topography relief and trmm derived rainfall variations along the himalaya 1 along the southern himalayan topographic front the indian summer monsoon modulates erosive processes and rates to investigate the influence of topography and relief on rainfall generation and resultant erosion we processed satellite rainfall amounts for the last 8 years 1998 2005 from the tropical rainfall measurement mission trmm based upon a spatial resolution of 5 5 km for the himalaya we identify 1 the spatial distribution of rainfall and 2 the large scale relationships between topography relief and rainfall locations our results show two distinct rainfall maxima along strike in the himalaya the first outer rainfall peak occurs along the southern margin of the lesser himalaya within a narrow band of mean elevation 0 9 0 4 km and mean relief 1 2 0 2 km the second discontinuous inner band typically occurs along the southern flank of the greater himalaya elevation and relief both 2 1 0 3 km

flow regimes of himalayan rivers of nepal nature and spatial patterns abstract a large scale perspective is provided upon the spatial distribution of river flow regimes across the nepalese himalaya by classifying long term average monthly runoff data for 28 river basins the classification methodology is shown to be a useful tool for identifying underlying spatial structure in flow regime shape timing of peak and magnitude low intermediate and high in an extreme physical environment where hydrological patterns are complex and poorly known low marked august peak regimes occur across far western nepal but also in some eastern basins which have a short summer monsoon and snow and ice melt low july august peak regimes are found in the central to eastern high mountains and high himalaya and the eastern middle mountains where the summer monsoon arrives earliest meltwaters contribute but topography limits precipitation amount low intermediate august september peak regimes dominate the central middle mountains due to an extended summer monsoon and greater groundwater contributions intermediate high magnitude regimes occur along the middle mountains high mountains boundary with july august peaks in western central areas and marked august peaks at higher elevations in eastern central and eastern nepal reflecting differences in summer monsoon penetration the practical implications of these results for assessment of water resources and prediction of runoff from ungauged basins are highlighted

the formation of supraglacial debris covers by primary dispersal from transverse englacial debris bands glaciological controls on debris cover formation are investigated from the perspective of primary dispersal of supraglacial debris across a melting ice surface this involves the migration of angled debris septa outcrops across a melting thinning glacier ablation zone three measures of a glacier s ability to evacuate supraglacial debris are outlined 1 a concentration factor describing the focusing of englacial debris into specific supraglacial mass loads 2 the rate of migration of a septum outcrop relative to the local ice surface and 3 a downstream velocity differential between a slower septum outcrop and the faster ice surface velocity measures 1 and 2 are inversely related while measure 3 increases down glacier to explain why slow moving thinning ice rapidly becomes debris covered data from glacier d estelette italian alps are used to illustrate these processes and to explore the potential for debris cover formation and growth in different glaciological environments the transition from a clean transport dominated to a debris covered ablation dominated glacier is explained by the melting out of more closely spaced debris septa in combination with the geometric nteractions of angled septa and ice surface in a field of reducing flow and increasing ablation the growth and shrinkage of debris covers are most sensitive to glaciological changes at glaciers with gently dipping debris bearing foliation but less sensitive at high compression glaciers whose termini are constrained by moraine dams and other forms of obstruc tion these findings show that a variety of debris covered glacier types will show a spectrum of response characteristics to negative mass balance copyright 2013 john wiley sons ltd

glacier meltwater and runoff modelling keqicar baqi glacier southwestern tien shan china meltwater and runoff from keqicar baqi glacier a large glacier in the southwestern tien shan northwestern china are simulated using a modified degree day model including potential clear sky direct solar radiation coupled with a linear reservoir model for the period 1 july to 12 september 2003 there is good agreement between modelled and measured meltwater at ablation stakes and between simulated and observed runoff at the glacier terminus a reconstruction of glacier meltwater and runoff from an assumed debris free surface during the study period shows that the effect of the debris layer on glacier meltwater generation crucially affects glacier runoff the model is also used to calculate glacier runoff given the climate scenario resulting from a doubling of co2 as projected by the recm2 regional climate model the projected changes in temperature and precipitation vary from 0 to 2 78c and from 0 to 25 respectively results indicate that glacier runoff increases linearly with temperature over these ranges whether or not the debris layer is taken into consideration the effect of change in temperature is much more noticeable than that for change in precipitation due to the debris layer predominantly covering and insulating the ablation area the response of glacier runoff is less sensitive to temperature increase with a debris covered surface than with a debris free surface glacier runoff is also markedly reduced when a reduced glacier area is prescribed in the 2 78c scenario

climatic effects and bedrock control on rapid fluctuations of chhota shigri glacier northwest himalaya india active tectonism in the himalaya and the long fault lineament controlling the east west river valleys play an important role in melt at the snouts of glaciers or their fluctuations during the year lower glacier limits are controlled by high winds from the indian plains flowing along the valleys fluctuations of the chhota shigri glacier depend on temperature variations at the junction with the chandra river valley and in the unconsolidated morainic debris below the glacier ice high flow rates in the ablation zone indicate that basal sliding is the main movement mechanism melt takes place mainly from advection and this process of melting during the summer season occurs both day and night

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

proglacial lakes character behaviour and geological importance proglacial lakes are ubiquitous within the quaternary record and can provide exceptional breadth and depth of palaeoenvironmental information present deglaciation is increasing the number and size of proglacial lakes around the world this study provides a synthesis of knowledge on proglacial lake character and behaviour and critically evaluates the importance of proglacial lakes from a geological perspective we show how ice marginal or ice contact lakes and other distal proglacial lakes can be distinguished from each other by geomorphological sedimentological chemical and biological characteristics the key controls on proglacial lake geomorphology and sedimentology are outlined and discussed proglacial lakes can exacerbate mountain glacier and ice sheet margin ablation via mechanical and thermal stresses but very large lakes can moderate summer air temperatures and relatively retard summer ice ablation proglacial lakes interrupt meltwater flux and are very efficient sediment traps hydrological routing and consequent geomorphological activity can be radically modified by sudden drainage of proglacial lakes and resultant glacial lake outburst floods exceptionally large proglacial lake drainages affected global ocean circulation and global climate during the quaternary overall analyses of proglacial lakes can provide a valuable insight into i patterns character and behaviour of mountain glaciers ice sheets and glaciations and ii the impacts of past present and future deglaciation

combination of srtm3 and repeat aster data for deriving alpine glacier flow velocities in the bhutan himalaya abstract the present study evaluates the fusion of dems from the advanced spaceborne thermal emission and reflection radiometer aster instrument and the shuttle radar topography mission srtm the study area consists of high elevation glaciers draining through the rough topography of the bhutan himalayas it turns out that the aster derived and srtm3 dems have similar accuracy over the study area but the srtm3 dem contains less gross errors however for rough topography large sections of the srtm3 dem contain no data we therefore compile a combined srtm3 aster dem from this final composite master dem we produce repeat aster orthoimages from which we evaluate the dem quality and derive glacier surface velocities through image matching the glacier tongues north of the himalayan main ridge which enter the tibet plateau show maximum surface velocities in the order of 100 200 m year 1 in contrast the ice within the glacier tongues south of the main ridge flows with a few tens of meters per year these findings have a number of implications among others for glacier dynamics glacier response to climate change glacier lake development or glacial erosion the study indicates that space based remote sensing can provide new insights into the magnitude of selected surface processes and feedback mechanisms that govern mountain geodynamics

aster measurement of supraglacial lakes in the mount everest region of the himalaya we demonstrate an application of advanced spaceborne thermal emission and reflection radiometer aster images to detect and monitor supraglacial lakes on glaciers in the mount everest region in tibet xizang and nepal aster offers powerful capabilities to monitor supraglacial lakes in terms of 1 surface area growth and disappearance spatial resolution 15m 2 turbidity 15m resolution and 3 temperature 90m resolution preliminary results show an overall similarity of supraglacial lakes on three glaciers lakes have widely varying turbidity as indicated by color in visible near infrared bands 1 3 the largest lakes being bright blue highly turbid cold near 0 c and hydraulically connected with other lakes and supraglacial streams while small lakes are mostly darkblue relatively clear water warmer 4 c and appear hydraulically isolated high levels of turbidity in supraglacial lakes indicate high rates of meltwater input from streams or erosion of ice cliffs and thus are an indirect measure relating to the activity and hydraulic integration of the lake with respect to other lakes and streams in the glacier

hydrology of debris covered glaciers in high mountain asia abstract the hydrological characteristics of debris covered glaciers are known to be fundamentally different from those of clean ice glaciers even within the same climatological geological and geomorphological setting understanding how these characteristics influence the timing and magnitude of meltwater discharge is particularly important for regions where downstream communities rely on this resource for sanitation irrigation and hydropower such as high mountain asia the hydrology of debris covered glaciers is complex rugged surface topographies typically route meltwater through compound supraglacial englacial systems involving both channels and ponds as well as pathways that remain unknown low gradient tongues that extend several kilometres retard water conveyance and promote englacial storage englacial conduits are frequently abandoned and reactivated as water supply changes new lines of permeability are exploited and drainage is captured due to high rates of surface and subsurface change seasonal influences such as the monsoon are superimposed on these distinctive characteristics reorganising surface and subsurface drainage rapidly from one season to the next recent advances in understanding have mostly come from studies aimed at quantifying and describing supraglacial processes little is known about the subsurface hydrology particularly the nature or even existence of subglacial drainage in this review we consider in turn the supraglacial englacial subglacial and proglacial hydrological domains of debris covered glaciers in high mountain asia we summarise different lines of evidence to establish the current state of knowledge and in doing so identify major knowledge gaps finally we use this information to suggest six themes for future hydrological research at high mountain asian debris covered glaciers in order to make timely long term predictions of changes in the water they supply

mechanisms of englacial conduit formation and their implications for subglacial recharge abstract ideas about the character and evolution of englacial drainage systems have been deeply influenced by the theoretical model developed by shreve 1972 movement of water in glaciers journal of glaciology 11 62 205 214 the shreve model is based on three main assumptions 1 englacial drainage is in steady state 2 englacial water will flow along the steepest hydraulic gradient within the glacier and 3 pressure head equals the pressure of the surrounding ice minus a small component due to melting of the walls the shreve model has been widely adopted as a fundamental component of englacial drainage theory there is no evidence however that the model provides a realistic picture of actual glacial drainage systems to evaluate shreve s theory we used speleological techniques to directly survey englacial conduits we mapped a total of 8 25 km of passage in 27 distinct englacial conduits in temperate polythermal cold based and debris covered glaciers between 2005 and 2008 new information reported here is supplemented by published data on 40 other englacial conduits located worldwide and surveyed to ice depths of 176 m using speleological techniques in all cases englacial drainage systems consisted of a single unbranching conduit englacial conduit morphologies were found to be intimately linked to the orientation of a glacier s principal stresses or the presence of pre existing lines of high hydraulic conductivity if a sufficient supply of water is available hydrofracturing forms vertical conduits in zones of longitudinal extension and subhorizontal conduits where longitudinal stresses are compressive on unfractured glacier surfaces relatively shallow subhorizontal conduits with migrating nickpoints form by cut and closure provided channel incision is significantly faster than surface lowering conduits can also form along permeable debris filled crevasse traces that connect supraglacial lake basins of different potential our results suggest that shreve type englacial drainage systems do not exist and implies that englacial conduits can only penetrate through thick ice to recharge the bed where supraglacial water bodies either intersect or are advected through zones of acceleration

connecting source and transport suspended sediments in the nepal himalayas understanding the dynamics of sediment fluxes is a key issue to constrain modern erosion rates in mountain belts and determine the still debated level of control exerted by precipitation topography and tectonics the well defined monsoon seasonality in the himalayas together with active tectonics and strong relief provide an ideal environment to assess these possible interactions for this purpose we present a new compilation of daily suspended sediment data for 12 stations of the major rivers of the nepal himalayas we analyze the relationships of sediment transport with daily river discharge and precipitation data as well as with morphometric parameters we show that suspended sediment concentrations vary systematically through the seasons and asynchronously to river discharge displaying a hysteresis effect this clockwise hysteresis effect disappears when suspended sediment fluxes are directly compared with direct storm discharge therefore we attribute the hysteresis effect to groundwater dilution rather than a sediment supply limitation we infer a rating model to calculate erosion rates directly from long river discharge chronicles we show that when normalized by drainage area and mean sediment flux all rivers exhibit the same trend this similarity implies that all river basins have the same erosion behavior independent of location size and catchment characteristics erosion rates calculated from suspended sediment fluxes range between 0 1 and 2 8 mm yr the erosion rates of the three main basins of nepal are in the range 0 9 1 5 mm yr erosion rates in the higher himalayas are relatively low 0 5 mm yr except for kali gandaki while in the lesser himalayas they range from 0 2 to 2 mm yr we propose that material transport in the rivers depends on hillslope sediment supply which is in turn controlled by those rainfalls producing direct runoff in other words the rivers in the nepal himalayas are supply limited and the hillsopes as a contributing source are transport limited we also show that erosion processes are not as much controlled by infrequently occurring extreme precipitation events than by moderate ones with a high recurrence interval

rescaled range analysis of paleoclimatic proxies two geophysical measurements have been widely used as paleoclimatic indicators oxygen isotope ratios from deep sea cores and magnetic susceptibility of loess sediments both types of record have been shown to possess climatic information as they share the same dominant frequencies of the earth s orbital movements which according to milankovitch s theory drive the climatic system but these two physical quantities may respond to climatic variations in different ways consequently they may possess different long term characteristics which can be detected by the technique of rescaled range r s analysis here we report results from four sets of data two oxygen isotope records and two loess susceptibility profiles analysis indicates that hurst exponents of about 0 8 are typical for deep sea oxygen data whereas values of about 0 9 characterize loess susceptibility sequences if mandelbrot s explanation is taken these distinct values imply that the loess data are more self correlated and possess str

backwasting rate on debris covered koxkar glacier tuomuer mountain china a physically based energy balance model with improved parameterization of solar radiation for a sloped ice surface has been developed to estimate the backwasting rate of an ice cliff in a debris covered area the model has been tested against observations between 5 august and 5 september 2008 on 38 ice cliffs in the debris covered area of koxkar glacier tuomuer mountain china we calculated that the energy balance model gave a good estimate of the backwasting rates with errors in the range 1 96 cm d 1 and root mean square errors of 0 99 cm d 1 errors arising from setting of surface albedo and turbulent flux parameterization were limited we found that shortwave radiation is the most important heat source for ice cliff ablation contributing about 76 of the total heat available for ice melt while the sensible heat flux provides nearly 24 of the total heat for ice cliff wastage the latent heat flux and net longwave radiation are comparatively small according to the model calculation the mean backwasting rate of ice cliffs in the debris covered area of koxkar glacier is estimated at 7 64 m a 1 when the winter ablation is neglected with this annual backwasting rate and given a mean slope angle of 46 48 the backwasting of ice cliffs produces about 1 60 10 6 m 3 of meltwater accounting for about 7 3 of the total melt runoff from the debris covered area

a model of ablation dominated medial moraines and the generation of debris mantled glacier snouts medial moraines form striking dark stripes that widen non linearly steepen laterally and increase in relief down glacier from the equilibrium line coalescence of these low ablation rate features can feed back strongly on the mass balance of a glacier snout ablation dominated medial moraines originate from debris delivered to glacier margins producing a debris rich septum between tributary streams of ice below their confluence emergence of this ice below the equilibrium line delivers debris to the glacier surface which then moves down local slopes of evolving morainal topography a quantitative description of moraine evolution requires specification of the debris concentration field within the glacier treatment of the melt rate dependence on debris thickness and characterization of processes that transport debris once it emerges onto the ice surface debris concentration at glacier tributary junctions scales with the erosion rates and the lengths of the tributary valley walls and inversely with the tributary ice speeds melt rate is damped exponentially by debris with a 10 cm decay scale debris flux across the glacier surface scales with the product of debris thickness and local slope analytical and numerical results show that medial moraines should develop cross glacier profiles with parabolic crests and linear slopes and should widen with age and hence distance down glacier debris should be both thin and uniform over the moraine observed faster than linear growth of moraine widths with distance reflects the increasing ablation rate down glacier increase in medial moraine cover reduces the local average ablation rate allowing the glacier to extend further down valley than meteorology alone would suggest this feedback is especially effective when moraines merge

englacial drainage systems formed by hydrologically driven crevasse propagation recent work has shown that surface to bed drainage systems re form annually on parts of the greenland ice sheet and some high arctic glaciers leading to speed up events soon after the onset of summer melt surface observations and geophysical data indicate that such systems form by hydrologically driven fracture propagation herein referred to as hydrofracturing although little is known about their characteristics using speleological techniques we have explored and surveyed englacial drainage systems formed by hydrofracturing in glaciers in svalbard nepal and alaska in hansbreen svalbard vertical shafts were followed through 60 m of cold ice and 10 m of temperate basal ice to a subglacial conduit deep hydrofracturing occurred at this site due to a combination of extensional ice flow and abundant surface meltwater at a glacier confluence the englacial drainage systems in khumbu glacier nepal and matanuska glacier alaska usa formed in areas of longitudinal compression and transverse extension and consist of vertical slots that plunge down glacier at angles of 558 or less the occurrence of englacial drainages initiated by hydrofracturing in diverse glaciological regimes suggests that it is a very widespread process and that surface to bed drainage can occur wherever high meltwater supply coincides with ice subjected to sufficiently large tensile stresses

thermo erosional notch development at fresh water calving tasman glacier new zealand controls on glacier calving rates are receiving increased scientific interest at fresh water calving glaciers limnological factors might be more important than glaciological ones measurements of thermo erosional notch development at the calving ice cliff of tasman glacier new zealand suggest that the calving rates at this glacier are directly controlled by the rate of thermal undercutting notch formation rates typically vary between 10 and 30 cm d 1 maximum rate 65 cm d 1 in summer corresponding to an average calving rate of 34 m a 1 notch formation is slower than waterline melt and is controlled by water temperatures and circulation cliff geometry debris supply and water level fluctuations the latter shift the position of undercutting resetting the level of the notch formation process and thereby slowing it the geometry of the notch and the debris supply determine the extent of influence of the lake on notch water temperatures and circulation hence water temperatures in the lake are not necessarily indicative of the rate of notch formation the prediction of rate of notch formation from far field variables is hampered by the complex interaction of the influencing factors the significance of thermal undercutting as a calving rate controlling process decreases with increasing ice velocities calving rates and surface gradients

growth and drainage of supraglacial lakes on debris mantled ngozumpa glacier khumbu himal nepal ablation of debris mantled glaciers in nepal has resulted in the formation of several potentially unstable moraine dammed lakes some of which constitute serious hazards ngozumpa glacier khumbu himal has undergone significant downwasting in recent decades and is believed to lie close to the threshold for moraine dammed lake formation the debris mantled ablation area of the glacier is studded with numerous supraglacial lakes the majority of which occupy closed basins with no perennial connections to the englacial drainage system perched lakes perched lakes can undergo rapid growth by subaerial and water line melting of exposed ice faces and calving subaerial and subaqueous melting beneath thick 1 m debris mantles is comparatively insignificant although lake expansion can contribute substantially to ablation of the glacier perched lakes cannot continue to grow indefinitely but are subject to rapid drainage once a connection is made to englacial conduits the level of one of the lakes on the ngozumpa however is controlled by the altitude of a spillway through the lateral moraine of the glacier this lake underwent only limited growth in the period 1998 2000 but is likely to experience monotonic growth if glacier mass balance continues to be negative

ice ablation and meteorological conditions on the debris covered area of baltoro glacier karakoram pakistan during the recent italian expedition k2 2004 50 years later june july 2004 on baltoro glacier karakoram pakistan glaciological field experiments were carried out on the debris covered area of this high elevation glacier the aim was to investigate the ice ablation and its relations with debris thermal properties and meteorological conditions ablation measurements along the glacier up to about 5000 m and within a dedicated test field were combined with meteorological data from two automatic weather stations located at urdukas 4022 m a s l and at k2 base camp 5033 m a s l in addition temperature measurements of the debris cover at different depth levels along the glacier allowed the calculation of debris surface temperature and of the debris thermal resistance r using the air temperature the local mean lapse rate 0 00758 cm 1 and the measured ablation the degree day factors k at different locations on the glacier were calculated the ice ablation rates were related to debris thickness and elevation they are typically on the order of 4 cm d 1 during the observation period however it was found that the surface topography slope aspect has an influence on the total ablation similar to that of the debris thickness thermal resistance of the debris cover and its distribution over the glacier were estimated finally a best guess estimate of the total meltwater production was calculated from available climate data

thermal regime of a supraglacial lake on the debris covered koxkar glacier southwest tianshan china a supraglacial lake was surveyed on the koxkar glacier in southwest tianshan from july to september 2007 and july to september 2008 and the temperature variation characteristics of the lake debris and debris free ice were analyzed at different depths to determine the thermal regimes in addition the discrepancies of temperature variation characteristics were investigated for different geomorphic units of the ablation zone of the koxkar glacier it was found that daily temperature variation curves for deep water are v shaped because meltwater from the glacier surface at temperatures of around 0 c feeds the lake and mixes with the relatively high temperature surface water during the day as the water temperature rises to approximately 4 c the mixed water sinks and forms a low temperature trough in the deep water of the lake in the middle of the day the vertical lapse rate of the lake water temperature against depth 0 33 c m has a magnitude lower than that of the debris 4 29 c m and that of the debris free ice 0 38 c m in the koxkar glacier s ablation zone the temperature curve for the surface water largely varied between the temperature curves for the debris at depths of 0 2 and 0 5 m the surface thermal condition of the ablation zone is significantly affected by the daily weather and there is a limited influence in debris at a depth of 1 m and in the lake at a depth of 5 m

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

a groundwater conceptual model and karst related carbon sink for a glacierized alpine karst aquifer southwestern china summary in the jade dragon snow mountain jdsm region yunnan province sw china an extensive hydrochemical and stable isotopic study of a glacierized alpine karst aquifer was conducted during the period 2011 2014 the objectives of the study were first to establish a conceptual hydrogeological model of the karst groundwater system second to estimate the proportion of extra glacier melt water infiltrating the karst aquifer that is being induced by the regional climate warming third to calculate the karst related flux of carbon into the karst aquifer knowledge of the local hydrogeological background from previous work was the starting point of the hydrochemical and stable isotopic study some representative spring waters and recharge waters i e glacier melt water and rainwater were investigated both spatially and temporally by hydrochemical and isotopic techniques including analysis of major and some minor ions and o and h stable isotopes a conceptual hydrogeological model of a fracture diffuse flow karst groundwater aquifer was proposed the proportion of glacier melt water infiltrating into the karst aquifer was estimated by using the karst spring as a natural pluviometer and with stable isotope analysis results show that 1 the jdsm karst aquifer is a diffuse flow system 2 it has a number of discharge areas and the jinsha river is the karst drainage base level 3 the proportion of the glacier melt water penetrating the karst aquifer is 29 and 4 the karst related carbon sink is 26 67 3 44 t km 2 a 1 as co 2 which is lower than that in non glacierized karst aquifers but over ten times larger than the carbon sink flux from silicate weathering in non karst areas showing the control of both climate and lithology on the rock weathering related carbon sink and the significance of carbonate weathering in the global carbon cycle

sedimentological geomorphological and dynamic context of debris mantled glaciers mount everest sagarmatha region nepal abstract this paper presents the sediment landform and dynamic context of four avalanche fed valley glaciers khumbu imja lhotse and chukhung in the mount everest sagarmatha region of nepal all four glaciers have a mantle of debris dominated by sandy boulder gravel that suppresses melting to an increasing degree towards the snout leading to a progressive reduction in the overall slope of their longitudinal profile prominent lateral terminal moraine complexes also comprising sandy bouldergravel enclose the glaciers these terminal moraines originally grew by accretion of multiple sedimentary facies of basal glacial and supraglacial origin probably by folding and thrusting when the glaciers were more dynamic during the little ice age the four glaciers are in various stages of recession and demonstrate a range of scenarios from down wasting of the glacier tongue through morainedammed lake development to post moraine dam breaching khumbu glacier is at the earliest stage of supraglacial pond formation and shows no sign yet of developing a major lake although one is likely to develop behind its 250 m high composite terminal moraine imja glacier terminates in a substantial body of water behind a partially ice cored moraine dam as determined from geophysical surveys but morphologically appears unlikely to be an immediate threat chukhung glacier already has a breached moraine and a connected debris fan and therefore no longer poses a threat lhotse glacier has an inclined free draining tongue that precludes hazardous lake development from the data assembled a conceptual model applicable to other himalayan glaciers is proposed to explain the development of large lateral terminal moraine complexes and associated potentially hazardous moraine dams 2008 elsevier ltd all rights reserved

mass loss on himalayan glacier endangers water resources 1 ice cores drilled from glaciers around the world generally contain horizons with elevated levels of beta radioactivity including 36 cl and 3 h associated with atmospheric thermonuclear bomb testing in the 1950s and 1960s ice cores collected in 2006 from naimona nyi glacier in the himalaya tibet lack these distinctive marker horizons suggesting no net accumulation of mass ice since at least 1950 naimona nyi is the highest glacier 6050 masl documented to be losing mass annually suggesting the possibility of similar mass loss on other high elevation glaciers in low and mid latitudes under a warmer earth scenario if climatic conditions dominating the mass balance of naimona nyi extend to other glaciers in the region the implications for water resources could be serious as these glaciers feed the headwaters of the indus ganges and brahmaputra rivers that sustain one of the world s most populous regions

glacier velocities across the central karakoram optical matching of aster advanced spaceborne thermal emission and reflection radiometer satellite image pairs is used to determine the surface velocities of major glaciers across the central karakoram the aster images were acquired in 2006 and 2007 and cover a 60 120 km region over baltoro glacier pakistan and areas to the north and west the surface velocities were compared with differential global position system gps data collected on baltoro glacier in summer 2005 the aster measurements reveal fine details about ice dynamics in this region for example glaciers are found to be active over their termini even where they are very heavily debris covered the characteristics of several surge type glaciers were measured with terminus advances of several hundred meters per year and the displacement of trunk glaciers as surge glaciers pushed into them this study is the first synthesis of glacier velocities across this region and provides a baseline against which both past and future changes can be compared

soil landscape relationships in the basalt dominated highlands of tigray ethiopia article i nfo though knowledge about the distribution and properties of soils is a key issue to support sustainable land management existing knowledge of the soils in tigray northern ethiopian highlands is limited to either maps with a small scale or with a small scope the goal of this study is to establish a model that explains the spatial soil variability found in the may leiba catchment and to open the scope for extrapolating this information to the surrounding basalt dominated uplands a semi detailed scale 1 40000 soil survey was conducted in the catchment profile pits were described and subjected to physico chemical analysis and augerings were conducted this information was combined with information from aerial photographs and geological and geomorphologic observations the main driving factors that define the variability in soil types found were 1 geology through soil parent material and the occurrence of harder layers often acting as aquitards or aquicludes 2 different types of mass movements that occupy large areas of the catchment and 3 severe human induced soil erosion and deposition these factors lead to red black skeletic cambisol pellic vertisol catenas on basalt and calcaric regosol colluvic calcaric cambisols calcaric vertisol catenas on limestone the driving factors can be derived from aerial photographs this creates the possibility to extrapolate information and predict the soil distribution in nearby regions with a comparable geology a model was elaborated which enables the user to predict soil types using topography geomorphology geology and soil colours all of which can be derived from aerial photographs this derived model was later applied to other catchments and validated in the field

modelling the feedbacks between mass balance ice flow and debris transport to predict the response to climate change of debris covered glaciers in the himalaya many himalayan glaciers are characterised in their lower reaches by a rock debris layer this debris insulates the glacier surface from atmospheric warming and complicates the response to climate change compared to glaciers with clean ice surfaces debris covered glaciers can persist well below the altitude that would be sustainable for clean ice glaciers resulting in much longer timescales of mass loss and meltwater production the properties and evolution of supraglacial debris present a considerable challenge to understanding future glacier change existing approaches to predicting variations in glacier volume and meltwater production rely on numerical models that represent the processes governing glaciers with clean ice surfaces and yield conflicting results we developed a numerical model that couples the flow of ice and debris and includes important feedbacks between debris accumulation and glacier mass balance to investigate the impact of debris transport on the response of a glacier to recent and future climate change we applied this model to a large debris covered himalayan glacier khumbu glacier in nepal our results demonstrate that supraglacial debris prolongs the response of the glacier to warming and causes lowering of the glacier surface in situ concealing the magnitude of mass loss when compared with estimates based on glacierised area since the little ice age khumbu glacier has lost 34 of its volume while its area has reduced by only 6 we predict a decrease in glacier volume of 8 10 by ad2100 accompanied by dynamic and physical detachment of the debris covered tongue from the active glacier within the next 150 yr this detachment will accelerate rates of glacier decay and similar changes are likely for other debris covered glaciers in the himalaya

refined energy balance modelling of a supraglacial pond langtang khola nepal supraglacial ponds on debris covered glaciers present a mechanism of atmosphere glacier energy transfer that is poorly studied and only conceptually included in mass balance studies of debris covered glaciers this research advances previous efforts to develop a model of mass and energy balance for supraglacial ponds by applying a free convection approach to account for energy exchanges at the subaqueous bare ice surfaces we develop the model using field data from a pond on lirung glacier nepal that was monitored during the 2013 and 2014 monsoon periods sensitivity testing is performed for several key parameters and alternative melt algorithms are compared with the model the pond acts as a significant recipient of energy for the glacier system and actively participates in the glacier s hydrologic system during the monsoon melt rates are 2 4 cm d 1 total of 98 5 m3 over the study period for bare ice in contact with the pond and 1 mm d 1 total of 10 6 m3 for the saturated debris zone the majority of absorbed atmospheric energy leaves the pond system through englacial conduits delivering sufficient energy to melt 2612m3 additional ice over the study period 38 4 m3 d 1 such melting might be expected to lead to subsidence of the glacier surface supraglacial ponds efficiently convey atmospheric energy to the glacier s interior and rapidly promote the downwasting process

glaciological characteristics of the ablation zone of baltoro glacier karakoram pakistan baltoro glacier in the karakoram pakistan is one of the world s largest valley glaciers it drains an area of about 1500 km 2 and is 60km long in 2004 an italian german expedition carried out a glaciological field program on the ablation zone of the glacier focusing on the ablation conditions and the dynamic state of the glacier as baltoro glacier is a debris covered glacier ice ablation also depends on the debris properties stake measurements of ice ablation and debris cover in combination with meteorological data from automatic weather stations close by have been used to determine the local melt conditions results from these calculations have been combined with an analysis of different classes of surface cover and information about precipitation using remote sensing techniques in order to calculate mass fluxes for the upper part of baltoro glacier the dynamic state of the glacier has been investigated by gps based surface velocity measurements along the stake network a comparison of these short term measurements during the melt season with surface velocities computed from feature tracking of satellite images shows a high seasonal variability of the ice motion we have shown that this variability is up to 100 of the annual mean velocity on the basis of these investigations the mass fluxes at the concordia cross section have been quantified this approach can now be used together with the ablation calculations to reconstruct the variability of glacier extent and volume in the past using available climate data from the central karakoram from the comparison of historical measurements and photographs it is shown that the snout of baltoro glacier is oscillating back and forth a couple of hundred metres otherwise it seems not to react with the same magnitude as other glaciers to the climatic change elevation changes at concordia are a few tens of metres at the most

a distributed energy balance melt model of an alpine debris covered glacier distributed energy balance melt models have rarely been applied to glaciers with extensive supraglacial debris cover this paper describes the development of a distributed melt model and its application to the debris covered miage glacier western italian alps over two summer seasons sub debris melt rates are calculated using an existing debris energy balance model deb model and melt rates for clean ice snow and partially debris covered ice are calculated using standard energy balance equations simulated sub debris melt rates compare well to ablation stake observations melt rates are highest and most sensitive to air temperature on areas of dirty crevassed ice on the middle glacier here melt rates are highly spatially variable because the debris thickness and surface type varies markedly melt rates are lowest and least sensitive to air temperature beneath the thickest debris on the lower glacier debris delays and attenuates the melt signal compared to clean ice with peak melt occurring later in the day with increasing debris thickness the continuously debris covered zone consistently provides 30 of total melt throughout the ablation season with the proportion increasing during cold weather sensitivity experiments show that an increase in debris thickness of 0 035 m would offset 1 c of atmospheric warming

calculating ice melt beneath a debris layer using meteorological data generalized numerical models of sub debris ice ablation are preferable to empirical approaches for predicting runoff and glacier response to climate change as empirical methods are site specific and strongly dependent upon the conditions prevailing during the measurement period we present a modified surface energy balance model to calculate melt beneath a surface debris layer from daily mean meteorological variables despite numerous simplifications the model performs well and modelled melt rates give a good match to observed melt rates suggesting that this model can produce reliable estimates of ablation rate beneath debris layers several decimetres thick this is a useful improvement on previous models which are inappropriate for thick debris cover

calving processes at a grounded ice cliff repeat photographs and field survey reveal the mechanism of short term ice cliff evolution at maud glacier a temperate lake calving glacier in new zea land calving is cyclic each cycle involving four stages 1 waterline melting and collapse of the roof of a sub horizontal notch at the cliff foot 2 calving of ice flakes from the cliff face leading to a growing overhang from the waterline upwards and crack propagation from the glacier surface 3 large but infrequent calving of slabs in response to the devel oping overhang returning the cliff to an initial vertical profile 4 rare subaqueous cal ving of a submerged ice foot results indicate that the rate controlling process is the speed of waterline melting and that calving rate is independent of water depth at least at time scales of weeks to months slowly calving lake terminating glaciers have mass balances more negative than land terminating glaciers but nevertheless advance and retreat in response to mass balance driven changes in ice velocity