monitoring glacier variations on geladandong mountain central tibetan plateau from 1969 to 2002 using remote sensing and gis technologies using geographical information system gis and remote sensing technologies we describe quantitative measurements of glacier variations in the geladandong mountain region of central tibet data from landsat images at three different times 1973 76 1992 and 2002 are compared with glacier areas digitized from a topographic map based on aerial photographs taken in 1969 we find that while some glaciers have advanced during the past 30 years others have retreated the area of retreat is much larger than that of advance the total glacier area has decreased from 889 km 2 in 1969 to 847 km 2 in 2002 a reduction of almost 43 km 2 i e 4 8 decrease or an average of 1 29 km 2 a 1 the variation of glacier area in the geladandong mountain region is not as large as in other regions within the tibetan plateau glacier areas decreased 4 7 km 2 i e an average of 0 68 km 2 a 1 during 1969 76 15 4 km 2 0 96 km 2 a 1 during 1976 92 and 22 4 km 2 2 24 km 2 a 1 during 1992 2002 suggesting accelerated glacier retreat in recent years the recession rates of glacier termini also increased it is likely that the increase in summer air temperature is the major reason for glacier shrinkage in the geladandong mountain region

glaciological applications with landsat 7 imagery early assessments enhanced thematic mapper plus etm data from landsat 7 are providing glaciologists with an ever expanding data set that makes a comprehensive monitoring of the global cryosphere feasible for the first time in history examples of etm data illustrate its ability to satisfy major scientific needs in the glaciological subdisciplines of sea ice glacier ice cap and ice sheet research with high resolution optical satellite imagery examples shown include use as proxy ground truth positioning glacier termini and snowlines and determining snow facies boundaries the additional etm panchromatic band at a higher spatial resolution of 15 m improves the spatial accuracy of these applications the glaciological aspects of the landsat 7 long term acquisition plan are discussed to show how the timing and location of the image acquisitions will generate a cryospheric data set of unprecedented utility for future research

hydrological regimes under the conjunction of westerly and monsoon climates a case investigation in the astore basin northwestern himalaya in a changing climate river basins with limited summer precipitation but abundant snow and glacier melt water are affected severely by reductions and seasonal alterations in annual stream flows however high altitude glacio hydrological observations and investigations to address the linkage between the timing of glacier changes and river runoff fluctuations remain ambiguous particularly in the northwestern himalayan region of pakistan in this context the hydrological regime of the astore basin a sub catchment of the upper indus river basin was comprehensively investigated by employing in situ hydro meteorological observations in combination with satellite remote sensing data two thirds of the annual precipitation in the astore basin falls in winter and spring mainly deposited by westerly winds whereas summer and autumn precipitation deposited by the monsoon and local jet streams accounts for only one third some 14 of the basin area is covered by glaciers and added to the accumulated seasonal snow deposited by westerly circulations this can reach 80 85 of the basin area therefore more than 75 of the annual basin runoff depends on melt water produced by the predominant seasonal snow and glacier ablation the non parametric mann kendall trend test was applied to the whole time series of hydro meteorological data this indicated a lowering of annual and summer mean temperatures during the period 1980 1995 and slight warming during the 1996 2010 period similarly annual winter and summer precipitation and annual mean discharge increased from 1980 to 1995 but in contrast a slight decrease in annual and summer precipitation was observed during the 1996 2010 period however discharge evidence is slight making any increase in this period insignificant in addition the spearman and mann kendall correlation results depict annual stream flow fluctuations during the 1980 2010 decades in the astore river that were predominantly influenced by precipitation variations but not by any alteration in catchment temperatures and so not governed by enhanced glacier ablation and retreat the results of the analysis presented here were also substantiated by satellite remote sensing investigation which points to evidence of stable conditions in the astore basin glaciers during this period

quantifying global warming from the retreat of glaciers records of glacier fluctuations compiled by the world glacier monitoring service can be used to derive an independent estimate of global warming during the last 100 years records of different glaciers are made comparable by a two step scaling procedure one allowing for differences in glacier geometry the other for differences in climate sensitivity the retreat of glaciers during the last 100 years appears to be coherent over the globe on the basis of modeling of the climate sensitivity of glaciers the observed glacier retreat can be explained by a linear warming trend of 0 66 kelvin per century

contribution of small glaciers to global sea level observed long term changes in glacier volume and hydrometeorological mass balance models yield data on the transfer of water from glaciers excluding those in greenland and antarctica to the oceans the average observed volume change for the period 1900 to 1961 is scaled to a global average by use of the seasonal amplitude of the mass balance these data are used to calibrate the models to estimate the changing contribution of glaciers to sea level for the period 1884 to 1975 although the error band is large these glaciers appear to account for a third to half of observed rise in sea level approximately that fraction not explained by thermal expansion of the ocean

calving rates in fresh water new data from southern patagonia data relating to calving dynamics in fresh water are scarce especially for deep water sites a linear dependence of calving velocity vc onwater depth hw is commonly accepted for both tidewater and fresh water calving glaciers herewe use recent data from temperate patagonian glaciers to propose a revised relationship for calving in fresh water the new ratio is derived from glaciers calving rapidly into deep water documented using sequential satellite images and depth soundings the main data source is a detailed remotely sensed dataset of the rapidly retreating glaciarupsala complementedwith global positioning system field surveys and precise ice proximal bathymetric surveys the areaintegrated mean water depth between glacier positions in 1996 and 2000 is 490m with a maximum recorded depth of4700m in the same period image analysis reveals surface area loss of 1 37 km a 4 8 km and an average calving rate of 1880ma the resulting vc hw ratio is of a similar order of magnitude to that recently derived for nearby glaciar moreno but is well above the range of values commonly reported for lacustrine calving

study of temporal response 1976 2019 and associated mass movement event during 2017 of meru glacier bhagirathi valley garhwal himalaya india abstract impact of climate change on glaciers brings the favorable conditions of lakes formation within glacier moraines these lakes may produce outburst floods and transport the huge amount of debris debris flow in downstream settlements the present study addresses the current knowledge on mass movement activity occurred in the gangotri glacier area garhwal himalaya uttarakhand temporal response terminus retreat and frontal area loss of meru glacier during 1976 2019 using the images of landsat mss 1976 tm 1990 2011 etm 2001 oli 2019 and event of intense mass movement occurred along meru glacier during 2017 is assessed our estimations clearly reveals that the meru glacier is retreating continuously since 1976 with inconsistent rate considering the time span 1976 1990 1990 2001 2001 2011 2011 2019 the terminus receded with 12 42 m y 1 7 72 m y 1 6 00 m y 1 11 50 m y 1 and vacated the frontal area at the rate of 2330 70 m2 y 1 2185 88 m2 y 1 1425 18 m2 y 1 1452 66 m2 y 1 respectively field observations and high resolution imagery of liss iv suggest that the lower area of meru glacier experienced the event of intense mass movement in july 2017 this event breached the continuity of left morainic wall of bhagirathi valley this mass movement event influenced the initial course of bhagirathi river 1559 m length and also modified the morphology of the gaumukh region the precipitation data from indian meteorological department imd and satellite images of different years suggest that the multiple factors such as intense precipitation large amount of sediment transport from the upper reaches to lower area slope failure collapse of frontal part of meru glacier were the main causative factors for this event

area change of glaciers across northern ellesmere island nunavut between 1999 and 2015 using a variety of optical satellite scenes this study quantifies the change in the areal extent of 1773 glaciers across northern ellesmere island between 1999 and 2015 our results show that the regional ice coverage decreased by 1705 3 km 2 over the 16 year period a loss of 5 9 ice shelves had the greatest losses relative to their size of 42 4 glaciers feeding into ice shelves reduced in area by 4 7 while tidewater glaciers reduced in area by 3 3 marine terminating glaciers with floating ice tongues reduced in area by 4 9 and 19 of these 27 ice tongues disintegrated causing these glaciers to retreat to their grounding lines land terminating glaciers lost 4 9 of their 1999 area including the complete loss of three small ice caps 2 our study highlights the high sensitivity of the ice cover of northern ellesmere island to recent climate warming and the continued losses that are likely to occur in the future in particular the ice masses most susceptible to further losses are marine terminating glaciers with floating termini and small land terminating ice caps at low elevations

geomorphic effectiveness sandur development and the pattern of landscape response during jokulhlaups skeiðararsandur southeastern iceland by contrast with other historical outburst floods on skeitararsandur the 1996 jokulhlaup was unprecedented in its magnitude and duration attaining a peak discharge of f53 000 m 3 s in 17 h using a combination of field sampling and remote sensing techniques landsat tm sar interferometry airphotos and laser altimetry we document the sandur wide geomorphic impacts of this event these impacts varied widely across the skeitararsandur and cannot be singularly attributed to jokulhlaup magnitude because pre jokulhlaup glacial dynamics and the extant setting largely conditioned the spatial pattern type and magnitude of these impacts topographic lowering and asymmetric retreat of the ice front during the late twentieth century has decoupled the ice sheet from the moraine sandur complex along the central and western sandur this glacial control in combination with the convex topography of the proximal sandur promoted a shift from a primarily diffuse source braided outwash system to a more point sourced channelized discharge of water and sediment deposition dominated within the proglacial depression with approximately 3 8 10 7 m 3 of sediment and along channel systems that remained connected to subglacial sediment supplies this shift to a laterally dissimilar channelized routing system creates a more varied depositional pattern that is not explicitly controlled by the concave longitudinal profile down sandur laterally contiguous units therefore may vary greatly in age and sediment character suggesting that current facies models inadequately characterize sediment transfers when the ice front is decoupled from its sandur water was routed onto the sandur in a highly organized fashion and this jokulhlaup generated major geomorphic changes including sandur incision in normally aggradational distal settings and eradication of proximal glacial landforms dating to fa d 1892 d 2002 elsevier science b v all rights reserved

a method for monitoring glacier mass balance using satellite albedo measurements application to vatnajskull iceland we compare satellite albedo images of vatnajokull iceland with mass balance measurements for the years 1991 99 we find that the equilibrium line is mostly not visible when it is located above its position of the previous year s equilibrium line detection is further hindered by clouds and a gradual transition between ice and firn or snow consequently firn line elevation at the end of the melting season is not particularly useful for estimating the annual mass balance instead we propose to study the mean albedo of the entire ice cap throughout the melting season so that all available information about the surface albedo is taken into account the mean net potential global radiation which can be estimated from the mean surface albedo alone both depends on and influences summer melt it also depends on winter precipitation and integrated over the melting season is found to relate linearly to the specific mass balance b r 0 87 and 0 94 for different outlets of vatnajokull b can be estimated quantitatively when this relation is known and qualitatively when it is not the uncertainty in the satellite derived value of b is 0 5 0 8 m w e which for vatnajokull corresponds to about 27 of the interannual variability of b

measurements of glacier variation in the tibetan plateau using landsat data glaciers on the tibetan plateau play an important role in the earth s climate system because of high altitude and difficulties in access regular systematic surveys of glacier variation are almost impossible in some regions of the tibetan plateau as a result remote sensing is at present the primary in many cases the only way to measure the state of glaciers in combination with geographic information system gis it provides an efficient tool to analyze the current state and changes in glaciers we used a technique of integrated remote sensing and gis to map and measure changes in glaciers using a 21 year series of landsat images from 1973 to 1994 and topographic maps of a study site on the tibetan plateau the details of glacier fluctuation such as area of glaciers and changes in the magnitude of recession or advance of a glacier terminus on different dates are described based on the results of image analysis including coregistration classification vector analysis and area calculation within the study area during the 21 years it was determined that the northern glaciers advanced and the southern glaciers retreated the average rate of change was 50 m a 1 to 105 m a 1 the results show that landsat data provide an important source of information for studies of glacier variation

spatio temporal fluctuations over chorabari glacier garhwal himalaya india between 1976 and 2017 abstract the current research work deals with the health of chorabari glacier between 1976 and 2017 using multi spectral and multi dated satellite data series of landsat mss tm and etm and resourcesat ii liss iv result closely reveals that the studied glacier receding continuously with inconsistent rate for the last 41 years and rate of receding dominates significantly after 2012 it lost 306 43 61 m total length 7 46 1 48 m a 1 0 074 km2 frontal area 0 0018 km2 a 1 0 31 km2 24 glaciated area 0 007 km2 a 1 0 015 km3 32 60 glaciated volume the upward migration of sla snow line altitude from 5265 m to 5290 m also suggests that the melting process were prevailing during the study tenure an existence of supra glacial lakes and its successive growth over the surface of chorabari glacier further justifies that the temperature of the surroundings has increased significantly and influences the melting process as well the melting process between 1976 and 1990 of the studied glacier directly influenced by the frequent episodes of precipitation and temperature anomalies of central himalayan region during 1960 1990 while the melting process after 1990 is directly influenced by the increase in average mean temperature and decrease in average mean precipitation of garhwal himalayan region the tree ring data of garhwal himalaya region also well matches the precipitation data of imd indian meteorological department the overall analysis explains that the chorabari glacier is retreating continuously since 1976

changes in the elevation and extent of two glaciers along the yanglonghe river qilian shan china we use topographic maps historical data multispectral satellite data and real time kinematic gps data to analyze glacier area length and ice elevation changes of two glaciers in the central qilian shan china between 1956 and 2007 we find that the fronts of yanglonghe glacier no 1 5y432a1 and yanglonghe glacier no 5 5y432a5 have retreated by 266 5 37 1 m 5 2 0 73 m a 1 and 181 4 37 1 m 3 6 0 73 m a 1 respectively and that this retreat accelerated after 1999 during the study period the glacier areas decreased by 4 1 and 15 9 respectively in addition spatially non uniform thinning which averaged 20 2 11 m 0 4 0 22 m a 1 and 16 9 11 m 0 33 0 22 m a 1 in the ablation areas of 5y432a1 and 5y432a5 respectively is observed using digital elevation models constructed using data from 1956 1977 and 2007 the ice volume depletion from 5y432a1 2 91 10 7 m 3 was 2 7 times greater than from the smaller 5y432a5 1 08 10 7 m 3 based on records from nearby tuole weather station increasing annual temperatures are principally responsible for the observed glacier thinning and retreat

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

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

monitoring glacier zones and snow firn line changes in the qinghai tibetan plateau using c band sar imagery abstract small glaciers and ice caps in mountainous areas are often sensitive indicators of local and global climate change in this paper typical continental glaciers the dongkemadi and its neighbouring glaciers in the central area of the qinghai tibetan plateau are monitored using multi sensor c band synthetic aperture radar sar imagery the study includes analysis of the alternating processes of ablation and freezing the glacier zones detected on sar images and the changing snow firn line across different days seasons and years experiments show that in late summer the wet snow firn ice boundary which is termed the late summer wet snow firn line wsfl is easily detected on sar images and it is relatively stable over multiple days also the detected late summer wsfl and the recorded yearly equilibrium line which reflects glacier mass balance are close in a positive mass balance year but the detected late summer wsfl is lower than the equilibrium line in a negative mass balance year by combining pit and sar observations it was found that the firn can be divided into two parts on the glaciers the thick firn that lies in the neve basin is distinct on sar images in winter but the firn surrounding the basin with thickness ranging from 0 to 20 cm is difficult to recognize the thick firn line the lower boundary of neve basin is stable in observations eight years apart based on the c band vv polarization sar image experiments field work and existing records the spatiotemporal backscatter signature specific to the typical continental glacier is identified the spatiotemporal backscatter signature helps to understand mass balance proxies and surface melt patterns of the glaciers in sar images

changes in the glacier extent and surface elevation along the ningchan and shuiguan river source eastern qilian mountains china we investigate the changes at nine glaciers in the ningchan and shuiguan river source eastern qilian mountains between 1972 and 2010 according to analysis of topographic maps and multispectral satellite data all nine glaciers in the study area have retreated by a maximum of 250 57 4 m and a minimum of 91 57 4 m the total glacier area decreased by 1 20 km 2 corresponding to 9 9 of the glacierized area in 1972 comparing the two dems generated from the topographic maps and real time kinematic gps data the mean glacier thinning rate was 0 64 m yr 1 between 1972 and 2010 the most significant thinning generally occurred on the termini the ice volume loss was about 106 8 46 7 x 10 3 km 3 equal to 90 8 39 7 x 10 3 km 3 w e which suggested a mean water discharge of 0 1 0 05 m 3 s during 1972 2010 based on analysis of meteorological data the summer temperature june august tends to increase over a similar time period the consistency of temperature increase and glacier shrinkage allows us to suggest that air temperature plays an important role in glacier changes in this region c 2014 university of washington published by elsevier inc all rights reserved

late 20th century changes in glacier extent in the caucasus mountains russia georgia glaciers occupy an area of 1600 km2 in the caucasus mountains there is widespread evidence of retreat since the little ice age but an up to date regional assessment of glacier change is lacking in this paper satellite imagery landsat thematic mapper and enhanced thematic mapper plus is used to obtain the terminus position of 113 glaciers in the central caucasus in 1985 and 2000 using a manual delineation process based on a false colour composite bands 5 4 3 measurements reveal that 94 of the glaciers have retreated 4 exhibited no overall change and 2 advanced the mean retreat rate equates to 8 m a 1 and maximum retreat rates approach 38 m a 1 the largest 10 km2 glaciers retreated twice as much 12 m a 1 as the smallest 1 km2 glaciers 6 m a 1 and glaciers at lower elevations generally retreated greater distances supraglacial debris cover has increased in association with glacier retreat and the surface area of bare ice has reduced by 10 between 1985 and 2000 results are compared to declassified corona imagery from the 1960s and 1970s and detailed field measurements and mass balance data for djankuat glacier central caucasus it is concluded that the decrease in glacier area appears to be primarily driven by increasing temperatures since the 1970s and especially since the mid 1990s continued retreat could lead to considerable changes in glacier runoff with implications for regional water resources

volume calculation and analysis of the changes in moraine dammed lakes in the north himalaya a case study of longbasaba lake glacial lake outburst flood hazards in the himalayan region have received considerable attention in recent years accurate volume estimation for glacial lakes is important for calculating outburst flood peak discharge and simulating flood evolution longbasaba lake a potentially dangerous moraine dammed lake is located on the north side of the himalaya its depth was surveyed using the syqwest hydrobox high resolution echo sounder and 6916 measurements were collected in september 2009 the maximum and average depths of the lake were 102 2 and 48 2 m respectively the morphology of the lake basin was modeled by constructing a triangulated irregular network and the lake was found to have a storage capacity of 0 064 0 002 km 3 multi source remote sensing images from landsat mss landsat tm etm and terra aster and a topographic map were digitized to delineate the outlines of the lake between 1977 and 2009 the results indicate that the length and area of the lake have increased during the past 32 years with a drastic expansion occurring since 2000 based on volume and area data of longbasaba lake in different periods we deduced an empirical equation of the lake volume area relationship that can be used to calculate the storage capacity of similar moraine dammed lakes in the himalayan region

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

gas driven filter pressing in magmas most silicic and some mafic magmas expand via second boiling if they crystallize at depths of about 10 km or less the buildup of gas pressure due to second boiling can be relieved by expulsion of melt out of the region of crystallization and this process of gas driven filter pressing assists the crystallization differentiation of magmas for gas driven filter pressing to be effective the region of crystallization must inflate slowly relative to buildup of pressure and expulsion of melt these conditions are satisfied in undercooled magmatic inclusions and in thin sheets of primitive magma underplating cooler magma reservoirs gas driven filter pressing thereby adds fractionated melt to magma bodies gas driven filter pressing is probably the dominant process by which highly evolved melts segregate from crystal mush to form aplitic dikes in granitic plutons this process could also account for the production of voluminous crystal poor rhyolites

glacial cover mapping 1987 1996 of the cordillera blanca peru using satellite imagery multitemporal glacier area mapping is a key element in accurately determining fresh water reserves as well as providing an indicator of climate change in peru the first glacier inventory was based on visual interpretation of aerial photos requiring several years of effort landsat thematic mapper satellite imagery on the other hand provides an increasingly employed alternative for the monitoring of changes in glacier area and in other glaciological parameters by means of normalized difference snow index ndsi computations on tm images an estimate of the glacierized area in cordillera blanca peru was carried out for 1987 643 63 km2 and 1996 600 61 km2 compared to an estimate of 721 km2 in 1970 it can be concluded that the glacier area has retreated in this massif by more than 15 in 25 years

evaluation of remote sensing techniques to measure decadal scale changes of hofsjokull ice cap iceland dynamic surficial changes and changes in the position of the firn line and the areal extent of hofsjokull ice cap iceland were studied through analysis of a time series 1973 98 of synthetic aperture radar sar and landsat data a digital elevation model of hofsjokull which was constructed using sar interferometry was used to plot the sar backscatter coefficient vs elevation and air temperature along transects across the ice cap seasonal and daily patterns are caused by freezing or thawing of the ice cap surface and abrupt changes in are noted when the air temperature ranges from 5 to 0 c late summer 1997 sar and reflectance landsat boundaries agree and appear to be coincident with the firn line and a sar boundary that can be seen in the january 1998 sar image in january 1994 through 1998 the elevation of this boundary on the ice cap was quite stable ranging from 1000 to 1300 m while the equilibrium line altitude as measured on the ground varied considerably thus the equilibrium line may be obscured by firn from previous years techniques are established to measure long term changes in the elevation of the firn line and changes in the position of the ice margin

glacier area changes in the central chilean and argentinean andes 1955 2013 14 to improve our knowledge of glacier area changes in the central chilean and argentinean andes 32 9 s 33 4 s two new glacier inventories from 1989 to 2013 14 are compared with a reinterpreted inventory from 1955 comparisons show glacier area retreat of 30 3 since 1955 decreasing from 134 to 94 km2 in 2013 14 whilst the annual rate of area loss showed a small increase insignificant between the periods of 1955 1989 and 1989 2013 14 separate analysis of the 1989 and 2013 14 inventories including a larger sample revealed a higher rate of glacier change compared with the smaller samples of these inventories additionally an analysis at 5 year intervals for six major glaciers 1955 2013 indicates large variability in response times and area loss magnitudes glacier olivares alfa for example lost 63 of its ice area while the juncal norte glacier lost only 10 1955 2013 the findings from this study improve our current knowledge base concerning widespread glacier decline in the southern andes and furthers monitoring efforts in this poorly described region of the world a region containing vital water resources for populated areas in south america

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

geodetic airborne laser altimetry of breidamerkurjokull and skeidararjokull iceland and jakobshavns isbrae west greenland

glacier variations in response to climate change from 1972 to 2007 in the western lenglongling mountains northeastern tibetan plateau global warming is causing widespread glacier retreat with small glaciers disappearing we investigate changes in glaciers over the western lenglongling mountains located in the northeastern margin of the tibetan plateau glacier extent over the western lenglongling mountains is estimated by comparing digitized glacier outlines obtained from aerial photographs and satellite imagery these results suggest that all 179 glaciers in the western lenglongling mountains shrunk between 1972 and 2007 the total area loss was similar to 24 4 km 2 accounting for similar to 28 3 0 81 a 1 of the glacierized area in 1972 the average area retreat rates differ over different time intervals they are approximately 0 68 0 90 0 77 and 0 56 km 2 a 1 over the periods 1972 95 1995 99 1999 2002 and 2002 07 respectively based on analysis of meteorological data glacier shrinkage in the study area can probably be attributed to the increase in air temperature furthermore the smaller glaciers display a higher shrinkage rate than larger glaciers and glaciers on southwest facing slopes appear to retreat faster than those on northeast facing slopes

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

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

comparison of satellite derived with ground based measurements of the fluctuations of the margins of vatnajokull iceland 1973 92 vatnajokull iceland is the earth s most studied ice cap and represents a classical glaciological field site on the basis of s palsson s seminal glaciological field research in the late 18th century since the 19th century vatnajokull has been the focus of an array of glaciological studies by scientists from many nations including many remote sensing investigations since 1951 landsat derived positions of the termini of 11 outlet glaciers of vatnajokull were compared with frontal positions of six of these 11 outlet glaciers determined by field observations during the period 1973 92 the largest changes during the 19 year period 1973 92 occurred in the large lobate surge type outlet glaciers along the southwestern western and northern margins of vatnajokull tungnaarjokull receded 1413 112 m 1380 1 m from ground observations and bruarjokull receded 1975 191 m 2096 5 m from extrapolated ground observations between 1973 and 1992 satellite images can be used to delineate glacier margin changes on a time lapse basis if the glacier margin can be spectrally discriminated from terminal moraines and sandur deposits and if the advance recession is larger than maximum image pixel size local knowledge of glaciers is critically important however in the accurate delineation of glacier margins on landsat images

consideration of the errors inherent in mapping historical glacier positions in austria from the ground and space 1893 2001 the historical record of in situ measurements of the terminus positions of the pasterze and kleines fleiskees glaciers in the eastern alps of austria is used to assess uncertainties in the measurement of decadal scale changes using satellite data topographic maps beginning in 1893 and satellite data from 1976 to 2001 were studied in concert with ground measurements to measure glacier changes ground measurements show that the tongue of the pasterze glacier receded f1150 m from 1893 to 2001 while satellite derived measurements using august 2001 landsat enhanced thematic mapper plus etm data registered to an 1893 topographic map show a recession of 1300 1800 m with an unknown error the measurement accuracy depends on the registration technique and the pixel resolution of the sensor when two satellite images are used when using topographic maps an additional source of error is the accuracy of the glacier position shown on the map between 1976 and 2001 landsat derived measurements show a recession of the terminus of the pasterze glacier of 479f136 m at an average rate of 19 1 m a 1 while measurements from the ground showed a recession of 428 m at an average rate of 17 1 ma 1 four meter resolution ikonos satellite images from 2000 and 2001 reveal a shrinkage of 22 096f46 m 2 in the pasterze tongue the nearby kleines fleiskees glacier lost 30 of its area between 1984 and 2001 and the area of exposed ice increased by 0 44f0 0023 km 2 according to landsat satellite measurements as more recent satellite images are utilized especially data that are geocoded the uncertainty associated with measuring glacier changes has decreased it is not possible to assess the uncertainty when an old topographic map and a satellite image are coregistered

variations in water level and glacier mass balance in nam co lake nyainqentanglha range tibetan plateau based on icesat data for 2003 09 water level fluctuations of inland lakes are related to regional scale climate changes and reflect variations in evaporation precipitation and glacier meltwater flowing into the lake area in its catchment in this paper ice cloud and land elevation satellite icesat altimeter data and landsat imagery 2002 09 are used to estimate nam co lake nyainqentanglha range tibetan plateau water elevation changes during 2002 09 in 2003 nam co lake covered an area of 1998 8 4 2 km 2 and was situated at 4723 m a s l over such inland water bodies icesat altimeter data offer both wide coverage and spatial and temporal accuracy we combine remote sensing and gis technology to map and reconstruct lake area and increased volume changes during a 7 year time series nam co lake water level increased by 2 4 0 12 m 0 33 m a 1 between 23 february 2003 and 1 october 2009 and lake volume increased by 4 9 0 5 km 3 in the past 7 years nam co lake area has increased from 1998 78 5 4 to 2023 8 3 4 km 2 the glacier covered area has decreased from 832 34 to 821 0 km 2 and the drainage basin area has decreased from 201 1 4 2 to 196 1 2 3 km 2 however the most spectacular feature is the continual water level rise from 2003 to 2009 without an obvious associated increase in precipitation based on digital elevation models dems from shuttle radar topography mission srtm dem data and corrected icesat elevation data significant changes to glacier mass balance in the western nyainqentanglha mountains are indicated nyainqentanglha mountain glacier surface elevations decreased by 8 39 0 45 m during 2003 09 over the same period at least 1 01 km 3 of glacial meltwater flowed into nam co lake assuming a glacial runoff coefficient of 0 6 the mean glacier mass balance value is 490 mm w e over the corresponding period indicating that glacier meltwater in the catchment contributes to lake level rise the contribution rate of glacial meltwater to lake water volume rise is 20 75 the temporal lake level fluctuation correlates with temperature variations over the same time span

tectonic interpretation of west verging folds in the selkirk allochthon of the southern canadian cordillera the selkirk allochthon a composite tectonic slice composed of north american paleocontinental margin deposits and more distal possibly marginal basin suspect terrane was displaced eastward toward the craton in the late jurassic and late cretaceous the carnes nappe a major west verging recumbent anticline within the selkirk allochthon is considered the southern continuation of scrip nappe which in the monashee mountains has an inverted limb length of 50 km the west verging nappe and associated structures are interpreted as having originated in the early to middle jurassic during accretion of western allochthonous terranes and prior to eastward displacement of the selkirk allochthon the reversal from westward vergence away from the north american craton to eastward vergence is considered as marking a fundamental change in the evolution of the orogenic belt and may reflect a transition from underthrusting of western allochthonous terranes on blind shear zones to east directed breakthrough thrusts

detailed dynamic geometric and supraglacial moraine data for glaciar pio xi the only surge type glacier of the southern patagonia icefield chilean government through centers of excellence base financing program of comision nacional de investigacion y tecnologica de chile conicyt

elevation changes measured during 1966 2010 on the monsoonal temperate glaciers ablation region gongga mountains china abstract temperate glaciers are more sensitive to climate change than are polar or continental glaciers and can drive remarkable runoff variation in local water catchments changes in the glacier area and surface elevation of the three monsoonal temperate glaciers in the gongga mountains china were analyzed using series of remote sensing images and digital elevation model dem data all possible sources of uncertainty were considered in detail the results showed that the total glacier area decreased by 4 3 km 2 6 7 between 1966 and 2010 a comparison of glacier surface elevations using dems derived from dual frequency differential gps dgps surveys in 2010 and from 1966 to 1989 from topographic maps the three glaciers underwent significant mass loss from 1966 to 2010 and the mean surface elevation changes were 0 90 0 45 m y 1 06 0 45 m y and 1 12 0 45 m y for hailuogou hlg dagongba dgb and yanzigou yzg glaciers respectively from 1966 to 2010 analysis of the meteorological data showed that the mean annual air temperature increase was the main reason for the thinning and volume loss thinning of the glacier tongue and volume loss was more intense in the period 1989 2010 than in 1966 89 debris thickness and other factors are also believed to play important roles in differential thinning among different areas and periods

automatic identification of the lake area at qinghai tibetan plateau using remote sensing images abstract the lake area of the qinghai tibetan plateau qtp was identified using an automatic waterbody interpretation method the spectral reflectance of water is much lower than that of other land surface materials in remote sensing images the method made use of this characteristic and divided the lake area into pure water pixels and mixed pixels in total 4051 field collected ground control points of the boundaries of the 17 lakes were used to calibrate and validate the method the lake area changes from the 1980s to 2015 were also analyzed it can deal with the mismatch between the grid image boundaries and vector real lake boundaries results indicate that it is necessary to consider this mismatch when identifying waterbodies based on remote sensing images especially in the case of waterbodies with an irregular shape the method can distinguish waterbodies from wetlands and glaciers and the interpretation accuracy was improved in 2015 1177 lakes with an area larger than 1 km2 were recorded the total lake area of the qtp was 43873 6 km2 in general the qtp lakes have expanded during the past several decades the lake area has increased by 18 3 from the 1980s to 2015 this indicates expansion in the northern tibetan plateau and shrinkage in the southern region of the qtp the changes of precipitation were the main reasons for lake area changes on the qtp however the increased glacier melt runoff played a dominant role in the upper regions of the yalungzangbo and yellow rivers the method proposed herein can be easily applied to other studies to monitor waterbodies based on remote sensing images especially in the case of large waterbodies