topographic controls on the surface energy balance of a high arctic valley glacier 1 this paper presents the results of a distributed two dimensional surface energy balance model used to investigate the spatial and temporal variations in the surface energy balance of midre lovenbreen a small valley glacier in northwest spitsbergen svalbard over the summer of 2000 we utilize high resolution airborne lidar data to derive a digital elevation model of the glacier and surrounding topography on which a surface energy balance is computed driven by meteorological data obtained from a meteorological station located on the glacier and a synoptic station maintained at the nearby ny alesund research base given the high resolution topographic data we focus particularly on whether the long duration of sunshine at high latitudes compensates for the higher solar zenith angles on the season long energy balance and whether shading by the surrounding topography plus glacier surface slope and aspect play an increased role in the patterns of solar radiation receipt and hence melt over the glacier surface the model results are validated using a combination of mass balance data from the glacier measured surface lowering at the glacier meteorological station and by comparing a derived energy balance component from the model with a measured energy flux overall the model performance is very good glacier topography is found to play a fundamental role in determining the surface energy balance topographic shading slope and aspect and correction of the surface albedo for high solar zenith angles are found to play a crucial role in determining spatial patterns of surface energy balance and therefore melt

long runout rockslide on glacier at tsar mountain canadian rocky mountains potential triggers seismic and glaciological implications a rhomboidal shaped rockslide with a length of 2 2 km and an area of 1 35 km2 covers 30 of a small clemenceau icefield group cirque glacier by means of remote sensing airborne photography climate and seismic data analysis the extent timing possible trigger mechanisms and rockslide effects on the glacier are discussed an ml 2 0 seismic event on 14 september 2000 represents the rockslide and has a spindle shaped waveform and high energy in the low frequencies based on a strong signal duration of 56 108 seconds the rockslide had an average runout velocity of 22 45 m s 1 stress fatigue and a combination of rain and snow followed by rapid melt and night time freezing could have co triggered the slide additional seismic events with epicentres 40 km from the cirque were recorded 26 times since 1985 and range between ml 0 9 3 3 but none were caused by or triggered large mass movement with a rock source volume of 1 6 106 m3 and a deposited volume of 2 4 106 m3 the sum of bulking and entrainment is between 25 and 150 five melt seasons post event levees 20 30 m wide tower 30 m over the surrounding glacier rockslide characteristics and its fahrboschung of 15 height length h l 0 28 indicate that this rockslide is quite typical for long runout rockslides on glaciers however the basal friction coefficient was higher than found on other glaciers and could relate to the presence of medial moraines transverse to the flowline and to pre slide debris cover the difference between the coefficient of friction in the main flowline 0 11 0 14 and that in a lobe confined between two medial moraines 0 065 suggests that confinement increases mobility by 70 115 apart from reduced ablation under the rock debris effects of the rockslide on the glacier were minimal copyright 2010 john wiley sons ltd

a unique glimpse into asteroidal melting processes in the early solar system from the graves nunatak 06128 06129 achondrites the recently recovered antarctic achondrites graves nunatak 06128 and 06129 are unique meteorites that represent high temperature asteroidal processes in the early solar system never before identified in any other meteorite they represent products of early planetesimal melting 4564 25 0 21 ma and subsequent metamorphism of an unsampled geochemical reservoir from an asteroid that has characteristics similar to the brachinite parent body this melting event is unlike those predicted by previous experimental or geochemical studies and indicates either disequilibrium melting of chondritic material or melting of chondritic material under volatile rich conditions

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

karakoram geodetic glacier mass balances between 2008 and 2016 persistence of the anomaly and influence of a large rock avalanche on siachen glacier karakoram glaciers experienced balanced or slightly positive mass budgets since at least the 1970s here we provide an update on the state of balance of central and eastern karakoram glaciers 12 000 km2 between 2008 and 2016 by differencing dems derived from satellite optical images the mass budget of central karakoram glaciers was slightly positive 0 12 0 14 m w e a 1 while eastern karakoram glaciers lost mass 0 24 0 12 m w e a 1 the glacier wide mass balances of surge type and nonsurge type glaciers were not statistically different our elevation change data also depict the effect of a 100 mm3 rock avalanche on siachen glacier ablation area in september 2010 it covered a 4 km2 area with a thick debris layer that unexpectedly led to locally enhanced glacier mass loss during the following years enhanced melt opened a 100 m deep 2 km2 depression and contributed to 6 of the mass loss of siachen glacier from 2010 to 2016 0 39 m w e a 1 we hypothesize that sub or englacial melt may be responsible for this intriguing behaviour this study contributes to a better knowledge of the regional pattern of the karakoram anomaly and of the influence of rock avalanches on glacier mass changes

an assessment of landform composition and functioning with the first proglacial systems dataset of the central european alps abstract proglacial systems are enlarging as glacier masses decline they are in a transitory state from glacier dominated to hillslope and fluvially dominated geomorphological processes they are a very important meltwater sediment and solute source this study makes the first quantitative systematic and regional assessment of landform composition and functioning within proglacial systems that have developed in the short term since the little ice age lia proglacial system extent was thus defined as the area between the lia moraine ridges and the contemporary glacier we achieved this assessment via a series of topographic analyses of 10 m resolution digital elevation models dems covering the central european alps specifically of austria and switzerland across the 2812 proglacial systems that have a combined area of 933 km2 the mean proportional area of each proglacial system that is directly affected by glacial meltwater is 37 however there are examples where there is no glacial meltwater influence whatsoever due to complete disappearance of glaciers since the lia and there are examples where 90 of the proglacial area is probably affected by glacial meltwater in all of the major drainage basins the inn drava venetian coast po rhine rhone and danube the proportions of the combined land area belonging to each landform class is remarkably similar with 10 fluvial 35 alluvial and debris fans 50 moraine ridges and talus scree and 10 bedrock which will be very helpful for considering estimates of regional sediment yield and denudation rates we find groupings of the relationship between proglacial system hypsometric index and lithology and of a slope threshold discriminating between hillslope and fluvial dominated terrain both of which we interpret to be due to grain size we estimate of contemporary total volume loss from all of these proglacial systems of 44 m m3a 1 which equates to a mean of 0 3 mm a 1 contemporary surface lowering overall these first quantifications of proglacial landform and landscape evolution will be an important basis for inter and intra catchment considerations of climate change effects on proglacial systems such as land stability and changing water sediment and solute source fluxes our datasets are made freely available

source regions and formation of the loess sediments on the high mountain regions of northwestern china loess on the high mountains of northwestern china is largely controlled by the topographic features distributed mainly on the northern slopes of the tianshan and kunlun mountains as well as in the ili valley between the northern and central tianshan ranges loess distributed in different regions has different ages with the oldest early pleistocene loess occurring in the ili valley geochemical mineralogical and granulometric analyses demonstrate that the loess in the three different regions has different provenance the loess on the northern tianshan and kunlun mountains is mainly derived from the junggar and taklimakan deserts respectively whereas the loess in the ili valley is derived mainly from the sary ishikotrau desert located in the republic of kazakhstan however these deserts serve mostly as holding areas for the silts rather than original source regions the production of the silt sized particles is mainly associated with glacial abrasion and tectonic induced rock denudation thus the loess in the studied regions can be described as mountainous loess rather than simply glacial loess or desert loess it is unlikely that the mechanisms of loess formation are the same in different regions given their dependence on specific geomorphological conditions and associated processes

atmospheric circulation during holocene lake stands in the mojave desert evidence of regional climate change it is commonly thought that the climate conditions that supported lakes over a period of years in the mojave desert in southern california only existed before 8 000 yr bp and that the environment has been arid since1 2 here we look at a drill core in the silver lake playa at the terminus of the mojave river and find holocene lake deposits which indicate that shallow lakes existed for at least a few decades these deposits were radiocarbon dated at 3620 70 and 390 90 yr bp corresponding to the early neo glacial and the little ice age respectively3 to identify the conditions necessary to produce these holocene lake events we have examined the modern climate and hydrological patterns that produce ephemeral lakes in this usually arid watershed available data indicate that there is a link between anomalous winter atmospheric conditions over the north pacific and mojave river floods that produced ephemeral lakes in the silver lake playa and that the mojave river filters out small to medium floods and allows only the extreme floods to reach the terminal playa and leave a record of the anomalous conditions we suggest that the late holocene lakes may have resulted from persistent similar atmospheric circulation patterns and winter floods

soil geomorphic significance of land surface characteristics in an arid mountain range mojave desert usa abstract mountains comprise an extensive and visually prominent portion of the landscape in the mojave desert california landform surface properties influence the role these mountains have in geomorphic processes such as dust flux and surface hydrology across the region the primary goal of this study was to describe and quantify land surface properties of arid mountain landforms as a step toward unraveling the role these properties have in soil geomorphic processes as part of a larger soil geomorphic study four major landform types were identified within the southern fry mountains in the southwestern mojave desert on the basis of topography and landscape position mountaintop mountainflank mountainflat intra range low relief surface and mountainbase a suite of rock vegetation and morphometric land surface characteristic variables was measured at each of 65 locations across the study area which included an associated piedmont and playa our findings show that despite the variation within types landforms have distinct land surface properties that likely control soil geomorphic processes we hypothesize that surface expression influences a feedback process at this site where water transports sediment to low lying areas on the landscape and wind carries dust and soluble salts to the mountains where they are washed between rocks incorporated into the soil and retained as relatively long term storage recent land based video and satellite photographs of the dust cloud emanating from the sierra cucapa mountains in response to the 7 2 magnitude earthquake near mexicali mexico support the hypothesis that these landforms are massive repositories of dust

map based methods for estimating glacier equilibrium line altitudes we examine the validity of two methods for estimating glacier equilib rium line altitudes elas from topographic maps the ela determined by contour inflection the kinematic ela andthe mean elevation of the glacier correlate extremely well with the ela determined from mass balance data observed ela however the range inglacierelevations above sea level is much larger thanthe variation in ela mak ing this correlation unhelpful the data were normalized and a reasonable correlation r 2 0 59 was found between observed and kinematic ela the average of the normal ized kinematic elas was consistently located down glacier fromthe observed ela con sistent withtheory thenormalized mean elevationoftheglacierexhibitedno correlation and suggests that the toe headwall altitude ratio is not a good approximation for the ela kinematic waves had no effect on the position of the kinematic ela therefore topographic maps of glacier surfaces can be used to infer the position of the ela and provide a method for estimating past elas from historic topographic maps

topographic controls on plateau icefield recession insights from the younger dryas monadhliath icefield scotland plateau icefields are a common form of mountain ice mass frequently found in mid latitude to high arctic regions and increasingly recognized in the quaternary record their top heavy hypsometry makes them highly sensitive to changes in climate when the equilibriaum line altitude ela lies above the plateau edge allowing ice to expand significantly as regional elas decrease and causing rapid recession as climate warms with respect to future climate warming it is important to understand the controls on plateau icefield response to climate change in order to better predict recession rates with implications for water resources and sea level rise improving knowledge of the controls on glacier recession may also enable further palaeoclimatic information to be extracted from the quaternary glacial record we use the distribution of moraines to examine topographic controls on younger dryas icefield recession in scotland we find that overall valley morphology influences the style of recession through microclimatic and geometric controls with bed gradient affecting moraine spacing ice mass reconfiguration may occur as recession progresses because ice divide migration could alter the expected response based on hypsometric distribution these results add to a growing body of research examining controls on glacier recession and offer a step towards unravelling non linear ice mass behaviour less

estimating the longevity of glaciers in the xinjiang region of the tian shan through observations of glacier area change since the little ice age using high resolution imagery

holocene and latest pleistocene fluctuations of stutfield glacier canadian rockies the holocene and late glacial history of fluctuations of stutfield glacier are reconstructed using moraine stratigraphy tephrochronology and dendroglaciology stratigraphic sections in the lateral moraines contain tills from at least three glacier advances separated by volcanic tephras and paleosols the oldest pre mazama till is correlated with the crowfoot advance dated elsewhere to be younger dryas equivalent a neoglacial till is found between the mazama tephra and a paleosol developed on the bridge river tephra a log dating 2400 bp from the upper part of this till indicates that this glacier advance correlated with the peyto advance culminated shortly before deposition of the bridge river tephra radiocarbon and tree ring dates from overridden trees exposed in moraine sections indicate that the initial cavell little ice age lia advance overrode this paleosol and trees after a d 1271 three subsequent phases of the cavell advance were dated by dendrochronology the maximum glacier extent occurred in the mid 18th century predating 1743 on the southern lateral although ice still occupied and tilted a tree on the north lateral in 1758 subsequent glacier advances occurred ca 1800 1816 and in the late 19th century the relative extent of the lia advances at stutfield differs from that of other major eastward flowing outlets of the columbia icefield which have maxima in the mid late 19th century this is the first study from the canadian rockies to demonstrate that the large morphologically simple lateral moraines defining the lia glacier limits are actually composite features built up pro gressively but discontinuously over the holocene and contain evidence of multiple holocene and crowfoot age gla cier advances resume la stratigraphie des moraines la tephrochronologie et la dendroglaciologie des moraines ont servi a recons truire les fluctuations a l holocene et au cours de l histoire glaciaire tardive du glacier stutfield les sections stratigra phiques dans les moraines laterales contiennent des tills d au moins trois avancees glaciaires separees par des tephras volcaniques et des paleosols le plus ancien le till pre mazama est correle a l avancee crowfoot dont on a determine l ge ailleurs comme etant un equivalent du dryas recent un till de l epoque neo glaciaire se retrouve entre le tephra mazama et un paleosol developpe sur le tephra de bridge river un billot date 2400 bp provenant de la partie supe rieure de ce till indique que cette avancee glaciaire correlee a l avancee de peyto a culmine peu de temps avant la deposition du tephra de bridge river des datations au 14 c et des series chronlogiques provenant d arbres recouverts puis exposes dans des sections de moraine indiquent que l avancee cavell initiale petit ge glaciaire a chevauche ce paleosol et les arbres apres l an 1271 la dendrochronologie a permis la datation de trois phases subsequentes de l avancee cavell l etendue glaciaire maximale eut lieu au milieu du 18e siecle avant 1743 sur le cote sud bien que la glace fut encore presente sur le cote nord et y ait bascule un arbre en 1758 des avancees glaciaires subsequentes ont eu lieu vers 1800 1816 et vers la fin du 19e siecle l etendue relative des avancees du petit ge glaciaire a stutfield differe de celles d autres glaciers majeurs du champ de glace columbia s ecoulant vers l est et qui ont eu leur maxi mum dans la deuxieme moitie du 19e siecle cette etude est la premiere provenant des rocheuses canadiennes a de monter que les grandes moraines laterales morphologiquement simples definissant les limites du glacier au petit ge glaciaire sont en fait des elements composites developpes progressivement mais de facon discontinue tout au cours de l holocene et qu elles contiennent des evidences d avancees glaciaires multiples d ge holocene et crowfoot

evolution of the norwegian plateau icefield hardangerjokulen since the little ice age the maximum little ice age lia glacier extent provides a significant baseline to assess long term glacier change and to place currently observed rates of glacier recession in a broader temporal

flow and structure in a dendritic glacier with bedrock steps sherpa romeo green journal open access article creative commons attribution 4 0 international cc by 4 0 applies

a distributed surface energy balance model for a small valley glacier i development and testing for haut glacier d arolla valais switzerland this paper describes the development and testing of a distributed surface energy balance model used to calculate rates of surface melting at haut glacier d arolla valais switzerland the model uses a digital elevation model dem of the glacier surface and surrounding topography together with meteorological data collected at a site in front of the glacier to determine hourly or daily totals of the energy balance components and hence of melting over the entire surface of the glacier with a spatial resolutio of 20 m the model can also be used to determine temporal and spatial variations in snow depth snow line position and glacier surface albedo calculations from the model are compared with observations made along the glacier centre line in 1990 and in general the model performs very well the correlation coefficients between calculated and measured snow line elevation albedo and ablation are 0 99 0 85 and 0 81 respectively the main source of error between modelled and measured values of these variables is probably inadequacies in the parameterization of albedo used in the model

controls on the distribution of surge type glaciers in svalbard we analyzed the possible controls on the distribution of surge type glaciers in svalbard using multivariate logit models including 504 glaciers and a large number of glacial and geological attributes specifically we examined the potential effect of geological boundaries mass balance conditions and thermal regime on surging it was found that long glaciers with relatively steep slopes overlying young fine grained sedimentary lithologies with orientations in a broad arc clockwise from northwest to southeast are most likely to be of surge type no relation between lithological boundaries and surge potential could be established possible explanations for length being conducive to surging are transport distance related substrate properties distance related attenuation of longitudinal stresses and the possible relation between thermal regime and glacier size analysis of glaciers with recorded radioecho sounding reveals that a polythermal regime accumulation area ratios close to balance and a large elevation span increase the surge potential the logit models also enabled us to detect 19 new surge type glaciers to reclassify six glaciers as normal and to identify unusual surge type glaciers our model results suggest that a polythermal regime and fine grained potentially deformable beds are conducive to the surge potential of svalbard glaciers

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

large near surface nitrate pools in soils capped by desert pavement in the mojave desert california we found exceptionally high nitrate levels up to 12 750 kg ha 1 at shallow depths 1 m in soils mantled by desert pavement a common land surface feature in arid regions nearby soils without desert pavement had nitrate contents that were one to two orders of magnitude lower the soil conditions coincident with desert pavement i e stability antiquity and virtually no leaching favor the retention and accumulation of nitrate delivered by atmospheric deposition or in situ fixation the nitrate stored in soils under desert pavement is a previously unrecognized pool of nitrogen that has the potential to increase the global nitrogen inventory for near surface desert soils to five times previous estimates its near surface occurrence makes this labile nitrogen pool particularly susceptible to mobilization by climate change or human disturbance risking contamination of surface and groundwaters

recent changes in glacier area and volume within the southern canadian cordillera net changes in glacier area in the region 50 518 n 116 1258 w which includes the columbia and rocky mountains 1951 52 2001 and the coast mountains 1964 65 2002 were determined through a comparison of historic aerial photography and contemporary landsat 7 etm imagery the volumes of individual glaciers were estimated using an empirical volume area scaling relationship the area of glaciers in the coast mountains decreased by 120 10 km 2 or 5 of the initial ice covered area here the areas of glaciers in the columbia and rocky mountains decreased by 20 and 6k m 2 respectively corresponding to relative changes in total area of 5 and 15 the estimated total ice volume loss from the whole region was 13 3k m 3 in all parts of the study area the relative changes in area of individual glaciers showed considerable variability while the smallest glaciers remained essentially unchanged this suggests that local factors unique to individual glaciers largely determine their sensitivity to climatic change and that the very small glaciers are collectively less sensitive to such change

influences of eolian and pedogenic processes on the origin and evolution of desert pavements well developed desert pavements are present above eolian deposits that mantle flows of the cima volcanic field located in the mojave desert california soil stratigraphic data and geochemical data demonstrate that eolian and pedogenic processes play major roles in the evolution of these pavements eolian dust 1 accelerates mechanical fragmentation of flow rock providing the source material for pavements and 2 accumulates slowly below basaltic colluvium in flow depressions eventually promoting development of cumulate soils below the evolving stone pavement an increase in dust flux during the holocene has raised ancient pleistocene pavements as much as 20 cm above the former land surface the results of our studies demonstrate for the first time that most desert pavements do not form by deflation by overland flow or by upward migration of stones through a slowly formed clayey argillic horizon desert pavements are born and maintained at the surface

changes in clemenceau icefield and chaba group glaciers canada related to hypsometry tributary detachment length slope and area aspect relations we compiled a detailed glacier inventory of 176 glaciers in the clemenceau icefield group cig and adjacent chaba group ch canada based on 2001 landsat 7 and 2000 03 aster satellite imagery and natural resources canada digital elevation models we used this inventory to measure length and mass balance changes and their possible controls a classification of glacier hypsometry in the form of a hypsometric index was used to assess the sensitivity of different glacier systems to a unit rise in snowline the altitude and aar of possible steady state elas was derived using several methods and was compared to late summer snowlines of 2001 we further compared planar glacier area to slope corrected area and compared the effects on the shape of the hypsometric curves on the total glacier area and on the aspect area distribution in 2001 cig had a glaciated area of 271 km 2 and had lost 42 km 2 since the mid 1980s ch had a total area of 69 km 2 and had lost 28 km 2 average retreat rates are 14 m a 1 for the period 1850 2001 n 39 and 21 m a 1 for 1986 87 2001 n 23 indicating accelerated retreat larger glaciers and those that experience tributary detachment tend to retreat faster the difference between planar and slope corrected glacier areas ranges from 5 to 20 with a 6 increase for the entire cig ch region the area increase does not change the shape of the hypsometric curves

reconstruction of glacier variability from lake sediments reveals dynamic holocene climate in svalbard abstract the arctic is warming faster than anywhere else on earth holocene proxy time series are increasingly used to put this amplified response in perspective by understanding arctic climate processes beyond the instrumental period however available datasets are scarce unevenly distributed and often of coarse resolution glaciers are sensitive recorders of climate shifts and variations in rock flour production transfer this signal to the lacustrine sediment archives of downstream lakes here we present the first full holocene record of continuous glacier variability on svalbard from glacier fed lake hajeren this reconstruction is based on an undisturbed lake sediment core that covers the entire holocene and resolves variability on centennial scales owing to 26 dating points a toolbox of physical geochemical xrf and magnetic proxies in combination with multivariate statistics has allowed us to fingerprint glacier activity in addition to other processes affecting the sediment record evidence from variations in sediment density validated by changes in ti concentrations reveal glaciers remained present in the catchment following deglaciation prior to 11 300 cal bp culminating in a holocene maximum between 9 6 and 9 5 ka cal bp correspondence with freshwater pulses from hudson strait suggests that early holocene glacier advances were driven by the melting laurentide ice sheet lis we find that glaciers disappeared from the catchment between 7 4 and 6 7 ka cal bp following a late hypsithermal glacier reformation around 4250 cal bp marks the onset of the neoglacial supporting previous findings between 3380 and 3230 cal bp we find evidence for a previously unreported centennial scale glacier advance both events are concurrent with well documented episodes of north atlantic cooling we argue that this brief forcing created suitable conditions for glaciers to reform in the catchment against a background of gradual orbital cooling these findings highlight the climate sensitivity of the small glaciers studied which rapidly responded to climate shifts the start of prolonged neoglacial glacier activity commenced during the little ice age lia around 700 cal bp in agreement with reported advances from other glaciers on svalbard in conclusion this study proposes a three stage holocene climate history of svalbard successively driven by lis meltwater pulses episodic atlantic cooling and declining summer insolation

pedogenesis on talus slopes the buckskin range nevada usa abstract soil development on steep mountainous topography generally leads to thin and undifferentiated pedons on talus slopes of the buckskin mountains a fault blocked range of west central nevada usa thick differentiated pedons occur talus occurs on the western front where block rotation has formed very steep slopes and consists of angular dacite cobbles and boulders the study area is arid averaging less than 20 cm of precipitation per year typical pedons consist of surface talus filled with vesicular non structured sandy loam to loam material this material overlies clay textured prismatic and blocky structured horizons mostly rock free that in places are over 1 m thick pedons are classified as fine mixed mesic xeralfic paleargids soil macro and micromorphological features soil mineralogy and soil chemical and physical attributes suggest the following developmental sequence which began sometime before the middle pleistocene the talus serves as a baffle to collect eolian dust once eolian dust accumulates to a threshold thickness primary minerals are transformed in situ mostly to a smectitic clay as clay content increases a second threshold level is reached at which time the horizon of clay enrichment has sufficient strength and shrink swell potential to support and raft the talus upward the exposed talus can then continue to trap eolian dust the soil profile thickens and the pedon is protected from erosion a variation of this soil cumulation process may be partially responsible for textural b horizon formation in avid and semiarid climates

canada and the world glacier inventory this paper reviews the origins of the world glacier inventory program and canada s participation it tracks the program of the canadian federal government from its initiation to its demise today progress is geared towards the international glims and globglacier programs to which scientists from several canadian universities are making contributions achievements during the past decade towards providing data on canada s glacierized areas in the arctic and in western canada are documented

hypsometry and sensitivity of the mass balance to changes in equilibrium line altitude the case of the southern patagonia icefield we study the relation between glacier hypsometry and sensitivity of mass balance rate to changes in equilibrium line altitude ela our aim is to assess whether hypsometry can be reliably used as an estimator of the sensitivity of unmeasured glaciers to changes in ela we express the sensitivity of mass balance rate to ela d dot b dela as a function of accumulation area ratio aar its derivative against altitude daar dela and mass balance functions of ela we then apply the concept to 139 glaciers in the southern patagonia icefield for which we derive hypsometry and aar and analyze the influence of hypsometry on their mass balance rate sensitivity we confirm that glaciers where the bulk of area is located above the ela are the least sensitive whereas those where the bulk of area is located below the ela are the most sensitive glaciers with unimodal hypsometric curves where the peak of area fraction is around the present ela and glaciers with bi or multimodal area distributions with the ela located approximately between the bulges have intermediate sensitivities we conclude that hypsometry can be used as a first order estimator of the mass balance rate sensitivity to ela change

distributed glacier mass balance modelling as an important component of modern multi level glacier monitoring modern concepts of worldwide glacier monitoring include numerical models for 1 interconnecting the different levels of observations local mass balance representative length change glacier inventories for global coverage and 2 extrapolations in space coupling with climate models and time backward and forward in this context one important new tool is distributed mass balance modelling in complex mountain topography this approach builds on simplified energy balance models and can be applied for investigating the spatio temporal representativity of the few mass balance measurements for estimating balance values at the tongue of unmeasured glaciers in order to derive long term average balance values from a great number of glaciers with known length change and for assessing special effects such as the influence of sahara dust falls on the albedo and mass balance or autocorrelation effects due to surface darkening of glaciers with strongly negative balances experience from first model runs in the swiss alps and from applications to the extreme conditions in summer 2003 provides evidence about the usefulness of this approach for glacier monitoring and analysis of glacier changes in high mountain regions the main difficulties concern the spatial variability of the input parameters e g precipitation snow cover and surface albedo and the uncertainties in the parameterizations of the components of the energy balance field measurements remain essential to tie the models to real ground conditions

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

an estimate of glacier mass balance for the chandra basin western himalaya for the period 1984 2012 an improved understanding of fresh water stored in the himalaya is crucial for water resource management in south asia and can be inferred from glacier mass balance estimates however field investigations in the rugged himalaya are limited to a few individual glaciers and short duration therefore we have recently developed an approach that combines satellite derived snowlines a temperature index melt model and the accumulation area ratio method to estimate annual mass balance of glaciers at basin scale and for a long period in this investigation the mass balance of 146 glaciers in the chandra basin western himalaya is estimated from 1984 to 2012 we estimate the trend in equilibrium line altitude of the basin as 113 m decade 1 and the mean mass balance as 0 61 0 46 m w e a 1 our basin wide mass balance estimates are in agreement with the geodetic method during 1999 2012 sensitivity analysis suggests that a 20 increase in precipitation can offset changes in mass balance for a 1 degrees c temperature rise a water loss of 18 of the total basin volume is estimated and 67 for small and low altitude glaciers during 1984 2012 indicating a looming water scarcity crisis for villages in this valley

the little ice age in the canadian rockies abstract this paper reviews the evidence and history of glacier fluctuations during the little ice age lia in the canadian rockies episodes of synchronous glacier advance occurred in the 12th 13th early 18th and throughout the 19th centuries regional ice cover was probably greatest in the mid 19th century although in places the early 18th century advance was more extensive glaciers have lost over 25 of their area in the 20th century selective preservation of the glacier record furnishes an incomplete chronology of events through the 14th 17th centuries in contrast varve sequences provide continuous annually resolved records of sediments for at least the last millennium in some highly glacierized catchments such records have been used to infer glacier fluctuations evaluation of recent proxy climate reconstructions derived from tree rings provides independent evidence of climate fluctuations over the last millennium most regional glacier advances follow periods of reduced summer temperatures reconstructed from tree rings particularly ca 1190 1250 1280 1340 1690s and the 1800s reconstructed periods of higher precipitation at banff alberta since 1500 are 1515 1550 1585 1610 1660 1680 and the 1880s glacier advances in the early 1700s the late 1800s and in places the 1950 1970s reflect both increased precipitation and reduced summer temperatures negative glacier mass balances from 1976 to 1995 were caused by decreased winter balances the glacier fluctuation record does not contain a simple climate signal it is a complex response to several interacting factors that operate at different timescales evaluation of climate proxies over the last millennium indicates continuous variability at several superimposed timescales dominated by decade century patterns only the 19th century shows a long interval of sustained cold summers this suggests that simplistic concepts of climate over this period should be abandoned and replaced with more realistic records based on continuous proxy data series the use of the term lia should be restricted to describing a period of extended glacier cover rather than being used to define a period with specific climate conditions

an inventory and morphometric analysis of british columbia glaciers canada we describe an automated method to generate an inventory of glaciers and glacier morphometry from a digital topographic database containing glacier boundaries and a digital elevation model for british columbia canada the inventory contains over 12 000 glaciers with a total cumulative area that exceeds 25 000 km 2 based on mapping from aerial photographs circa the mid 1980s we use the inventory to examine dimensional characteristics among glaciers namely the scaling relations between glacier length width and area glacier length is a good predictor of glacier area and its predictive ability improves when glaciers are stratified by the number of up valley accumulation basins the spatial pattern of glacier mid range altitude parallels glaciation limits previously mapped for british columbia and similarly reflects large scale controls of orographic precipitation and continentality the inventory is also used to refine models that relate glacier mid range and terminus altitudes to regional position aspect and in the case of terminus altitudes an index of glacier shape relations between glacier altitude limits and controlling spatial and topographic factors are used to make further climatic and mass balance inferences from the glacier inventory