Ponds that form on sea ice can cause it to thin or break-up, which can promote calving from an adjacent ice shelf. Studies of sea ice ponds have predominantly focused on Arctic ponds formed by in situ melting/ponding. Our study documents another mechanism for the formation of sea ice ponds. Using Landsat 8 and Sentinel-2 images from the 2015–16 to 2018–19 austral summers, we analyze the evolution of sea ice ponds that form adjacent to the McMurdo Ice Shelf, Antarctica. We find that each summer, meltwater flows from the ice shelf onto the sea ice and forms large (up to 9 km2) ponds. These ponds decrease the sea ice's albedo, thinning it. We suggest the added mass of runoff causes the ice to flex, potentially promoting sea-ice instability by the ice-shelf front. As surface melting on ice shelves increases, we suggest that ice-shelf surface hydrology will have a greater effect on sea-ice stability.

Ice cores recently drilled to bedrock on the col of Huascarán (9°06′ S, 77°36′ W, 6047 m a.s.l.) offer the potential for a long, annually resolved climate record from tropical South America. This paper presents the record from 1950 to 1993 preserved in microparticle and nitrate concentrations and oxygen-isotopic ratios. Average monthly temperatures from a satellite-linked automatic weather station installed on nearby Hualcán in 1991 are presented. Annual temperatures from local high-altitude meteorological stations, along with the annual Huascarán isotopic record, show a warming trend over the last two decades. The marked preservation of the climate record in oxygen-isotopic ratios on Huascarán is absent at lower-elevation sites, which have been affected by the recent warming. This paper demonstrates the establishment of a time-scale for the Huascarán core, the preservation of the climatic signal with depth and the linkage of the ice-core “proxy-climate” parameters with measured climatic variations.

An ice-flow model has been developed and applied to Law Dome, East Antarctica, at the location of the Dome Summit South deep borehole. The results are used to reconstruct an ice-sheet history of accumulation rate, ice thickness and the rate of change in ice thickness. The focus of this study is on the effect of the variation in anisotropic flow properties on the ice-sheet surface elevation change. The enhancement factor, defined as the ratio of the strain rate for anisotropic ice to the strain rate for isotropic ice, is used in the ice-flow relations to account for the anisotropic properties of the ice with fabric development. The model is run with the various ice rheologies which represent anisotropic or isotropic ice-flow properties. The results show that the model incorporating anisotropic flow properties of the ice is more sensitive to the climate-change history.

To understand the formation of hard snow in the field and its relationship to the physical parameters of snow surfaces, we carried out snowpack observations at a flat and snow-covered field in Barrow, Alaska. These observations were performed in the middle of winter and included two drifting snow events. After the end of each drifting snow event, the minimum snow surface density increased slightly with time and there was a rapid increase in the minimum snow surface hardness. There was no rain during our observations. Therefore, the strong bonds among the snow surface particles were not due to melting and refreezing; they formed because of hardening during water-vapor transport under a temperature gradient and also by exposure of the inner snow layer through erosion. As a consequence, the snow formed a hard surface following the drifting snow events.

High-latitude interactions of local-scale processes in the atmosphere-ice-ocean system have effects on the local, Antarctic and global climate. Phenomena including polynyas and leads are examples of such interactions which, when combined, have a significant impact on larger scales. These small-scale features, which are typically parameterized in global models, can be explicitly simulated using high-resolution regional climate system models. As such, the study of these interactions is well suited to a regional model approach and is considered here using the Arctic Regional Climate System Model (ARCSyM). This model has been used for many simulations in the Arctic, and is now implemented for the Antarctic. Observations of such processes in the Antarctic are limited, which makes model validation difficult. However, using the best available observations for an annual cycle, we have determined a suite of model parameterization which allows us to reasonably simulate the Antarctic climate. This work considers a fine-resolution (20 km) simulation in the Cosmonaut Sea region, with the eventual goal of elucidating the mechanisms in the formation and maintenance of the sensible-heat polynya which is a regular occurrence in this area. It was found in an atmosphere-sea-ice simulation that the ocean plays an important role in regulating the sea-ice cover in this region in compensating for the cold atmospheric conditions.

Snow ice (SI) forms from freezing wet snow, known as slush, and contributes to the thickness of level and brash ice. However, the mechanism of snow-slush-snow ice transformation has not been extensively investigated to date, despite the difference in the freezing rate of slush in comparison with water is important for estimating the ice thickness. In this study, we examined the growth of initial congelation ice (CI) and snow ice (SI) in a fresh water tank exposed to outdoor weather conditions in Luleå, northern Sweden. The tank of size 1.8 × 0.65 × 1.2 m in length, width and height was divided into two compartments to facilitate the simultaneous growth of CI and SI. A total of 12 experiments were conducted in the years 2021 and 2022. The transformation from slush to snow ice was achieved by submerging various amounts of snow in the compartments. It was observed that approximately 35% of the initial snow transformed into SI. Snow ice grew 4 mm°C−0.5 d−0.5 faster than congelation ice. The CI growth under SI was 1 mm°C−0.5 d−0.5 slower than the CI growth under CI. This study provides valuable insights for modelling snow-slush-snow ice transformation and designing future laboratory-scale experiments.

On RADARSAT imagery, the southern margin of the onset zone of Bindschadler Ice Stream, West Antarctica, manifests a multi-banded feature, with brightness varying across the bands and oscillating along each band. Ground-based radar profiles across the margin reveal folds in the firn stratigraphy associated with this pattern and provide evidence for correlation between the depth of shallow isochrones and the RADARSAT backscatter intensity on each profile, allowing us to interpret the banded feature for firn-layer geometry in three dimensions. We use a kinematic model of isochrone depth evolution to show how layer folding and the band expression may result from deformation and advection in the near-surface flow field at ice-stream margins, even with steady flow. The model predicts the formation of longitudinally patterned bands when the ice-stream acceleration fluctuates along flow. Concerted study of the planform and stratigraphy of other RADARSAT-detected features on the ice sheets may help us understand their origin.

A new calorimeter was designed for measuring the free water content of wet snow, aiming at simplicity in mechanism and handling as well as high accuracy and speed in measurements. The mass of hot water to melt the sample and the mass of the mixture (snow sample and hot water) are measurable indoors with sufficient accuracy; therefore, in the field we need only two measurements of temperature (T and T ); this calorimeter reduces the time of measurement of one snow sample to four or five minutes. Using artificially made wet snow, having a known value of free water content, 121 tests were conducted. Standard deviation of the error was 0.82%

We carried out snow-pit observations at Nagaoka, Niigata prefecture, Japan, where the snow layers were at the melting point. It was observed that the water content in the snowpack was nearly constant at approximately 10%, and the coarsening rate of snow particles was about 0.4×10–3mm3 h–1, which was in the range between the rate for dry snow and that for snow soaked in water. The isotope change of snow particles by melting and freezing in a closed system under isothermal conditions at 0˚C was modeled. The temporal change in isotope concentration was calculated for wet snow layers, based on the fractionation between snow particles and liquid water in between the particles, in association with the coarsening of snow particles. The results compared well with field observations. These results suggest that the isotope concentration of the pore water that flows downward from the surface contributed significantly to the isotope change of snow particles.

Mid -winter flooding of the Drift River was caused by melting of snow and glacier ice during the 1989–90 eruption of Redoubt Volcano. “Drift” Glacier (unofficial name) was beheaded when 110 to 120 × 106 m3 of perennial snow and ice were mechanically entrained by the four largest volcanically initiated flows. The flow volumes were increased by incorporation of the seasonal snowpack on the lower glacier surface and in the flooded river valley. The seasonal snow contributed a volume equivalent to about 35 × 106 m3 of water to the flows, increasing the cumulative flood volume by almost 30%. No large amounts of meltwater were stored on or under the glacier before any of the flows took place. The threat of flooding was significantly reduced after the second major eruption removed the remainder of the easily erodible snow and ice.

Open-water leads in sea ice dominate the exchange of heat between the ocean and atmosphere in ice-covered regions, and so must be included in climate models. A parameterization of leads used in one such model is compared to observations and the results of a detailed Arctic sea-ice model. Such comparisons, however, are hampered by the errors in observed lead fraction, but the parameterization appears to compare better in winter than in summer. Simulations with an atmospheric general circulation model (AGCM), using prescribed sea-surface temperatures and ice extent, are used to illustrate the effect of parameterized lead fraction on atmospheric climate, and so provide some insight into the importance of improved lead-fraction parameterizations and observations. The effect of leads in the AGCM is largest in Northern Hemisphere winter, with zonal mean surface-air temperatures over ice increasing by up to 5 K when lead fraction is increased from 1% to near 5%. The effect of leads on sensible heat loss in winter is more important than the effect on radiative heat gain in summer. No significant effect on sea-level pressure, and hence on atmospheric circulation, is found, however. Indirect effects, due to feedbacks between the atmosphere and ice thickness and extent, were not included in these simulations, but could amplify the response.

As more data are recorded in digital form the importance of automatically extracting parameters of glaciological significance increases. This paper addresses the problem, with particular reference to tracking bedrock or internal reflectors in digitally recorded Radio Echo Sounding (RES) data. It has been found that the simplest solution to this problem is a “supervised” system, where operator decisions may be added interactively, either on operator command or upon loss of track. Increasing internal decision making within the program may reduce the number of operator interventions required, but is unlikely to eliminate them completely.

Algorithms are presented and discussed for determining the position of the interface, for predicting the position of the interface in successive records, for determining the loss of track condition, and for re-acquiring track after loss of track.

The transformation of snow to ice under compressive stress is a very slow process unless meltwater is present. A qualitative measure of permeability variation with depth was continuously determined for various shallow-ice cores from the dry-snow zones in both Greenland and Antarctica to investigate this transformation process. Results of the study provide insight into snow densification mechanisms and generally characterize the pore close-off phenomena. Measurements show that bulk densities may be expressed as a function of overburden; pore close-off takes place when the overburden is approximately 3.0–4.5 bar.

In the Himalaya, ice thickness data are limited, and field measurements are even scarcer. In this study, we employed the GlabTop model to estimate ice reserves in the Jhelum (1.9 ± 0.6 km3) and Drass (2.9 ± 0.9 km3) sub-basins of the Upper Indus Basin. Glacier ice thickness in the Jhelum ranged up to 187 ± 56 m with a mean of ~24 ± 7 m, while the Drass showed ice thickness up to 202 ± 60 m, with a mean of ~17 ± 5 m. Model results were validated using Ground Penetrating Radar measurements across four profiles in the ablation zone of the Kolahoi glacier in the Jhelum and nine profiles across the Machoi glacier in the Drass sub-basin. Despite underestimating ice-thickness by ~10%, the GlabTop model effectively captured glacier ice-thickness and spatial patterns in most of the profile locations where GPR measurements were taken. The validation showed high correlation coefficient of 0.98 and 0.87, low relative bias of ~ −13% and ~ −3% and a high Nash–Sutcliffe coefficient of 0.94 and 0.93 for the Kolahoi and Machoi glaciers, respectively, demonstrating the model's effectiveness. These ice-thickness estimates improve our understanding of glacio-hydrological, and glacial hazard processes over the Upper Indus Basin.

Aldegondabreen is a relatively small (5.3 km2) land-terminating glacier located in Nordeskiöld Land of Svalbard, ~10 km southwest of Barentsburg. Cumulative mass balance during 2002–20 equalled −21.79 m w.e., which corresponds to 37% of the total mass loss. The annual mass balance (Ba) varied from −0.24 to −2.19 m w.e., while the winter mass balance (Bw) ranged between 0.36 and 0.85 m w.e. Ba and Bw were strongly correlated with the positive degree-day sums and solid precipitation amounts, respectively, measured at the Barentsburg weather station. There was also a strong correlation (r = 0.76) between Ba and Bw, which shows that winter accumulation amplifies the consecutive summer ice melt by changing the surface albedo. The trend in both observational series is not detectable because the period from 2005 to 2013 was characterized by relatively high Bw and not very negative Ba values. This was also observed on the other Svalbard glaciers, and was related to prevailing north-westerly flows over Svalbard during the summer. Therefore, the decadal periodicity of the Aldegondabreen mass balance follows general archipelago patterns that are determined by regional-scale factors. Thus, the surface mass-balance time series, which is now the longest one in the central part of the Spitsbergen Island, is representative for the archipelago.

Snow cover contains various impurities from natural and anthropogenic sources. These impurities percolate into the soil, groundwater and surface water during snowmelt, significantly influencing their composition. We consider the metals content in snow cover in south Sakhalin, Sea of Okhotsk. Samples were taken in February–April 2011 by the Laboratory of Avalanche and Debris-flow Processes of the Sakhalin Department of the FEGI FEB RAS. Sample analysis was performed by the Laboratory of Analytical Chemistry, FEGI FEB RAS. Overall, the metals present in the highest concentrations were Ca, K, Mg and Na. Other metals have low concentrations at the level of total mineralization of surface water and groundwater. Thus, the main sources of metals in south Sakhalin snow cover are the water surface of the sea and anthropogenic sources.

Due to the extremely low rate at which the major glacial variations occurred during the Pleistocene it is not possible to explain these variations by direct calculation of the fundamental fluxes of heat, momentum, and water mass that must be involved. Instead, we approach the problem in a more inductive manner by trying to formulate a physically plausible dynamical system, representing the net effects of these fluxes, that can account for the observed variance with a minimum number of adjustable parameters, given the known forcing due to Earth-orbital (Milankovitch) variations. Our model involves three “slow-response” variables: the global ice mass, the concentration of atmospheric greenhouse gases (notably CO2, methane, and water vapor), and a measure of the thermal-biological-chemical state of the ocean (perhaps measured by the stratification) that may control the Earth’s carbon cycle over the Pleistocene time period. These variables are connected by a nonlinear dynamical system comprised of three ordinary differential equations that can exhibit instability and free oscillatory behavior of a period close to 100 000 years (the period at which the maximum ice-age variability is found to exist in the late Pleistocene) despite relatively small external Earth-orbital forcing. We calculate the rate constants needed for the model to account for the main features of the ice variations, including the mid-Pleistocene transition from a period of low global ice mass devoid of the 100 000 year oscillation. The implied variations of the greenhouse gases over the past 150 000 years are in good agreement with the recent Vostok ice-core analyses.

We examine the role of the propagation of atmospheric mid-latitudes wave trains in modulating the Amundsen and Bellingshausen sea-ice area (SIA), Antarctica, on intra-seasonal timescales (20–100 days). Spectral analysis of passive microwave estimates of SIA in the Amundsen and Bellingshausen Seas for 1979–2004 shows significant peaks on intra-seasonal timescales. Previous studies have suggested that variations in SIA are linked to disturbances in atmospheric circulation and sea surface temperature. We show that extreme SIA anomalies on intra-seasonal timescales lag the propagation of subtropical wave trains in the Southern Hemisphere by approximately 10–15 days. The sign of the SIA anomaly depends on the phase of the wave. We present evidence that the number of disturbances that cause extreme anomalies of SIA on intra-seasonal timescales has increased in the last 14 years.