after six decades of monitoring glacier mass balance we still need data but it should be richer data this paper reviews data on glacier mass balance together with extra metadata on topography and climate to put the data into context the 2007 intergovernmental panel on climate change ipcc estimates of global average glacier mass balance may not be much different from simple averages a more mathematically correct approach is to analyse long and continuous mass balance series measured in different regions but there are few long series and they do not cover the globe in any representative way however 30 year series from 30 glaciers confirm a recent 1996 2005 trend to very negative mass balance after two decades of nearly zero mass balance climate data from a global gridded climatology are applied to datasets for global glacier cover for 318 glaciers with mass balance data for at least 1 year and for 30 glaciers with 30 year series of measurements results show that mean precipitation is relatively low in the global glacier cover dataset and much higher for the observed glaciers this shows that current mass balance measurements are biased towards wetter conditions than are typical for global glacier cover we urgently need to find better ways of analysing sparse datasets with complex spatial and temporal patterns like the present mass balance dataset

is the north atlantic oscillation reflected in scandinavian glacier mass balance records the north atlantic oscillation nao is one of the modes of climate variability in the north atlantic region the atmospheric circulation during the winter season in this region commonly displays a strong meridional north south pressure contrast with low air pressure cyclone centred close to iceland and high air pressure anticyclone near the azores this pressure gradient drives the mean surface winds and the mid latitude winter storms from west to east across the north atlantic bringing mild moist air to northwest europe the nao index is based on the difference of normalised sea level pressures slp between ponta delgada azores and stykkisholmur iceland the slp anomalies at these stations are normalised by division of each monthly pressure by the long term 1865 1984 standard deviation interannual atmospheric climate variability in northwest europe especially over great britain and western scandinavia has during the last decades been attributed mainly to the nao causing variations in the winter weather over the northeast north atlantic and the adjacent land areas a comparison between the nao index and the winter december march precipitation between ad 1864 and 1995 in western norway shows that these are strongly linked correlation coefficient 0 77 variations in the nao index are also reflected in the mass balance records of glaciers in western scandinavia the nao index is best correlated with mass balance data from maritime glaciers in southern norway e g alfotbreen r 2 0 51 the record of holocene last ca 11 500 cal yr glacier variations of maritime glaciers in western scandinavia is thus a proxy of pre instrumental nao variations copyright 2000 john wiley sons ltd

the mass balance of circum arctic glaciers and recent climate change the sum of winter accumulation and summer losses of mass from glaciers and ice sheets net surface mass balance varies with changing climate in the arctic glaciers and ice caps excluding the greenland ice sheet cover about 275 000 km2of both the widely glacierized archipelagos of the canadian norwegian and russian high arctic and the area north of about 60 n in alaska iceland and scandinavia since the 1940s surface mass balance time series of varying length have been acquired from more than 40 arctic ice caps and glaciers most arctic glaciers have experienced predominantly negative net surface mass balance over the past few decades there is no uniform recent trend in mass balance for the entire arctic although some regional trends occur examples are the increasingly negative mass balances for northern alaska due to higher summer temperatures and increasingly positive mass balances for maritime scandinavia and iceland due to increased winter precipitation the negative mass balance of most arctic glaciers may be a response to a step like warming in the early twentieth century at the termination of the cold little ice age arctic ice masses outside greenland are at present contributing about 0 13 mm yr 1to global sea level rise

surface elevation change and mass balance of icelandic ice caps derived from swath mode cryosat 2 altimetry we apply swath processing to cryosat 2 interferometric mode data acquired over the icelandic ice caps to generate maps of rates of surface elevation change at 0 5 km postings this high resolution mapping reveals complex surface elevation changes in the region related to climate ice dynamics and subglacial geothermal and magmatic processes we estimate rates of volume and mass change independently for the six major icelandic ice caps 90 of iceland s permanent ice cover for five glaciological years between october 2010 and september 2015 annual mass balance is highly variable during the 2014 2015 glaciological year the vatnajokull ice cap 70 of the glaciated area experienced positive mass balance for the first time since 1992 1993 our results indicate that between glaciological years 2010 2011and 2014 2015 icelandic ice caps have lost 5 8 0 7 gt a 1 on average 40 less than the preceding 15 years contributing 0 016 0 002 mm a 1 to sea level rise

recent changes 1991 2010 in glacier mass balance and air temperature in the european alps we estimate temperature sensitivity of observed mass balance for glaciers in the alps to compare with our earlier estimates from modelling we treat 1961 1990 as our reference period and compare mass balance for 1991 2010 with this reference period there are eight alpine glaciers with long enough records the mean mass balance for the eight glaciers is close to zero for the reference period very negative for 1991 2010 and highly negative in the exceptionally warm year 2003 mass balance changes are compared with 1991 2010 temperature anomalies to give an average temperature sensitivity of about 0 7 0 2 m w e a 1 k 1 for the eight glaciers there is considerable variation between individual glaciers with higher sensitivity for western glaciers and lower sensitivity for more eastern glaciers temperature sensitivity for the eight glaciers is strongly correlated with the standard deviation of observed mass balance which from earlier work is known to be correlated with winter balance the mean temperature sensitivity for observed mass balance is in reasonable agreement with values from earlier models but changes in glacier hypsometry during 1991 2010 may have further increased observed mass loss

downscaled precipitation applied in modelling of mass balance and the evolution of southeast vatnajokull iceland simulations of the post little ice age evolution of three outlet glaciers of southeast vatnajokull iceland skalafellsjokull heinabergsjokull and flaajokull are presented a coupled shallow ice approximation ice flow and degree day mass balance model is applied that is calibrated with a 14 year record of in situ mass balance measurements the measured mass balance cannot be realistically represented by constant horizontal and vertical precipitation gradients high resolution 1 km precipitation fields derived from downscaled orographic atmospheric circulation models of precipitation are required to capture the spatial variation of the winter mass balance the observed ice volume around 1890 15 30 larger than in 2000 can be simulated with 1 c lower temperatures and a 20 reduction in the annual precipitation relative to the reference climate period 1980 2000 the sensitivity of each glacier s annual balance to a change in temperature is 1 51 to 0 97 m w e a 1 c 1 and 0 16 to 0 65 m w e a 1 for a 10 increase in precipitation a steady state experiment applying a step increase in temperature of 2 c 3 c and precipitation increase of 10 results in a 50 80 90 decrease in ice volume

south cascade glacier mass balance 1935 2006 a simple model uses daily observations of precipitation and temperature at a nearby weather station to estimate glacier average seasonal mass balance components at south cascade glacier washington usa from 1935 24 years before measurements began at the glacier this is 13 years earlier than measurements that can be derived using the ncep ncar reanalysis database begins 1 january 1948 although the model s error in estimating winter balance and summer balance over 1959 2006 is greater than that of a model using the reanalysis database its error in estimating net balance is comparable the model uses an empirically determined precipita tion ratio between the station and the glacier and a seasonally varying temperature lapse rate de termined from 9 years of measurements at the glacier temperature is used with a degree day for mulation to estimate ablation and to partition precipitation between rain and snow for estimating accumulation both processes are assumed to exist throughout the year and model results are compared seasonally with adjusted observations of winter and summer balances the published mass balance series is adjusted to a constant topography 1970 series in an attempt to remove the influence of changing topography on the glacier s response to climate the reconstructed values prior to 1959 are also with respect to the 1970 glacier topography because precipitation is measured at the weather station rather than being inferred from other meteorological variables it enables us to distinguish more accurately between wet day and dry day conditions including vertical lapse rates of temperature

influence of upper air conditions on glaciers in scandinavia a simple model using once daily us national centers for environmental prediction us national center for atmospheric research ncep ncar re analysis upper air values estimates winter balance summer balance and net balance at ten glaciers in norway and two in sweden with 0 37 r 2 0 90 the october may arctic oscillation ao an index of sea level pressure slp in the northern hemisphere correlates with winter balance and net balance with 0 09 r 2 0 82 lower than the model in all but 3 of the 24 cases the october may north atlantic oscillation nao an slp gradient in the north atlantic has lower correlations than the ao for all but 5 of the 24 cases at all ten glaciers with records beginning before 1987 net balance became more positive after 1988 owing mainly to increased winter balance with summer balance changing little although winter temperatures increased they were still well below freezing so the rain snow division of the precipitation was only slightly affected increase in winter balance was due to increased precipitation caused by a change in atmospheric circulation resulting in more frequent westerly flow concurrent with the warming at 850 hpa westerly flow is 2 5 c warmer than easterly flow westerly flow warmed by 0 3 c easterly by 0 7 c both the ao and nao with which winter balance is positively correlated at all 12 glaciers were more positive after 1988

the effect of continentality on glacier response and mass balance the continentality index is a good measure of the nature of the climate in a region as it reflects not only the temperature but also the large scale circulation it correlates well with glacier mass balance parameters the climate along the west east transect slightly north of the arctic circle across the scandinavian caledonides is gov erned by the prevailing westerlies however during winter the eastern part of the caledo nides is ini1uenced by weather systems from the southeast the differences in continentality meant by temperature and precipitation have a major impact on the res ponse times of glaciers the climatic change in this area has been dominated by increased summer mean temperatures 1910 20 and increased maritime influence since the 1980s the slower reacting glaciers on the swedish side of the mountains are still adapting to the temperature increase at the beginning of the 20th century and the increase in maritime influence gradually becomes less important towards the west thus differences in the be haviour of glacier fronts along the west east transect mirror differences in continentality

relating glacier mass balance to meteorological data using a seasonal sensitivity characteristic we propose to quantify the climate sensitivity of the mean specific balance b of a glacier by a seasonal sensitivity characteristic ssc the ssc gives the dependence of b on monthly anomalies in temperature and precipitation it is calculated from a mass balance model we show and discuss examples for franz josef glacier new zealand nigardsbreen norway hintereisferner austria peyto glacier canadian rockies abramov glacier kirghizstan and white glacier canadian arctic with regard to the climate sensitivity of b the sscs clearly show that summer temperature is the most important factor for glaciers in a dry climate for glaciers in a wetter climate spring and fall temperatures also make a significant contribution to the overall sensitivity the ssc is a 2 12 matrix multiplying it with monthly perturbations of temperature and precipitation for a particular year yields an estimate of the balance for that year we show that with this technique mass balance series can be re constructed from long meteorological records or from output of atmospheric models

glacier changes in alaska can mass balance models explain grace mascon trends temperature and precipitation data from three weather stations in the st elias mountains of alaska and northwestern canada were used to drive one dimensional 1 d elevation dependent and 0 d degree day mass balance models model outputs were optimized against a 10 day resolution time series of mass variability during 2003 07 obtained from gravity recovery and climate experiment grace mass concentration mascon solutions the models explained 52 60 of the variance in the grace time series modelled mass variations matched the phase of the grace observations and all optimized model parameters were within the range of values determined from conventional mass balance and meteorological observations we describe a framework for selecting appropriate weather stations and mass balance models to represent glacier variations of large regions there is potential for extending these calibrated mass balance models forwards or backwards in time to construct mass balance time series outside of the grace measurement window

holocene glacier and climate variations in vestfirðir iceland from the modeling of drangajokull ice cap abstract drangajokull is a maritime ice cap located in northwest vestfir ir iceland drangajokull s evolution is therefore closely linked to atmospheric and ocean variability in order to better constrain the holocene climate and glacier history of vestfir ir we model the past evolution of drangajokull ice cap simulations from 10 ka to present are forced by general circulation model output ice core based temperature reconstructions and sea surface temperature reconstructions based on these 10 thousand year simulations drangajokull did not persist through the holocene we estimate that air temperatures were 2 5 3 0 c higher during the holocene thermal maximum than the local 1960 1990 average simulations support drangajokull s late holocene inception between 2 and 1 ka though intermittent ice likely occupied cirques as early as 2 6 ka drangajokull is primarily a little ice age ice cap it expanded between 1300 and 1750 ce with the most rapid growth occurring between 1600 and 1750 ce the maximum holocene extent of drangajokull occurred between 1700 and 1925 ce despite the lowest late holocene temperatures occurring between 1650 and 1720 ce between 1700 and 1925 ce temperatures were likely 0 6 0 8 c lower than the 1950 2015 reference temperature the modern equilibrium line altitude ela is bracketed by topographic thresholds a 1 c temperature increase from the modern ela would eliminate the ice cap s accumulation area while a reduction of 0 5 c would lead to the rapid expansion of the ice cap across vestfir ir the proximity of drangajokull to topographic thresholds may explain its late inception and rapid expansion during the little ice age

temperature and precipitation climate at the equilibrium line altitude of glaciers expressed by the degree day factor for melting snow several authors relate accumulation or precipitation at the glacier equilibrium line altitude ela to summer mean temperature using exponential or power law functions i analyze the accumulation temperature relation at the ela with a degree day model using data from the 1992 paper by a ohmura and others the dataset includes estimates at the ela of winter balance and of winter balance plus summer precipitation which represent respectively low and high estimates of annual accumulation which is seldom measured the ohmura dataset only lists summer mean temperature but i recover monthly temperatures for the whole year for 66 of the glaciers by assuming sinusoidal temperature variation through the year and using annual temperature range from a gridded climatology monthly degree day sums are then estimated from monthly mean temperature and summed to give annual totals so degree day factors for melting snow at the ela are obtained the degree day factors fall close to those reported in the literature for glacier snowmelt with averages of 3 5 1 4 and 4 6 1 4 mm d 1 k 1 for low and high accumulation estimates on the 66 glaciers the degree day model gives a family of accumulation temperature curves that depend upon the annual temperature range representing the contrast between maritime and continental climates

application of geomorphons for analysing changes in the morphology of a proglacial valley case study the scott river sw svalbard abstract the progressive degradation of the cryosphere of high arctic areas causes an increase in the dynamics of geomorphic processes that shape the valleys of rapidly retreating glaciers those especially sensitive to global environmental changes are the small land ending valley glaciers that are in the phase of strong retreat under these conditions the river valley s floors that are drained by proglacial waters are constantly undergoing intensive changes for the analysis of these changes two methods were used simultaneously as a synthesis to allow for quantitative and qualitative evaluation the first one is the increasingly more common dod method dem of difference which allows quantifying volumetric changes as a result of topographic differentiation the second one which was applied for the first time on a small valley spatial scale is the geomorphons method that makes it possible to assess the stability of landforms and to determine the directions of their new development to judge the applicability advantages and disadvantages of both methods for analysis of geomorphic changes in rapidly changing proglacial environments the study was carried out over a 3 3 km distance of the non glaciated section of the scott river valley course nw wedel jarlsberg land sw svalbard this area 1 3 km2 is currently shaped by a braided gravel bed river more accurately the study focused on the section spanning from the glacier terminus which is the source of the scott river to its outlet at the rechersche fjord bellsundfiorden the foundation for the development of comparative elevation models was a collection of terrestrial laser scanning tls surveys that were taken with a leica scanstation c10 scanner during the 2010 and 2013 snowmelt seasons on the basis of these surveys and with the use of tin interpolation high resolution 0 2 m digital terrain models dtms were generated the dtm models that had been prepared in this manner were used for the analysis of surface changes by employing geomorphic change detection gcd software and by simultaneously generating geomorphons maps for four selected test areas that covered characteristic fragments of the valley bottom 1 on the close forefield of the scott glacier terminus 2 in the immediate vicinity of the narrow valley outlet at the foot of the marginal moraine ridge 3 in the enlargement of the central section of the non glaciated valley floor 4 within the alluvial fan outlet to the fjord a comparison of the obtained results dod and geomorphons maps zonal statistics as well as a compilation of both the quantitative assessment of the scale of changes and the qualitative assessment of the transformation s direction allowed for reconstructing the range and rate of three year long changes in morphology at the analysed sections of the valley floor it was found that the pattern and rate of changes were closely related to the location of the test areas in the scott river s catchment system significant differences in the dynamics of processes shaping the valley landforms along the longitudinal valley course were found

glaciological conditions in seven contrasting regions estimated with the degree day model we apply the degree day model to seven glacial regions that offer contrasting conditions and are well documented in the world glacier inventory the regions are axel heiberg island in arctic canada svalbard northern scandinavia southern norway the alps the caucasus and new zealand we estimate the average equilibrium line altitude ela for each half degree latitude longitude grid square from the median elevations of glaciers within the square and we extrapolate temperature from the uea cru climate research unit of the university of east anglia gridded climatology using the degree day model we calculate annual accumulation at the ela equal to ablation at the ela and other quantities like summer mean temperature length of melt season balance gradients and the sensitivity of mass balance to temperature and or precipitation changes glaciers can be characterized on a scale from cold dry axel heiberg island to warm wet new zealand corresponding to the contrast between maritime and continental climates mass balance sensitivities to temperature and or precipitation changes are relatively small for dry cold climate and relatively high for warm wet climate we could extend the approach to other glacier regions but we note that there are large areas for which ela data are not available as they are still not covered by the world glacier inventory

climate sensitivity of storglaciaren sweden an intercomparison of mass balance models using era 40 re analysis and regional climate model data estimates of glacier contributions to future sea level rise are often computed from mass balance sensitivities derived for a set of representative glaciers our purpose is to investigate how mass b

static mass balance sensitivity of arctic glaciers and ice caps using a degree day approach the purpose of this study is to enhance our understanding of the response of glaciers to climate change global sea level is affected by changes in glacier ice volume and melt water from glaciers is a principal water source in many regions this study applies glacier mass balance modelling with varying complexity and spatial resolution ranging from individual glaciers to regional and global assessments of glacier mass losses glaciers located in maritime environments generally show considerably higher mass balance sensitivities than those in continental settings on average an assumed increase in annual precipitation of 10 tends to offset the effect of an annual temperature change of 1 k by roughly 20 two case studies at storglaciaren sweden and hofsjokull iceland involve model results of future mass balance change and glacier melt induced changes in runoff applying a temperature and precipitation scenario for iceland in 2050 results in increased total runoff from hofsjokull by roughly one third and results emphasize the role of the firn layer in delaying water flow through glaciers yielding a redistribution of discharge within the year based on a global gridded data set of glacierized area the sea level equivalent from all mountain glaciers and ice caps outside the ice sheets in greenland and antarctica during 1961 2004 caused by changes in temperature and precipitation is estimated to be 0 58 0 34 mm a 1 the mountain glaciers and ice caps around antarctica alone contribute almost 40 of the global estimate and hence their contribution is considerably larger than previously assumed

upper air model of summer balance on mount rainier usa in 2003 07 summer balance was measured at altitudes between 1700 and 3382 m a s l on two glaciers on mount rainier washington state usa 46 85 n 121 72 w 4400 m a s l south facing nisqually glacier and east northeast facing emmons glacier upper air temperatures at the nearest gridpoint in the ncep ncar reanalysis database are used in a distributed over altitude positive degree day pdd model for each glacier the model used the same coefficients at all altitudes for all years the rms model error was 0 65 r 2 0 87 and 0 78 m a 1 w e r 2 0 93 for nisqually and emmons glaciers respectively although pdd work generally uses different coefficients for snow and ice surfaces and the duration of exposure of those surfaces varies with altitude error in this single coefficient model is nearly uncorrelated with altitude values of coefficients obtained are within the range of those found in other pdd work the degree day coefficient however differs markedly between the two glaciers and is shown to be controlled by the difference between them in vertical gradient of measured summer balance it is smaller for nisqually glacier where solar radiation is a stronger contributor to melt and larger for emmons glacier where it is a weaker contributor over 1948 2007 when the model calibrated over 2003 07 was applied to the upper air temperatures estimated summer balance was 0 4 m a 1 less negative over 1962 83 than before and 0 6 m a 1 less negative than after corresponding roughly with changes of the northeast pacific sea surface temperatures

distributed mass balance and climate sensitivity modelling of engabreen norway department of geosciences university of oslo po box 1047 blindern no 0316 oslo norwayabstract assessing the impact of possible climate change on the water resources of glacierized areasrequires a reliable model of the climate glacier mass balance relationship in this study we simulate themass balance evolution of engabreen norway using a simple mass balance model based on dailytemperature and precipitation data from a nearby climate station ablation is calculated using adistributed temperature index method including potential direct solar radiation while accumulation isdistributed linearly with elevation the model was run for the period 1974 75 2001 02 for whichannual mass balance measurements and meteorological data are available parameter values weredetermined by a multi criteria validation including point measurements of mass balance mass balancegradients and specific mass balance the modelled results fit the observed mass balance well simplesensitivity experiments indicate a high sensitivity of the mass balance to temperature changes asexpected for maritime glaciers the results suggest further that the mass balance of engabreen is moresensitive to warming during summer than during winter while precipitation changes affect almostexclusively the winter balance

surface energy balance in the ablation zone of langfjordjokelen an arctic maritime glacier in northern norway glaciers in northern and southern norway are subject to different daily and seasonal cycles of incoming solar radiation which is presumably reflected in the importance of net solar radiation in their surface energy balance we present a 3 year continuous record from an automatic weather station in the ablation zone of the ice cap langfjordjokelen one of the most northerly glaciers of mainland norway despite its location at 708 n langfjordjokelen was found to have a maritime climate with an annual mean air temperature of 1 08c frequent cloud cover and end of winter snow depths over 3m in all three years the main melt season was may october but occasional melt events occurred on warm cloudy winter days net solar and longwave radiation together accounted for 58 of the melt energy with a positive contribution by net longwave radiation 7 the sensible and latent heat fluxes supplied the remainder of the melt energy cloud optical thickness over langfjordjokelen was larger than on two glaciers in southern norway especially in the summer months this resulted in a smaller contribution of net solar radiation to surface melt on langfjordjokelen the effect of the higher latitude on net solar radiation was found to be small

observed volume fluxes in the bosphorus strait 1 pairs of moorings containing acoustic doppler current profilers adcps were deployed at each end of the bosphorus strait as a part of the united states naval research laboratory s exchange processes in ocean straits epos project the moorings were deployed in september 2008 and remained in place for about half a year for the first time current velocity profiles were collected concurrently at both ends of the strait they well resolved the two layer exchange flow and were used to estimate volume flux time series these estimates clearly indicated that there was a mean net volume flux of over 100 km3 yr directed from the black sea to the sea of marmara over this period the upper layer fluxes showed distinct temporal variability whereas the lower layer fluxes varied less volume fluxes were maximized at over 1500 km3 yr in the upper layer and over 1100 km3 yr in the lower layer with an upper layer mean of about 400 km3 yr and a lower layer mean of about 300 km3 yr fluxes in both layers were highly coherent with the bottom pressure difference between the southern and northern ends of bosphorus strait and they can be fairly well predicted from this pressure difference the fluxes in the upper layer were also influenced by atmospheric forcing but generally less so than by the bottom pressure difference

geodetic mass balance of azarova glacier kodar mountains eastern siberia and its links to observed and projected climatic change the kodar mountains in eastern siberia accommodate 30 small cold based glaciers with a combined surface area of about 19 km2 very little is known about these glaciers with the first survey conducted in the late 1950s in this paper we use terrestrial photogrammetry to calculate changes in surface area elevation volume and geodetic mass balance of the azarova glacier between 1979 and 2007 and relate these to meteorological data from nearby chara weather station 1938 2007 the glacier surface area declined by 20 6 9 and surface lowered on average by 20 1 8 m mean thinning 0 71 m a 1 resulting in a strongly negative cumulative and average mass balance of 18 1 6 m w e and 640 60 mm w e a 1 respectively the july august air temperature increased at a rate of 0 036oc a 1 between 1979 and 2007 and the 1980 2007 period was on average around 1oc warmer than 1938 1979 the regional climate projections for a2 and b2 co2 emission scenarios developed using precis regional climate model indicate that summer temperatures will increase in 2071 2100 by 2 6 4 7 c and 4 9 6 2 c respectively in comparison with 1961 1990 the annual total of solid precipitation will increase by 20 under b2 scenario but decline by 3 under a2 scenario the length of the ablation season will extend from july august to june september the azarova glacier exhibits high sensitivity to climatic warming due to its low elevation exposure to comparatively high summer temperatures and the absence of a compensating impact of cold season precipitation further summer warming and decline of solid precipitation projected under the a2 scenario will force azarova to retreat further while impacts of an increase in solid precipitation projected under the b2 scenario require further investigation

sporteggbreen western norway in the past present and future simulations with a two dimensional dynamical glacier model a two dimensional shallow ice flow model yielding the glacier geometry at selected time intervals is used to simulate the development of sporteggbreen 1 from 8000 cal yr bp to the present 2 from ad 2011 to 2050 and 3 extending forward in time to ad 2100 and 2200 glacier surface geometry subglacial topography mass balance data internal deformation and subglacial sliding are used as input data for the model runs to force the model from 8000 cal yr bp to the present a mass balance series based on the equilibrium line altitude ela variations on jostedalsbreen to the west of sporteggbreen is applied a 50 reduction of the ela amplitude at jostedalsbreen is used to construct a new mass balance series and it was found that this gives a reasonably good coherence between the modelled and the real glacier the modelled time series for ela and length changes indicate that the glacier melted away c 7300 cal yr bp and was absent for c 1700 years it reformed c 5400 cal yr bp because of a mo

quantifying the effects of climate and surface change on glacier mass balance when a mass balance is computed using an outdated map that computation does not reveal the actual mass change but older maps often must be used for practical reasons we present a method by which with a few additional measurements each year a mass balance computed with an outdated map can be transformed into an actual mass change this is done by taking into account the influence of changes in areal extent and changes in the surface elevation of the glacier since the map was made this method is applied to south cascade glacier washington u s a as an example the computed cumulative mass balance from 1970 to 1997 would have been 16 too negative if the 1970 map had not been updated while the actual volume change of a glacier is relevant to hydrological studies the change that would have occurred on a constant or static surface is more relevant to certain glacier dynamics problems and most climate problems we term this the reference surface balance and propose that such a balance which deliberately omits the influence of changes in area and surface elevation is better correlated to climatic variations than the conventional one which incorporates those influences

cdp mapping to obtain the fine structure of the crust and upper mantle from seismic sounding data an example for the southeastern china abstract we present an efficient and general approach of common depth point cdp mapping to image the fine structure of the crust and upper mantle we use velocity model and reflector geometries which are the results of conventional interpretation as a reference model to construct our cdp mapping of crust and upper mantle after three steps the calculation of cdp points and reflecting traveltimes the determination of cdp mapping trajectories and the implementation of cdp imaging reflection images were created by cdp mapping technique in which each time element of a seismic trace beginning with the direct arrival is mapped to reflection point our test of the method presented in this paper shows that the algorithm can quickly accurately image the subsurfaces of the given model the result of cdp mapping in the southeastern china shows that the depth of moho is about 34 km there are numerous reflection interfaces within the upper crust and the moho is a transition zone with a thickness of 2 3 km the cdp mapping approach presented here can easily be extended to three dimensions and complex anisotropic media the method can also be used to develop seismic attribute images of the crust and upper mantle

reconstruction of the annual mass balance of chhota shigri glacier western himalaya india since 1969 this study presents a reconstruction of the mass balance mb of chhota shigri glacier western himalaya india and discusses the regional climatic drivers responsible for its evolution since 1969 the mb is reconstructed by a temperature index and an accumulation model using daily air temperature and precipitation records from the nearest meteorological station at bhuntar observatory the only adjusted parameter is the altitudinal precipitation gradient the model is calibrated against 10 years of annual altitudinal mb measurements between 2002 and 2012 and decadal cumulative mbs between 1988 and 2010 three periods were distinguished in the mb series periods i 1969 85 and iii 2001 12 show significant mass loss at mb rates of 0 36 0 36 and 0 57 0 36mw e a 1 respectively whereas period ii 1986 2000 exhibits steady state conditions with average mbs of 0 01 0 36mw e a 1 the comparison among these three periods suggests that winter precipitation and summer temperature are almost equally important drivers controlling the mb pattern of chhota shigri glacier at decadal scale the sensitivity of the modelled glacier wide mb to temperature is 0 52 m w e a 1 c 1 whereas the sensitivity to precipitation is calculated as 0 16mw e a 1 for a 10 change

degree day glacier mass balance modelling with applications to glaciers in iceland norway and greenland a degree day glacier mass balance model is applied to three glaciers in iceland norway and greenland for which detailed mass balance measurements are available over a period of several years model results are in good agreement with measured variations in the mass balance with elevation over the time periods considered for each glacier in addition the model explains 60 80 of the year to year variance in the elevation averaged summer season mass balance measurements on the glaciers using a single parameter set for each glacier the increase in ablation on the glaciers due to a warming of 2 c is predicted to range from about 1 m w e year 1 at the highest elevations to about 2 5 m w e year 1 at the lowest elevations predicted changes in the winter balance measured between fixed date are relatively small except at the lowest elevations on the icelandic and norwegian glaciers where the winter balance is significantly reduced equilibrium line altitudes are raised by 200 300 m on the icelandic and norwegian glaciers except at the highest elevations the winter balance of the icelandic and norwegian glaciers is predicted to decrease even if the warming is accompanied by a 10 increase in the precipitation no firm evidence of a climate related variation in the degree day factors or in the temperature lapse rate on the same glacier could be found the model furthermore reproduces large variations in the mass balance with elevation and from year to year on each glacier using the same parameter set we assume therefore that these parameters will not change significantly for the climate scenarios considered here

surface mass balance thinning and iceberg production columbia glacier alaska 1948 2007 a mass balance model using upper air meteorological data for input was calibrated with surface mass balance measured mainly during 1977 78 at 67 sites on columbia glacier alaska between 135 and 2645 m a s l root mean square error model vs measured is 1 0 m w e a 1 w ithr 2 0 88 a remarkable result of the analysis was that both precipitation and the factor in the positive degree day model used to estimate surface ablation were constant with altitude the model was applied to reconstruct glacier wide components of surface mass balance over 1948 2007 surface ablation 4k m 3 ice eq a 1 ice equivalent has changed little throughout the period from 1948 until about 1981 when drastic retreat began the surface mass balance was positive but changes in glacier geometry were small so the positive balance was offset by calving 0 9 km 3 ice eq a 1 during retreat volume loss of the glacier accounted for 92 of the iceberg production calving increased to 4 3 km 3 ice eq a 1 from 1982 to 1995 and after that until 2007 to 8 0 km 3 ice eq a 1 which was about twice the loss by surface ablation whereas prior to retreat it was only about a quarter as much calving is calculated as the difference between glacier wide surface mass balance and geodetically determined volume change

climate sensitivity of glaciers in southern norway application of an energy balance model to nigardsbreen hellstugubreen and alfotbreen three glaciers in southern norway with very different massbalance characteristics are studied with an energy balance model of the ice snow surface the model simulates the observed mass balance profiles in a satisfactory way and can thus be used with some confidence in a study of climate sensitivity calculated changes in equilibrium line altitude for a 1 k temperature increase are 110 108 and 135 in for nigardsbreen hellstugubreen and alfotbreen respectively the corresponding changes in mass balance averaged over the entire glacier area are 0 88 0 715 and 1 11 in year water equivalent runs with an ice flow model for nigardsbreen to which calculated mass balance profiles are imposed predict that the front will advance by 3 km for a 1 k cooling and will retreat by as much as 6 5 km for a 1 k warming the response to a 10 increase in precipitation would be a 2 km advance of the snout whereas a 4 km retreat is predicted for a 10 decrease this large sensitivity as compared to many other glaciers is to a large extent due to the geometry of nigardsbreen

climate at the equilibrium line of glaciers the relationships between temperature precipitation and radiation on glacier equilibrium lines are investigated using 70 glaciers for which the mass balance and meteorological observations have been carried out for sufficiently long periods it is found that the characteristic climate at glacier equilibrium lines can be described using the summer 3 months temperature in a free atmosphere annual total precipitation and the sum of global and long wave net radiation all of these are measured at or very near the equilibrium line altitudes then it is shown how the shift of the equilibriumline will occur as a result of a climatic change finally the effect of the shift of the equilibrium line on the annualmean specific mass balance is analytically derived and compared with observations the present results make it possible to identify the altitudes in climate models where glacierization should begin and to evaluate the mass balance changes as a result of possible future changes in the climate

mountain glaciers and ice caps around antarctica make a large sea level rise contribution the intergovernmental panel on climate change ipcc estimates that the sum of all contributions to sea level rise for the period 1961 2004 was 1 1 0 5 mm a 1 leaving 0 7

estimating the contribution of arctic glaciers to sea level change in the next 100 years in this paper we report on an approach to estimate the contribution of arctic glaciers to sea level change in our calculation we assume that a static approach is feasible we only calculate changes in the surface balance from modelled sensitivities these sensitivities summarized in the seasonal sensitivity characteristic can be used to calculate the change in the surface mass budget for given anomalies of monthly temperature and precipitation we have based our calculations on a subdivision of all arctic ice into 13 regions four sectors of the greenland ice sheet the canadian arctic 74 n the canadian arctic 60 n as forcing for the calculations we have used the output from five climate models for the period 2000 2100 these models were forced by the same greenhouse gas scenario ipcc b2 the calculated contributions to sea level rise in the year 2100 vary from almost zero to about 6 cm the differences among the models stem first of all from differences in the precipitation the largest contribution to sea level change comes from the greenland ice sheet the glaciers in alaska also make a large contribution not because of the area they cover but because they are more sensitive than other glaciers in the arctic the climate models do not agree on regional patterns the runoff from svalbard glaciers for instance increases for two models and decreases for the three other models we conclude that the uncertainty due to a simple representation of the glaciological processes is probably smaller than the uncertainty induced by the differences in the climate change scenarios produced by the models

the geodetic mass balance of eyjafjallajokull ice cap for 1945 2014 processing guidelines and relation to climate mass balance measurements of icelandic glaciers are sparse through the 20th century however the large archive of stereo images available allows estimates of glacier wide mass balance dot b in decadal time steps since 1945 combined with climate records they provide further insight into glacier climate relationship this study presents a workflow to process aerial photographs 1945 1995 spy satellite imagery 1977 1980 and modern satellite stereo images since 2000 using photogrammetric techniques and robust statistics in a highly automated open source pipeline to retrieve seasonally corrected decadal glacier wide geodetic mass balances in our test area eyjafjallajokull s iceland 70 km 2 we obtain a mass balance of cdata dot curr b curr 1945 curr 2014 curr 0 27 pm 0 03 rm curr m w rm curr e rm rm curr a rm ndash curr 1 with a maximum and minimum of dot curr b curr 1984 curr 1989 curr 0 77 curr pm 0 19 rm curr m curr w rm curr e rm curr rm curr a rm curr ndash 1 and dot curr b curr 1994 curr 1998 curr 1 94 curr pm 0 34 rm curr m w rm curr e rm curr rm curr a rm curr ndash 1 respectively attributed to climatic forcing and dot curr b curr 2009 curr 2010 curr 3 39 rm curr pm rm curr 0 43 rm curr m w rm curr e rm curr rm curr a rm curr ndash 1 mostly caused by the april 2010 eruption the reference surface mass balances correlate with summer temperature and winter precipitation and linear regression accounts for 80 of the mass balance variability yielding a static sensitivity of mass balance to summer temperature and winter precipitation of 2 1 0 4 m w e a 1 k 1 and 0 5 0 3 m w e a 1 10 1 respectively this study serves as a template that can be used to estimate the mass balance changes and glaciers response to climate

sharply increased mass loss from glaciers and ice caps in the canadian arctic archipelago the canadian arctic archipelago contains one third of the global volume of land ice outside the ice sheets but its contribution to sea level change is largely unknown gardner et al use three independent techniques to reveal that mass loss from the archipelago was 92 12 gigatonnes per year in 2007 09 about three times greater than in 2004 06 and coincident with warmer summer temperatures the record is too short to allow a firm conclusion on longer term trends but it is clear that the canadian arctic archipelago is a significant contributor to sea level rise mountain glaciers and ice caps are contributing significantly to present rates of sea level rise and will continue to do so over the next century and beyond1 2 3 4 5 the canadian arctic archipelago located off the northwestern shore of greenland contains one third of the global volume of land ice outside the ice sheets6 but its contribution to sea level change remains largely unknown here we show that the canadian arctic archipelago has recently lost 61 7 gigatonnes per year gt yr 1 of ice contributing 0 17 0 02 mm yr 1 to sea level rise our estimates are of regional mass changes for the ice caps and glaciers of the canadian arctic archipelago referring to the years 2004 to 2009 and are based on three independent approaches surface mass budget modelling plus an estimate of ice discharge smb d repeat satellite laser altimetry icesat and repeat satellite gravimetry grace all three approaches show consistent and large mass loss estimates between the periods 2004 2006 and 2007 2009 the rate of mass loss sharply increased from 31 8 gt yr 1 to 92 12 gt yr 1 in direct response to warmer summer temperatures to which rates of ice loss are highly sensitive 64 14 gt yr 1 per 1 k increase the duration of the study is too short to establish a long term trend but for 2007 2009 the increase in the rate of mass loss makes the canadian arctic archipelago the single largest contributor to eustatic sea level rise outside greenland and antarctica

the response of two icelandic glaciers to climatic warming computed with a degree day glacier mass balance model coupled to a dynamic glacier model a degree day glacier mass balance model is coupled to a dynamic glacier model for temperate glaciers the model is calibrated for two outlet glaciers from the hofsjokull ice cap in central iceland it is forced with a climate scenario that has recently been defined for the nordic countries for the purpose of outlining the hydrological consequences of future greenhouse warming the scenario for iceland specifies a warming rate of 0 25 c per decade in mid summer and 0 35 c per decade in mid winter with a sinusoidal variation through the year the volume of the glaciers is predicted to decrease by approximately 40 over the next century and the glaciers essentially disappear during the next 200 years runoff from the area that is presently covered by the glaciers is predicted to increase by approximately 0 5 m a 1 30 years from now due to the reduction in the volume of the glaciers the runoff increase reaches a flat maximum of 0 5 2 0 m a 1 100 150 years from now and levels off after that the predicted runoff increase leads to a significant increase in the discharge of rivers fed by meltwater from the outlet glaciers of the ice cap and may have important consequences for the operation and planning of hydroelectric power plants in iceland

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

interdecadal variability of degree day factors on vestari hagafellsjokull langjokull iceland and the importance of threshold air temperatures the skill of degree day glacier melt models is highly dependent on the choice of degree day factor ddf which is often assumed to remain constant in time here we explore the validity of this assumption in a changing climate for two locations on vestari hagafellsjokull 1979 2012 using a surface energy balance seb approach that isolates the effect of changes in the prevailing weather on the ddf at lower elevation we observe stable ddf during the period of study however at higher elevation ddf is noted to be more variable and a statistically significant downward trend is observed this is found to result from an inappropriate threshold air temperature t crit from which to initiate the positive degree day sum and is removed by setting t crit to 1 83 c rather than the usual value of 0 c used in degree day melt models the stationarity of ddf once t crit is adjusted contradicts previous research and lends support to the use of constant ddf for projecting future glacier melt optimizing t crit also improves the skill of melt simulations at our study sites this research thus highlights the importance of t crit for both melt model performance and the evaluation of ddf stationarity in a changing climate

derivation of melt factors from glacier mass balance records in western canada melt factors for snow k s and ice k i were derived from specific mass balance data and regionally interpolated daily air temperature series at nine glaciers in the western cordillera of canada fitted k s and k i were relatively consistent across the region with mean values standard deviations of 3 04 0 38 and 4 59 0 59 mm d 1 c 1 respectively the interannual variability of melt factors was investigated for two long term datasets calculated annually snow and ice melt factors were relatively stable from year to year standard deviations for snowmelt factors were 0 48 17 and 0 42 18 at peyto and place glaciers respectively while standard deviations of ice melt factors were 1 17 25 and 0 81 14 while fitted values of k s are comparable to those presented in previous observational and modeling studies fitted k i are substantially and consistently lower across the region fitted melt factors were sensitive to the choice of lapse rate used in the air temperature interpolation melt factors fitted to mass balance data from a single site place glacier provided reasonable summer balance predictions at most other sites representing both maritime and continental climates although there was a tendency for under prediction at several sites the combination of regionally interpolated air temperatures and a degree day model appears capable of generating first order estimates of regional summer balance which can provide a benchmark against which to judge the predictive ability of more complex e g energy balance models applied at a regional scale mass balance sensitivity analyses indicate that a temperature increase of 1 k will increase summer ablation in the region by 0 51 m w e a 1 on average

rapid wastage of alaska glaciers and their contribution to rising sea level we have used airborne laser altimetry to estimate volume changes of 67 glaciers in alaska from the mid 1950s to the mid 1990s the average rate of thickness change of these glaciers was 0 52 m year extrapolation to all glaciers in alaska yields an estimated total annual volume change of 52 15 km 3 year water equivalent equivalent to a rise in sea level sle of 0 14 0 04 mm year repeat measurements of 28 glaciers from the mid 1990s to 2000 2001 suggest an increased average rate of thinning 1 8 m year this leads to an extrapolated annual volume loss from alaska glaciers equal to 96 35 km 3 year or 0 27 0 10 mm year sle during the past decade these recent losses are nearly double the estimated annual loss from the entire greenland ice sheet during the same time period and are much higher than previously published loss estimates for alaska glaciers they form the largest glaciological contribution to rising sea level yet measured

sensitivities of glacier mass balance and runoff to climate perturbations in norway this study evaluates sensitivities of glacier mass balance and runoff to both annual and monthly perturbations in air temperature and precipitation at four highly glacierized catchments engabreen in northern norway and alfotbreen nigardsbreen and storbreen which are aligned along a west east profile in southern norway the glacier mass balance sensitivities to changes in annual air temperature range from 1 74mw e k 1 for alfotbreen to 0 55mw e k 1 for storbreen the most maritime and the most continental glaciers in this study respectively the runoff sensitivities of all catchments are 20 25 per degree temperature change and 6 18 for a 30 precipitation change a seasonality of the sensitivities becomes apparent with increasing continentality the sensitivity of mass balance and runoff to temperature perturbations during summer increases and the sensitivity of annual runoff to both temperature and precipitation perturbations is constricted towards changes during the ablation period comparing sensitivities in northern and southern norway as well as the variability across southern norway reveals that continentality influences sensitivities more than latitude does

sensitivities of the equilibrium line altitude to temperature and precipitation changes along the andes abstract equilibrium line altitudes elas of alpine glaciers are sensitive indicators of climate change and have been commonly used to reconstruct paleoclimates at different temporal and spatial scales however accurate interpretations of ela fluctuations rely on a quantitative understanding of the sensitivity of elas to changes in climate we applied a full surface energy and mass balance model to quantify ela sensitivity to temperature and precipitation changes across the range of climate conditions found in the andes model results show that ela response has a strong spatial variability across the glaciated regions of south america this spatial variability correlates with the distribution of the present day mean climate conditions observed along the andes we find that elas respond linearly to changes in temperature with the magnitude of the response being prescribed by the local lapse rates ela sensitivities to precipitation changes are nearly linear and are inversely correlated with the emissivity of the atmosphere temperature sensitivities are greatest in the inner tropics precipitation becomes more important in the subtropics and northernmost mid latitudes these results can be considered an important step towards developing a framework for understanding past episodes of glacial fluctuations and ultimately for predicting glacier response to future climate changes