Glacier mass balance

At present most alpine glaciers are not in equilibrium with the current climate, as a result they are undergoing a dramatic mass loss. Monitoring glacial variations is crucial to assess the consequences of climate change on the territory. In this work different geomatics techniques are exploited to measure and monitor the Rutor glacier over the years. In this study two different techniques were adopted to generate 3 digital surface models (DSMs): aerial and satellite photogrammetry. Two photogrammetric aerial surveys were carried out: at the end of the hydrological year 2019/20 and at the end of the following hydrological year. Additionally, a very high-resolution satellite stereo pair, acquired by the Pléiades-1A platform in 2017, was processed to assess whether satellite images can be applied to extract the 3D surface of the Rutor glacier. In order to evaluate the Rutor glacier mass-balance throughout the years several reference points were positioned and measured before the 2021 aerial flight. Thanks to the presence of the materialized points the 2021 model is considered as the 'Reference Model' against which subsequent models can be compared for glacier analysis. This model was validated by means of a comparison with the authoritative Regional DSM based on LiDAR surveys. In alpine glaciers, the positioning of artificial square cross target in time invariant areas is crucial to enable a multitemporal 4D analysis. The use of very high-resolution satellite imagery allows large areas to be mapped in 3D, but with lower accuracies proportionally decreasing with respect to slope and exposure.

Formation of glacier lakes and glacier lake outburst floods (GLOF) are not a new phenomenon in the Karakoram Himalaya. This case study focuses on sudden expansion of Shishper glacier termini and subsequent formation of an ice-dammed glacier lake occupying ~ 3 km moraine following Mochuwar glacier retreat in the Karakoram. A method based on a combination of space (remote sensing) and ground observations is applied to reconstruct spatio-temporal glacier termini change and lake extent. Moreover, the likely glacier-mass losses are determined above and below the Equilibrium Line Altitude (ELA) contours based on recommended values of Accumulation-Area-Ratio and Accumulation-Area-Balance-Ratio for mountain glaciers. Potential implications of glacier surge and ice-dammed glacier lake on downstream infrastructure and hydrological system are assessed. The results show that the Shishper glacier termini advanced 90% from 1980s to 1999 and 78.7% from 1999 to 2019 as compared to 188% and 421% retreat in the Mochuwar glacier termini for the same years, respectively. The current unusual surge of debris-covered Shishper glacier termini created a ~ 152 m deep ice-dammed glacier lake representing a total area increase of 500% over 6 months. The ratio of glacier accumulation to ablation is low for the Hassanabad glacier system, therefore there is a significant influence on forward movement of Shishper glacier termini. Water discharge from the glacier lake increased with increase in summer temperatures causing inundation of part of the Karakoram Highway at Hassanabad village. The current unusual surge of the Shishper glacier can be characterized as type-I as it involves an in-built unsteadiness without any regular intervals due to an unknown mechanism producing very high movement of debris-covered glacial ice and sediments.

Characterization of glacier changes in the terminus, elevation, and surface velocity was worked out for the Jankar Chhu Watershed (JCW) of Lahaul Himalaya using freely available satellite remote sensing data and the limited number of field observations. We studied changes using Corona (1971), Landsat (1993-2017), Sentinel 2A (2016), the SRTM Digital Elevation Model (DEM; 2000), and the global TanDEM-X DEM (2014). Change detection for 15 nine select glaciers was studied in detail. Our results showed that changes in glacier terminus (-4.7 ± 0.4 m a¯¹) between 1971 and 2016 are smaller than previously reported. An intricate pattern of mass changes across the JCW was observed, with surface lowering on an average of -0.7 ± 0.4 m a¯¹ which equates to a geodetic mass balance of -0.6 ± 0.4 m w.e. a¯¹ during 2000-14. The computed glacier surface velocities reveal nearly stagnant debris-covered ablation zone but the dynamically active main trunk. Field observations/measurements also support 20 the findings. This study provides valuable insights into the recent glacier variations, which are of critical importance to assess the future glacier dynamics on a regional scale in areas like the present one. The dataset is freely accessible at (Das and Sharma, 2019b).

We describe the mass balance of Langjökull ice cap (920 km2, 190 km3) during several time intervals that span most of the 20th century until present, hence for different climate conditions. Langjökull located in midwest Iceland is highly sensitive to climate change, with an elevation range 460-1440 m asl, zero balance ELA of 960 m and a zero balance mass turnover of 1.75 m/yr w. eq.. Since 1997 the mass balance of Langjökull has been monitored by conventional mass balance measurements at 22 sites on the glacier, ...

Regional climate model runs using the fifth-generation Pennsylvania State University-National Center for Atmospheric Research Mesocale Model modified for use in polar regions (Polar MM5), calibrated by independent in situ observations, demonstrate coherent regional patterns of Greenland ice sheet surface mass balance (SMB) change over a 17-yr period characterized by warming (1988)(1989)(1990)(1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004). Both accumulation and melt rates increased, partly counteracting each other for an overall negligible SMB trend. However, a 30% increase in meltwater runoff over this period suggests that the overall ice sheet mass balance has been increasingly negative, given observed meltwater-induced flow acceleration. SMB temporal variability of the whole ice sheet is best represented by ablation zone variability, suggesting that increased melting dominates over increased accumulation in a warming scenario. The melt season grew in duration over nearly the entire ablation zone by up to 40 days, 10 days on average. Accumulation area ratio decreased by 3%. Albedo reductions are apparent in five years of the Moderate Resolution Imaging Spectroradiometer (MODIS) derived data . The Advanced Very High Resolution Radiometer (AVHRR)-derived albedo changes were less consistent spatially. A conservative assumption as to glacier discharge and basal melting suggests an ice sheet mass loss over this period greater than 100 km 3 yr Ϫ1 , framing the Greenland ice sheet as the largest single glacial contributor to recent global sea level rise. Surface mass balance uncertainty, quantified from residual random error between model and independent observations, suggests two things: 1) changes smaller than approximately 200 km 3 yr Ϫ1 would not satisfy conservative statistical significance thresholds (i.e., two standard deviations) and 2) although natural variability and model uncertainty were separated in this analysis, the magnitude of each were roughly equivalent. Therefore, improvements in model accuracy and analysis of longer periods (assuming larger changes) are both needed for definitive mass balance change assessments.

Freshwater runoff to fjords with marine-terminating glaciers along the Greenland Ice Sheet margin has an impact on fjord circulation and potentially ice sheet mass balance through increasing heat transport to the glacier front. Here, the authors use the high-resolution (5.5 km) HIRHAM5 regional climate model, allowing high detail in topography and surface types, to estimate freshwater input to Godthåbsfjord in southwest Greenland. Model output is compared to hydrometeorological observations and, while simulated daily variability in temperature and downwelling radiation shows high correlation with observations (typically >0.9), there are biases that impact the results. In particular, overestimated albedo leads to underestimation of melt and runoff at low elevations. In the model simulation (1991–2012), the ice sheet experiences increasing energy input from the surface turbulent heat flux (up to elevations of 2000 m) and shortwave radiation (at all elevations). Southerly wind anoma...

This study focuses on an Egesen-stadial moraine located at 1906-1920 m asl in the NE Maritime Alps, Europe. Three moraine boulders are dated, via cosmogenic isotope analyses, to 12,490 ± 1120, 12,260 ± 1220 and 13,840 ± 1240 yr, an age compatible with the Younger Dryas cooling event. The reconstructed glacier that deposited the moraine has an equilibrium line altitude of 2349 ± 5 m asl, calculated with an Accumulation Area Balance Ratio of 1.6. The result is very similar to the equilibrium line altitude of another reconstructed glacier that deposited a moraine also dated to Younger Dryas, in the SW Maritime Alps. The similarity suggests comparable climatic conditions across the region during the cooling event. The Younger Dryas palaeoprecipitation is 1549 ±26 mm/yr, calculated using the empirical law that links precipitation and temperature at a glacier equilibrium line altitude, with palaeotemperatures obtained from nearby palynological and chironomids studies. The palaeoprecipitation is similar to the present, thus indicating non-arid conditions during the Younger Dryas. This is probably due to the Maritime Alps peculiar position, at the crossroads between air masses from the Mediterranean and the North Atlantic, the latter displaced by the southward migration of the polar front. The equilibrium line altitude interval defined by the two reconstructed glaciers, is used to model the extent of another 66 potential Younger Dryas glaciers in the region. Each modelled glacier is reconstructed by iteratively changing the position of its front until the reconstructed glacier has an ELA that falls within the interval. The result, which is checked against geomorphological evidence, shows that glaciers covered 83.74 km 2 during the Younger Dryas, with a volume of 5.39 km 3 . All valley heads were occupied by ice, except for the Maddalena/Larche Pass (1999 m asl), an ideal site for future archaeological, palaeoecological and palaeozoological studies.

Uncertainties in estimates of glacier and ice-cap contribution to sea-level rise exist in part due to poor quantification of mass-balance errors, particularly those resulting from extrapolation of sparse measurements. Centre-line data are often assumed to be representative of the glacier as a whole, with little attention paid to extrapolation errors or their effect on mass-balance estimates. Here we present detailed digital elevation model (DEM) measurements of glacier-wide elevation changes over the last $40 years at two glaciers on Svalbard, Norwegian Arctic. Austre Brøggerbreen and Midtre Love ´nbreen are shown to have lost 27.54 AE 0.98 and 9.65 AE 0.76 Â 10 7 m 3 of ice, respectively, between 1966 and 2005, findings that we relate to trends in average summer air temperatures and winter accumulation. These volume losses correspond to geodetic balances of -0.58 AE 0.03 and -0.41 AE 0.03 m w.e. a -1 , respectively. Our analysis revealed high spatial complexity in patterns of elevation change, varying between glaciers, between measurement intervals and within and between elevation bins. Balances from extrapolated centre-line geodetic data were the same (within errors) as those from full-coverage DEM differencing in the majority of comparisons, yet significantly underestimated balance in three instances. Additionally, field mass balance from centre-line ablation stake data underestimated balances from full-coverage geodetic measurements during three of six measurement periods. These findings may support the hypothesis that field measurements underestimate Svalbard glacier mass loss, at least partly as a result of the failure of centre-line measurements to account for glacier-wide variations in ablation. Our results demonstrate the importance of deriving accurate interpolation functions and constraining extrapolation errors from sparse measurements.

The Greenland ice sheet is experiencing increasing rates of mass loss, the majority of which results from changes in discharge from tidewater glaciers. Both atmospheric and ocean drivers have been implicated in these dynamic changes, but understanding the nature of the response has been hampered by the lack of measurements of glacier flow rates predating the recent period of warming. Here, using Landsat-5 data from 1985 onwards, we extend back in time the record of surface velocities and ice-front position for 16 of Greenland's fastest-flowing tidewater glaciers, and compare these to more recent data from Landsat-7 and satellite-borne synthetic-aperture radar. Climate re-analysis data and sea surface temperatures from 1982 show that since 1995 most of Greenland and its surrounding oceans have experienced significant overall warming, and a switch to a warming trend. During the period from 1985 to 1995 when Greenland and the surrounding oceans were not warming, major tidewater outlet glaciers around Greenland, including Kangerdlugssuaq and Helheim, were dynamically stable. Since the mid-1990s, glacier discharge has consistently been both greater and more variable. Together, these observations support the hypothesis that recent dynamic change is a rapid response to climate forcing. Both air and ocean temperatures in this region are predicted to continue to warm, and will therefore likely drive further change in outlet glacier discharge.

48.45° N 121.03° W 1) Countries and glaciers are listed in alphabetical order. 2) Ye a r s o f f i r s t a n d m o s t r e c e n t s u r v e y a v a i l a b l e t o th e W G M S 3) Coordinates in decimal notation 4) Chacaltaya disappeared entirely in 2009. 5) In 1993, Urumqi Glacier No. 1 separated into two parts: East Branch and West Branch. 6) In 2005, Caresèr separated into two parts: Caresèr orientale and Caresèr occidentale. 7) Perennial snowfield or glacieret No. Glacier Name 1) 1st/last survey 2) Country Location Coordinates 3)

Due to ongoing global climate change, the glaciers in the Himalaya are shrinking and the glacial lakes are increasing in number and area. This study investigates the glacier area change, mass balance and associated glacial lake evolution in the headwaters of Kawari basin, western Nepal using optical remote sensing images. The results indicate that eleven glaciers in the study area have shrunk by 1.64 km2 between 1994 and 2021. In the same period, due to glacier recession glacial lake formed and expanded by 0.0103 km2 yr-1 reaching 0.34±0.042 km2 in 2021. Surface elevation change of glaciers revealed that the ablation zone of glacier thinned up to -8.18 m between 2000 and 2019. The specific mass balance of eleven glaciers was calculated to be -0.3 m w. e. yr-1 from 2000 to 2019. The study of glaciers is important as they are visible signals of climate change, and their changes often impact water resources and mountain hydrology. 

This document is the slightly extended online version of a paper named "Recommendations for the compilation of glacier inventory data from digital sources" that was published by the International Glaciological Society in the Annals of Glaciology volume 50 (53), 119-126. The document was prepared in the framework of the ESA project GlobGlacier by all authors and with the help of the GlobGlacier consortium and user group.

The Paris agreement aims to hold global warming to well below 2 • C and to pursue efforts to limit it to 1.5 • C relative to the pre-industrial period. Recent estimates based on population growth and intended carbon emissions from participant countries suggest global warming may exceed this ambitious target. Here we present glacier volume projections for the end of this century, under a range of high-end climate change scenarios, defined as exceeding +2 • C global average warming relative to the pre-industrial period. Glacier volume is modelled by developing an elevation-dependent mass balance model for the Joint UK Land Environment Simulator (JULES). To do this, we modify JULES to include glaciated and unglaciated surfaces that can exist at multiple heights within a single grid box. Present-day mass balance is calibrated by tuning albedo, wind speed, precipitation, and temperature lapse rates to obtain the best agreement with observed mass balance profiles. JULES is forced with an ensemble of six Coupled Model Intercomparison Project Phase 5 (CMIP5) models, which were downscaled using the high-resolution HadGEM3-A atmosphere-only global climate model. The CMIP5 models use the RCP8.5 climate change scenario and were selected on the criteria of passing 2 • C global average warming during this century. The ensemble mean volume loss at the end of the century plus or minus 1 standard deviation is -64 ± 5 % for all glaciers excluding those on the peripheral of the Antarctic ice sheet. The uncertainty in the multi-model mean is rather small and caused by the sensitivity of HadGEM3-A to the boundary conditions supplied by the CMIP5 models. The regions which lose more than 75 % of their initial volume by the end of the century are Alaska, western Canada and the US, Iceland, Scandinavia, the Russian Arctic, central Europe, Caucasus, high-mountain Asia, low latitudes, southern Andes, and New Zealand. The ensemble mean ice loss expressed in sea level equivalent contribution is 215.2 ± 21.3 mm. The largest contributors to sea level rise are Alaska (44.6 ± 1.1 mm), Arctic Canada north and south (34.9 ± 3.0 mm), the Russian Arctic (33.3 ± 4.8 mm), Greenland (20.1 ± 4.4), high-mountain Asia (combined central Asia, South Asia east and west), (18.0 ± 0.8 mm), southern Andes (14.4 ± 0.1 mm), and Svalbard (17.0±4.6 mm). Including parametric uncertainty in the calibrated mass balance parameters gives an upper bound global volume loss of 281.1 mm of sea level equivalent by the end of the century. Such large ice losses will have inevitable consequences for sea level rise and for water supply in glacier-fed river systems.

Very small glaciers (glacierets) react strongly to climatic variations. This is well expressed in their interannual size changes, which are most evident in autumn, at the end of the glacial mass balance year. This study presents results from the detailed research of two very small glaciers in the highest northern part of the Pirin Mountains of Bulgaria: Snezhnika and Banski suhodol. Systematic size measurements of these firn-ice bodies, which started in the 1990s and have been made simultaneously for a period of 13 years, show large inter-annual amplitudes against the background of a decreasing trend in response to climate warming. However, the relations are not straightforward, which is demonstrated when comparing size changes to climate data, including logger data obtained from glacier vicinity. This fact makes predictions for the changes in the local climate of high mountain cirques still relatively uncertain.

Very small glaciers (glacierets) react strongly to climatic variations. This is well expressed in their interannual size changes, which are most evident in autumn, at the end of the glacial mass balance year. This study presents results from the detailed research of two very small glaciers in the highest northern part of the Pirin Mountains of Bulgaria: Snezhnika and Banski suhodol. Systematic size measurements of these firn-ice bodies, which started in the 1990s and have been made simultaneously for a period of 13 years, show large inter-annual amplitudes against the background of a decreasing trend in response to climate warming. However, the relations are not straightforward, which is demonstrated when comparing size changes to climate data, including logger data obtained from glacier vicinity. This fact makes predictions for the changes in the local climate of high mountain cirques still relatively uncertain.

Two net balance records of neighboring glaciers under different conditions are analyzed to extract temporal variations in glacier melting in the Himalayas. Significant melt was observed every year at one site (wet site), whereas no melt occurred at the second site because of its high elevation (dry site). Accumulation at the wet site of a glacier is estimated from the dry site neighboring another glacier through a measured precipitation record for a short time period. The difference between the estimated accumulation and the net balances at the wet site is obtained as the ''melt index,'' which represents the glacier melting conditions. The melt index with an interannual timescale is significant as a climatic proxy at high elevation since no relationship between stable isotopes and temperature is established and few long-term temperature records are available at high elevations in the Himalayas. The melt index showed a decadal fluctuation with a major amplitude never reported in previous studies with respect to temperature and ice cores analyses in the Himalayas. Ice cores from a site where significant melt occurs every year have not been considered available in reconstructing past climates since climatic signals in ice were disturbed by meltwater infiltration. However, we suggest a new approach to glean temperature information by a combination of wet and dry cores, not obtainable from a good-quality ice core alone.

Recent satellite measurements of glacier mass balance show mountain glaciers all over the world had generally negative mass balances in the first decades of the 21st century. We analyse archived data for surface mass balance and summer temperature for 37 Northern Hemisphere glaciers with data for 1961-2020. We compare mean annual balances for 1961-90 and 1991-2020, and for 25 glaciers explain the changes in annual balance by changes in winter and summer balances. Mean balances 1961-90 were already substantially negative for 19 out of the 25 glaciers. Changes in winter balances from 1961-90 to 1991-2020 average close to zero but changes in summer balance are strongly negative. Mean balance 1991-2020 is strongly correlated with change in summer balance, weakly correlated with winter balance change, and strongly correlated with mean balance 1961-90. We estimate 1991-2020 summer temperature anomalies for the 37 glaciers and confirm that summer temperature anomalies for 1991-2020 were higher for the Alps, by nearly 1.5°C, than for other areas. Substantial variations in the temperaturesensitivity of summer balances for individual glaciers of -0.2 to -1.0 m w.e. a -1 °C-1 deserve further study.

To better understand the spatio-temporal variability of the glaciological environment in Dronning Maud Land (DML), East Antarctica, a 2800-km-long Japanese-Swedish traverse was carried out. The route includes ice divides between two ice-coring sites at Dome Fuji and EPICA DML. We determined the surface mass balance (SMB) averaged over various time scales in the late Holocene based on studies of snow pits and firn cores, in addition to radar data. We find that the large-scale distribution of the SMB depends on the surface elevation and continentality, and that the SMB differs between the windward and leeward sides of ice divides for strong-wind events. We suggest that the SMB is highly influenced by interactions between the large-scale surface topography of ice divides and the wind field of strong-wind events that are often associated with high-precipitation events. Local variations in the SMB are governed by the local surface topography, which is influenced by the bedrock topography. In the eastern part of DML, the accumulation rate in the second half of the 20th century is found to be higher by ∼15 %

Survey ofthe marginal area of Gljúfurárjökull in 1983 has showed the glacier to have advanced 25 m between 1981 and 1983. Further lichenometric work was undertaken re-examining some of the problems encountered earlier in establishing the character of recent deglaciation. A number of permanent lichen sites were also set up to eventually make direct observations of lichen growth rates. Detailed surveying and sampling of a largely depositional feature found at the ice margin was also undertaken and it is suggested that it was formed very rapidly due to a "burst" of water in the ice-marginal zone during the 1982-83 winter season.

This paper presents changes in the range and thickness of glaciers in Antarctic Specially Protected Area (ASPA) No. 128 on King George Island in the period 1956–2015. The research indicates an intensification of the glacial retreat process over the last two decades, with the rate depending on the type of glacier front. In the period 2001–2015, the average recession rate of the ice cliffs of the Ecology Glacier and the northern part of the Baranowski Glacier was estimated to be approximately 15–25 m a−1 and 10–20 m a−1, respectively. Fronts of Sphinx Glacier and the southern part of the Baranowski Glacier, characterized by a gentle descent onto land, show a significantly lower rate of retreat (up to 5–10 m a−1 1). From 2001 to 2013, the glacier thickness in these areas decreased at an average rate of 1.7–2.5 m a−1 for the Ecology Glacier and the northern part of the Baranowski Glacier and 0.8–2.5 m a−1 for the southern part of the Baranowski Glacier and Sphinx Glacier. The presented ...

Iceberg calving is a major component of the total mass balance of the Greenland ice sheet (GrIS). A century-long record of Greenland icebergs comes from the International Ice Patrol's record of icebergs (I48N) passing latitude 48° N, off Newfoundland. I48N exhibits strong interannual variability, with a significant increase in amplitude over recent decades. In this study, we show, through a combination of nonlinear system identification and coupled ocean–iceberg modelling, that I48N's variability is predominantly caused by fluctuation in GrIS calving discharge rather than open ocean iceberg melting. We also demonstrate that the episodic variation in iceberg discharge is strongly linked to a nonlinear combination of recent changes in the surface mass balance (SMB) of the GrIS and regional atmospheric and oceanic climate variability, on the scale of the previous 1–3 years, with the dominant causal mechanism shifting between glaciological (SMB) and climatic (ocean temperature) ...

The Greenland blocking index (GBI), an indicator of the synoptic-scale circulation over Greenland, has been anomalously positive during summers since the late 1990s. Such changes in atmospheric circulation have led to an increase in Greenland summer temperatures, a decrease in cloud cover and greater surface melt. The GBI is therefore a key indicator of melting and surface mass balance variability over the Greenland ice sheet. However, the fifth phase of the Coupled Model Intercomparison Project (CMIP5) models do not represent any increase in GBI as suggested by observations. Until 2100, no significant long-term trend in the GBI, and therefore no circulation changes, are projected. In this study the new generation of CMIP6 Earth-system models is evaluated in order to analyze the evolution of the future GBI. All CMIP5 and CMIP6 projections reveal the same trend towards a decrease of the GBI until 2100 and no model reproduces the strong increase in GBI observed over the last few decades. Significant melting events related to a highly positive GBI, as observed this summer 2019, are still not considered by CMIP6 models and therefore the projected surface melt increase of the ice sheet is likely to be underestimated if such circulation changes persist in the next decades.

Results from a regional climate simulation over the Greenland ice sheet (GrIS) reveals that more than 97% of the interannual variability of the modelled Surface Mass Balance (SMB) can be explained by the GrIS summer temperature anomaly and the GrIS annual precipitation anomaly. This multiple regression is then used to empirically estimate the GrIS SMB since 1900 from climatological time series. The projected SMB changes in the 21st century are investigated with the set of simulations performed with atmosphere-ocean general circulation models (AOGCMs) of the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR4). These estimates show that the high surface mass loss rates of recent years are not unprecedented in the GrIS history of the last hundred years. The minimum SMB rate seems to have occurred earlier in the 1930s and corresponds to a zero SMB rate. The AOGCMs project that the SMB rate of the 1930s would be common at the end of 2100. The temperature would be higher than in the 1930s but the increase of accumulation in the 21st century would partly offset the acceleration of surface melt due to the temperature increase. However, these assumptions are based on an empirical multiple regression only validated for recent/current climatic conditions, and the accuracy and time homogeneity of the data sets and AOGCM results used in these estimations constitute a large uncertainty.

O presente artigo objetivou caracterizar as concepcoes docentes frente ao processo de inclusao escolar de alunos com necessidades educacionais especiais (NEE). Para tanto, contou com uma amostra de 60 professores, atuantes em duas escolas publicas de uma cidade da regiao do Sul de Minas Gerais/MG. Para a coleta de dados foi utilizado como instrumento um questionario, composto por questoes fechadas e mistas, que foram analisadas quantitativamente. Como resultados, constatou-se um cenario de incertezas para a efetivacao da educacao inclusiva nas escolas, ao se constatar que somente 48,3% dos docentes da amostra apontam possuir conhecimento e participacao em cursos e palestras alusivas a tematica, fato que pode estar embasando a compreensao apontada por 45,5% da amostra de participantes que nao considera ser de sua responsabilidade dispensar atencoes educacionais aos alunos com NEEs. Quanto as concepcoes educacionais inclusivas, a compreensao atrelada a inclusao como direito e possibil...

A number of glaciological observations on debris-covered glaciers around the globe have shown a delayed length and mass adjustment in relation to climate variability, a behavior normally attributed to the ice insulation effect of thick debris layers. Dynamic interactions between debris cover, geometry and surface topography of debris-covered glaciers can nevertheless govern glacier velocities and mass changes over time, with many glaciers exhibiting high thinning rates in spite of thick debris cover. Such interactions are progressively being incorporated into glacier evolution research. In this paper we reconstruct changes in debris-covered area, surface velocities and surface features of three glaciers in the Patagonian Andes over the 1958–2020 period, based on satellite and aerial imagery and Digital Elevation Models. Our results show that debris cover has increased from 40 ± 0.6 to 50 ± 6.7% of the total glacier area since 1958, whilst glacier slope has slightly decreased. The ge...

ABSTRACTDespite renewed efforts to better understand glacier change and recognize glacier change trends in the Andes, relatively large areas in the Andes of Argentina and Chile are still not investigated. In this study, we report on glacier elevation and mass changes in the outer region of the Northern and Southern Patagonian Icefields in the Southern Patagonian Andes. A newly-compiled Landsat ETM+ derived glacier inventory (consisting of 2253 glaciers and ~1314 ± 66 km2of ice area) and differencing of the SRTM and SPOT5 DEMs were used to derive glacier-specific elevation changes over the 2000–12 period. The investigated glaciers showed a volume change of −0.71 ± 0.55 km3a−1, yielding a surface lowering of 0.52 ± 0.35 m a−1on average and an overall mass loss of 0.46 ± 0.37 m w.e. a−1. Highly variable individual glacier responses were observed and interestingly, they were less negative than previously reported for the neighboring Patagonian Icefields.

Long-term climate records are rare at high elevations in Southern Europe. Here, we reconstructed the evolution of Ossoue Glacier (42°46' N, 0.45 km<sup>2</sup>), located in the Pyrenees (3404 m a.s.l.), since the Little Ice Age (LIA). Glacier length, area, thickness and mass changes indicators were generated from historical datasets, topographic surveys, glaciological measurements (2001–2013), a GPR survey (2006) and stereoscopic satellite images (2013). The glacier has receded considerably since the end of the LIA, losing 40 % of its length and 60% of its area. Three periods of marked ice depletion can be identified: 1850–1890, 1928–1950 and 1983–2013, as well as two periods of stabilization or slightly growth: 1905–1928 and 1950–1983; these agree with climatic datasets (air temperature, precipitation, North Atlantic Oscillation, Atlantic Multidecadal Oscillation). In the early 2000s, the area of the glacier dropped below 50% of its area at the end of the LIA. Geode...

14 Changes in glacierized area in the Kazakhstani sector of the Tekes River basin were assessed 15 using Landsat and KH-9 imagery from 2013, 1992 and 1976. Between 1992 and 2013, the 16 combined area of 118 glaciers declined from 121.4±9.2 km to 105.0±5.5 km. The total area 17 loss was 16.4±5.9 km or 13.5±7.5%. The rate of area reduction was 0.78 km a or 0.64% a. 18 This rate is lower than in other regions of northern Tien Shan because of the presence of several 19 large glaciers in the sample. The combined glacier area in 2013 exceeds the combined glacier 20 area reported by the RGI5.0 / GAMDAM inventories for 1999-2003 by 24% because the latter 21 did not include glacierized areas on slopes exceeding 40 and a number of small glaciers. 22 Changes in the recession rates between 1976, 1992 and 2013 were examined using a sub-sample 23 of 28 glaciers which occupied 61% of the total glacierized area in 1992 and 64 % in 2013. These 24 glaciers lost 8.3±5.6% in the 1976-1992 period, 8.4±5...

Continuous measurements of glaciological mass balance have been conducted at the Central Tuyuksu glacier, Tuyuksu group of glaciers, Ile Alatau, northern Tien Shan since 1957, showing that cumulative mass balance was negative since the 1970s. Geodetic mass balance was calculated for the 1958-1998 and 1998-2016 periods using multitemporal digital elevation models derived from the historic photogrammetric surveys from 1958 and 1998 and the high-resolution Pléiades satellite stereo imagery from 2016. The geodetic measurements revealed a mean surface lowering of 23.2 ± 2.2 m (0.40 ± 0.04 m a −1) and a reduction in volume of (67.7 ± 6.7) × 10 6 m 3 in 1958-2016 at the Central Tuyuksu glacier, yielding a geodetic mass balance of −21.8 ± 2.6 m w.e. Similar trends were observed at other glaciers of the Tuyuksu group, which lost in total 83.4 × 10 6 m 3 of ice. The mass balance annual rates have not changed significantly from 1958-1998 (−0.39 ± 0.05 m w.e. a −1) to 1998-2016 (−0.35 ± 0.18 m w.e. a −1) at the Central Tuyuksu and at other glaciers of the Tuyuksu group whose maximum elevations exceed 4,000 m a.s.l. While glacier thinning intensified in the ablation zone and affected a larger area in 1998-2016, extending to 3,600-3,700 m a.s.l., the accumulation increased at higher elevations in 1998-2016. Geodetic mass balance was more negative in 1998-2016 than in 1958-1998 at the smaller glaciers with lower maximum elevations. At the Central Tuyuksu, the geodetic mass balance was in close agreement with the glaciological mass balance, particularly in 1958-1998 when the difference between the geodetic and the cumulative glaciological mass balance values did not exceed 5%. During 1998-2016, this difference increased to 14%, with the glaciological method producing a more negative mass balance. This discrepancy

Impacts of projected climate and glacier change on river discharge in five glacierized catchments in the northern Tien Shan, Kazakhstan are investigated using a conceptual hydrological model HBV-ETH. Regional climate model PRECIS driven by four different GCM-scenario combinations (HadGEM2.6, HadGEM8.5, A1B using HadCM3Q0 and ECHAM5) is used to develop climate projections. Future changes in glaciation are assessed using the Blatter–Pattyn type higher-order 3D coupled ice flow and mass balance model. All climate scenarios show statistically significant warming in the 21st Century. Neither projects statistically significant change in annual precipitation although HadGEM and HadCM3Q0-driven scenarios show 20–37% reduction in July–August precipitation in 2076–2095 in comparison with 1980–2005. Glaciers are projected to retreat rapidly until the 2050s and stabilize afterwards except under the HadGEM8.5 scenario where retreat continues. Glaciers are projected to lose 38–50% of their volume...

Glacier shrinkage is a globally occurring phenomena. High-resolution change detection based on frequent mapping and monitoring of high-altitude glaciers is necessary to precisely evaluate future water availability and to understand glacier evolution under different climatic scenarios in the Hindukush-Karakoram-Himalayan (HKH) region. This also holds true for the Bhaga basin of the western Himalaya. This study investigates glacier and glacier lake changes in the Bhaga basin, over the last five decades based on satellite imagery including Corona KH4 (1971), Landsat 7 Enhanced Thematic Mapper Plus (ETM+; 2000), Linear Imaging Self-Scanning Sensor (LISS IV; 2013), and Sentinel 2 (2020). Regional temperature and precipitation trends were evaluated from gridded climatic datasets (1900-2020). In the Bhaga basin 306 glaciers (>0.2 km²) were mapped with a total area of 360.3 ± 4.0 km², of which 55.7 ± 0.6 km² was covered with debris in 2013. The total glacier covered area decreased by ∼8.2 ± 1.5 % (0.16 ± 0.03 % yr-1) during the entire observation period 1971-2020, with noticeable heterogeneity between tributary watersheds. In the past two decades (2000-2020), the deglaciation rate has increased significantly (0.25 % yr-1) compared to the previous decades (1971-2000; 0.12 % yr-1). Glacier lake area increased by 0.6 ± 0.1 km² (0.012 km² yr-1) between 1971 and 2020. The NCEP/NCAR climatic data reveals an increase of 0.63°C in temperature and a decrease of 6.39 mm in precipitation for the period 1948-2018. In comparison, APHRODITE data shows an increasing trend in temperature of 1.14°C between 1961 and 2015 and decreasing trend in precipitation of 31 mm between 1951 and 2007. Both NCEP/NCAR and APHRODITE data reveal significant temperature increase and precipitation decrease since the 1990s, which have probably augmented ice loss in the Bhaga basin during the early 21 st century.

The Cordillera Darwin Icefield loses mass at a similar rate as the Northern and Southern Patagonian Icefields, showing contrasting individual glacier responses, particularly between the north-facing and south-facing glaciers, which are subject to changing climate conditions. Detailed investigations of climatic mass balance processes on recent glacier behavior are not available for glaciers of the Cordillera Darwin Icefield and surrounding icefields. We therefore applied the coupled snow and ice energy and mass balance model in Python (COSIPY) to assess recent surface energy and mass balance variability for the Schiaparelli Glacier at the Monte Sarmiento Massif. We further used COSIPY to simulate steady-state glacier conditions during the Little Ice Age using information of moraine systems and glacier areal extent. The model is driven by downscaled 6-hourly atmospheric data and high resolution precipitation fields, obtained by using an analytical orographic precipitation model. Preci...

The contribution to sea level rise from Patagonian icefields is one of the largest mass losses outside the large ice sheets of Antarctica and Greenland. However, only a few studies have provided large-scale assessments in a spatially detailed way to address the reaction of individual glaciers in Patagonia and hence to better understand and explain the underlying processes. In this work, we use repeat radar interferometric measurements of the German TerraSAR-X-Add-on for Digital Elevation Measurements (TanDEM-X) satellite constellation between 2011/12 and 2016 together with the digital elevation model from the Shuttle Radar Topography Mission (SRTM) in 2000 in order to derive surface elevation and mass changes of the Southern Patagonia Icefield (SPI). Our results reveal a mass loss rate of −11.84 ± 3.3 Gt•a −1 (corresponding to 0.033 ± 0.009 mm•a −1 sea level rise) for an area of 12573 km 2 in the period 2000-2015/16. This equals a specific glacier mass balance of −0.941 ± 0.19 m w.e.•a −1 for the whole SPI. These values are comparable with previous estimates since the 1970s, but a magnitude larger than mass change rates reported since the Little Ice Age. The spatial pattern reveals that not all glaciers respond similarly to changes and that various factors need to be considered in order to explain the observed changes. Our multi-temporal coverage of the southern part of the SPI (south of 50.3 • S) shows that the mean elevation change rates do not vary significantly over time below the equilibrium line. However, we see indications for more positive mass balances due to possible precipitation increase in 2014 and 2015. We conclude that bi-static radar interferometry is a suitable tool to accurately measure glacier volume and mass changes in frequently cloudy regions. We recommend regular repeat TanDEM-X acquisitions to be scheduled for the maximum summer melt extent in order to minimize the effects of radar signal penetration and to increase product quality.

Drastic changes have been detected in glacial systems of the Antarctic Peninsula in the last few decades and are well documented in numerous scientific publications. However, the spatial and temporal distribution of glacier changes on the Antarctic Peninsula remains largely restricted to ice fronts. To expand the current monitoring of a few glaciers, unevenly distributed along the peninsula, to a representative set, we developed a method to simplify the detection of boundaries between glacier zones using satellite SAR data. The evolution of glacier zones is greatly influenced by local and regional climatic and meteorological settings. Their variations in response to changes in energy or mass balance are considered as good indicators of climatic changes. In this paper, we describe the results of knowledge-based image analysis algorithms on test areas located at Trinity Peninsula and near Marguerite Bay. In general, the two analyzed areas show different patterns of glacier zone develo...

The Laurichard active rock glacier is the permafrost‐related landform with the longest record of monitoring in France, including an annual geodetic survey, repeated geoelectrical campaigns from 1979 onwards and continuous recording of ground temperature since 2003. These data were used to examine changes in creep rates and internal structure from 1986 to 2006. The control that climatic variables exert on rock glacier kinematics was investigated over three time scales. Between the 1980s and the early 2000s, the main observed changes were a general increase in surface velocity and a decrease in internal resistivity. At a multi‐year scale, the high correlation between surface movement and snow thickness in the preceding December appears to confirm the importance of snow cover conditions in early winter through their influence on the ground thermal regime. A comparison of surface velocities, regional climatic datasets and ground sub‐surface temperatures over six years suggests a strong ...

Chronologies of glacier deposits in the Transantarctic Mountains provide important constraints on grounding-line retreat during the last deglaciation in the Ross Sea. However, between Beardmore Glacier and Ross Island-a distance of some 600 km-the existing chronologies are generally sparse and far from the modern grounding line, leaving the past dynamics of this vast region largely unconstrained. We present exposure ages of glacial deposits at three locations alongside the Darwin-Hatherton Glacier System-including within 10 km of the modern grounding line-that record several hundred meters of Late Pleistocene to Early Holocene thickening relative to present. As the ice sheet grounding line in the Ross Sea retreated, Hatherton Glacier thinned steadily from about 9 until about 3 ka. Our data are equivocal about the maximum thickness and Mid-Holocene to Early Holocene history at the mouth of Darwin Glacier, allowing for two conflicting deglaciation scenarios: (1) ∼ 500 m of thinning from 9 to 3 ka, similar to Hatherton Glacier, or (2) ∼ 950 m of thinning, with a rapid pulse of ∼ 600 m thinning at around 5 ka. We test these two scenarios using a 1.5-dimensional flowband model, forced by ice thickness changes at the mouth of Darwin Glacier and evaluated by fit to the chronology of deposits at Hatherton Glacier. The constraints from Hatherton Glacier are consistent with the interpretation that the mouth of Darwin Glacier thinned steadily by ∼ 500 m from 9 to 3 ka. Rapid pulses of thinning at the mouth of Darwin Glacier are ruled out by the data at Hatherton Glacier. This contrasts with some of the available records from the mouths of other outlet glaciers in the Transantarctic Mountains, many of which thinned by hundreds of meters over roughly a 1000-year period in the Early Holocene. The deglaciation histories of Darwin and Hatherton glaciers are best matched by a steady decrease in catchment area through the Holocene, suggesting that Byrd and/or Mulock glaciers may have captured roughly half of the catchment area of Darwin and Hatherton glaciers during the last deglaciation. An ensemble of three-dimensional ice sheet model simulations suggest that Darwin and Hatherton glaciers are strongly buttressed by convergent flow with ice from neighboring Byrd and Mulock glaciers, and by lateral drag past Minna Bluff, which could have led to a pattern of retreat distinct from other glaciers throughout the Transantarctic Mountains.

There have been numerous studies of glaciers in the Greater Caucasus, but none that have generated a modern glacier database across the whole mountain range. Here, we present an updated and expanded glacier inventory at three time periods (1960, 1986, 2014) covering the entire Greater Caucasus. Large-scale topographic maps and satellite imagery (Corona, Landsat 5, Landsat 8 and ASTER) were used to conduct a remote-sensing survey of glacier change, and the 30 m resolution Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Model (ASTER GDEM; 17 November 2011) was used to determine the aspect, slope and height distribution of glaciers. Glacier margins were mapped manually and reveal that in 1960 the mountains contained 2349 glaciers with a total glacier surface area of 1674.9 ± 70.4 km 2. By 1986, glacier surface area had decreased to 1482.1 ± 64.4 km 2 (2209 glaciers), and by 2014 to 1193.2 ± 54.0 km 2 (2020 glaciers). This represents a 28.8 ± 4.4 % (481 ± 21.2 km 2) or 0.53 % yr −1 reduction in total glacier surface area between 1960 and 2014 and an increase in the rate of area loss since 1986 (0.69 % yr −1) compared to 1960-1986 (0.44 % yr −1). Glacier mean size decreased from 0.70 km 2 in 1960 to 0.66 km 2 in 1986 and to 0.57 km 2 in 2014. This new glacier inventory has been submitted to the Global Land Ice Measurements from Space (GLIMS) database and can be used as a basis data set for future studies.

Glacier melt provides important contributions to streamflow in many mountainous regions. Hydrologic model calibration in glacier-fed catchments is difficult because errors in modelling snow accumulation can be offset by compensating errors in glacier melt. This problem is particularly severe in catchments with modest glacier cover, where goodness-of-fit statistics such as the Nash-Sutcliffe model efficiency may not be highly sensitive to the streamflow variance associated with glacier melt. While glacier mass balance measurements can be used to aid model calibration, they are absent for most catchments. We introduce the use of glacier volume change determined from repeated glacier mapping in a guided GLUE (generalized likelihood uncertainty estima-Quantifying the contribution of glacier runoff to streamflow G. Jost et al.

We applied photogrammetric methods with aerial photography from 11 different years between 1946 and 2005 to assess changes in area and volume of 33 glaciers in the Cariboo Mountains of British Columbia for the latter half of the 20th century. These are used to identify changes in extent and elevation primarily for the periods

Knowledge of supra-glacial debris cover and its changes remain incomplete in the Greater Caucasus, in spite of recent glacier studies. Here we present data of supraglacial debris cover for 659 glaciers across the Greater Caucasus based on Landsat and SPOT images from the years 1986, 2000 and 2014. We combined semi-automated methods for mapping the clean ice with manual digitization of debris-covered glacier parts and calculated supraglacial debris-covered area as the residual between these two maps. The accuracy of the results was assessed by using high-resolution Google Earth imagery and GPS data for selected glaciers. From 1986 to 2014, the total glacier area decreased from 691.5 ± 29.0 to 590.0 ± 25.8 km 2 (15.8 ± 4.1 %, or ∼ 0.52 % yr −1), while the clean-ice area reduced from 643.2 ± 25.9 to 511.0 ± 20.9 km 2 (20.1 ± 4.0 %, or ∼ 0.73 % yr −1). In contrast supra-glacial debris cover increased from 7.0 ± 6.4 %, or 48.3 ± 3.1 km 2 , in 1986 to 13.4 ± 6.2 % (∼ 0.22 % yr −1), or 79.0 ± 4.9 km 2 , in 2014. Debris-free glaciers exhibited higher area and length reductions than debris-covered glaciers. The distribution of the supra-glacial debris cover differs between the northern and southern and between the western, central and eastern Greater Caucasus. The observed increase in supra-glacial debris cover is significantly stronger on the northern slopes. Overall, we have observed up-glacier average migration of supra-glacial debris cover from about 3015 to 3130 m a.s.l. (metres above sea level) during the investigated period.

We estimate the glacier mass balance of a 9.5 km 2 mountain glacier using three approaches for balance years 2009, 2010 and 2011. The photogrammetric, GPS and glaciological methods yielded sampling densities of 100, 5 and 2 points km-2 , with measurement precisions of AE0.40, AE0.10 and AE0.10 m w.e. respectively. Our glaciological measurements likely include a positive bias, due to omission of internal and basal mass balance, and uncertainty in determining the interface between snow and firn with a probe (AE0.10 m w.e.). Measurements from our photogrammetric method include a negative bias introduced by the manual operator and our temperature index model used to correct for different dates of imaging (0.15 m w.e.), whereas GPS measurements avoid these biases. The photogrammetric and GPS methods are suitable for estimating glacier-wide annual mass balance, and thus provide a valuable measure that complements the glaciological method. These approaches, however, cannot be used to estimate mass balance at a point or mass-balance profiles without a detailed understanding of the vertical component of ice velocity.