a review of catastrophic drainage of moraine dammed lakes in british columbia abstract moraine dammed lakes are common in the high mountains of british columbia most of these lakes formed when valley and cirque glaciers retreated from advanced positions achieved during the little ice age many moraine dams in british columbia are susceptible to failure because they are steep sided have relatively low width to height ratios comprise loose poorly sorted sediment and may contain ice cores or interstitial ice in addition the lakes commonly are bordered by steep slopes that are prone to snow and ice avalanches and rockfalls moraine dams generally fail by overtopping and incision the triggering event may be a heavy rainstorm or an avalanche or rockfall that generates waves that overtop the dam the dam can also be overtopped by an influx of water caused by sudden drainage of an upstream ice dammed lake jokulhlaup melting of moraine ice cores and piping are other possible failure mechanisms failures of moraine dams in british columbia produce destructive floods orders of magnitude larger than normal streamflows most outburst floods are characterized by an exponential increase in discharge followed by an abrupt drop to background levels when the water supply is exhausted peak discharges are controlled by dam characteristics the volume of water in the reservoir failure mechanisms and downstream topography and sediment availability for the same potential energy at the dam site floods from moraine dammed lakes have higher peak discharges than floods from glacier dammed lakes the floodwaters may mobilize large amounts of sediment as they travel down steep valleys producing highly mobile debris flows such flows have larger discharges and greater destructive impact than the floods from which they form moraine dam failures in british columbia and elsewhere are most frequent following extended periods of cool climate when large lateral and end moraines are built a period of protracted warming is required to trap lakes behind moraines and create conditions that lead to dam failure this sequence of events occurred only a few times during the holocene epoch most notably during the last several centuries glaciers built large moraines during the little ice age mainly during the 1700s and 1800s and lakes formed behind these moraines when climate warmed in the 1900s twentieth century climate warming is also responsible for recent moraine dam failures in mountains throughout the world warming from the late 1800s until about 1940 and again from 1965 to today destabilized moraine dams with interstitial or core ice the warming also forced glaciers to retreat prompting ice avalanches landslides and jokulhlaups that have destroyed some moraine dams

on the accuracy of glacier outlines derived from remote sensing data deriving glacier outlines from satellite data has become increasingly popular in the past decade in particular when glacier outlines are used as a base for change assessment it is important to know how accurate they are calculating the accuracy correctly is challenging as appropriate reference data e g from higher resolution sensors are seldom available moreover after the required manual correction of the raw outlines e g for debris cover such a comparison would only reveal the accuracy of the analyst rather than of the algorithm applied here we compare outlines for clean and debris covered glaciers as derived from single and multiple digitizing by different or the same analysts on very high 1 m and medium resolution 30 m remote sensing data against each other and to glacier outlines derived from automated classification of landsat thematic mapper data results show a high variability in the interpretation of debris covered glacier parts largely independent of the spatial resolution area differences were up to 30 and an overall good agreement for clean ice with sufficient contrast to the surrounding terrain differences 5 the differences of the automatically derived outlines from a reference value are as small as the standard deviation of the manual digitizations from several analysts based on these results we conclude that automated mapping of clean ice is preferable to manual digitization and recommend using the latter method only for required corrections of incorrectly mapped glacier parts e g debris cover shadow

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

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

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

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

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

shock melting of k feldspar and interlacing with cataclastically deformed plagioclase in granitic rocks at toqqusap nunaa southern west greenland implications for the genesis of the maniitsoq structure abstract folded sheets of mesoarchaean leucocratic plagioclase k feldspar mesoperthite bearing granitic rocks in the toqqusap nunaa area of the maniitsoq structure west greenland are characterised by their very fine grain sizes and microstructures without normal igneous or planar linear tectonic fabrics quartz forms equidimensional and branching ductilely deformed aggregates and bifurcating panels with protrusions constrictions and chains of ball shaped grains with healed radiating intergranular fractures plagioclase an10 20 was cataclastically deformed and comminuted whereas k feldspar and mesoperthite are devoid of cataclastic microstructures k feldspar forms dispersed highly irregular grains with numerous cusps and saddles indicating almost ubiquitous direct shock melting of this mineral it is commonly located along former fractures in plagioclase resulting in an interlaced feldspar microstructure with contact shapes indicating subsequent melting of plagioclase directly adjacent to k feldspar mesoperthite forms separate rounded and irregular grains with protrusions and cusped margins indicating crystallisation from melts some mesoperthite grains are texturally and compositionally heterogeneous and contain internal lenses of k feldspar and or plagioclase other mesoperthite grains comprise coarsened unzipped areas presumably due to localised fluid controlled dissolution reprecipitation processes the ternary feldspar precursor of the mesoperthite is interpreted as having crystallised from variably effectively mixed k feldspar shock melts and plagioclase contact melts direct melting of k feldspar but no whole rock melting requires shock metamorphism with a short lived temperature excursion to above the melting temperature of k feldspar 1300 c the presence of three different feldspar species and absence of chemical zonation magmatic mantling or metamorphic coronas furthermore hinders interpretations solely by means of endogenic magmatic or ultrametamorphic processes the feldspar microstructures with direct k feldspar melts in the leucocratic orthogneisses of the toqqusap nunaa area thus confirm that the recently discovered maniitsoq structure represents the deep crustal remnants of a giant mesoarchaean meteorite impact

the 2015 chileno valley glacial lake outburst flood patagonia abstract glacial lake outburst floods glofs have become increasingly common over the past century in response to climate change posing risks for human activities in many mountain regions in this paper we document and reconstruct the sequence of events and impact of a large glof that took place in december 2015 in the chileno valley patagonia hydrograph data suggests that the flood continued for around eight days with an estimated total discharge of 105 6 106 m3 of water the sequence of events was as follows 1 a large debris flow entered the lake from two steep and largely non vegetated mountain gullies located northeast of the chileno glacier terminus 2 water displaced in the lake by the debris flow increased the discharge through the chileno lake outflow 3 lake and moraine sediments were eroded by the flood 4 eroded sediments were redistributed downstream by the glof the post glof channel at the lake outlet widened in some places by 130 m and the surface elevation of the terrain lowered by a maximum of 38 8 1 5 m farther downstream large amounts of entrained sediment were deposited at the head of an alluvial plain and these sediments produced an 340 m wide fan with an average increase in surface elevation over the pre glof surface of 4 6 1 5 m we estimate that around 3 5 million m3 of material was eroded from the flood affected area whilst over 0 5 million m3 of material was deposited in the downstream glof fan the large debris flow that triggered the glof was probably a paraglacial response to glacier recession from its little ice age limits we suggest that glofs will continue to occur in these settings in the future as glaciers further recede in response to global warming and produce potentially unstable lakes detailed studies of glof events are currently limited in patagonia and the information presented here will therefore help to inform future glacial hazard assessments in this region

analysis and dynamic modeling of a moraine failure and glacier lake outburst flood at ventisquero negro patagonian andes argentina summary although moraine dams are inherently prone to failure because of their often weak structure loose internal composition and lack of an engineered spillway the understanding of dam breaching processes remains largely incomplete and appropriate modeling approaches are scarce this paper analyzes a recent glacier lake outburst caused by the failure of the terminal moraine of ventisquero negro patagonian andes argentina in may 2009 the dam breach trigger breaching and lake emptying processes plus the dynamics of the outburst flood were reconstructed based on field evidence and the application of a dynamic dam break model results indicate that the moraine failure was caused most probably by a rising lake level due to heavy precipitation resulting in high lake outflow which led to dam erosion and finally to dam failure the lake volume of ca 10 106 m3 was released in ca 3 h producing high discharge ca 4100 m3 s 1 debris flows and hyperconcentrated flows as the escaping water entrained large volumes of clastic material the methodology presented in this paper provides valuable insights into complex dam breach and glof processes and closes a critical gap in dynamic dam break modeling aimed at providing the lake outburst hydrograph an accurate determination of outburst hydrographs constitutes one of the most crucial aspects for hazard assessment of unstable lakes and will gain further importance with ongoing glacier retreat and glacier lake formation

secular trend of the equilibrium line altitude on the western side of the southern andes derived from radiosonde and surface observations the altitude of the 08c isotherm obtained from radiosonde data of the aerological chilean stations antofagasta quintero santo domingo puerto montt and punta arenas are analyzed along with surface temperature and precipitation records from nearby stations the strong effect of the 1976 77 climate shift due to a change in the pacific decadal oscillation is evident in the temperature and precipitation data the data are used as input for an empirical model which reconstructs annually the equilibrium line altitude ela for the last 49 years on the western side of the southern andes the model takes air temperature precipitation and altitude as the main parameters and was first developed by fox 1993 and applied by condom and others 2007 from the radiosonde data a significant positive trend of the 08c isotherm has occurred in the northern central and southern regions indicating an ela rise due to regional warming general glacier retreat ice thinning and negative mass balance observed during the past few decades in virtually all the chilean andes concur with the observed ela reconstruction in the punta arenas radiosonde record there is slight evidence for precipitation increase but no evidence for significant warming in the past few decades this results in a slight lowering of the ela according to the model reconstruction which does not agree with the strong and increased glacier retreat observed in recent decades in patagonia

modeling glacier thickness distribution and bed topography over entire mountain ranges with glabtop application of a fast and robust approach 1 the combination of glacier outlines with digital elevation models dems opens new dimensions for research on climate change impacts over entire mountain chains of particular interest is the modeling of glacier thickness distribution where several new approaches were proposed recently the tool applied herein glabtop glacier bed topography is a fast and robust approach to model thickness distribution and bed topography for large glacier samples using a geographic information system gis the method is based on an empirical relation between average basal shear stress and elevation range of individual glaciers calibrated with geometric information from paleoglaciers and validated with radio echo soundings on contemporary glaciers it represents an alternative and independent test possibility for approaches based on mass conservation and flow as an example for using glabtop in entire mountain ranges we here present the modeled ice thickness distribution and bed topography for all swiss glaciers along with a geomorphometric analysis of glacier characteristics and the overdeepenings found in the modeled glacier bed these overdeepenings can be seen as potential sites for future lake formation and are thus highly relevant in connection with hydropower production and natural hazards the thickest ice of the largest glaciers rests on weakly inclined bedrock at comparably low elevations resulting in a limited potential for a terminus retreat to higher elevations the calculated total glacier volume for all swiss glaciers is 75 22 km3 for 1973 and 65 20 km3 in 1999 considering an uncertainty range of 30 these results are in good agreement with estimates from other approaches

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

ice volumetric changes on active volcanoes in southern chile most of the glaciers in southern chile have been retreating and shrinking during recent decades in response to atmospheric warming and decrease in precipitation however some glacier fluctuations are directly associated with the effusive and geothermal activity of ice covered active volcanoes widely distributed in the region the aim of this paper is to study the ice volumetric changes by comparing several topographic datasets a maximum mean ice thinning rate of 0 81 0 45 m a 1 was observed on the ash debris covered ablation area of volcan villarrica between 1961 and 2004 whilst on volcan mocho the signal to noise ratio was too small to yield any conclusion an area reduction of 0 036 0 019 km 2 a 1 since 1976 was obtained on glaciar mocho while on volcan villarrica the area change was 0 090 0 034 km 2 a 1 between 1976 and 2005 glaciers on active volcanoes are therefore shrinking mainly in response to climatic driving factors however volcanic activity is affecting glaciers in two opposite ways ash debris advection is helping to reduce surface ablation at lower reaches by insulating the ice from solar radiation while geothermal activity is probably enhancing melting and water production at the bedrock resulting in negative ice elevation changes

a new glacier inventory for the jostedalsbreen region norway from landsat tm scenes of 2006 and changes since 1966 pronounced changes in glacier mass and length were observed for the monitored glaciers in the jostedalsbreen region norway since the last glacier inventories were compiled in the 1960s and 1980s however the current overall extent of the glaciers in the region is not well known to obtain this information we have compiled a new inventory from two mosaicked landsat thematic mapper tm scenes acquired in 2006 that have excellent snow conditions for glacier mapping the first suitable scenes for this purpose after 22 years of imaging with tm drainage divides and topographic inventory parameters were derived from a 25 m national digital elevation model for 1450 glaciers by digitizing glacier outlines from 1 50 000 scale topographic maps of 1966 we calculated changes in glacier area for 300 glaciers cumulative length changes for the 1997 2006 period were derived from an additional tm scene and compared with field measurements for nine glaciers overall we find a 9 area loss since 1966 with a clear dependence on glacier size however seasonal snow in 1966 in some regions made area determination challenging the satellite derived length changes confirmed the observed high spatial variability and were in good agreement with field data 1 pixel apart from glacier tongues in cast shadow the new inventory will be freely available from the global land ice measurements from space glims glacier database

low sea level rise projections from mountain glaciers and icecaps under global warming the mean sea level has been projected to rise in the 21st century as a result of global warming such projections of sea level change depend on estimated future greenhouse emissions and on differing models but model average results from a mid range scenario a1b suggests a 0 387 m rise by 2100 refs 1 2 the largest contributions to sea level rise are estimated to come from thermal expansion 0 288 m and the melting of mountain glaciers and icecaps 0 106 m with smaller inputs from greenland 0 024 m and antarctica 0 074 m here we apply a melt model and a geometric volume model to our lower estimate of ice volume and assess the contribution of glaciers to sea level rise excluding those in greenland and antarctica we provide the first separate assessment of melt contributions from mountain glaciers and icecaps as well as an improved treatment of volume shrinkage we find that icecaps melt more slowly than mountain glaciers whose area declines rapidly in the 21st century making glaciers a limiting source for ice melt using two climate models we project sea level rise due to melting of mountain glaciers and icecaps to be 0 046 and 0 051 m by 2100 about half that of previous projections

a new glacier inventory for the svartisen region norway from landsat etm data challenges and change assessment glaciers are widely recognized as key indicators of climate change and their meltwater plays an important role in hydropower production in norway since the last glacier inventory was compiled in northern norway in the 1970s marked fluctuations in glacier length and mass balance have been reported for individual glaciers and the current overall glacier state is thus not well known within the framework of the global land ice measurements from space glims initiative we have created a new inventory for 489 glaciers in the svartisen region northern norway using a landsat enhanced thematic mapper plus etm satellite scene from 7 september 1999 and automated multispectral glacier mapping thresholded band ratios in addition visual inspection and correction of the generated glacier outlines has been applied adverse snow conditions and uncertain drainage divides made glacier mapping challenging in some regions of the study site glacier outlines from 1968 as digitized from a topographic map were used for a quantitative change assessment for a selection of 300 glaciers the overall area change of this sample from 1968 to 1999 was close to zero but with a strongly increasing scatter towards smaller glaciers large area gains 50 for small glaciers 1 km 2 and an unexpected stronger relative area loss towards the wetter coast the overall size changes are small 1 for the three largest ice masses in the study region vestisen ostisen and blamannsisen

landsat based inventory of glaciers in western canada 1985 2005 abstract we report on a glacier inventory for the canadian cordillera south of 60 n across the two western provinces of british columbia and alberta containing 30 000 km2 of glacierized terrain our semi automated method extracted glacier extents from landsat thematic mapper tm scenes for 2005 and 2000 using a band ratio tm3 tm5 we compared these extents with glacier cover for the mid 1980s from high altitude aerial photography for british columbia and from landsat tm imagery for alberta a 25 m digital elevation model dem helped to identify debris covered ice and to split the glaciers into their respective drainage basins the estimated mapping errors are 3 4 and arise primarily from seasonal snow cover glaciers in british columbia and alberta respectively lost 10 8 3 8 and 25 4 4 1 of their area over the period 1985 2005 the region wide annual shrinkage rate of 0 55 a 1 is comparable to rates reported for other mountain ranges in the late twentieth century least glacierized mountain ranges with smaller glaciers lost the largest fraction of ice cover the highest relative ice loss in british columbia 24 0 4 6 occurred in the northern interior ranges while glaciers in the northern coast mountains declined least 7 7 3 4

subglacial basins their origin and importance in glacial systems and landscapes closed topographic basins are found beneath contemporary ice masses and within the footprint of former ice masses in all glaciated regions we present the first integrated review of subglacial basin occurrence and formation and the implications of such basins for glaciological processes and the evolution of landscape our purpose is to motivate research in areas where understanding of basin origin and process significance is weak basins on the order of 10 102 m deep and 102 103 m long are produced by glacial erosion of subglacial rock and or sediment and are known as overdeepenings outlet and valley glaciers can overdeepen their beds far below sea level or local fluviatile base level larger basins typically in ice sheet contexts may have a pre glacial usually tectonic origin subglacial basins are important glaciologically because they require ice water and sediment to ascend an adverse subglacial slope in order to exit the glacial system the efficiency of which is dependent upon the gradient of the adverse slope and that of the ice surface basins thus influence subglacial drainage system morphology and transmissivity the thickness and distribution of basal ice and sediment layers and the mechanisms and dynamics of ice flow adverse gradients that exceed 11 times that of the ice surface may even permit the formation of subglacial lakes we speculate that in comparison to ice masses with few or no subglacial basins those with numerous or very large basins may respond to climatic changes with unexpected vigour in addition erosion rates and transport pathways of water and sediment through the glacial system and the expression of these processes in the sediment and landform record may be unexpectedly complex further our review shows that in a warming climate ice masses resting on adverse slopes will be vulnerable to rapid and potentially catastrophic retreat new lakes in subglacial basins exposed by mountain glacier retreat will present an increasing hazard and subglacial lakes may drain catastrophically on even longer time scales we speculate that the glacial excavation and post glacial filling of basins in mountainous regions should contribute importantly to climate related changes in isostasy and relief although the controls on overdeepening and their influence on other glacial and landscape processes remain uncertain we hypothesise that overdeepened glacial systems reflect an equilibrium ice bed geometry that maximises the efficiency of ice discharge improved understanding of overdeepening processes especially overdeepened bed hydrology is therefore necessary to understand fully the dynamic behaviour of valley and outlet glaciers and thus the fate of earth s largest ice masses

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

regional cooling in a warming world recent temperature trends in the southeast pacific and along the west coast of subtropical south america 1979 2006 1 while it is widely accepted that the global mean atmospheric temperature has increased in recent decades the spatial distribution of global warming has been complex in this study we comprehensively characterize the spatial pattern including vertical structure of temperature trends along the subtropical west coast of south america continental chile for the period 1979 2006 and examine their consistency with expectations based on the cmip 3 ensemble of coupled ocean atmosphere simulations for the late 20th century in central and northern chile 17 37 s the most notable feature is a strong contrast between surface cooling at coastal stations 0 2 c decade and warming in the andes 0 25 c decade only 100 200 km further inland coastal radiosonde data imply that the coast andes variation is largely due to strong vertical stratification of temperature trends in the atmosphere west of the andes the coastal cooling appears to form part of a larger scale la nina like pattern and may extend below the ocean mixed layer to depths of at least 500 m over continental chile the cmip 3 gcm ensemble predicts temperature trends similar to those observed in the andes the cooling along the chilean coast is not reproduced by the models but the mean sst warming is weaker there than any other part of the world except the southern ocean it is proposed that the intensification of the south pacific anticyclone during recent decades which is also a simulated consequence of global warming is likely to play a major role in maintaining cooler temperatures off the coast of chile

shear wave splitting and earthquake forecasting seismic shear wave splitting sws monitors the low level deformation of fluid saturated microcracked rock we report evidence of systematic sws changes recorded above small earthquakes monitoring the accumulation of stress before earthquakes that allows the time and magnitude of impending large earthquakes to be stress forecast the effects have been seen with hindsight before some 15 earthquakes ranging in magnitude from an m1 7 seismic swarm event in iceland to the ms7 7 chi chi earthquake in taiwan including a successfully stress forecast of a m5 0 earthquake in sw iceland characteristic increases in sws time delays are observed before large earthquakes which abruptly change to deceases shortly before the earthquake occurs there is a linear relationship between magnitudes and logarithms of durations of both increases and decreases in sws time delays before large impending earthquakes however suitably persistent swarms of small earthquakes are too scarce for routine stress forecasting reliable forecasting requires controlled source cross hole seismics between neighbouring boreholes in stress monitoring sites sms it would be possible to stress forecast damaging earthquakes worldwide by a global network of sms in real time

modelling the retreat of grosser aletschgletscher switzerland in a changing climate for more than a century alpine glaciers have been retreating dramatically and they are expected to shrink even more quickly over the coming decades this study addresses the future evolution of grosser aletschgletscher switzerland the largest glacier in the european alps a three dimensional combined surface mass balance and glacier dynamics model was applied the ice flow was described with the full stokes equations the glacier surface evolution was obtained by solving a transport equation for the volume of fluid daily surface melt and accumulation were calculated on the basis of climate data the combined model was validated against several types of measurements made throughout the 20th century for future climate change scenarios based on regional climate models in the ensembles project were used according to the median climatic evolution aletschgletscher was expected to lose 90 of its ice volume by the end of 2100 even when the model was driven using current climate conditions the past two decades the glacier tongue experienced a considerable retreat of 6 km indicating its strong disequilibrium with the present climate by including a model for the evolution of supraglacial debris and its effect in reducing glacier melt we show that this factor can significantly slow future glacier retreat

the new remote sensing derived swiss glacier inventory i methods a new swiss glacier inventory is to be compiled from satellite data for the year 2000 the study presented here describes two major tasks 1 an accuracy assessment of different methods for glacier classification with landsat thematic mapper tm data and a digital elevation model dem 2 the geographical information system gis based methods for automatic extraction of individual glaciers from classified satellite data and the computation of three dimensional glacier parameters such as minimum maximum and median elevation or slope and orientation by fusion with a dem first results obtained by these methods are presented in part ii of this paper kaab and others 2002 thresholding of a ratio image from tm4 and tm5 reveals the best suited glacier map the computation of glacier parameters in a gis environment is efficient and suitable for worldwide application the methods developed contribute to the u s geological survey led global land ice measurements from space glims project which is currently compiling a global inventory of land ice masses within the framework of global glacier monitoring haeberli and others 2000

a new semi automatic approach for dividing glacier complexes into individual glaciers many glaciological and hydrological studies require outlines of individual glaciers rather than total ice cover here we develop a new semi automatic algorithm that uses a digital elevation model dem and outlines of glacier complexes to calculate the extents of individual glaciers the algorithm first applies hydrological modeling tools to a modified dem to calculate flowsheds it then merges flowsheds that belong to individual glaciers using a distance based approach whose required empirical parameters are derived from the juneau icefield area in alaska in this region 2 of similar to 1300 glaciers were misclassified the algorithm was validated on 25 000 km 2 of ice in other regions in alaska and on 40 000 km 2 of ice in arctic canada resulting in similar to 2 and similar to 3 misclassified glaciers respectively results indicate that the algorithm is robust provided the dem and the outlines are of good quality

assessment of multispectral glacier mapping methods and derivation of glacier area changes 1978 2002 in the central southern alps new zealand from aster satellite data field survey and existing inventory data we have measured the glacier area changes in the central southern alps new zealand between 1978 and 2002 and have compiled the 2002 glacier outlines using an image scene from the advanced spaceborne thermal emission and reflection radiometer aster three automated classification methods were tested 1 band ratio 2 normalized difference snow index and 3 supervised classification the results were compared with the glacier outlines photo interpreted from the aster data and were further validated using gps aided field mapping of selected test glaciers the aster 3 4 band ratio provided the best results however all the classification methods failed to extract extensive debris covered parts of the glaciers therefore the photo interpreted 2002 outlines were used when comparing with the existing 1978 glacier inventory derived from aerial photographs our results show a 17 reduction of glacier area mainly driven by the retreat of the large valley glaciers despite the large climatic gradient from west to east glaciers on both sides of the main divide lost similar percentages of area except franz josef and fox glaciers which advanced smaller glaciers were found to have changed very little in the study period

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

climate sensitivity of a high precipitation glacier in new zealand the sensitivity of glaciers to climatic change is key information in assessing the response and sea level implications of projected future warming new zealand glaciers are important globally as an example of how maritime glaciers will contribute to sea level rise a spatially distributed energy balance model is applied to brewster glacier new zealand in order to calculate glacier mass balance run off and sensitivity to climate change the model successfully simulates four annual mass balance cycles close to half 52 of the energy available for melt on the glacier is supplied by turbulent heat fluxes with radiation less important except during the winter model sensitivity to temperature change is one of the largest reported on earth at 2 0 m w e a 1 8c 1 in contrast a 50 change in precipitation is required to offset the mass balance change resulting from a 18c temperature change meltwater run off sensitivity is also very high increasing 60 with a 18c warming the extreme sensitivity of mass balance to temperature change suggests that significant ice loss will occur with even moderate climate warming

decadal changes in glacier parameters in the cordillera blanca peru derived from remote sensing we present spatial patterns of glacier fluctuations from the cordillera blanca peru glacier area terminus elevations median elevations and hypsography at decadal timescales derived from 1970 aerial photography 2003 spot5 satellite data geographic information systems gis and statistical analyses we derived new glacier outlines from the 2003 spot images and ingested them in the global land and ice measurements from space glims glacier database we examined changes in glacier area on the eastern and western side of the cordillera in relation to topographic and climate variables temperature and precipitation results include 1 an estimated glacierized area of 569 6 21 km 2 in 2003 2 an overall loss in glacierized area of 22 4 from 1970 to 2003 3 an average rise in glacier terminus elevations by 113 m and an average rise in the median elevation of glaciers by 66 m showing a shift of ice to higher elevations especially on the eastern side of the cordillera and 4 an increase in the number of glaciers which indicates disintegration of ice bodies annual air temperature showed a significant upward trend in the last 30 years with larger temperature increases at lower elevations there was a slight but not significant decrease in precipitation our results are consistent with glacier retreat and warming trends noted in the last three decades in the tropics

global variations of local asymmetry in glacier altitude separation of north south and east west components north south and east west differences in firn line altitude equilibrium line altitude or middle altitudes of glaciers can be separated by regression on the cosine and sine of glacier aspect accumulation area azimuth allowing for regional trends in altitude the north south differences expected from radiation and shade effects can be reliably quantified from world glacier inventory wgi data the north south differences are greater in sunnier climates mid latitudes and steeper relief local altitude differences between north and south facing glaciers are commonly 70 320 m such asymmetry is near universal although weak in the arctic and tropics east west contrasts are less and found mainly in the tropics and areas most exposed to strong winds altitude latitude glacier gradient and height range calculable from most of the wgi data are potential controls on the degree of north south contrast as well as surrogates for climatic controls temperature precipitation radiation and cloudiness an asymmetric sine cosine power model is developed to describe the variation of north south contrast with latitude multiple regression over 51 regions shows altitude and latitude to be the strongest controls of this contrast aspect altitude analysis for former glaciers provides new evidence of cloudiness

glacier fluctuations in extratropical south america during the past 1000 years article i nfo this paper presents an updated extensive review of glacier fluctuations during the past 1000 years in the extratropical andes of south america between ca 17 and 55 s given the variety of environmental conditions and evidence available for glacier fluctuations across this wide latitudinal range regional accounts are given for the desert andes 17 31 s the andes of central chile and argentina 31 36 s and the north 36 45 s and south 45 55 s patagonian andes the techniques dating limitations and interpretations of the glacier records along this transect are also discussed information on glacier fluctuations in the desert andes is limited to the 20th century documentation on past glacier variations is more abundant in the central chilean argentinean andes but the number of chronologies dealing with glacier fluctuations prior to the 1900s is also limited most records indicate that glaciers were generally more extensive prior to the 20th century with dates of maximum expansion ranging from the 16th to the 19th centuries the number and extent of glaciers increase significantly in the patagonian region where the evidence available for dating glacier variations during the past centuries is more abundant and the dating control for glacier events is generally better than in the northern parts of the study area for some patagonian glaciers maximum little ice age lia or post lia advances have been precisely dated by dendro geomorphological determinations or in situ measurements however for most sites the evidence available is still preliminary and there is considerable variability in the extent and timing of events related to the maximum lia expansion identified in most areas between the 16th and 19th centuries evidence is starting to appear at a growing number of sites for glacier advances during the first half of the past millennium these events were generally less extensive than the lia maximum pulses despite the occurrence of several post lia readvances over the past 100 110 years most areas in the andes of extratropical south america have experienced a general pattern of glacier recession and significant ice mass losses the differences in the glacier histories observed at local and regional scales probably reflect the inherent limitations associated with the glacier records and or the dating techniques used in each case together with the varying dominance of precipitation temperature and other climatic and non climatic factors on glacier mass balance and glacier dynamics these differences indicate that the late holocene glacier history of southern south america is more complex than commonly assumed the evidence discussed in this study highlights not only the immense potential for glaciological studies of this region but also a significant need for an increased number of detailed well dated records of glacier fluctuations

monitoring ice capped active volcan villarrica southern chile using terrestrial photography combined with automatic weather stations and global positioning systems volc an villarrica 39 25 12 s 71 56 27 w 2847ma s l is an active ice capped volcano located in the chilean lake district the surface energy balance and glacier frontal variations have been monitored for several years using automatic weather stations and satellite imagery in recent field campaigns surface topography was measured using javad gps receivers daily changes in snow ice and tephra covered areas were recorded using an automatic digital camera installed on a rock outcrop in spite of frequently damaging weather conditions two series of consecutive images were obtained in 2006 and 2007 these photographs were georeferenced to a resampled 90m pixel size srtm digital elevation model and the reflectance values normalized according to several geometric and atmospheric parameters the resulting daily maps of surface albedo are used as input to a distributed glacier melt model during a 12 day mid summer period the spatial pattern of cumulative melt is complex and controlled by the distribution of airfall and wind blown tephra with extremely high melt rates occurring downwind of the crater and exposed ash banks the camera images are also used to visualize the pattern of glacier crevassing the results demonstrate the value of terrestrial photography in understanding the energy and mass balance of the glacier including the generation of meltwater and the potential value of the technique for monitoring volcanic activity and potential hazards associated with ice volcano interactions during eruptive activity

glacier area shrinkage in eastern nepal himalaya since 1992 using high resolution inventories from aerial photographs and alos satellite images to better understand the recent wide scale changes in glacier coverage we created and compared two glacier inventories covering eastern nepal based on aerial photographs 1992 and high resolution advanced land observing satellite alos imagery 2006 10 the alos derived inventory contained 1034 debris free and 256 debris covered glaciers with total and average areas of 440 2 33 3 and 0 42 km 2 and 1074 4 206 4 and 4 19 km 2 respectively we found that the debris free glaciers have lost 11 2 0 7 0 1 a 1 of their area since 1992 whereas the number of glaciers increased by 5 because of fragmentation the area change was significantly correlated by simple linear regression with minimum elevation r 0 30 maximum elevation r 0 18 altitudinal range r 0 50 glacier area r 0 62 and mean slope r 0 16 confirming that larger glaciers tended to lose a larger area but a smaller percentage than smaller glaciers the intra regional analysis of the glacier changes clearly showed higher shrinkage rates in the western massifs compared with the eastern massifs in addition 61 small glaciers covering an area of 2 4 km 2 have completely disappeared since 1992