Lake Vida is one of the largest lakes in the McMurdo dry valleys, Antarctica, and has the thickest known ice cover of any lake on Earth. For the first time, Lake Vida was drilled to a depth of 27m. With depth the ice cover changes from freshwater ice to salty ice interspersed with thick sediment layers. It is hypothesized that the repetition of sediment layers in the ice will reveal climatic and hydrologic variability in the region over the last 1000--3000 years.

Spatially distributed snow-cover data are available only for the recent past from remote sensing. Sometimes we need snow-cover data over a longer period for climate impact analysis for the calibration/validation of hydrological models. In this study we present a methodology to reconstruct snow cover in the past using available long-term in situ data and recently available remote sensing snow-cover data. The results show about 85% accuracy although only a limited number of stations (7) were used.

Permafrost peatlands are hydrological and biogeochemical hotspots in discontinuous permafrost areas. We estimate the depths to the permafrost table surface and base across a peatland in northern Sweden using ground penetrating radar and electrical resistivity tomography. Seasonal frost tables, taliks, and the permafrost base could be detected. The results highlight the added value of combining techniques for assessing distributions of permafrost in the rapidly changing sporadic permafrost zone.

The Greenland Ice Sheet surface shows a diverse range of characteristics, and hosts active microbial communities in debris-rich ''cryoconite holes'' (CHs). Field and satellite data for a complete melt season revealed significant links between surface albedo, CH coverage and biological activity. This suggests satellites may be able to monitor CH biological processes. Nevertheless, caution is needed when extrapolating point measurements of biological processes to larger space and time scales.

An overall negative glacier surface area change of 0.5±0.2% yr-1 was observed for the eastern Himalaya since 1962 based on remote sensing data. There were higher rates of area loss for clean glaciers (-34%, or -0.7% yr-1) compared to debris-covered glaciers (-14.3% or -0.3 yr-1) on a glacier-by-glacier basis. Patterns of area change are heterogenous and depend on topographic and climatic factors, glacier altitude (maximum, median, altitudinal range), glacier size, slope and aspect.

Based on satellite laser altimetry over the Pamir--Karakoram Himalaya we detect strongest elevation losses over east Nyainqentanglha Shan and Spiti--Lahaul but slight elevation gains over west Kunlun Shan rather than over Karakoram. The current sea-level contribution of Pamir--Karakoram Himalaya glaciers is about 10% of the total global contribution of glaciers outside the ice sheets. We also improve estimates of glacier imbalance contribution to river discharge in the Himalayas.

Numerical Weather Prediction (NWP) models are rarely verified for mountainous regions during the winter season, although avalanche forecasters and other decision makers frequently rely on NWP models. We verified two NWP models (GEM-LAM and GEM15) and a precipitation analysis system (CaPA) at approximately 100 stations in the mountains of western Canada and northwestern USA. Ultrasonic snow depth sensors and snow pillows were used to observe daily precipitation amounts.

This paper addresses the feedback between ice flow and melt rates. Using 20 years of data covering the whole ablation area, we show that there is not a strong positive correlation between annual ice velocities and melt rates. Rapid variations around the equilibrium line indicate the possibility of rapid variations high on the ice sheet.

This study presents the thermal state and recent evolution of permafrost at Cime Bianche. The analysis reveals that (i) spatial variability of MAGST is greater than its interannual variability and is controlled by snow duration and air temperature during the snow-free period, (ii) the ALT has a pronounced spatial variability caused by a different subsurface ice and water content, and (iii) permafrost is warming at significant rates below 8m of depth.

We present a new method to compute sea ice deformation fields from satellite-derived motion. The method particularly reduces the artificial noise that arises along discontinuities in the sea ice motion field. We estimate that this artificial noise may cause an overestimation of about 60% of sea ice opening and closing. The constant overestimation of the opening and closing could have led in previous studies to a large overestimation of freezing in leads, salt rejection and sea ice ridging.

On the Greenland Ice Sheet, a significant quantity of surface melt water refreezes after infiltrating into the cold underlying firn. This paper presents a new method for estimating the amount of water refreezing using temperature measurements. The method is applied to temperature data from a transect of 11 sites and the results provide some of the first measurement-based estimates of refreezing quantities which can be used to improve modeling and better understand the refreezing process.

Glacier velocity, glacier area, surface elevation and mass changes of the Southern and Northern Inylchek Glacier were investigated by using multi-temporal space-borne data sets. The mass balance of both SIG and NIG was negative(-0.43 ± 0.10 m w.e. a-1 and -0.25 ± 0.10 m w.e. a-1) from ~1975 to 2007. The thinning at the lake dam was higher, likely caused by calving into Lake Merzbacher. Thus, glacier thinning and glacier flow are significantly influenced by the lake.

The development of ground temperatures in permafrost areas is influenced by many factors varying on different spatial and temporal scales. We present numerical simulations of ground temperatures for the Zackenberg valley in NE Greenland, which take into account the spatial variability of snow depths, surface and ground properties at a scale of 10m. The ensemble of the model grid cells suggests a spatial variability of annual average ground temperatures of up to 5°C.

Ground ice in permafrost has not, until now, been considered to be a source of dissolved organic carbon (DOC), dissolved inorganic carbon (DIC) and other elements that are important for ecosystems and carbon cycling. Ice wedges in the Arctic Yedoma region hold 45.2 Tg DOC (Tg = 10^12g), 33.6 Tg DIC and a freshwater reservoir of 4200 km³. Leaching of terrestrial organic matter is the most relevant process of DOC sequestration into ground ice.

A time series of four Austrian glacier inventories (GIs) from the LIA maximum state up to the year 2006 show a decrease of glacier area to 44% of the LIA area. The annual relative area losses are 0.3%/year for the period GI LIA to GI 1 (1969), with one period with major glacier advances in the 1920s. From GI 1 to GI 2 (1969-1998, one advance period of variable length in the 1980s) glacier area decreased by 0.6%/year, and from GI 2 to GI 3 (10 years, no advance period) by 1.2%/year.

Many glaciers on Svalbard are surging glaciers. A surge is a rapid advance of the glacier snout during a few years, followed by a long period of quiescence. During the surge ice flows to lower terrain and experiences higher melt rates in summer. Here we investigate the impact of surging on the long-term effects of climate warming. We have modelled Abrahamsenbreen in northern Spitsbergen as a typical case. We show that surges tend to accelerate glacier retreat when temperature increases.

Slab tensile failure propensity is examined using a mechanical--statistical model of the slab–-weak layer (WL) system based on the finite element method. This model accounts for WL heterogeneity, stress redistribution by elasticity of the slab and the slab possible tensile failure. For realistic values of the parameters, the tensile failure propensity is mainly driven by slab properties. Hard and thick snow slabs are more prone to wide–scale crack propagation and thus lead to larger avalanches.

This paper provides a proof of concept approach for combining multiple observations and inferences to provide rigorous, error-bounded estimates of mass trends and surface processes for the Antarctic ice sheet. Here we apply the method to West Antarctica, using a time-invariant solution by way of proof of concept. Subsequent work will utilise a time evolving approach to the whole ice sheet.