contrasting patterns of early twenty first century glacier mass change in the himalayas glaciers are among the best terrestrial climate indicators an important water resource in mountains1 2 and a major contributor to global sea level rise3 4 in the hindu kush karakoram himalaya region hkkh a paucity of appropriate glacier data has prevented a comprehensive assessment of current regional mass balance5 however there are indirect evidences of a complex pattern of glacial responses5 8 in reaction to heterogeneous climate change signals9 here we provide the first coherent data set of detailed glacier thickness changes over the hkkh during 2003 2009 by combining satellite laser altimetry and a global elevation model in the eastern central and south western parts of the hkkh glacier wastage is widespread with regional thinning rates up to 0 66 0 09 m a 1 in the jammu kashmir region conversely in the karakoram glaciers are close to balance with only a slight thinning of 0 07 0 04 m a 1 regionally averaged thinning rates under debris mantled ice are similar to those of clean ice despite insulation by debris covers the 2003 2008 specific mass balance for our hkkh study region is 0 21 0 05 m a 1 water equivalent we significantly less negative than the global average of 0 7 m a 1 we for glaciers and ice caps4 10 this difference is mainly an effect of the balanced glacier mass budget in the karakoram the corresponding hkkh sea level contribution is 0 035 0 009 mm a 1 amounting to 1 of the present day sea level rise11 our 2003 2008 mass budget of 12 8 3 5 gt a 1 is more negative than recent satellite gravimetry based estimates of 5 6 gt a 1 over 2003 2010 ref 12 for the mountain catchments of the indus and ganges basins13 the glacier imbalance contributes 3 5 and 2 0 respectively to the annual average river discharge13 and up to 10 for the upper indus basin14

ice loss from the southern patagonian ice field south america between 2000 and 2012 1 a time series composed of 156 aster derived digital elevation models dems and a radar penetration bias corrected version of the shuttle radar topography mission srtm dem is used to derive ice surface height and volume changes at the southern patagonian ice field spi in southern south america the observations made between february 2000 and march 2012 indicate that the ice field is rapidly losing volume at many of the largest outlet glaciers and in most cases thinning extends to the highest elevations of the ice field mass loss is occurring at a rate of 20 0 1 2 gt a 1 which when summed with mass loss at the adjacent northern patagonian ice field results in a combined rate of 24 4 1 4 gt a 1 equivalent to 0 067 0 004 mm a 1of sea level rise our decade long mass loss rates are substantially higher than those derived during the last three decades of the 20th century but are in good agreement with recent grace observations our volume loss estimate is sensitive to constraints applied to the amount of thickening in the accumulation zone new field measurements and a continued dem time series will be required to refine our estimates

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

spatially variable response of himalayan glaciers to climate change affected by debris cover the present state and future evolution of himalayan glaciers has been controversial an analysis of remotely sensed frontal changes and surface velocities from glaciers in the greater himalaya between 2000 and 2008 shows large regional variability in the responses of himalayan glaciers to climate change

glacier runoff and its impact in a highly glacierized catchment in the southeastern tibetan plateau past and future trends we investigate past and future trends in glacier runoff and the associated hydrological impacts on river runoff in the hailuogou catchment a highly glacierized catchment with extensive debris cover in the southeastern tibetan plateau using a catchment scale glacio hydrological model past trends in various runoff components of the catchment indicate that glacier runoff has been a large component of total runoff contributing similar to 53 4 of total runoff during the period 1952 2013 future changes in runoff calculated using the outputs of ten global climate models for representative concentration pathway rcp 4 5 and rcp8 5 reveal that glacier runoff plays different roles in the water supply of the catchment for the two rcps and the discrepancies between the two rcps increase in the second half of this century leading to a considerable difference in the hydrological regime of the catchment in particular changes are more remarkable under rcp8 5 under which all glaciers are projected to retreat dramatically and total runoff to decrease slightly by the end of this century an experimental analysis in which no debris cover is assumed on glacier ablation zones indicates that excess meltwater from the debris covered area provides an 8 1 increase in total runoff relative to the no debris assumption case

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

deglacial rapid sea level rises caused by ice sheet saddle collapses a simulation of ice sheet retreat reveals two meltwater pulses coinciding with mwp 1a and the 8 200 year event caused by saddle collapses between ice domes during the last deglaciation the retreating ice sheets occasionally released massive amounts of fresh water these meltwater pulses are often implicated as important influences on abrupt climate change but the underlying triggering mechanisms are not clear here lauren gregoire et al show that saddle zones that connect adjacent high domes on ice sheets can be lowered by ongoing warming to an elevation at which they rapidly degrade leading to separate domes and a meltwater pulse that is consistent with geological observations although the mechanism itself is not novel the authors establish that two important sudden cooling events meltwater pulse 1a and the 8 200 year event were probably caused by saddle separation the last deglaciation 21 to 7 thousand years ago was punctuated by several abrupt meltwater pulses which sometimes caused noticeable climate change1 2 around 14 thousand years ago meltwater pulse 1a mwp 1a the largest of these events produced a sea level rise of 14 18 metres over 350 years3 although this enormous surge of water certainly originated from retreating ice sheets there is no consensus on the geographical source or underlying physical mechanisms governing the rapid sea level rise4 5 6 here we present an ice sheet modelling simulation in which the separation of the laurentide and cordilleran ice sheets in north america produces a meltwater pulse corresponding to mwp 1a another meltwater pulse is produced when the labrador and baffin ice domes around hudson bay separate which could be associated with the 8 200 year event the most pronounced abrupt climate event of the past nine thousand years7 for both modelled pulses the saddle between the two ice domes becomes subject to surface melting because of a general surface lowering caused by climate warming the melting then rapidly accelerates as the saddle between the two domes gets lower producing nine metres of sea level rise over 500 years this mechanism of an ice saddle collapse probably explains mwp 1a and the 8 200 year event and sheds light on the consequences of these events on climate

changes of the hailuogou glacier mt gongga china against the background of climate change during the holocene large changes have occurred at hailuogou glacier mt gongga china during the holocene various data indicate that it retreated by 1 88 km during the 20th century and mass balance records show that it suffered a sustained mass loss of snow and ice in the period 1959 60 2003 04 with an accumulated mass balance of 10 83 m water equivalent hydrological data demonstrate that runoff from the glacier has been increasing both seasonally and annually the principal cause being an increase of ice and snow melt water as the mean temperature in the hailuogou basin rose by 0 1 degrees c between 1994 and 2004 the runoff increased by 2 6 m 3 s 1 changes of glacier morphology which occurred during this period include a decrease of thickness enlargement of glacial caves and reduction of the size of seracs the hailuogou glacier advanced three times during the little ice age in response to three cold periods in the mt hengduan region there also were three noticeable advances in the neoglacial there was a very clear relationship between glacier change climate change and forest line change in the period 3000 a bp 100 a bp overall it is clear that changes of the hailuogou glacier in the holocene have been responded to climatic fluctuations but quantitative evaluation of the relationship is difficult owing to the sparse spatial coverage of reliable evidence and the limited available longer term data c 2008 elsevier ltd and inqua all rights reserved

northwestward propagation of the intraseasonal oscillation in the western north pacific during the boreal summer structure and mechanism abstract the convection of the intraseasonal timescale in the western north pacific during the boreal summer tends to propagate northwestward in the philippine sea to near 20 n and then continues propagating westward the formation of enhanced convection in the western north pacific is a result of the merging of a convective system moving eastward along the equator and a westward propagating low level convergence anomaly which is located to the east of a vortex in the subtropics a positive feedback between the anomalous circulation and convection leads to a rapid enhancement of the system the strengthened southwesterly associated with the vortex enhances evaporation over the oceans e g the eastern indian ocean the bay of bengal and the south china sea and transports moisture northeastward the moisture converges at the northwestern corner of the convection and results in a potentially unstable atmosphere the result is the northwestward propagation of the coupled circulation convection system in

multi decadal ice velocity and elevation changes of a monsoonal maritime glacier hailuogou glacier china digital elevation models dems of the ablation area of hailuogou glacier china produced from advanced spaceborne thermal emission and reflection radiometer aster data obtained in 2009 differential gps dgps data surveyed in 2008 and aerial photographs acquired in 1966 and 1989 are differenced to estimate long and short term glacier surface elevation change dh dt the mean dh dt of the ablation area over 43 years 1966 2009 is 1 1 0 4 m a 1 since 1989 the thinning has accelerated significantly ice velocities measured by dgps at 28 fixed stakes implanted in the ablation area increase with distance from the glacier terminus ranging from 41 0 m a 1 approaching the glacier terminus to a maximum of 205 0 m a 1 at the base of an icefall our results reveal that the overall average ice velocity in the ablation area has undergone significant temporal variability over the past several decades changes in glacier surface elevation in the ablation area result from the combined effects of climate change and glacier dynamics which are driven by different factors for different regions and periods

contribution of alaskan glaciers to sea level rise derived from satellite imagery over the last 50 years retreating glaciers and ice caps gic contributed 0 5 mm yr to sea level rises slr and one third is believed to originate from ice masses bordering the gulf of alaska however these estimates of ice wastage in alaska are based on methods that measure a limited number of glaciers and extrapolate the results to estimate ice loss for the many thousands of others how these methods capture the complex pattern of decadal elevation changes at the scale of individual glacier and mountain range is unclear here combining a comprehensive glacier inventory with elevation changes derived from sequential digital elevation models dems we found that between 1962 and 2006 alaskan glaciers lost 41 9 8 6 km 3 yr water equivalent w e and contributed 0 12 0 02 mm yr to slr our ice loss is 34 lower than previous estimates reasons for our lower values include the higher spatial resolution of our glacier inventory and the reduction of ice thinning under debris and at the glacier margins which were not resolved in earlier work estimates of mass loss from gic in other mountain regions could be subject to similar revisions

spatio temporal variability in elevation changes of two high arctic valley glaciers uncertainties in estimates of glacier and ice cap contribution to sea level rise exist in part due to poor quantification of mass balance errors particularly those resulting from extrapolation of sparse measurements centre line data are often assumed to be representative of the glacier as a whole with little attention paid to extrapolation errors or their effect on mass balance estimates here we present detailed digital elevation model dem measurements of glacier wide elevation changes over the last 40 years at two glaciers on svalbard norwegian arctic austre broggerbreen and midtre lovenbreen are shown to have lost 27 54 0 98 and 9 65 0 76 10 7 m 3 of ice respectively between 1966 and 2005 findings that we relate to trends in average summer air temperatures and winter accumulation these volume losses correspond to geodetic balances of 0 58 0 03 and 0 41 0 03 m w e a 1 respectively our analysis revealed high spatial complexity in patterns of elevation change varying between glaciers between measurement intervals and within and between elevation bins balances from extrapolated centre line geodetic data were the same within errors as those from full coverage dem differencing in the majority of comparisons yet significantly underestimated balance in three instances additionally field mass balance from centre line ablation stake data underestimated balances from full coverage geodetic measurements during three of six measurement periods these findings may support the hypothesis that field measurements under estimate svalbard glacier mass loss at least partly as a result of the failure of centre line measurements to account for glacier wide variations in ablation our results demonstrate the importance of deriving accurate interpolation functions and constraining extrapolation errors from sparse measurements

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

a reconciled estimate of glacier contributions to sea level rise 2003 to 2009 glaciers distinct from the greenland and antarctic ice sheets are losing large amounts of water to the world s oceans however estimates of their contribution to sea level rise disagree we provide a consensus estimate by standardizing existing and creating new mass budget estimates from satellite gravimetry and altimetry and from local glaciological records in many regions local measurements are more negative than satellite based estimates all regions lost mass during 2003 2009 with the largest losses from arctic canada alaska coastal greenland the southern andes and high mountain asia but there was little loss from glaciers in antarctica over this period the global mass budget was 259 28 gigatons per year equivalent to the combined loss from both ice sheets and accounting for 29 13 of the observed sea level rise

heterogeneous mass loss of glaciers in the aksu tarim catchment central tien shan revealed by 1976 kh 9 hexagon and 2009 spot 5 stereo imagery the meltwater released by the glaciers in the aksu tarim catchment south of tomur peak central tien shan feeds the tarim river which is the main artery for the oases at the northern margin of the taklamakan desert the correct modeling of the contribution of the glaciers meltwater to the total runoff of the tarim river is hampered by the lack of mass balance data multi temporal digital terrain models dtms allow the determination of volume changes for large samples of glacier here we present the mass changes for 12 glaciers using 1976 kh 9 hexagon 2000 srtm3 and 2009 spot 5 datasets the results show that most of the glaciers have been losing mass since 1976 the largest glaciers koxkar and west qongterang lost 0 27 0 15 m w e a 1 and 0 43 0 15 m w e a 1 between 1976 and 2009 despite thick debris cover however some smaller glaciers show mass gain at their tongues indicating glacier surges using srtm3 data the volume gain of qinbingtan glacier no 74 could be dated to the time period 1999 2009 the overall mass budget of 0 33 0 15 m w e a 1 for 1976 2009 of the investigated glaciers is within the variability range of the global average however in the recent years 1999 2009 a slightly decelerated mass loss of 0 23 0 19 m w e a 1 could be observed c 2012 elsevier inc all rights reserved

spatial variability of glacier elevation changes in the swiss alps obtained from two digital elevation models 1 massive glacier thinning in the alps during the past 20 years is documented by direct mass balance measurements on nine regularly observed glaciers how representative this limited sample of glaciers is for the entire alps however remained uncertain the near global digital terrain model from the srtm enables a closer analysis of this question which is of fundamental importance to assess overall glacier volume change here we present elevation changes from 1985 to 1999 for about 1050 glaciers in the swiss alps the analysis reveals extreme thickness losses 80 m for flat low lying glacier tongues and a strong overall surface lowering the mean cumulative mass balance of the nine glaciers with direct measurements 10 8 m w e agrees well with the mean change of the entire region from dem differencing 11 m w e and can thus be considered to be representative mean thickness change of individual glaciers is correlated with their size elevation and exposure to solar irradiation this implies that mass losses of large glaciers can be underestimated when they are directly inferred from values measured at much smaller glaciers

heterogeneous changes of glaciers over the western kunlun mountains based on icesat and landsat 8 derived glacier inventory abstract glaciers in the northwestern qinghai tibet plateau qtp including the karakoram and western kunlun mountains wkm exhibited heterogeneous changes in recent years a latest glacier inventory of the wkm region is generated by using landsat 8 oli images year 2013 and srtm3 dem the icesat ice cloud and land elevation satellite elevation data in combination with the dem is then employed to investigate glacier thickness changes the wkm region consists of 537 glaciers 0 02 km 2 with a total area of 3137 km 2 in 2013 out of these 16 groups of glaciers covering an area about 1234 km 2 2013 showed varying surface elevation trends ranging from 0 4 0 20 m a to 0 7 24 m a over 2003 2008 except the serious thinning trend 1 15 0 41 m a detected at a surging glacier the surging glacier the zhongfeng glacier is characterized by drastic elevation variations up to 80 m and contrasting trends over the accumulation areas due to cave in and rapid transfer of ice to the downstream the heterogeneous glacier behavior in the wkm region was not only exemplified in the varying mass balances of individual glaciers but also the spatial variability of elevation trends over different glacier parts accumulation ablation areas analysis of the heterogeneity shows that such glacier dynamics were probably associated with local glacier parameters including altitude aspect glacier hypsometry and ice flow the mechanisms for the mass gain and glacier surging in the wkm region require further studies with more observations

mass loss of greenland s glaciers and ice caps 2003 2008 revealed from icesat laser altimetry data 1 the recently finalized inventory of greenland s glaciers and ice caps gic allows for the first time to determine the mass changes of the gic separately from the ice sheet using space borne laser altimetry data corrections for firn compaction and density that are based on climatic conditions are applied for the conversion from volume to mass changes the gic which are clearly separable from the icesheet i e have a distinct ice divide or no connection lost 27 9 10 7 gt a 1 or 0 08 0 03 mm a 1 sea level equivalent sle between october 2003 and march 2008 all gic including those with strong but hydrologically separable connections lost 40 9 16 5 gt a 1 0 12 0 05 mm a 1 sle this is a significant fraction 14 or 20 of the reported overall mass loss of greenland and up to 10 of the estimated contribution from the world s gic to sea level rise the loss was highest in southeastern and lowest in northern greenland

changes in glacier volume on mt gongga southeastern tibetan plateau based on the analysis of multi temporal dems from 1966 to 2015 the accelerated retreat of glaciers and the reduction of glacier ice reserves caused by climate change can significantly affect regional water resources and hydrological cycles changes in glacier thickness are among the key indicators that reflect this process we analyzed changes observed in the elevation of glacier surfaces in the gongga mountains ggm using multi temporal digital elevation models dems derived from topographic maps srtm icesat and zy 3 data the results showed that the mean rate of change in glacier surface altitude in the ggm was 26 7 2 03 m 0 54 0 04 m a 1 between 1966 and 2015 the mean melt rates differed over different time periods latterly showing an accelerating trend as a general rule glaciers appear to be losing more volume at lower than at higher elevations further analysis of these results suggests that supraglacial debris coverage in the ggm promotes higher rates of mass loss

catchment scale reconstruction of glacier mass balance using observations and global climate data case study of the hailuogou catchment south eastern tibetan plateau summary debris covered glaciers are common in the tibetan plateau where ablation zones are mantled in a supraglacial debris cover that influences glacier mass balance runoff and response to climate change by affecting the melt rate of the underlying ice the impact of debris cover has not yet been taken into account in regional or global scale assessments of glacier mass balances and freshwater resources by using physically based numerical models here a surface energy mass balance model that accounts for the significance of debris cover and its effect on the ice melt rate is applied to reconstruct the glacier mass balance of hailuogou catchment which is located in the south eastern tibetan plateau and contains three debris covered and four debris free monsoonal maritime glaciers according to our calculations the glaciers in hailuogou catchment show a mean annual balance of 0 42 m water equivalent w e per year for a total mass loss of 24 3 m w e over the period 1952 2009 a comparison of summer temperature and precipitation mass balance equilibrium line altitude ela relations indicates that the glaciers in the catchment are much more sensitive to temperature change than to precipitation change in the last 20 yrs increasing summer temperature is the main cause of rapid wasting of the glacier mass in the catchment meanwhile the presence of supraglacial debris markedly accelerates glacier mass loss resulting in the unstable termini of debris covered glaciers in hailuogou catchment this highlights the importance of debris cover for understanding glacier mass balance and hydrology in the tibetan plateau

spot5 hrs digital elevation models and the monitoring of glacier elevation changes in north west canada and south east alaska abstract monitoring the response of land ice to climate change requires accurate and repeatable topographic surveys the spot5 hrs high resolution stereoscopic instrument covers up to 120 km by 600 km in a single pass and has the potential to accurately map the poorly known topography of most glaciers and ice caps the acquisition of a large hrs archive over ice covered regions is planned by the french space agency cnes and spotimage france during the 2007 2008 international polar year ipy here we report on the accuracy and value of hrs digital elevation model dem over ice and snow surfaces a dem is generated by combining tools available from cnes with the pci orthoengine se software using hrs images acquired in may 2004 over south east alaska usa and northern british columbia canada the dem is evaluated through comparison with shuttle radar topographic mission srtm dem and icesat data on and around the glaciers a horizontal shift of 50 m is found between the hrs and srtm dems and is attributed to errors in the srtm dem over ice free areas hrs elevations are 7 m higher than those of srtm with a standard deviation of 25 m for the difference between the two dems the 7 m difference is partly attributed to the differential penetration of the electromagnetic waves visible for hrs microwave for srtm in snow and vegetation we also report on the application of sequential dems srtm dem in february 2000 and hrs dem in may 2004 for the monitoring of glacier elevation changes we map the topographic changes induced by a surge of one tributary of ferris glacier maximum surface lowering of 42 10 m and rising of 77 10 m are observed in the 4 years time interval thinning rates up to 10 2 5 m yr are observed at low altitudes and confirm the ongoing wastage of glaciers in south east alaska

distribution of debris thickness and its effect on ice melt at hailuogou glacier southeastern tibetan plateau using in situ surveys and aster imagery debris cover is widely present in glacier ablation areas of the tibetan plateau and its spatial distribution greatly affects glacier melt rates high resolution in situ measurements of debris thickness on hailuogou glacier mount gongga southeastern tibetan plateau show pronounced inhomogeneous debris distribution an analysis of transverse and longitudinal profiles indicates that the ground surveyed debris thicknesses and advanced spaceborne thermal emission and reflection radiometer aster derived thermal resistances of debris layers correlate strongly over the entire ablation area across and along glacier patterns of aster derived thermal resistance correspond well with spatial patterns of debris thickness which may reflect large scale variations in the extent and thickness of the debris cover the ice melt rate variability over the ablation area simulated by a surface energy balance model that considered thermal resistance of the debris layer indicates clearly the crucial role of debris and its spatial continuity in modifying the spatial characteristics of melt rates because of the inhomogeneous distribution of debris thickness about 67 of the ablation area on hailuogou glacier has undergone accelerated melting whereas about 19 of the ablation area has experienced inhibited melting and the sub debris melt rate equals the bare ice melt rate in only 14 of the ablation area

recent changes in glacier velocities and thinning at novaya zemlya abstract ice loss from the glaciers of novaya zemlya nvz is the dominant contributor to sea level for the russian arctic here we present maps of glacier elevation change rates dh dt and velocities at novaya zemlya that reveal evidence of the impact of both calving flux and surface melt on ice mass loss dh dt are calculated by applying a weighted linear regression to stacked digital elevation models dems from a 1952 map and dems created from stereo pairs of worldview images acquired between 2012 and 2014 the 60 year average mass change rate is 0 23 0 04 m w e yr 1 the recent short term 2012 2013 2014 average mass change rate is 0 40 0 09 m w e yr 1 we apply the same weighted linear regression to stacked worldview dems and icesat elevations from 2003 to 2009 as well as stacked worldview dems and aster dems from 2000 to 2013 the dh dt from both datasets confirm that thinning has been more rapid than the 60 year average since 2000 average mass loss has accelerated at the lower elevations of land terminating glaciers suggesting that recent near surface warming and increased melt have led to greater thinning marine terminating glaciers along the barents sea coast have substantially higher thinning rates near their termini in recent years than adjacent land terminating glaciers suggesting that calving flux is an important contributor to overall ice mass loss in the region flow velocities are generated by feature tracking on optical and radar image pairs marine terminating glaciers along the barents sea coast have the highest frontal velocities of any glaciers on nvz our surface velocity measurements constrain the calving flux at the two fastest retreating glaciers inostrantseva ino and vil kitskogo vis which are both on the barents sea coast we find that the calving flux is high enough to drive frontal thinning and retreat at those two glaciers summer terminus speeds at inostrantseva glacier have accelerated from a 2006 maximum of 3 m day 1 to a 2012 maximum of 9 to 10 m day 1 and the front has retreated by more than 3 km between 2006 06 27 and 2013 08 17

impact of resolution and radar penetration on glacier elevation changes computed from dem differencing regional glacier mass balances can be measured by subtracting multi temporal digital elevation models dems however dems are often biased with altitude and it remains unclear whether the elevation differences observed on the ice free terrain can be used to correct biases on ice covered areas iwe investigate such altitude related biases using dems from three different sensors spot5 srtm c band and srtm x band the bias due to different original resolutions can be corrected using a relationship between curvature and elevation difference calculated on ice free terrain the impact of c band radar penetration into snow and ice can be evaluated for a specific region by comparing srtm c band and srtm x band dems in our test area karakoram the resolution related bias has a minor influence on region averaged elevation change conversely not accounting for c band penetration would significantly biased the mean elevation change

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

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

biases of srtm in high mountain areas implications for the monitoring of glacier volume changes because of its nearly global coverage the shuttle radar topographic mission srtm topography is a promising data set for estimating mountain glacier volume changes but first its absolute accuracy must be thoroughly investigated in a glacial environment we use topographic data available in the french alps to assess the usefulness of srtm for the monitoring of glacier volume variations we observe clear biases with altitude both on ice free and glacier covered areas at high altitudes srtm elevations are underestimated by up to 10 m these biases can have a significant impact on any estimate of glacier volume changes if srtm is the most recent of the two compared topographies the volume loss is overestimated and vice versa we cannot conclude definitively on the origin of these biases and whether they affect all high mountain areas but our findings invite reconsideration of previous estimates of glacier wastage based on srtm

slight mass gain of karakoram glaciers in the early twenty first century the mass balance of hindu kush karakoram himalaya glaciers has been debated partly because of a severe lack of observations from the region an analysis of the regional mass balance of karakoram glaciers by comparison of digital elevation models from 1999 to 2008 reveals a small glacier mass gain in the area

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

precipitation driven glacier changes in the pamir and hindu kush mountains glaciers in the pamir hindu kush karakoram appear to be less influenced by global warming and have instead experienced slight gains in mass unlike most other glaciers around the world here we apply laser altimetry and satellite derived precipitation products to characterize the relationship between the glaciers and precipitation we found a strong correlation r 0 92 p 0 005 between the year to year changes in glacier thickness and precipitation in the pamir and hindu kush from 2003 to 2008 indicating the primary role of precipitation in the glacier changes the amount of precipitation in the glacial region is underestimated by approximately 7 2 times in the gridded precipitation product this underestimation is attributed to the low resolution and lack of orographic precipitation in the gridded products the long term precipitation data show strong interannual variations which probably cause similar variations in glaciers and biases in previous glacier mass change estimates

recent contributions of glaciers and ice caps to sea level rise satellite measurements of earth s gravity field show that the mass loss of glaciers and ice caps contributed to sea level rise by approximately 0 4 millimetres per year between 2003 and 2010 the extent to which mass loss from ice covered land areas contributes to sea level rise is not known accurately in part because previous global estimates use different techniques for glaciers ice caps and ice sheets the gravity recovery and climate experiment grace satellite has provided monthly measurements of the global gravity field since 2002 using grace data jacob et al assess regional mass loss between 2003 and 2010 and conclude that mass loss from ice covered land areas contributed almost 1 5 mm per year to the sea level rise estimated mass loss from the high mountains of asia was negligible in contrast to some other reports glaciers and ice caps gics are important contributors to present day global mean sea level rise1 2 3 4 most previous global mass balance estimates for gics rely on extrapolation of sparse mass balance measurements1 2 4 representing only a small fraction of the gic area leaving their overall contribution to sea level rise unclear here we show that gics excluding the greenland and antarctic peripheral gics lost mass at a rate of 148 30 gt yr 1 from january 2003 to december 2010 contributing 0 41 0 08 mm yr 1 to sea level rise our results are based on a global simultaneous inversion of monthly grace derived satellite gravity fields from which we calculate the mass change over all ice covered regions greater in area than 100 km2 the gic rate for 2003 2010 is about 30 per cent smaller than the previous mass balance estimate that most closely matches our study period2 the high mountains of asia in particular show a mass loss of only 4 20 gt yr 1 for 2003 2010 compared with 47 55 gt yr 1 in previously published estimates2 5 for completeness we also estimate that the greenland and antarctic ice sheets including their peripheral gics contributed 1 06 0 19 mm yr 1 to sea level rise over the same time period the total contribution to sea level rise from all ice covered regions is thus 1 48 0 26 mm 1 which agrees well with independent estimates of sea level rise originating from land ice loss and other terrestrial sources6

icesat measurements of sea ice freeboard and estimates of sea ice thickness in the weddell sea 1 sea ice freeboard heights in the weddell sea of antarctica are derived from the ice cloud and land elevation satellite icesat laser altimeter measurements which have a unique range precision to flat surfaces of 2 cm within 70 m footprints spaced at 172 m along track although elevations of flat surfaces can be obtained to an accuracy of 10 cm 1s per footprint direct determination of freeboard heights is precluded by errors in knowledge of the geoid and temporal variability of the ocean surface therefore freeboards are determined relative to an ocean reference level detected over areas of open water and very thin ice within the sea ice pack using an along track filtering method the open water thin ice selections show good agreement in the combined analysis of icesat segments and envisat synthetic aperture radar sar imagery the average residual between the icesat measured ocean level and the egm96 geoid is 1 4 m estimates of snow depth on the sea ice from amsr e passive microwave data along with nominal densities of snow water and sea ice are used to estimate sea ice thickness four periods of icesat data in may june fall and october november late winter of 2004 and 2005 between longitudes 298e and 360e are analyzed in the fall the mean freeboards are 0 28 m in 2004 and 0 29 m in 2005 and the mean thicknesses are 1 33 m in 2004 and 1 52 m in 2005 in late winter the freeboards grew to 0 37 m in 2004 and 0 35 in 2005 and the thicknesses grew to 2 23 m in 2004 and 2 31 m in 2005 the interannual differences in freeboard are small and the larger interannual change in estimated thickness mainly represents differences in the snow depth estimates seasonal changes in the spatial patterns of freeboard and thickness over the 4 months correlate with the expected circulation of sea ice in the weddell sea as indicated by sea ice velocity fields

marbles and carbonate rocks from central morocco a petrographic mineralogical and geochemical study petrographic mineralogical and stable isotopes 13c 18o values compositions were used to characterise marbles and sedimentary carbonate rocks from central morocco which are considered to be a likely source of ornamental and building material from roman time to the present day this new data set was used in the frame of an archaeometric provenance study on roman artefacts from the town of thamusida kenitra north morocco to assess the potential employment of these rocks for the manufacture of the archaeological materials a representative set of samples from marbles and other carbonate rocks limestone dolostone were collected in several quarries and outcrops in the moroccan meseta in a region extending from the meknes khenifra alignment to the atlantic ocean all the samples were studied using a petrographic mineralogical and geochemical methods the petrographic and minerological investigations optical microscopy electron microscopy x ray diffraction allowed to group the carbonate rocks in limestones foliated limestone diagenetic breccias and dolostone the limestones could be further grouped as mudstones wackestones packstones crinoid grainstones oolitic grainstone and floatstones textural differences allowed to define marbles varieties the stable carbon and oxygen isotope composition proved to be quite useful in the discrimination of marble sources with apparently less discriminatory potential for carbonate rocks

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

glacier mass changes in rongbuk catchment on mt qomolangma from 1974 to 2006 based on topographic maps and alos prism data abstract elevation changes of glacier surfaces were investigated in rongbuk catchment rc on the northern slopes of mt qomolangma in the central himalayas by comparing a digital elevation model dem generated from the 2006 alos prism imageries with the base dem1974 derived from the 1 50 000 topographic maps the average elevation change rate of glacier surfaces in rc was estimated at 0 47 0 23 m a 1 between 1974 and 2006 such surface lowering rates varied significantly with glaciers and altitudes one of the notable results is that the debris covered ice thinned much more rapidly than the exposed ice at higher altitudes overall glaciers in rc have lost mass of 0 06 0 04 gt a 1 during 1974 2006 glacier imbalance constitutes about 50 or more of the rongbuk runoff