Summer surface albedo over Greenland decreased at a rate of 0.02 per decade between 1996 and 2012. The decrease is due to snow grain growth, the expansion of bare ice areas, and trends in light-absorbing impurities on snow and ice surfaces. Neither aerosol models nor in situ observations indicate increasing trends in impurities in the atmosphere over Greenland. Albedo projections through to the end of the century under different warming scenarios consistently point to continued darkening.

We implemented a level-set method in the ice sheet system model. This method allows us to dynamically evolve a calving front subject to user-defined calving rates. We apply the method to Jakobshavn Isbræ, West Greenland, and study its response to calving rate perturbations. We find its behaviour strongly dependent on the calving rate, which was to be expected. Both reduced basal drag and rheological shear margin weakening sustain the acceleration of this dynamic outlet glacier.

We investigate snow depth distribution at peak accumulation over a small Alpine area using photogrammetry-based surveys with a fixed wing unmanned aerial system. Results reveal that UAS estimations of point snow depth present an average difference with reference to manual measurements equal to -0.073 m. Moreover, in this case study snow depth standard deviation (hence coefficient of variation) increases with decreasing cell size, but it stabilizes for resolutions smaller than 1 m.

We present an extensive data set of ground-based and airborne electromagnetic ice thickness measurements covering Fram Strait in summer between 2001 and 2012. An investigation of back trajectories of surveyed sea ice using satellite-based sea ice motion data allows us to examine the connection between thickness variability, ice age and source area. In addition, we determine across and along strait gradients in ice thickness and associated volume fluxes.

This study provides homogenised and partly calibrated data series of glaciological and geodetic mass balance for the 10 Norwegian glaciers with long-term observations. In total, 21 periods of data were compared. Uncertainties were quantified for relevant sources of errors, both in the glaciological and geodetic series. The reanalysis processes altered seasonal, annual, and cumulative as well as ELA and AAR values for many of the years for the 10 glaciers presented.

This first multi-parametric analysis of the basal ice layer of the NEEM ice core reveals that its formation does not result from a mixing process between local relict ice and the deepest ice layers of the advancing ice sheet during its growth phase. Instead, it is shown that the basal sequence partly originates from melting and refreezing processes acting at the ice/bedrock interface under a well-developed ice sheet. These have partially destroyed the paleoclimatic records of the ice.

This study involves the analysis of MODIS Level 3500 m snow products, complemented with 250 m Level 1B data, to monitor ice cover during the break-up period on the Mackenzie River, Canada. Results from the analysis of data for 13 ice seasons (2001–2013) show that ice-off begins between days of year (DOYs) 115 and 125 and ends between DOYs 145 and 155, resulting in average melt durations of about 30–40 days; we conclude that MODIS can monitor ice break-up.

Accurate observations of lead fraction are of high importance for model evaluation and/or assimilation into models. In this work, consistent quantitative error estimation of an existing lead fraction data set obtained from passive microwave observations is completed using Synthetic Aperture Radar data. A significant bias in the data set is found, and possible improvement in the methodology is suggested, so that the pixel-wise error is reduced by a factor of 2 on average.

We use a regional 3-D outlet glacier model to simulate the behaviour of Jakobshavn Isbræ (JI) during 1990–2014. The model simulates two major accelerations in 1998 and 2003 that are consistent with observations. We find that most of the JI retreat during the simulated period is driven by the ocean parametrization used, and the glacier's subsequent response, which is largely governed by bed geometry. The study shows progress in modelling the temporal variability of the flow at JI.

The magnitude and makeup of error in cryospheric radiation observations due to small sensor misalignment in in situ measurements of solar irradiance is evaluated. It is shown that relatively minor sensor misalignments give significant errors in irradiance and hence albedo measurements. The total measurement error introduced by sensor tilt is dominated by the direct component. Significant measurement error can also persist in integrated daily irradiance and albedo.

We use a numerical model based on approximated ice flow physics and calibrated against field-based evidence to present numerical simulations of multiple advance and retreat phases of the former Cordilleran ice sheet in North America during the last glacial cycle (120 000 to 0 years before present).

In spite of quite abundant literature focusing on fine debris deposition over snow of glacier accumulation areas, less attention has been paid to the ice of the glacier melting surface. Accordingly, we developed a method for estimating ice albedo from fine debris cover quantified by a semi-automatic method. Our procedure was tested on the surface of the Forni Glacier (Italian Alps), acquiring parallel data sets of in situ measurements of ice albedo and high-resolution images.

This paper analyzes the evolution of the Monte Perdido Glacier, Spanish Pyrenees, since 1981. Changes in ice volume were estimated by geodetic methods and terrestrial laser scanning. An acceleration in ice thinning is detected during the 21st century. Local climatic changes observed during the study period do not seem sufficient to explain the acceleration. The strong disequilibrium between the glacier and the current climate and feedback mechanisms seems to be the most plausible explanation.

This work analyses the longer mass balance series of Italian glaciers. All glaciers experienced mass loss in the observation period, with increasing mass loss rates mainly due to increased ablation during longer and warmer ablation seasons. Low-altitude glaciers with low range of elevation are more out of balance than the higher, larger and steeper glaciers, which maintain accumulation areas. Because most of the monitored glaciers are at risk of extinction, they require a soon replacement.

This article presents the percentage and quantitative changes in the number and area of glaciers for all Georgian Caucasus in the years 1911–1960–2014, by individual river basins, by comparing recent Landsat and ASTER images (2014) with older topographical maps (1911, 1960) along with middle and high mountain meteorological stations data.

We identify and correct station-tilt-induced biases in insolation observed by automatic weather stations on the Greenland Ice Sheet. Without tilt correction, only 40 % of clear days have the correct solar noon time (±0.5 h). The largest hourly bias exceeds 20 %. We estimate the tilt angles based on solar geometric relationship between insolation observed on horizontal surfaces and that on tilted surfaces, and produce shortwave radiation and albedo that agree better with independent data sets.

This study presents observational characterization of interactions between wind-induced surface roughness and aeolian erosion over a rough surface in coastal East Antarctica. It is shown that the drag caused by small-scale roughness elements can significantly affects the aeolian snow mass flux during an erosion event, depending on the ability of the surface to adjust according to the main wind. Such measurements are essential to improve parameterization schemes for aeolian snow transport models.

This paper explores the influence of a subglacial lake on ice dynamics and internal layers by means of numerical modelling as well as simulating the effect of a subglacial drainage event on isochrones. We provide an explanation for characteristic dip and ridge features found at the edges of many subglacial lakes and conclude that draining lakes can result in travelling waves at depth within isochrones, thus indicating the possibility of detecting past drainage events with ice penetrating radar.

We assimilate the summer SICCI sea ice concentration data with an ensemble-based Kalman Filter. Comparing with the approach using a constant data uncertainty, the sea ice concentration estimates are further improved when the SICCI-provided uncertainty are taken into account, but the sea ice thickness cannot be improved. We find the data assimilation system cannot give a reasonable ensemble spread of sea ice concentration and thickness if the provided uncertainty are directly used.

Geometric effects induced by tilt errors lead to erroneous measurement of snow albedo. These errors are corrected where tilts of sensors and slopes are unknown. Atmospheric parameters are taken from a nearby reference measurement or a radiation model. The developed model is fitted to the measured data to determine tilts and directions which vary daily due to changing atmospheric conditions and snow cover. The results show an obvious under- or overestimation of albedo depending on the slope direction.

Changes of the porous ice structure were observed in a snow sample. Sublimation occurred due to the slight undersaturation of the incoming air into the warmer ice matrix. Diffusion of water vapor opposite to the direction of the temperature gradient counteracted the mass transport of advection. Therefore, the total net ice change was negligible, leading to a constant porosity profile. However, the strong recrystallization of water molecules in snow may impact its isotopic or chemical content.

We describe the growth of a very large diameter pingo in the Tuktoyaktuk Coastlands. Analysis of historical data showed that ground uplift initiated sometime between 1935 and 1951 following lake drainage and is largely caused by the growth of intrusive ice. This study demonstrates that satellite radar can successfully contribute to understanding the dynamics of terrain uplift in response to permafrost aggradation and ground ice development in remote polar environments.

The thickness of ice shelves is typically inferred using hydrostatic equilibrium which requires knowledge of the firn density. Here, we infer density from wide-angle radar using a novel algorithm including traveltime inversion and ray tracing. We find that firn is denser inside a 2 km wide ice-shelf channel which is confirmed by optical televiewing of two boreholes. Such horizontal density variations must be accounted for when using the hydrostatic ice thickness for determining basal melt rate.

Our results show a strong association between calcium and nitrate ions in snow from two different regions that are > 2000 km apart in East Antarctica. Such association could have formed during the interaction between long-range transported dust with the atmospheric nitrate. This study also implies that apart from other well-known sources of nitrate in Antarctica, nitrate associated with mineral dust could form a significant portion of total nitrate deposited in Antarctic snow.

The relationship between water isotope ratios and temperature is investigated in precipitation snow at Vostok and Dome C, as well as in surface snow along traverses. The temporal slope of the linear regression for the precipitation is smaller than the geographical slope. Thus, using the latter could lead to an underestimation of past temperature changes. The processes active at remote sites (best glacial analogs) are explored through a combination of water isotopes in short snow pits.

We analyze how snowpack processes and soil properties impact the soil temperature profiles over northern Eurasian regions using a land surface model. A correct representation of snow compaction is critical in winter while snow albedo is dominant in spring. In summer, soil temperature is more affected by soil organic carbon content, which strongly influences the maximum thaw depth in permafrost regions. This work was done to improve the representation of boreal region processes in climate models.

In the paper a new method to calculate airflow speeds in static ice caves by using air temperature data is presented. As most study sites are in very remote places, where it is often not possible to use sonic anemometers and other devices for the analysis of the cave climate, we show how one can use the given database for calculating airflow speeds. Understanding/quantifying all elements of the specific cave climate is indispensable for understanding the evolution of the ice body in ice caves.

In this paper, we compare the regional mass changes of the Greenland ice sheet between the solutions based on GRACE data and input/output method. Differences are found in some regions and indicate errors in those solutions. Therefore we improve our GRACE and IOM solutions by applying a simulation. We show the improved regional mass changes approximations are more consistent in regions. The remaining difference in the northwester Greenland is due to the underestimated uncertainty in IOM solution.

Presently, sea ice drift data do not provide sufficient resolution to estimate convergence and divergence fields on a spatial scaling of a few kilometres. Our goal is to exploit recent improvements and developments in computer vision by adopting a state-of-the-art feature-tracking algorithm to derive high-resolution sea ice drift. A computationally efficient algorithm has been considered, tuned and compared with other available feature-tracking algorithms.

Glacier Echaurren Norte (ECH, 34° S) has the longest (> 35 yrs) mass-balance record in South America. A minimal model that explains 78 % of the variance in the ECH annual record identifies precipitation as the most important forcing. A regional streamflow series allows for extending the ECH annual record back to 1909 and shows a clear cumulative ice-mass loss. Similarities with documented glacier advances and other shorter mass-balance series suggest the ECH reconstruction is regionally representative.