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Citizen science and related engagement programmes have proliferated in recent years throughout the sciences but have been reasonably limited in the cryospheric sciences. In the semiarid Andes we at the Centro de Estudios Avanzados en Zonas Áridas have developed a range of initiatives together with the wider community and stakeholder institutions to improve our understanding of the role snow and ice play in headwater catchments. In this paper we reflect on ongoing engagement with communities living and working in and near study sites of cryospheric science in northern Chile as a strategy that can both strengthen the research being done and empower local communities. [ABSTRACT FROM AUTHOR]

Mountain glaciers are crucial sources of fresh water, contributing directly and indirectly to water, energy and food supplies for hundreds of millions of people. Assessing the impact of diminishing glacial meltwater contributions to the security of this resource is critical as we seek to manage and adapt to changing freshwater dynamics in a warming world. Both water quantity and quality influence water (in)security, so understanding the fluxes of water, sediment and contaminants through glacial and proglacial systems is required for holistic assessment of meltwater contribution to downstream resource security. In this paper we consider the socio-environmental role of and pressures on glacier-fed waters, discuss key research priorities for the assessment of both the quantity and quality of meltwater and reflect on the importance of situating our understanding within a transdisciplinary and inclusive research landscape. [ABSTRACT FROM AUTHOR]

Cryospheric change occurs in unequal spaces. Societies living near ice are divided by race, class, gender, geography, politics and other factors. Consequently, impacts of ice loss are not shared equally, and everyone experiences cryospheric changes differently. Responsibility for recent ice loss is also driven by a relatively small portion of humanity: those who emit the most greenhouse gases. Additionally, people who study the cryosphere come from institutions and societies where inequality is often systemic, making research on ice and snow a symptom of and contributor to social inequality. To better understand unequal effects of cryospheric change within and across diverse communities, including research communities, this paper focuses on three areas, drawing primarily from glacier-related work: (1) the social context of cryospheric changes; (2) attribution and responsibility for cryospheric changes and (3) imbalances in knowledge about the cryosphere. Addressing these dimensions of ice loss requires transdisciplinary approaches that connect research to societies and link glaciology and other cryospheric sciences with social sciences and humanities. These concepts, cases and suggestions to help address inequalities also reveal that no singular conceptualization of sustainability exists. Different societies, residents and researchers possess distinct understandings of and goals for 'ice in a sustainable society'. [ABSTRACT FROM AUTHOR]

In March 2020, COVID-19 lockdowns in many countries resulted in university classes moving online and scientific meetings being cancelled. Shortly afterwards the International Glaciological Society (IGS) started a weekly I IGS Global Seminar Series i . This special edition of the I Annals of Glaciology i celebrates the success of the I IGS Global Seminar Series i by showcasing 31 Letters (short papers) resulting from seminars presented during the first two years of the series. [Extracted from the article]

Citizen science and related engagement programmes have proliferated in recent years throughout the sciences but have been reasonably limited in the cryospheric sciences. In the semiarid Andes we at the Centro de Estudios Avanzados en Zonas Áridas have developed a range of initiatives together with the wider community and stakeholder institutions to improve our understanding of the role snow and ice play in headwater catchments. In this paper we reflect on ongoing engagement with communities living and working in and near study sites of cryospheric science in northern Chile as a strategy that can both strengthen the research being done and empower local communities. [ABSTRACT FROM AUTHOR]

Mountain glaciers are crucial sources of fresh water, contributing directly and indirectly to water, energy and food supplies for hundreds of millions of people. Assessing the impact of diminishing glacial meltwater contributions to the security of this resource is critical as we seek to manage and adapt to changing freshwater dynamics in a warming world. Both water quantity and quality influence water (in)security, so understanding the fluxes of water, sediment and contaminants through glacial and proglacial systems is required for holistic assessment of meltwater contribution to downstream resource security. In this paper we consider the socio-environmental role of and pressures on glacier-fed waters, discuss key research priorities for the assessment of both the quantity and quality of meltwater and reflect on the importance of situating our understanding within a transdisciplinary and inclusive research landscape. [ABSTRACT FROM AUTHOR]

In this paper, we present an electric-thermal drill with a novel design of a melting head that was developed within the EnEx-RANGE project. The design combines a short melting head with a large surface area of parabolic shape. It was succesfully tested in the laboratory as well as on Alpine glaciers (Langenferner and Mittelbergferner) and at the Ross Ice Shelf in Antarctica. In all these different environments, a high melting speed per specific power of typically 8.8 cm3 w-1 h-1 is achieved that is close to the ideal maximum bound of ~10.5-11.8 cm³ w-1 h-1 when neglecting all heat losses. It has also been demonstrated that the melting probe can be operated with typical equipment of small-scale field camps including a small power generator. [ABSTRACT FROM AUTHOR]

The Autonomous Pinger Unit (APU) is an electro-thermal drill with acoustic instrumentation developed for the project EnEx-RANGE in view of a future space mission for the sub-surface exploration of Saturn's moon Enceladus. A main goal is the development of navigation technology for an acoustic guidance system allowing maneuvering a probe through glacial ice. In total 13 APUs were built and tested in terrestrial analog scenarios on alpine glaciers. The APUs form a spatially distributed network that defines a system of reference for the navigation of the maneuverable probe to a point of interest. The APUs have a novel melting head, slow control systems, and a modern system-on-chip (SoC) module that controls the probe and processes the recorded data. The APUs use acoustic emitters and receivers to measure the transit time of acoustic signals between them, allowing for the position reconstruction of all APUs by trilateration. Several auxiliary sensors monitor the internal state of the probe and assist the position estimation. With this instrumentation, the APUs have the ability of dynamically optimizing themselves within the network by changing their position. This paper gives an overview of the developed APU hardware and presents performance results from the field tests. [ABSTRACT FROM AUTHOR]

The Institute of Low Temperature Science at Hokkaido University conducted ice-core drilling in alpine glaciers in the northern North Pacific region to reconstruct climate change in this region for the past few hundred years. We drilled two ice cores in the Kamchatka Peninsula, Russia. An ice core with a length of 211 m was drilled on a glacier at the summit caldera of Ushkovsky mountain in 1998. A second core, with a length of 115 m (until bedrock was reached), was drilled on a glacier at the summit caldera of Ichinsky mountain in 2006. We drilled three further ice cores in Alaska, USA. Two ice cores with lengths of 50 and 212 m were drilled on a glacier at the summit caldera of Mount Wrangell in 2003 and 2004. The third ice core was drilled on the ice divide among three glaciers, Black Rapids, Trident and Susitna glaciers, which represent a flat saddle north of Aurora Peak in the Alaska Range. This paper details the field operations and characteristics of the different ice-drilling systems used and the problems encountered. [ABSTRACT FROM AUTHOR]

Water level fluctuations of inland lakes are related to regional-scale climate changes, and reflect variations in evaporation, precipitation and glacier meltwater flowing into the lake area in its catchment. In this paper, Ice, Cloud and land Elevation Satellite (ICESat) altimeter data and Landsat imagery (2002-09) are used to estimate Nam Co lake (Nyainqentanglha range, Tibetan Plateau) water elevation changes during 2002-09. In 2003 Nam Co lake covered an area of ~1998.8±4.2 km² and was situated at 4723ma.s.l. Over such inland water bodies, ICESat altimeter data offer both wide coverage and spatial and temporal accuracy. We combine remote-sensing and GIS technology to map and reconstruct lake area and increased volume changes during a 7 year time series. Nam Co lake water level increased by 2.4±0.12m (0.33ma-1) between 23 February 2003 and 1 October 2009, and lake volume increased by 4.9±0.5 km³. In the past 7 years, Nam Co lake area has increased from 1998.78±5.4 to 2023.8±3.4 km², the glacier-covered area has decreased from 832.34 to 821.0 km² and the drainage basin area has decreased from 201.1±4.2 to 196.1±2.3 km². However, the most spectacular feature is the continual water level rise from 2003 to 2009 without an obvious associated increase in precipitation. Based on digital elevation models (DEMs) from Shuttle Radar Topography Mission (SRTM) DEM data and corrected ICESat elevation data, significant changes to glacier mass balance in the western Nyainqentanglha mountains are indicated. Nyainqentanglha mountain glacier surface elevations decreased by 8.39±0.45m during 2003-09. Over the same period, at least 1.01 km³ of glacial meltwater flowed into Nam Co lake, assuming a glacial runoff coefficient of 0.6. The mean glacier mass-balance value is -490mmw.e. over the corresponding period, indicating that glacier meltwater in the catchment contributes to lake level rise. The contribution rate of glacial meltwater to lake water volume rise is 20.75%. The temporal lake level fluctuation correlates with temperature variations over the same time span. [ABSTRACT FROM AUTHOR]

A comparison of major ion chemistry of subglacial boreholes and discharging subglacial waters reveals three fundamentally different glacier hydrochemical regimes. Subglacial waters from alpine glaciers have chemistry distinct from the subglacial waters of Greenland or Antarctica. Greenland and Antarctica also differ fundamentally from each other, with Greenland Ice Sheet waters, at least during the summer melt season, remaining dilute and unaffected by saturation reactions and Antarctic Ice Sheet waters controlled by a range of saturation states. Some Antarctic waters form concentrated brines, capable of depressing the freezing point by >10°C. While these waters have only been directly sampled where they rarely emerge, geophysical observations from Devon Ice Cap and Greenland show liquid water at the glacier bed in locations where ice is thin and slowly moving and a cold bed is otherwise expected. This raises the possibility that lithogenic subglacial brines could be widespread and that our existing subglacial hydrochemical measurements might be biased by seasonal sampling of freely discharging water. The potential for diverse ranges of subglacial environments under ice sheets suggests the need for new and ambitious sampling programs to characterize difficult to access subglacial waters and quantify their impact on glacier dynamics, geobiology and global geochemical cycling. [ABSTRACT FROM AUTHOR]

Bed topography is a critical parameter for determining the modern-day and future dynamics of ice sheets and their outlet glaciers. This is because the topography controls the state of stress for glaciers. At glacier termini, topography can influence the timing of terminus retreat by controlling access to warm ocean waters and/or by influencing the ability of a glacier terminus to retreat over bed bumps (moraines). Inland from the terminus, the topography can also influence where glacier retreat and thinning can stabilize. In part, this is because of knickpoints in bed topography created through glacial erosion that may influence the extent to which thinning can diffuse inland for an individual glacier and thus, the timing and magnitude of long-term mass loss. Here we provide a review of the current literature on these topics. While much of the reviewed literature assumes that topography is stable on relevant timescales to humans, new research suggests that topography may change much faster than previously thought and this further complicates our ability to project future outlet glacier change. [ABSTRACT FROM AUTHOR]

Glacier-bed characteristics that are poorly known and modeled are important in projected sea-level rise from ice-sheet changes under strong warming, especially in the Thwaites Glacier drainage of West Antarctica. Ocean warming may induce ice-shelf thinning or loss, or thinning of ice in estuarine zones, reducing backstress on grounded ice. Models indicate that, in response, more-nearly-plastic beds favor faster ice loss by causing larger flow acceleration, but more-nearly-viscous beds favor localized near-coastal thinning that could speed grounding-zone retreat into interior basins where marine-ice-sheet instability or cliff instability could develop and cause very rapid ice loss. Interpretation of available data indicates that the bed is spatially mosaicked, with both viscous and plastic regions. Flow against bedrock topography removes plastic lubricating tills, exposing bedrock that is eroded on up-glacier sides of obstacles to form moats with exposed bedrock tails extending downglacier adjacent to lee-side soft-till bedforms. Flow against topography also generates high-ice-pressure zones that prevent inflow of lubricating water over distances that scale with the obstacle size. Extending existing observations to sufficiently large regions, and developing models assimilating such data at the appropriate scale, present large, important research challenges that must be met to reliably project future forced sea-level rise. [ABSTRACT FROM AUTHOR]

Glacier-bed characteristics that are poorly known and modeled are important in projected sea-level rise from ice-sheet changes under strong warming, especially in the Thwaites Glacier drainage of West Antarctica. Ocean warming may induce ice-shelf thinning or loss, or thinning of ice in estuarine zones, reducing backstress on grounded ice. Models indicate that, in response, more-nearly-plastic beds favor faster ice loss by causing larger flow acceleration, but more-nearly-viscous beds favor localized near-coastal thinning that could speed grounding-zone retreat into interior basins where marine-ice-sheet instability or cliff instability could develop and cause very rapid ice loss. Interpretation of available data indicates that the bed is spatially mosaicked, with both viscous and plastic regions. Flow against bedrock topography removes plastic lubricating tills, exposing bedrock that is eroded on up-glacier sides of obstacles to form moats with exposed bedrock tails extending downglacier adjacent to lee-side soft-till bedforms. Flow against topography also generates high-ice-pressure zones that prevent inflow of lubricating water over distances that scale with the obstacle size. Extending existing observations to sufficiently large regions, and developing models assimilating such data at the appropriate scale, present large, important research challenges that must be met to reliably project future forced sea-level rise. [ABSTRACT FROM AUTHOR]

A comparison of major ion chemistry of subglacial boreholes and discharging subglacial waters reveals three fundamentally different glacier hydrochemical regimes. Subglacial waters from alpine glaciers have chemistry distinct from the subglacial waters of Greenland or Antarctica. Greenland and Antarctica also differ fundamentally from each other, with Greenland Ice Sheet waters, at least during the summer melt season, remaining dilute and unaffected by saturation reactions and Antarctic Ice Sheet waters controlled by a range of saturation states. Some Antarctic waters form concentrated brines, capable of depressing the freezing point by >10°C. While these waters have only been directly sampled where they rarely emerge, geophysical observations from Devon Ice Cap and Greenland show liquid water at the glacier bed in locations where ice is thin and slowly moving and a cold bed is otherwise expected. This raises the possibility that lithogenic subglacial brines could be widespread and that our existing subglacial hydrochemical measurements might be biased by seasonal sampling of freely discharging water. The potential for diverse ranges of subglacial environments under ice sheets suggests the need for new and ambitious sampling programs to characterize difficult to access subglacial waters and quantify their impact on glacier dynamics, geobiology and global geochemical cycling. [ABSTRACT FROM AUTHOR]

Bed topography is a critical parameter for determining the modern-day and future dynamics of ice sheets and their outlet glaciers. This is because the topography controls the state of stress for glaciers. At glacier termini, topography can influence the timing of terminus retreat by controlling access to warm ocean waters and/or by influencing the ability of a glacier terminus to retreat over bed bumps (moraines). Inland from the terminus, the topography can also influence where glacier retreat and thinning can stabilize. In part, this is because of knickpoints in bed topography created through glacial erosion that may influence the extent to which thinning can diffuse inland for an individual glacier and thus, the timing and magnitude of long-term mass loss. Here we provide a review of the current literature on these topics. While much of the reviewed literature assumes that topography is stable on relevant timescales to humans, new research suggests that topography may change much faster than previously thought and this further complicates our ability to project future outlet glacier change. [ABSTRACT FROM AUTHOR]

Passive seismology allows measurement of the structure of glaciers and ice sheets. However, most techniques used so far in this context are based on horizontally homogeneous media where parameters vary only with depth (1-D approximations), which are appropriate only for a subset of glaciers. Here, we analyze seismic noise records from three different types of glaciers (plateau, valley and avalanching glacier) to characterize the influence of the glacier geometry on the seismic wavefield. Using horizontal-to-vertical spectral ratios, polarization analysis and modal analysis, we show that the plateau glacier and the valley glacier can be seen as 1-D, whereas the relatively small avalanching glacier shows 3-D effects due to its bed topography and the deep crevasses. In principle, the techniques proposed here might allow monitoring such crevasses and their depth, and thus to constrain a key parameter of avalanching and calving glacier fronts. [ABSTRACT FROM AUTHOR]

Cryoconite holes are small depressions of the glacier surface filled with melting water and with a wind-blown debris on the bottom. These environments are considered hot spots of biodiversity and biological activities on glaciers and host communities dominated by bacteria. Most of the studies on cryoconite holes assume that their communities are stable. However, evidence of seasonal variation in cryoconite hole ecological communities exists. We investigated the variation of the bacterial communities of cryoconite holes of Forni Glacier (Central Italian Alps) during the melting seasons (July–September) 2013 and 2016, for which samples at three and five time-points, respectively were available. Bacterial communities were characterized by high-throughput Illumina sequencing of the hypervariable V5−V6 regions of 16S rRNA gene, while meteorological data were obtained by an automatic weather station. We found consistent trends in bacterial communities, which shifted from cyanobacteria-dominated communities in July to communities dominated by heterotrophic orders in late August and September. Temperature seems also to affect seasonal dynamics of communities. We also compared bacterial communities at the beginning of the melting season across 4 years (2012, 2013, 2015 and 2016) and found significant year-to-year variability. Cryoconite hole communities on temperate glaciers are therefore not temporally stable. [ABSTRACT FROM AUTHOR]

Albedo is an important parameter in the energy balance of bare-ice surfaces and modulates glacier melt rates. The prolongation of the ablation period enforces the albedo feedback and highlights the need for profound knowledge on impacts of bare-ice albedo on glacier mass balance. In this study, we assess the mass balance sensitivity of 12 Swiss glaciers with abundant long-term in-situ data on changes in bare-ice albedo. We use pixel-based bare-ice albedo derived from Landsat 8. A distributed mass-balance model is applied to the period 1997–2016 and experiments are performed to assess the impact of albedo changes on glacier mass balance. Our results indicate that glacier-wide mass-balance sensitivities to changes in bare-ice albedo correlate strongly with mean annual mass balances (r2 = 0.81). Large alpine glaciers react more sensitively to bare-ice albedo changes due to their ablation areas being situated at lower elevations. We find average sensitivities of glacier-wide mass balance of −0.14 m w.e. a−1 per 0.1 albedo decrease. Although this value is considerably smaller than sensitivity to air temperature change, we stress the importance of the enhanced albedo feedback that will be amplified due to atmospheric warming and a suspected darkening of glacier surface in the near future. [ABSTRACT FROM AUTHOR]

The retention and release of liquid water in glacierized basins was modelled with a conceptual, semi-distributed model of the water and ice balance designed for long-term averages with monthly resolution for 100 m elevation bands. Here we present the components of the liquid water balance of 86 mostly glacierized basins on either side of the main Alpine divide between 10 and 13°E in the period 1998–2006 and compare them with the records of 30 basins monitored from 1970 to 1997. Basin average of liquid water retention has maxima in excess of 100 mm per month in May, often followed by maximum release when the retaining snow matrix melts. Glacier storage peaks in August partly due to ice melt and the ensuing filling of the englacial reservoirs and partly on account of a precipitation maximum. These two components combined to a common maximum of storage in summer in the first period 1970–97 and developed two distinct maxima in the warmer period 1998–2006. A further maximum of liquid water storage that was often found in October is most likely due to a peak in precipitation in the southern part of the study region. [ABSTRACT FROM PUBLISHER]

Electromechanical auger core drills are widely used in shallow ice-coring practice on mountain glaciers and polar ice caps and sheets. Generally, these drills are lightweight, can be readily transported to remote drilling sites, are easily installed there and drill with relatively high rates of penetration and low power consumption. During the past few decades, dozens of electromechanical auger drills have been designed. However, the auger options were usually determined by experience, and the main parameters (auger angle and rotation speed) are varied in a wide range from drill to drill. In order to choose the optimal auger parameters, the discrete element method (DEM) is used to analyze the performance of cuttings transportation for different rotation speeds in the range 50-200 rpm and auger angles in the range 15-45°. To improve the efficiency of cuttings transportation, many factors have to be considered (e.g. particle sizes and their variability, ice temperature, material of the core barrel and jacket, and availability of needed driven motor-gears). For the conditions assumed in the present studies, the recommended rotation speed is 100 rpm at auger angles of 35-40°. [ABSTRACT FROM AUTHOR]

In 2010 a reflection seismic survey was carried out on the Alpine glacier Colle Gnifetti. The processed and depth-converted data could be compared to a nearby ice core, drilled almost to the bed. Comparisons showed that the depth of the P-wave bed reflection was too shallow, while the depth of the SH-wave bed reflection fitted the ice-core length well. We are now able to explain the major part of these differences using the existing crystal orientations of the ice at Colle Gnifetti. We calculate anisotropic velocities for P- and SH-waves that are usually picked for stacking and compare them with zero-offset velocities needed for the depth conversion. Here we take the firn pack at Colle Gnifetti into account for P- and S-wave analysis. To incorporate the S-wave analysis we first derive a new equation for the relationship between density and S-wave velocity from diving waves. We show that anisotropic fabrics observed at Colle Gnifetti introduce a difference of only 1% between stacking and depthconversion velocities for the SH-wave, but 7% for the P-wave. We suggest that this difference in stacking and depth-conversion velocity for the P-wave can be used to derive information about the existing anisotropy by combining our seismic data with, for example, radar data. [ABSTRACT FROM AUTHOR]

Glaciers in the Qilian mountains, located in the northeastern part of the Tibetan Plateau, constitute an important freshwater resource for downstream populations and natural systems. To enhance our understanding of the variability of the glaciers, temporally and spatially comprehensive information on them is needed. In this study, the glacier outlines of ~1990, ~2000 and ~2010 for the whole area were delineated in a semi-automated manner using band TM3/TM5 ratio images of Landsat ETM+ or TM scenes with the help of a merged ASTER GDEM/SRTM v4.1 digital elevation model. Combining our own results with those of previously published studies that span the period back to 1956, we found that the glacier area shrank by 30±8% from 1956 to 2010 and the shrinkage accelerated remarkably in the past two decades. The linear trends of annual air temperature and precipitation measured at weather stations within the glacierized areas were 0.03-0.058C a-1 (significant only after 2000) and 0.37-1.58mm a-1 (not significant) respectively from 1961 to 2010. Glaciers shrank mainly due to the increasing temperature. Glaciers in the Qilian mountains are very unlikely to have experienced positive mass balance over the past decade. Moreover, given the trend toward higher temperatures, the glaciers in this region will continue to shrink. [ABSTRACT FROM AUTHOR]

The Tibetan Plateau interior area (TPIA), often termed the Qangtang Plateau, is distinguished by many dome-like mountains higher than 6000ma.s.l. These mountains provide favourable conditions for the development of ice caps and glaciers of extreme continental/subpolar type. According to historical topographic maps (1959-80) and recent Landsat images (2004-11), continuous retreat was observed and the glacierized part of this area decreased by 9.5% (0.27% a-1) with respect to the total glacier area of 8036.4km² in the 1970s. Glaciers in the Zhari Namco basin have experienced the highest area shrinkage, with a reduction rate of 0.72% a-1, while the smallest reduction occurred in Bangong Co (0.12% a-1) and Dogai Coying basins (0.11% a-1). A regional gradient of area loss was found, with a larger decrease in the south and a smaller decrease in the north of the plateau. Comparisons indicate glaciers have experienced smaller shrinkage in the TPIA than in surrounding regions. Glacier shrinkage in the TPIA is mainly attributed to an increase in air temperature, while precipitation, glacier size and positive difference of glaciation also played an important role. [ABSTRACT FROM AUTHOR]

Contemporary glaciers of southeast Siberia are located on three high-mountain ridges (east Sayan, Baikalsky and Kodar). In this study, we present an updated glacier inventory based on high- to middle-resolution satellite imagery and field investigations. The inventory includes 51 glaciers with a total area of ~15 km². Areas of individual glaciers vary from 0.06 to 1.33km², lengths from 130 to 2010m and elevations from 1796 to 3490 m. The recent ice maximum extents (Little Ice Age) have been delineated from terminal moraines. On average, debris-free surface area shrunk by 59% between 1850 and 2006/11 (0.37% a-1), by 44% between 1850 and 2001/02 (0.29% a-1) and by 27% between 2001/ 02 and 2006/11 (3.39% a-1). The Kodar glaciers have experienced the largest area shrinkage, while the area loss on Baikalsky ridge was more moderate. Glacier changes are mainly related to regional summer temperature increase (by 1.7-2.6°C from 1970 to 2010). There are some differences in glacier response due to different spatial patterns of snow accumulation, local topography (e.g. glacier elevation, slope) and geological activity. The studied glaciers (especially of Kodar ridge) are the most sensitive in Siberia to climate change since the late 20th century. [ABSTRACT FROM AUTHOR]

In order to monitor changes in the glaciers in the Bhutan Himalaya, a repeat decadal glacier inventory was carried out from Landsat images of 1977/78 (~1980), 1990, 2000 and 2010. The base map of glaciers was obtained by the object-based image classification method using the multispectral Landsat images of 2010. This method is used separately to delineate clean-ice and debriscovered glaciers with some manual editing. Glacier polygons of 2000, 1990 and ~1980 were obtained by manual editing on 2010 by separately overlaying respective years. The 2010 inventory shows 885 glaciers with a total area of ~642±16.1 km2. The glacier area is 1.6% of the total land cover in Bhutan. The result of a repeat inventory shows 23.3±0.9% glacial area loss between ~1980 and 2010, with the highest loss (11.6±1.2%) between ~1980 and 1990 and the lowest (6.7±0.1%) between 2000 and 2010. The trend of glacier area change from the 1980s to 2010 is -6.4±1.6%. Loss of glacier area was mostly observed below 5600ma.s.l. and was greater for clean-ice glaciers. The equilibrium-line altitude has shifted upward from 5170±110ma.s.l. to 5350±150ma.s.l. in the years ~1980-2010. [ABSTRACT FROM AUTHOR]

The ongoing retreat of mountain glaciers necessitates the development of future scenarios of glacier runoff. These scenarios are not only governed by future climate scenarios influencing glacier mass balance but also by the glacier volumes, which are subject to melt. Ground-penetrating radar (GPR) is a valuable tool for measuring the thickness of mountain glaciers, although ground-based measurements are labour-intensive, so not all glaciers can be surveyed. This study presents the results of GPR surveys on 64 Alpine glaciers, carried out between 1995 and 2010. The glacier areas range from 0.001 to 18.4 km2, and their ice thickness was surveyed with an average density of 36 pointskm-2. The point measurements were extrapolated manually to derive volume maps. The mean ice thickness varies between 10 and 92 m; the maximum ice thickness is about three times the mean thickness. According to the glacier state recorded in the second glacier inventory, the 64 glaciers cover an area of 223.3±3.6km², with a mean thickness of 50±3m and a glacier volume of 11.9±1.1km³. The mean maximum ice thickness is 119±5m. [ABSTRACT FROM AUTHOR]

Although the glaciers in the Antarctic periphery make up a large fraction of all mountain glaciers and ice caps on Earth, a detailed glacier inventory of the region is lacking. We compile such an inventory, recording areas, area-altitude distributions, terminus characteristics and volume estimates. Glaciers on the mainland are excluded. The inventory is derived from the Antarctic Digital Database and some manual digitization. We additionally rely on satellite imagery, digital elevation models and a flowshed algorithm to classify ice bodies. We find 1133 ice caps and 1619 mountain glaciers covering a total of 132 867±6643 km². Estimated total volume corresponds to 0.121±0.010m sea-level equivalent. Of the total glacier area, 99% drains either into ice shelves (63%) or into the ocean (36%). The inventory will provide a database for glacier mass-balance assessments, modelling and projections, and help to reduce the uncertainties in previous studies. [ABSTRACT FROM AUTHOR]