Snowfall is central to Alpine environments, and its future changes will be associated with pronounced impacts. We here assess future snowfall changes in the European Alps based on an ensemble of state-of-the-art regional climate model experiments and on two different greenhouse gas emission scenarios. The results reveal pronounced changes in the Alpine snowfall climate with considerable snowfall reductions at low and mid-elevations but also snowfall increases at high elevations in midwinter.

Frazil or granular ice grows rapidly from turbulent water cooled beneath its freezing temperature. We analyse numerical models of a population of ice crystals to provide insight into the treatment of frazil ice in large-scale models and hence in the environment. We determine critical conditions for explosively rapid frazil growth. We show that frazil-ice processes impact whether a plume of ice shelf water beneath an Antarctic ice shelf intrudes at depth or reaches the end of the shelf.

The atmospheric temperature increase poses a real risk of ice sheets collapsing. We show that this risk might have been underestimated since variations in temperature will move the ice sheets to the tipping point of destabilization. We show this by using a simple computer model of a large ice sheet and investigate what happens if the temperature varies from year to year. The total volume of the ice sheet decreases because a cold year followed by an equally warm year do not cancel out.

Basal melting of ice shelves is a major factor in the decline of the Antarctic Ice Sheet, which can contribute significantly to sea-level rise. Here, we investigate a new basal melt model based on the dynamics of meltwater plumes. For the first time, this model is applied to all Antarctic ice shelves. The model results in a realistic melt-rate pattern given suitable data for the topography and ocean temperature, making it a promising tool for future simulations of the Antarctic Ice Sheet.

Before GRACE in 2002, few large-scale measurements of mass change over Greenland and Antarctica existed. We use a least squares inversion of satellite laser ranging (SLR) data to expand the polar mass change time series back to 1994. We explain the technique and analyze its errors, then apply it to SLR and GRACE data. We can estimate the summed mass change over Greenland and Antarctica with low uncertainty. SLR's noise causes interannual errors, but the 20-year estimate is reliable.

This is one of the first papers containing the Greater Caucasus glacier area and number change over the 1960–2014 period by individual river basins and countries. During the research we used old topographical maps and Corona imagery from the 1960s, and Landsat/ASTER imagery from 1986/2014. The separate sections and slopes have been revealed where there are the highest indices of the reduction in the area of the glaciers.

Glaciers that once every few years or decades suddenly advance in length – also known as surging glaciers – are found in many glaciated regions in the world. In the Karakoram glacier tongues are additionally located at low altitudes and relatively close to human settlements. We investigate a very recent and extremely rapid surge in the region that has caused a lake to form in the main valley with possible risks for downstream communities.

This study presents diminishing ice cover in the Kangri Karpo Mountains by 24.9 % ± 2.2 % or 0.71 % ± 0.06 % a⁻¹ from 1980 to 2015 but with nine glaciers advancing. By utilizing geodetic methods, glaciers have experienced a mean mass deficit of 0.46 ± 0.08 m w.e. a⁻¹ from 1980 to 2014. These glaciers showed slight accelerated shrinkage and significant accelerated mass loss during 2000–2015 compared to that during 1980–2000, which is consistent with the tendency of climate warming.

Carbon models suggest the permafrost carbon feedback (soil carbon emissions from permafrost thaw) acts as a slow, unobservable leak. We investigate if permafrost temperature provides an observable signal to detect feedbacks. We find a slow carbon feedback in warm sub-Arctic permafrost soils, but potentially rapid feedback in cold Arctic permafrost. This is surprising since the cold permafrost region is dominated by tundra and underlain by deep, cold permafrost thought impervious to such changes.

An important feature of the Arctic is large spatial heterogeneity in active layer conditions. We developed a modeling framework integrating airborne longwave radar and satellite data to investigate active layer thickness (ALT) sensitivity to landscape heterogeneity in Alaska. We find uncertainty in spatial and vertical distribution of soil organic carbon is the largest factor affecting ALT accuracy. Advances in remote sensing of soil conditions will enable more accurate ALT predictions.

We provide the first luminescence dating of the basal sediment of the Chongce ice cap in the western Kunlun Mountains on the north-western Tibetan Plateau (TP), which gives an upper constraint for the age of the bottom ice at the drilling site. The age is more than 1 order of magnitude younger than the previously suggested age of the basal ice of the nearby Guliya ice cap (~ 40 km away from the Chongce ice cap). This work provides an important step towards better understanding the TP ice cores.

We explain why snow pits across different sites in East Antarctica show visually similar isotopic variations. We argue that the similarity and the apparent cycles of around 20  cm in the δD and δ¹⁸O variations are the result of a seasonal cycle in isotopes, noise, for example from precipitation intermittency, and diffusion. The near constancy of the diffusion length across many ice-coring sites explains why the structure and cycle length is largely independent of the accumulation conditions.

As debris cover affects the meltwater production and behaviour of glaciers it is important to understand how, and over what timescales, it forms. Here we develop an advanced 3-D numerical model that describes transport of sediment through a glacier to the point where it emerges at the surface. The numerical performance of the model is satisfactory and it reproduces debris structures observed within real-world glaciers, thereby offering a useful tool for future studies of debris-covered glaciers.

We mapped submarine landforms in western Antarctic Peninsula bays. These landforms were formed by flowing ice and provide insight into the local controls on glacial ice advance and retreat. We combined data from various cruises to create seafloor maps. We conclude that the number of landforms found in the bays scales to the size of the bay, narrower bays tend to stabilize ice flow, and meltwater channels are abundant, and we hypothesize a recent glacial advance, likely the Little Ice Age.

We demonstrate how snow cover data from satellites can be used to constrain estimates of snow distributions at sites in the Arctic. In this effort, we make use of data assimilation to combine the information contained in the snow cover data with a simple snow model. By comparing our snow distribution estimates to independent observations, we find that this method performs favorably. Being modular, this method could be applied to other areas as a component of a larger reanalysis system.

About 150 of the 250 000 inventoried glaciers are currently monitored with surface mass balance (SMB) measurements. To increase this number, we propose a method to retrieve annual and summer SMB from optical satellite imagery, with an application over 30 glaciers in the French Alps. Computing the glacier-wide averaged albedo allows us to reconstruct annual and summer SMB of most of the studied glaciers, highlighting the potential of this method to retrieve SMB of unmonitored glaciers.

We observed how snowmelt is transported on a hillslope through multiple measurements of snow and soil moisture across a small headwater catchment. We found that snowmelt flows through the snow with less infiltration on north-facing slopes and infiltrates the ground on south-facing slopes. This causes an increase in snow water equivalent at the base of the north-facing slope by as much as 170 %. We present a conceptualization of flow path development to improve future investigations.

Greenland's glaciers that are in contact with the ocean undergo a special ice–ocean melting. To project numerically Greenland's centennial contribution to sea level rise, it is crucial to incorporate this special melting. We demonstrate that a numerically cheap model shows the qualitative same behavior as numerical expensive 2–3-dimensional models and calculates the same melting as empirical data show. Our analytical solution gives some insight in the yet poorly understood melting behavior.

Observations at the WAIS Divide site in West Antarctica show that near-surface snow is strongly altered by weather-related processes, such as strong winds and temperature fluctuations, producing features that are recognizable within the WDC06A ice core. Specifically, over 10 000 prominent crusts were observed in the upper 560 m of the core. We show that these crusts develop more often in summers, during relatively low-wind, low-humidity, clear-sky periods with intense daytime sunshine.

The paper demonstrates the use of SAR imagery in retrieving ice-ridging information for navigation. Based on image segmentation and several texture features extracted from SAR, we perform a classification into four ridging categories from level ice to heavily ridged ice. We compare our results with the manually drawn ice charts over the Baltic Sea. We conclude that the SAR-based product is more detailed than FIS and can be used by ships (non-icebreakers) to aid independent navigation.

This paper evaluates Antarctic sea ice simulated by global climate models against satellite observations. We find biases in high-concentration and low-concentration sea ice that are consistent across the population of 40 models, in spite of the differences in physics between different models. Targeted model experiments show that biases in low-concentration sea ice can be significantly reduced by enhanced lateral melt, a result that may be valuable for sea ice model development.

Snow farming is the conservation of snow during summer. Large snow piles are covered with a sawdust insulation layer, reducing melt and guaranteeing a specific amount of available snow in autumn, independent of the weather conditions. Snow volume changes in two heaps were monitored, showing that about a third of the snow was lost. Model simulations confirmed the large effect of the insulation on energy balance and melt. The model can now be used as a tool to examine future snow-farming projects.

In this study we use an existing ice cave at Chli Titlis (3030 m, central Switzerland) to obtain direct access to ice at the glacier base. Using standard glaciological tools as well as the analysis of the isotopic and physical properties we demonstrate that stagnant cold ice conditions still exist fairly unchanged more than 25 years after a pioneering exploration. Our radiocarbon dating of the basal ice indicates that Chli Titlis has likely been ice-covered for about the last 5000 years.