glacier changes between 1971 and 2016 in the jankar chhu watershed lahaul himalaya india glacier changes in the jankar chhu watershed jcw of chandrabhaga chenab basin lahaul himalaya were worked out based on corona and sentinel 2a images between 1971 and 2016 the jcw consists of 153 glaciers 0 02 km 2 with a total area of 185 6 3 8 km 2 that include 82 glaciers with debris covered ablation zone comprising 10 9 of the total glacierized area as in 2016 change analysis based on corona 1971 landsat 2000 and sentinel 2a 2016 was restricted to 127 glaciers owing to the presence of cloud cover on 26 glaciers in 1971 a subset of glaciers was also mapped using landsat thematic mapper tm 1989 image the total glacier area decreased by 14 7 4 3 km 2 0 3 0 1 km 2 a the number of glaciers in the jcw increased by four between 1971 and 2016 due to fragmentation more recently 2000 16 recession rate has increased clean ice area decreased by 21 8 3 8 km 2 0 5 0 1 km 2 a while debris covered ice increased by 7 2 0 4 km 2 0 2 0 01 km 2 a field observations of select glaciers also support derived recession trend in the jcw retreat rates in the jcw have been observed to be much lower than previously reported

accelerating shrinkage of patagonian glaciers from the little ice age ad 1870 to 2011 davies b j glasser n f 2012 accelerating shrinkage of patagonian glaciers from the little ice age similar to ad 1870 to 2011 journal of glaciology 58 212 1063 1084

a new satellite derived glacier inventory for western alaska glacier inventories provide the baseline data to perform climate change impact assessment on a regional scale in a consistent and spatially representative manner in particular a more accurate calculation of the current and future contribution to global sea level rise from heavily glacierized regions such as alaska is much needed we present a new glacier inventory for a large part of western alaska including kenai peninsula and the tordrillo chigmit and chugach mountains derived from nine landsat thematic mapper scenes acquired between 2005 and 2009 using well established automated glacier mapping techniques band ratio because many glaciers are covered by optically thick debris or volcanic ash and partly calve into water outlines were manually edited in these wrongly classified regions during post processing in total we mapped 8830 glaciers 0 02 km2 with a total area of 16 250 km2 large parts of the area 47 are covered by a few 31 large 100 km2 glaciers while glaciers less than 1 km2 constitute only 7 5 of the total area but 86 of the total number we found a strong dependence of mean glacier elevation on distance from the ocean and only a weak one on aspect glacier area changes were calculated for a subset of 347 selected glaciers by comparison with the digital line graph outlines from the us geological survey the overall shrinkage was 23 between 1948 57 and 2005 09

challenges and recommendations in mapping of glacier parameters from space results of the 2008 global land ice measurements from space glims workshop boulder colorado usa on 16 18 june 2008 the us national snow and ice data center held a glims workshop in boulder co usa focusing on formulating procedures and best practices for operational glacier mapping using satellite imagery despite the progress made in recent years there still remain many cases where automatic delineation of glacier boundaries in satellite imagery is difficult error prone or time consuming this workshop identified six themes for consideration by focus groups 1 mapping clean ice and lakes 2 mapping ice divides 3 mapping debris covered glaciers 4 assessing changes in glacier area and elevation through comparisons with older data 5 digital elevation model dem generation from satellite stereo pairs and 6 accuracy and error analysis talks presented examples and work in progress for each of these topics and focus groups worked on compiling a summary of available algorithms and procedures to address and avoid identified hurdles special emphasis was given to establishing standard protocols for glacier delineation and analysis creating illustrated tutorials and providing source code for available methods this paper summarizes the major results of the 2008 glims workshop with an emphasis on definitions methods and recommendations for satellite data processing while the list of proposed methods and recommendations is not comprehensive and is still a work in progress our goal here is to provide a starting point for the glims regional centers as well as for the wider glaciological community in terms of documentation on possible pitfalls along with potential solutions

hasty retreat of glaciers in northern patagonia from 1985 to 2011 mapping changes in glacier extent from repeat optical satellite data has revealed widespread glacier decline in nearly all regions of the world over the past few decades while numerous studies have documented the changes of the outlet glaciers of the northern and southern patagonia icefields npi spi information about glacier changes in the patagonian andes to the north of the npi is much scarcer here we present an assessment of area changes for glaciers mainly located in the palena district of chile based on glacier inventories for 1985 2000 and 2011 that were derived from two consecutive landsat scenes and a digital elevation model the analysis revealed a dramatic area decline for the largest glaciers and total area loss of 25 from 1985 to 2011 the lower parts of several larger glaciers 10 km 2 melted completely area loss below 1000 m elevation was 50 100 in both periods and 374 glaciers out of 1664 disappeared the number of proglacial lakes increased from 223 to 327 and their area expanded by 11 6 km 2 59 between 1985 and 2011 seasonal snow persisting at high elevations in the 2011 scene was a major obstacle to glacier delineation so the obtained area change rate of 1 a 1 over the entire period is a lower bound estimate the observed climate trends e g cooling in puerto montt are in contrast to the observed shrinkage

temporal change of glaciers area and geomorphometric parameters in parbati valley himachal pradesh india temporal change in the glacier coverage is analyzed for the period between 1962 and 2003 in parbati valley himachal pradesh it is observed that the total glacier cover has been decreased by 17 ranging between 8 and 100 for individual glacier the pattern of de glaciation shows a high degree of shrinkage in outer zone of parbati valley while least shrinkage is observed in the inner valley the present study is conducted to establish relationship between glacio geomorphic parameters and glaciers shrinkage pattern to predict the future glacier cover in warming scenario a systematic change is observed for glacio geomorphic parameters associated with temporal change in glacier cover it is observed that mean and minimum elevation slope relief and duration of insolation have changed substantially maximum elevation plan profile curvatures and aspect have shown less change from 1962 to 2003 a correlation matrix between glacio geomorphic parameters for glaciers between 1962 and 2003 shows that the recent glaciers are much more controlled by terrain characteristics than that in the recent past

compilation of a glacier inventory for the western himalayas from satellite data methods challenges and results abstract due to their sensitive reaction to changes in climatic conditions glaciers have been selected as an essential climate variable ecv although a large amount of ice is located in the himalayas this region is yet only sparsely represented in global glacier databases accordingly a sound and comprehensive change assessment or determination of water resources was not yet possible in this study we present a new glacier inventory for the western himalayas compiled from landsat etm scenes acquired between 2000 and 2002 coherence images from alos palsar image pairs the srtm digital elevation model dem and the aster global dem gdem several specific challenges for glacier mapping were found in this region and addressed they are related to debris cover orographic clouds locally variable snow conditions and creeping permafrost features in cold dry regions additional to seven topographic parameters that are obtained from the aster gdem for each glacier we also determined the relative amount of debris cover on the glacier surface the inventory contains 11 400 glaciers larger than 0 02 km2 which cover a total area of 9 310 km2 analysis of the inventory data revealed characteristic patterns of mean glacier elevation and relative debris cover amounts that might be related to the governing climatic conditions the full dataset will be freely available in the glims glacier database to foster further analyses and modeling of the glaciers in this region

estimation of lakes water storage and their changes on the northwestern tibetan plateau based on bathymetric and landsat data and driving force analyses abstract lake water storage changes in four lakes were analyzed based on in situ bathymetric survey data and landsat images in the extremely dry and cold northwestern tibetan plateau region the results indicated that bangdag co and aksai chin lake which are glacier fed and closed lakes showed decreasing trends from 1976 to 1996 then increasing trend from 1996 to 2015 during which period water storage increased by 1 24 km3 and 1 37 km3 respectively and 65 of the water storage increase in aksai chin lake during this period occurring in 2006 and 2013 longmu co which is a non glacier fed lake exhibited little variation from 1976 to 1996 and a slight increase of 0 1 km3 from 1996 to 2015 the precipitation temperature and potential evaporation ep trends indicated that lake shrinkage from 1976 to 1996 was attributed to less precipitation and less meltwater at lower surface air temperatures decreased ep 15 5 mm y contributed approximately 2 and 4 to the lake expansion of aksai chin lake and bangdag co from 2000 to 2009 based on the assumption of equal precipitation evaporation for the study area glacial meltwater contributed 76 6 to the lake expansion of bangdag co from 2000 to 2015 because change in lakes water storage showed a large difference between glacier fed lakes and non glacier fed lakes from 1996 to 2015 under relatively high precipitation conditions it is suggested that glacial meltwater exerted more influence on increasing lake water storage associated with rising temperatures

glacial lake inventory of bhutan using alos data methods and preliminary results the advanced land observing satellite alos is relatively new its optical sensors are capable of making high resolution digital surface models dsms for the first time the task of constructing a regional scale inventory of glacial lakes based on alos data has been undertaken this study presents the data processing methods and the results of validation and analysis on the alos based glacial lake inventory of bhutan in the himalaya the analysis based on gps measurements taken at metatshota lake in the mangde chu sub basin one of the glacial lakes assessed as presenting a potential flood danger shows a validation estimate of 9 5 m for the location of the alos based polygon with a root mean square of 11 7 m a comparison with digitized data from the international centre for integrated mountain development icimod shows that positioning and evaluation of terrain changes can be significantly improved using alos data preliminary analysis of the glacial lakes in four sub basins mo chu pho chu mangde chu and dangme chu reveals that the frequency distribution of lake sizes biases towards smaller lakes glacial lakes 0 01 0 05 km 2 in area account for 55 of the total number and occupy 13 of the total area together our results demonstrate the usefulness of high resolution alos data with accurate dsms for studying glacial lakes high priority must be given to continuously improving and updating the glacial lake inventory with high resolution satellite data

perspectives on the production of a glacier inventory from multispectral satellite data in arctic canada cumberland peninsula baffin island the consequences of global warming on land ice masses are difficult to assess in detail as two dimensional glacier inventory data are still missing for many remote regions of the world as the largest future temperature increase is expected to occur at high latitudes the glaciers and ice caps in the arctic will be particularly susceptible to the expected warming this study demonstrates the possibilities of space borne glacier inventorying at a remote site on cumberland peninsula a part of baffin island in arctic canada thereby providing glacier inventory data for this region our approach combines landsat etm and terra aster satellite data an aster derived digital elevation model dem and geographic information system based processing we used thresholded ratio images from etm bands 3 and 5 and aster bands 3 and 4 for glacier mapping manual delineation of little ice age trimlines and moraines has been applied to calculate area changes for 225 glaciers yielding an average area loss of 11 a size distribution has been obtained for 770 glaciers that is very different from that for alpine glaciers numerous three dimensional glacier parameters were derived from the aster dem for a subset of 340 glaciers the amount of working time required for the processing has been tracked and resulted in 5 min per glacier or 7 years for all estimated 160 000 glaciers worldwide

comparison of new and existing global digital elevation models aster g dem and srtm 3 1 a new global elevation dataset known as g dem based on the aster satellite imagery will be released in late 2008 g dem will be the best freely available global digital elevation model dem at a horizontal resolution of 1 arc second we assess the quality of g dem in comparison with 3 arc second srtm dem the best current global elevation dataset basic geomorphometric parameters elevation slope and curvature were examined for a pre release version of g dem and srtm dem for western japan g dem has fewer missing cells than srtm dem particularly in steep terrain also g dem gives smoother and more realistic representations of lowlands valleys steep slopes and mountain ridges whereas srtm dem includes many local spikes and holes and tends to overestimate valley floor elevation and underestimate ridge elevation g dem will be commonly used in geoscientific studies because of its higher resolution fewer missing data and better topographic representation than srtm dem

remote sensing based assessment of hazards from glacier lake outbursts a case study in the swiss alps glacier lakes are a common phenomenon in high mountain areas outbursts from glacier lakes have repeatedly caused the loss of human lives as well as severe damage to local infrastructure in several high mountain ranges around the world a grave uncertainty about the hazard potential of glacier lakes still exists especially with respect to the effects of accelerating rates of glacier retreat as a consequence of atmospheric warming area wide detection and modeling of glacier lake hazard potentials is therefore a major challenge in this study an approach integrating three scale levels allows for the progressive focus on critical glacier lakes remote sensing methods for application in glacier lake hazard assessment are presented and include channel indexing data fusion and change detection each method matches the requirements of a certain scale level for estimating potential disaster amplitudes assessments must be made of maximum discharge and runout distance of outbursts floods and debris flows existing empirical relations are evaluated and complementary ones as derived from available data are proposed tests with observations from a recent outburst event from a moraine dammed lake in the swiss alps show the basic applicability of the proposed techniques and the usefulness of empirical relations for first hazard assessments in particular the observed runout distance of the debris flow resulting from the outburst does not exceed the empirically estimated maximum runout distance a list of decision criteria and related remote sensing techniques are discussed in conclusion such a list is an essential tool for evaluating the hazard potential of a lake a systematic application of remote sensing based methods for glacier lake hazard assessment is recommended

glacier change in the poiqu river basin inferred from landsat data from 1975 to 2010 abstract the poiqu river basin is a transboundary basin that is highly prone to glacial lake outburst floods this basin is located in the middle of the himalayas between china and nepal fieldwork investigating nearby glaciers has indicated that glaciers in this region have ablated quickly in recent decades a new glacier database for the poiqu river basin was generated for the phases 1975 2000 and 2010 using automatic classification and manual visual interpretation based on long time series landsat data in 2010 the poiqu river basin had 124 glaciers with a total area of 203 4 5 3 km 2 eleven glaciers have debris covered tongues with the debris covering a total area of 51 0 1 5 km 2 during the period of 1975 2000 the area change rates of all glaciers in the basin clean ice and debris covered parts were 0 45 y 0 71 y and 0 96 y respectively from 2000 to 2010 these area change rates were 0 82 y 1 24 y and 0 73 y respectively the number of glaciers and area change of clean ice within various size classes indicate that the large glaciers shrink into small glaciers and smaller glaciers retreated faster the mean size of the glaciers in this basin is within the size class 1 0 5 0 km 2 the area change rate for 1 0 5 0 km 2 glaciers was similar to that of all glaciers in the poiqu river basin the altitude of the region with the fastest change rfc uplifted from 5200 m to 5500 m and the area change rate of glaciers in the rfc accelerated from 0 17 km 2 y to 0 21 km 2 y between the two periods 1975 to 2000 and 2000 to 2010 aspect analysis indicates that for a long time period glaciers with southward aspects including south east southeast and southwest in the poiqu river basin retreated faster than glaciers with northward aspects including west north northeast and northwest at the decade scale changes in areas of glaciers were more influenced by composition than aspect additionally the retreat rate of the glaciers in the poiqu river is in a state of accelerating ablation since 2000 despite elevation and aspect

recommendations for the compilation of glacier inventory data from digital sources modern geoinformatic techniques allow the automated creation of detailed glacier inventory data from glacier outlines and digital terrain models dtms once glacier entities are defined and an appropriate dtm is available several methods exist to derive the inventory data e g minimum maximum and mean elevation mean slope and aspect for each glacier from digital intersection of both datasets compared to the former manual methods the new grid based statistical calculations are very fast and reproducible the major aim of this contribution is to help in standardizing the related calculations to enhance the integrity of the global land ice monitoring from space glims database the recommendations were prepared by a working group and also contribute to the european space agency project globglacier the document follows the former unesco manual for the production of the world glacier inventory published in 1970 identifies the potential pitfalls and describes the differences from the former methods of compilation the online background material for this paper see http www glims org contains example scripts for calculation of each parameter and will be updated when required

sea level rise from glaciers and ice caps a lower bound 1 one of the most easily measured dimensions of a glacier the accumulation area is linked to future changes in glacier volume and consequent changes in sea level currently observed accumulation areas are too small forcing glaciers to lose 27 of their volume to attain equilibrium with current climate as a result at least 184 33 mm of sea level rise are necessitated by mass wastage of the world s mountain glaciers and ice caps even if the climate does not continue to warm if the climate continues to warm along current trends a minimum of 373 21 mm of sea level rise over the next 100 years is expected from glaciers and ice caps when compared to recent estimates from all other sources melt water from glaciers must be considered as a particularly important fraction of the total sea level rise expected this century

a more complete version of the world glacier inventory the world glacier inventory wgi was conceived half a century ago as an activity to be completed during the international geophysical year 1957 58 it consisted until very recently of nearly 70 000 glacier records covering slightly less than one quarter of the glacier ice outside the ice sheets a complete wgi must be a compromise if it is to be available and usable soon a more complete version called wgi xf is available and usable now and contains records for just over 131 000 glaciers and nearly half of the global extent of ice the additional glaciers come mainly from the assimilation of existing inventories but also from rescuing inventories that have been lost and from new inventories in canada and the subantarctic in wgi xf the xf stands for extended format flagging the fact that wgi xf conforms to a set of explicit specifications which enhance usefulness by eliminating low level inconsistencies two important features are nominal glaciers and glacier complexes a nominal glacier of which there are about 5000 in wgi xf is one about which little is known other than its existence and approximate location a glacier complex is one or more contiguous glaciers this term embodies the idea which is not new that inventories can be preliminary based upon vector outlines which await subdivision by trained glaciologists many regional studies have found that measurements of changes in single glaciers require accurate work and painstaking quality control wgi xf is not assuredly reliable as a source for such detailed work but there are several other subjects in which less detail would be a price worth paying for more complete coverage incomplete information about the dates of imagery and maps is a hindrance to analysis and the recovery of dates from metadata should have high priority

a new glacier inventory for the european alps from landsat tm scenes of 2003 challenges and results meltwater from glaciers in the european alps plays an important role in hydropower production and future glacier development is thus of economic interest however an up to date and alpine wide inventory for accurate assessment of glacier changes or modelling of future glacier development has not hitherto been available here we present a new alpine wide inventory covering austria france italy and switzerland derived from ten landsat thematic mapper tm scenes acquired within 7 weeks in 2003 combined with the globally available digital elevation model from the shuttle radar topography mission topographic inventory parameters were derived for each of the 3770 mapped glaciers covering 2050km2 the area class frequency distribution is very similar in all countries and a mean northerly aspect nw n ne is clearly favoured arithmetic counting mean glacier elevation is 2900 m with a small dependence on aspect the total area loss since the previous glacier inventory acquired around 1970 15 years is roughly one third yielding a current area loss rate of 2 a 1 digital overlay of the outlines from the latest austrian glacier inventory revealed differences in the interpretation of glacier extents that prohibit change assessment a comparison of tm derived outlines with manually digitized extents on a high resolution ikonos image returned 1 5 smaller glaciers with tm

recent glacier and glacial lake changes and their interactions in the bugyai kangri southeast tibet glaciers in the bugyai kangri are located in a transition zone from southeast tibet where monsoonal temperate glaciers dominate to inner tibet where continental glaciers dominate here we analyze glacier and glacial lake changes in this region using multi year inventories based on landsat images from 1981 2013 results show that the total area of 141 glaciers in the region decreased by 30 44 0 89 km 2 from 198 35 9 54km 2 1980s to 167 93 4 52 km 2 2010s the annual area shrinkage rate 0 48 a 1 is lower than that reported for southeastern tibet but higher than that of inner tibet both the number and total area of glacial lakes increased between 1981 and 2013 among all lakes proglacial lakes contribute most similar to 81 to the expansion the total area of ten proglacial lakes increased by 150 3 13 17 and of these ten lakes the four that expanded most sharply showed increased calving at their upper margins resulting in more rapid retreat of lake terminating glaciers than land terminating glaciers owing to rapid calving several lakes may undergo further growth in the near future increasing the potential risk of glacial lake outburst floods

application of inventory data for estimating characteristics of and regional climate change effects on mountain glaciers a pilot study with the european alps a parameterization scheme using simple algorithms for unmeasured glaciers is being applied to glacier inventory data to estimate the basic glaciological characteristics of the inventoried ice bodies and simulate potential climate change effects on mountain glaciers for past and potential climate scenarios glacier changes for assumed mass balance changes are calculated as step functions between steady state conditions for time intervals that approximately correspond to the characteristic dynamic response time a few decades of the glaciers in order to test the procedure a pilot study was carried out in the european alps where detailed glacier inventories had been compiled around the mid 1970s total glacier volume in the alps is estimated at about 130 km3 for the mid 1970s strongly negative mass balances are likely to have caused a loss of about 10 20 of this total volume during the decade 1980 90 backward calculation of glacier length changes using a mean annual mass balance of 0 25m w e a 1 since the end of the little ice age around 1850 ad gives considerable scatter but satisfactory overall results as compared with long term observations the total loss of alpine surface ice mass since 1850 can be estimated at about half the original value an acceleration of this development with annual mass losses of around 1 m a 1 or more as anticipated from ipcc scenario a for the coming century could eliminate major parts of the presently existing alpine ice volume within decades

derivation and analysis of a complete modern date glacier inventory for alaska and northwest canada we present a detailed complete glacier inventory for alaska and neighboring canada using multi sensor satellite data from 2000 to 2011 for each glacier we derive outlines and 51 variables including center line lengths outline types and debris cover we find 86 723 km 2 of glacier area 27 109 glaciers 0 025 km 2 similar to 12 of the global glacierized area outside ice sheets of this area 12 0 is drained by 39 marine terminating glaciers 74 km of tidewater margin and 19 3 by 148 lake and river terminating glaciers 420 km of lake river margin the overall debris cover is 11 with considerable differences among regions ranging from 1 4 in the kenai mountains to 28 in the central alaska range comparison of outlines from different sources on 2500 km 2 of glacierized area yields a total area difference of similar to 10 emphasizing the difficulties in accurately delineating debris covered glaciers assuming fully correlated systematic errors uncertainties in area reach 6 for all alaska glaciers but further analysis is needed to explore adequate error correlation scales preliminary analysis of the glacier database yields a new set of well constrained area length scaling parameters and shows good agreement between our area altitude distributions and previously established synthetic hypsometries the new glacier database will be valuable to further explore relations between glacier variables and glacier behavior

surface area changes of glaciers in the tibetan plateau interior area since the 1970s using recent landsat images and historical maps the tibetan plateau interior area tpia often termed the qangtang plateau is distinguished by many dome like mountains higher than 6000 m a 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 4 km 2 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

glacier status during the period 1973 2014 in the hunza basin western karakoram abstract glacier changes in the karakoram have shown a complex pattern since the recent decades with the coexistence of advancing retreating and stable glaciers but the mechanisms driving these changes remain for the most part unclear we examined the changes in glacier length area and elevation in the hunza basin of the upper indus river region western karakoram using corona remote sensing data landsat mss tm oli imagery srtm digital elevation model dem and glas icesat altimeter data we delineated 108 glaciers within the study area the total area of these glaciers decreased 28 86 km2 or 1 36 from 2115 48 km2 in 1973 2086 62 km2 in 2014 the most significant reduction in ice coverage occurred between 1992 and 1998 when glaciers retreated on average at a rate of 2 97 km2 yr 0 85 of the total coverage measured in the 1970s in contrast many glaciers advanced from 2008 to 2014 and glacial coverage increased by 0 19 0 00 km2 in comparison to fast retreating glaciers in the hindukush and the trans himalayan regions the glaciers in the hunza basin are relatively stable the topographical characteristics and the size of the glaciers have direct impacts on glacial changes in the hunza basin specifically significant changes occurred mainly below 5500 m above sea level glaciers retreated more extensively on steep slopes than on gentle slopes and small glaciers retreated relatively faster than large glaciers the overall pattern of glacial retreat is related to the warming trend in summer temperature whereas the relative stability of glaciers in the hunza basin as well as their recent advance 2008 2014 is likely driven by increasing autumn and winter precipitation

projected effects of temperature changes on the italian western tauri glaciers eastern alps a linear model was used to investigate the behaviour of the italian western tauri glaciers as a result of temperature changes projected for the 21st century the model estimates the temperature variations once the glacier snout length variations are known and vice versa it estimates the glacier snout length variations once the air temperature variations are known or predicted the 46 glaciers of the italian western tauri 35 76 of which have areas smaller than 0 5 km 2 and only 7 15 larger than 1 km 2 are mostly mountain type glaciers and only three are presently valley glaciers the model has been forced by the air temperature projections of the a1b emission scenario which indicates an increase in temperature of 2 7 c from 2015 to 2100 the results show a shortening of more than 35 for mountain glaciers by 2100 with a surface loss of more than 60 and smaller reductions for valley glaciers the consequent fragmentation into smaller units would lead to the extinction of 95 of the existing glaciers by the end of the century possibly leaving only the valley glaciers surviving

local aspect asymmetry of mountain glaciation a global survey of consistency of favoured directions for glacier numbers and altitudes abstract understanding aspect effects on present day glaciers provides essential background to the palaeoclimatic interpretation of reconstructed former glaciers or glacial cirques several factors influencing glacier mass balance vary with slope aspect these give more glaciers lower glaciers and possibly larger glaciers on favoured aspects their effects can be measured by either vector analysis of the number of glaciers with each aspect or fourier regression of glacier altitude or size against aspect both approaches are applied here to large data sets from the world glacier inventory for all available regions favoured aspect is measured by direction of the resultant vector mean and by the direction of minimum glacier altitude for 51 regions with a total of 66 084 glaciers the two directions are broadly consistent in mid latitudes and in the tropics but large differences occur in the arctic and nepal poleward aspects dominate especially in mid latitudes radiation receipt is the major factor with strong wind effects limited to areas with only moderate relief strength of asymmetry is measured by vector strength from glacier numbers or by a combination of first fourier coefficients from glacier altitudes measuring two different facets of degree of asymmetry they are essentially unrelated the fourier measure is the best estimate of local climatic asymmetry as vector strength is more influenced by topography

glacier inventory and recent glacier variations in the andes of chile south america the first satellite derived inventory of glaciers and rock glaciers in chile created from landsat tm etm images spanning between 2000 and 2003 using a semi automated procedure is presented in a single standardized format large glacierized areas in the altiplano palena province and the periphery of the patagonian icefields are inventoried the chilean glacierized area is 23 708 1185 km 2 including 3200 km 2 of both debris covered glaciers and rock glaciers glacier distribution varies as a result of climatic gradients with latitude and elevation with 0 8 occurring in the desert andes 17 30 32 s 3 6 in the central andes 32 36 s 6 2 in the lakes district and palena province 36 46 s and 89 3 in patagonia and tierra del fuego 46 56 s glacier outlines across all glacierized regions and size classes updated to 2015 using landsat 8 images for 98 complexes indicate a decline in areal extent affecting mostly clean ice glaciers 92 3 4 6 km 2 whereas debris covered glaciers and rock glaciers in the desert and central andes appear nearly unchanged in their extent glacier attributes estimated from this new inventory provide valuable insights into spatial patterns of glacier shrinkage for assessing future glacier changes in response to climate change

rapid disintegration of alpine glaciers observed with satellite data analyses of multispectral satellite data indicate accelerated glacier decline around the globe since the 1980s by using digitized glacier outlines inferred from the 1973 inventory and landsat thematic mapper tm satellite data from 1985 to 1999 we obtained area changes of about 930 alpine glaciers the 18 area reduction as observed for the period 1985 to 1999 1 3 a corresponds to a seven times higher loss rate compared to the 1850 1973 decadal mean extrapolation of area change rates and cumulative mass balances to all alpine glaciers yields a corresponding volume loss of about 25 km since 1973 highly individual and non uniform changes in glacier geometry disintegration indicate a massive down wasting rather than a dynamic response to a changed climate our results imply stronger ongoing glacier retreat than assumed so far and a probable further enhancement of glacier disintegration by positive feedbacks

glacier recession and glacial lake outburst flood studies in zanskar basin western himalaya abstract glacier recession and formation of glacial lakes along with outburst flood hazards are increasing in response to changing climate in the himalayan region this study describes evolution of dalung and padam glaciers and their associated lakes employing multi temporal datasets of landsat mss tm etm indian remote sensing liss iii google earthtm aster gdem and survey of india topographic maps the dalung glacier dg and lake dl are present in suru river catchment whereas the padam glacier pg and lake pl are present in tsarap river catchment of zanskar basin western himalaya from 1962 to 2015 the dg and pg have shrunk at different rates the dg has shrunk by 2 6 0 56 km2 19 2 4 1 at a rate of 0 05 0 01 km2 a 1 whereas the pg has shrunk by 3 4 0 65 km2 12 7 2 4 at a rate of 0 06 0 01 km2 a 1 the frontal recession was recorded as 1 240 0 02 km 15 7 2 0 at a rate of 20 0 4 m a 1 for dg and 2 690 0 5 m 21 3 2 1 at a rate of 50 7 0 1 m a 1 for pg consequently the proglacial glacial lakes have formed indicating an expansion of 20 3 4 dl and 58 4 5 pl during 1990 2015 using integrated criteria of standard indices for the identification of potentially dangerous glacial lakes pdgls the lakes were found to be vulnerable and have a potential to cause breaching in the coming years in order to provide inputs for the emergency action plan one dimensional mike 11 model was used to generate the peak flood hydrographs at the lake and other vulnerable sites downstream highest peak discharge of 3361 7 m3 s 1 dl and 4210 3 m3 s 1 pl were estimated at the lake sites which has reduced to 1520 9 m3 s 1 and 1722 4 m3 s 1 respectively at the outlet sites the reduced discharge at downstream sites still bears the potential to create dangerous flood hazards

glaciers of the levaya sygykta river watershed kodar ridge southeastern siberia russia modern morphology climate conditions and changes over the past decades kodar ridge 57 n 118 e southeastern siberia is a glaciarized mountain area of inner asia here we have studied areal changes of glaciers and mid summer snow cover in the levaya sygykta river watershed area 650 km2 60 of total ice cover we used 1 50 000 1 100 000 topographic maps landsat tm 1995 etm 2001 2002 high resolution cartosat 1 2009 and worldview 2 2013 imagery two digital elevation models dems and field survey data to quantify the areal changes of the glaciers since the end of the little ice age lia to 2013 in 2013 the exposed area of 18 small glaciers from 0 02 to 0 88 km2 in the study area was 3 917 0 064 km2 and volume 255 106 m3 between the lia maximum and 2013 the area has been decreased by 61 with rate of 0 377 a 1 the data available today suggest the areal shrinkage of kodar glaciers from the lia seems to be larger than elsewhere in siberia the rate of area decrease in 1995 2001 was five times greater than in 1850 2013 and in 1850 1995 1 7 times less than in 1850 2013 using regional climatic data we have found that climate conditions obviously stimulated glacier mass loss over the past at least 60 years the increased variability of absolute and relative changes in 1995 2013 was due to influence of local factors on the overall climate driven deglaciation trend comparison of two dems has showed that between 1970 and 2009 ice surfaces of 12 tested glacier tongues have been lowered on average by 29 15 m with a rate of 0 75 m a 1

combining satellite multispectral image data and a digital elevation model for mapping debris covered glaciers automated glacier mapping from satellite multispectral image data is hampered by debris cover on glacier surfaces supraglacial debris exhibits the same spectral properties as lateral and terminal moraines fluvioglacial deposits and bedrock outside the glacier margin and is thus not detectable by means of multispectral classification alone based on the observation of low slope angles for debris covered glacier tongues we developed a multisource method for mapping supraglacial debris the method combines the advantages of automated multispectral classification for clean glacier ice and vegetation with slope information derived from a digital elevation model dem neighbourhood analysis and change detection is applied for further improvement of the resulting glacier debris map a significant percentage of the processing can be done automatically in order to test the sensitivity of our method against different dem qualities it was also applied to a dem obtained from aster stereo data additionally we compared our multisource approach to an artificial neural network ann classification of debris using only multispectral data while the combination with an aster derived dem revealed promising results the ann classification without dem data does not

ice thickness measurements and volume estimates for glaciers in norway glacier volume and ice thickness distribution are important variables for water resource management in norway and the assessment of future glacier changes we present a detailed assessment of thickness distribution and total glacier volume for mainland norway based on data and modelling glacier outlines from a landsat derived inventory from 1999 to 2006 covering an area of 2692 81 km 2 were used as input we compiled a rich set of ice thickness observations collected over the past 30 years altogether interpolated ice thickness measurements were available for 870 km 2 32 of the current glacier area of norway with a total ice volume of 134 23 km 3 results indicate that mean ice thickness is similar for all larger ice caps and weakly correlates with their total area ice thickness data were used to calibrate a physically based distributed model for estimating the ice thickness of unmeasured glaciers the results were also used to calibrate volume area scaling relations the calibrated total volume estimates for all norwegian glaciers ranged from 257 to 300 km 3

the glaciers climate change initiative methods for creating glacier area elevation change and velocity products glaciers and their changes through time are increasingly obtained from a wide range of satellite sensors due to the often remote location of glaciers in inaccessible and high mountain terrain satellite observations frequently provide the only available measurements furthermore satellite data provide observations of glacier characteristics that are difficult to monitor using ground based measurements thus complementing the latter in the glaciers cci project of the european space agency esa three of these characteristics are investigated in detail glacier area elevation change and surface velocity we use a data from optical sensors to derive glacier outlines b digital elevation models from at least two points in time c repeat altimetry for determining elevation changes and d data from repeat optical and microwave sensors for calculating surface velocity for the latter the two sensor types provide complementary information in terms of spatio temporal coverage while c and d can be generated mostly automatically a and b require the intervention of an analyst largely based on the results of various round robin experiments multi analyst benchmark studies for each of the products we suggest and describe the most suitable algorithms for product creation and provide recommendations concerning their practical implementation and the required post processing for some of the products area velocity post processing can influence product quality more than the main processing algorithm

glacier changes in the garhwal himalaya india from 1968 to 2006 based on remote sensing glacier outlines are mapped for the upper bhagirathi and saraswati alaknanda basins of the garhwal himalaya using corona and advanced spaceborne thermal emission and reflection radiometer aster satellite images acquired in 1968 and 2006 respectively a subset of glaciers was also mapped using landsat tm images acquired in 1990 glacier area decreased from 599 9 15 6 km 2 1968 to 572 5 18 0 km 2 2006 a loss of 4 6 2 8 glaciers in the saraswati alaknanda basin and upper bhagirathi basin lost 18 4 9 0 km 2 5 7 2 7 and 9 0 7 7 km 2 3 3 2 8 respectively from 1968 to 2006 garhwal himalayan glacier retreat rates are lower than previously reported more recently 1990 2006 recession rates have increased the number of glaciers in the study region increased from 82 in 1968 to 88 in 2006 due to fragmentation of glaciers smaller glaciers 2 lost 19 4 2 5 0 51 0 07 a 1 of their ice significantly more than for larger glaciers 50 km 2 which lost 2 8 2 7 0 074 0 071 a 1 from 1968 to 2006 the debris covered glacier area increased by 17 8 3 1 0 46 0 08 a 1 in the saraswati alaknanda basin and 11 8 3 0 0 31 0 08 a 1 in the upper bhagirathi basin climate records from mukhim 1900 m a s l and bhojbasa 3780 m a s l meteorological stations were used to analyze climate conditions and trends but the data are too limited to make firm conclusions regarding glacier climate interactions

the randolph glacier inventory a globally complete inventory of glaciers the randolph glacier inventory rgi is a globally complete collection of digital outlines of glaciers excluding the ice sheets developed to meet the needs of the fifth assessment of the intergovernmental panel on climate change for estimates of past and future mass balance the rgi was created with limited resources in a short period priority was given to completeness of coverage but a limited uniform set of attributes is attached to each of the 198 000 glaciers in its latest version 3 2 satellite imagery from 1999 2010 provided most of the outlines their total extent is estimated as 726 800 34 000 km 2 the uncertainty about 5 is derived from careful single glacier and basin scale uncertainty estimates and comparisons with inventories that were not sources for the rgi the main contributors to uncertainty are probably misinterpretation of seasonal snow cover and debris cover these errors appear not to be normally distributed and quantifying them reliably is an unsolved problem combined with digital elevation models the rgi glacier outlines yield hypsometries that can be com bined with atmospheric data or model outputs for analysis of the impacts of climatic change on glaciers the rgi has already proved its value in the generation of significantly improved aggregate estimates of glacier mass changes and total volume and thus actual and potential contributions to sea level rise

changes in glaciation of the balkhash alakol basin central asia over recent decades we describe changes in glaciers of the balkhash alakol basin central asia and analyse unified glacier inventories of the zailiyskiy kungei and jungar glacier systems and the chinese part of the ili river basin as well as mass balance monitoring data from tsentralniy tuyuksu glacier for the period 1957 2014 in spite of significant inter basin differences glaciation of the three glacial systems in the ili river basin within kazakhstan as well as within chinese territory is changing simultaneously and similarly differences in the rates of glacier degradation are small and are affected primarily by the orientation of the flanks of the mountain ridges since the mid 1950s glaciation of the region has remained degraded and on average over the period examined glaciers shrank at a rate of about 0 8 a 1 in area and about 1 a 1 in ice volume glacial systems in large basins such as balkhash alakol change simultaneously linearly and at similar rates the average rates of glacier reduction of the zailiyskiy kungei jungar and upper ili glacier systems for the period 1955 56 2008 amounted to 0 76 0 75 and 0 73 a 1 respectively

the second chinese glacier inventory data methods and results the second chinese glacier inventory was compiled based on 218 landsat tm etm scenes acquired mainly during 2006 10 the widely used band ratio segmentation method was applied as the first step in delineating glacier outlines and then intensive manual improvements were performed the shuttle radar topography mission digital elevation model was used to derive altitudinal attributes of glaciers the boundaries of some glaciers measured by real time kinematic differential gps or digitized from high resolution images were used as references to validate the accuracy of the methods used to delineate glaciers which resulted in positioning errors of 10 m for manually improved clean ice outlines and 30 m for manually digitized outlines of debris covered parts the glacier area error of the compiled inventory evaluated using these two positioning accuracies was 3 2 the compiled parts of the new inventory have a total area of 43 087 km 2 in which 1723 glaciers were covered by debris with a total debris covered area of 1494 km 2 the area of uncompiled glaciers from the digitized first chinese glacier inventory is similar to 8753 km 2 mainly distributed in the southeastern tibetan plateau where no images of acceptable quality for glacier outline delineation can be found during 2006 10

astronomical calibration of 40ar 39ar reference minerals using high precision multi collector argusvi mass spectrometry the new generation of multi collector mass spectrometers e g argusvi permit ultra high precision 1 in 40k decay constants and the ages of natural reference minerals that form the basis of the technique for example reported ages for widely used 40ar 39ar reference materials such as the ca 28 ma fish canyon tuff sanidine fcts and the ca 1 2 ma alder creek rhyolite sanidine acrs vary by 1 recent attempts to independently calibrate these reference minerals have focused on k ar analyses of the same minerals and inter comparisons with astronomically tuned tephras in sedimentary sequences and u pb zircon ages from volcanic rocks most of these studies used older generation effectively single collector mass spectrometers that employed peak jumping analytical methods to acquire 40ar 39ar data in this study we reassess the inter calibration and ages of commonly used 40ar 39ar reference minerals fish canyon tuff sanidine fcts alder creek rhyolite sanidine acrs and mount dromedary biotite md2b equivalent to ga 1550 biotite relative to the astronomically tuned age of a1 tephra sanidine a1ts faneromeni section crete rivera et al 2011 using a multi collector argusvi mass spectrometer these analyses confirm the exceptional precision capability 0 1 in the 40ar 39ar ages of reference minerals without consideration of recoil artefacts thus limiting the benefits of high precision multi collector analyses significant improvement to the accuracy of the 40ar 39ar method 0 1 will require further inter laboratory 40ar 39ar studies utilizing multi collector mass spectrometry additional constraints on recoil 39ark loss from reference minerals further resolution of discrepancies between astronomically tuned sedimentary successions and refinement of the 238u 206pb zircon age cross calibration approach

the use of hypsometry to indicate long term stability and response of valley glaciers to changes in mass transfer a simple equation is derived relating the net mass balance and hypsometric curves of a steady state valley glacier it is used to examine how valley shape is linked to disparate extents and responses of glaciers subjected to similar climatic conditions examples are given which show that area based indices e g aar for estimating the equilibrium line altitude ela may be subject to a substantial built in variance because they implicitly rely upon similarity of glacier shape and regimen over a region if accurate topographic maps are available the equation may be used to infer the regimen of modern glaciers in the form of a dimensionless ratio of net mass balance gradients alternatively if similar information is available concerning regional glacier regimen disparate extents and responses may be collectively utilized to estimate values of ela or to infer climatic influence taking glacier hypsometry into account

constrained deformable layer tomostatics although first arrival tomography provides an effective waytoestimatenear surfacevelocitiesandstaticcorrections the undulation of velocity interfaces such as the base of the weatheredzonemaynotbeeasilydeterminedbythismethod the main reason is that first arrivals are insensitive to small geometric changes in velocity interfaces because their raypaths tend to traverse along those interfaces to improve the solution of interface geometry we developed a deformable layer tomostatics method that approximates the near surface velocity field as several layers of constant velocity and variablethicknessthatcanbeinvertedforthegeometryofthevelocityinterfaces weuseamultiscalemodelparameterization in the inversion for interface geometry synthetic and field datatestsshowedthatthemethodcandeterminetheinterface geometry constraining the depth range of the basal boundary of the weathered zone increases the convergence rate of the iterative inversion process tests on field data showed greater reflection coherency in a stacked section based on constrainedstaticcorrectionsthaninonefromunconstrained static corrections the method yielded a better match with statics computed from sand dune curves than does a match obtained by using two commercial grid tomography packages

glacier mass balance over the central nyainqentanglha range during recent decades derived from remote sensing data to obtain information on changes in glacier mass balance in the central nyainqentanglha range a comprehensive study was carried out based on digital elevation models derived from the 1968 topographic maps the shuttle radar topography mission dem 2000 and terrasar x tandem x 2013 glacier area changes between 1968 and 2016 were derived from topographic maps and landsat oli images this showed the area contained 715 glaciers with an area of 1713 42 51 82 km 2 in 2016 ice cover has been shrinking by 0 68 0 05 a 1 since 1968 the glacier area covered by debris accounted for 11 9 of the total and decreased in the se nw directions using digital elevation model differencing and differential synthetic aperture radar interferometry a significant mass loss of 0 46 0 10 m w e a 1 has been recorded since 1968 mass losses accelerated from 0 42 0 20 m w e a 1 to 0 60 0 20 m w e a 1 between 1968 2000 and 2000 2013 with thinning noticeably greater on the debris covered ice than the clean ice surface elevation changes can be influenced by ice cliffs as well as debris cover and land or lake terminating glaciers changes showed spatial and temporal heterogeneity and a substantial correlation with climate warming and decreased precipitation

glacier monitoring in the eastern mountain ranges of bolivia from 1975 to 2016 using landsat and sentinel 2 data tropical glaciers are sensitive to climate variations and more than 95 of them are located in the south american andes the present study estimated current glacial surface extent in the eastern mountain ranges of bolivia glacial surface changes were estimated using satellite images and available literature between 1975 and 2016 sentinel 2 images were used for the first time for glacier mapping in the tropical andes and landsat imagery for glacial surface area change estimated glacial area reduction between 1975 and 2016 in cordilleras apolobamba real and tres cruces nevado santa vera cruz was 48 8 50 7 and 59 4 respectively overall glacier shrinkage between 1975 and 2016 was 51 from 543 9 to 266 5 km2 for the same period total glacier area reduction in the bolivian cordillera oriental below 5000 m a s l was 91 a prevalent southward glacial orientation was accounted for glaciers along the cordillera oriental of bolivia furthermore meteorological data analysis showed a positive trend in the air temperature and a negative trend in precipitation in the region if current environmental conditions persist no glacial surface at low elevations 5000 m a s l will remain in the future this may seriously influence water resources in the region nevertheless glaciers above 5500 m a s l are considered relatively stable

glacier change of the columbia icefield canadian rocky mountains 1919 2009 we determined length area elevation and volume change of the columbia icefield using interprovincial boundary commission survey maps from 1919 eight sets of aerial photographs from 1948 to 1993 and satellite data from 1999 to 2009 over the period 1919 2009 glaciers on average retreated 1150 34 m and shrank by 2 4 0 2 km 2 total area loss was 59 6 1 2 km 2 23 5 and mean elevation change was 49 25 m w e resulting in a total volume loss of 14 3 2 0 km 3 w e large outlet glaciers experienced the greatest absolute ice loss while small detached glaciers lost the most relative length and area thinning rates of debris covered ice were 30 60 lower than those for clean ice all glacier changes were significantly correlated with each other p 0 01 with r values ranging from 0 54 to 0 82 temperature is correlated with length and area change over periods lagged 1 5 years p 0 05 and with elevation and volume change over periods lagged 9 18 years p 0 05 precipitation is correlated with glacier change over periods lagged 1 10 years p 0 05

last glacial maximum glaciers in the northern apennines reflect primarily the influence of southerly storm tracks in the western mediterranean abstract during the local last glacial maximum llgm the northern apennines hosted more than 100 valley and mountain glaciers covering collectively more than 260 km2 cosmogenic 10be exposure ages obtained for the first time along the apenninic range constrain the age of the llgm to pre date ca 21 ka the estimated volumes of these late pleistocene glaciers exceeded 9 1 km3 w e their reconstructed equilibrium line altitudes elas range from ca 1200 m a s l for northerly facing compound basin valley glaciers to ca 1620 m a s l for southerly facing mountain glaciers reconstructed elas in the western sector of the northern apennines were among the lowest recorded for the whole of the italian peninsula including the alps and also when compared with other mountain chains in the surrounding mediterranean basin these probably reflect exceptionally high accumulation rates fed by storm tracks in the western mediterranean which in turn has implications for the atmospheric circulation pattern that prevailed in the region at the time