avalanche path. The data obtained can be used to study the effect of the depositions on the retarding effect of the avalanche defence structures. However, because the similarity criteria for studying the interaction between structures and saltating particles in a wind tunnel cannot be met, the transfer of the results to reality must be performed with caution.

The present and future ice conditions around 100 years from present in the Baltic Sea are examined by two 10 year integrations of an ice-ocean model. Results from atmospheric climate-model simulations constitute the atmospheric forcing, one representing present climate conditions (control simulation), and the other global warming due to CO2 doubling (scenario simulation). The present-day climatological ice conditions and the interannual variability were realistically reproduced by the ice-ocean model. The modelled range of the maximum annual ice extent in the Baltic was 190−420 × 103km2 in the control simulation and 50−270 × 103km2 in the scenario simulation. The range of the annual maximum level-ice thickness was 45−85 and 20−58 cm in the control and scenario simulations, respectively.

Measurement of wind velocity, wind direction, air temperature, precipitation and humidity were obtained at various altitudes in order to describe micrometeorological conditions on the north slope of Mount Qogir (K2). Meteorological elements were monitored above the moraine surface in the proglacial area and over the ice surface in the ablation area and snow surface in the firn area of K2 glacier. Precipitation increases quickly with altitude from the dry valley to the firn area. Relative humidity also increases with elevation. In the K2 glacier area, the highest absolute humidity occurs over the glacier tongue. The effects of melting and freezing of the surface of the glacier in the ablation area on diurnal and day-to-day changes in air temperature influence air temperature in ablation areas, decreasing diurnal range by comparison with the firn areas. On clear days, a down-valley wind blows from the firn area before sunrise and an up-valley wind after sunrise. On days with precipitation, an up-valley wind predominates in the night-time and a down-valley wind in the day-time.

The sea-floor morphological features and sedimentary cover on the shelves of the northern Trinity Peninsula, Antarctica, result from glaciomarine processes. Roughness of the sea floor is apparent at scales from kilometre-wide Glacial troughs to metre-wide iceberg scours. The sedimentary cover is unequally distributed, with a preference for sheltered areas and sea-floor depressions where deposition obeys local controlling factors. An uppermost draping layer caused by settling of fine particles was observed in several of the studied settings. Large parts of the shelves are devoid of sediments, and there the sea floor shows widespread, mostly relict evidence of Glacial erosion. The observed sea-floor morphologies and sedimentary cover highlight the return to grade of the shelves from the northern Trinity Peninsula region.

The behaviour of a floating sheet of lake ice was investigated for the case when it becomes loaded by a layer of fresh snow which is later soaked with water. This latter condition interferes with the traditional horse races of St Moritz, which are held on the lake each year. A piezometric precision gauge which measures accurately the vertical movements of the floating ice relative to the free surface of the lake is described. The level of the lake, in turn, oscillates, depending on the use of water by the local power company. Detailed measurements from the winter of 1978-79 are presented, showing that the piezometric level rises in direct response to precipitation, and that it rises further when the snow becomes soaked with water. With a simple model it is shown that the ultimate level is a function of the snow density, and it is concluded that immediate compaction of falling snow is an appropriate measure to reduce the amount of water entering the snow. It is very unlikely that the oscillations of the level of the lake caused by the demands of the power company have an influence on the slush problem.

To compare results of icing studies conducted in wind tunnels with natural icing conditions, a series of rotor icing studies were made on top of Mt. Washington, New Hampshire. The results indicated that considerable differences exist between the two under conditions of similar liquid water content and temperature. The wet-to-dry growth transition temperature, for instance, with comparable temperature and liquid water content, may be more than 10°C higher under natural conditions than in wind tunnel studies. The possible cause of such discrepancies was found to be the vapor saturation existing in most laboratory experiments. The transition temperature of ice accretion measured in natural fog on board an aircraft agreed better with the results of the Mt. Washington study.