spatially integrated geodetic glacier mass balance and its uncertainty based on geostatistical analysis application to the western svartisen ice cap norway estimates of glacier mass balance using geodetic methods can differ significantly from estimates using direct glaciological field based measurements to determine if such differences are real or methodological there is a need to improve uncertainty estimates in both methods in this paper we focus on the uncertainty of geodetic methods and describe a geostatistical technique that takes into account the spatial correlation of the elevation differences when calculating spatially averaged elevation changes we apply this method to the western svartisen ice cap norway using elevation differences from the surrounding bedrock derived from stereophotogrammetry we show that the uncertainty is not only dependent on the standard error of the individual elevation differences but is also dependent on the size of the averaging area and the scale of the spatial correlation to assess if the geostatistical analysis made over bedrock is applicable to glacier surfaces we use concurrent photogrammetrical and laser scanning data from bedrock and a range of glacier surfaces to evaluate the dependency of the geostatistical analysis on the surface type the estimated geodetic mass balance and its uncertainty is 2 6 0 9 m w e for the period 1968 85 and 2 0 2 2 m w e for 1985 2002

a distributed temperature index ice and snowmelt model including potential direct solar radiation hourly melt and discharge of storglaciaren a small glacier in sweden were computed for two melt seasons applying temperature index methods to a 30 m resolution grid for the melt component the classical degree day method yielded a good simulation of the seasonal patient of discharge but the pronounced melt induced daily discharge cycles were not captured modelled degree day factors calculated for every hour and each gridcell from melt obtained from a distributed energy balance model varied substantially both diurnally and spatially a new distributed temperature index model is suggested attempting to capture both the pronounced diurnal melt cycles and the spatial variations in melt due to the effects of surrounding topography this is accomplished by including a radiation index in terms of potential clear sky direct solar radiation and thus without the need for other data besides air temperature this approach improved considerably the simulation of diurnal discharge fluctuations and yielded a more realistic spatial distribution of melt rates the incorporation of measured global radiation to account for the reduction in direct solar radiation due to cloudiness did not lead to additional improvement in model performance

glacier mass balance of norway 1961 2010 calculated by a temperature index model glacier mass balance in norway is only observed over a small portion 1 between 2000 and 2010 after four decades of zero to slightly positive annual mass balances

investigations on intra annual elevation changes using multi temporal airborne laser scanning data case study engabreen norway key issues of glacier monitoring are changes in glacier geometry and glacier mass as accurate direct measurements are costly and time consuming the use of various remote sensing data for glacier monitoring is explored one technology used and described here is airborne laser scanning the method enables the derivation of high quality digital elevation models dems with a vertical and horizontal accuracy in the sub metre range between september 2001 and august 2002 three laser scanner data acquisition flights were carried out covering the whole area of engabreen norway and corresponding well to the measurement dates for the mass balance year 2001 02 the data quality of the dems is assessed e g by comparing the values with a control area which has been surveyed independently or gps ground profiles measured during the flights for the whole glacier surface elevation change and consequently volume change is calculated quantified and compared with traditional mass balance data for the same time interval for the winter term emergence submergence velocity is determined from laser scanner data and snow depth data and is compared with velocity measurements at stakes the investigations reveal the high potential of airborne laser scanning for measuring the extent and the topography of glaciers as well as changes in geometry area volume

geodetic mass balance of the western svartisen ice cap norway in the periods 1968 1985 and 1985 2002 the geodetic mass balance of the western svartisen ice cap in northern norway is determined in this work from photogrammetry on vertical aerial photographs taken in 1968 1985 and 2002 the existing 1968 digital terrain model dtm was generated using analogue photogrammetry and the 1985 and 2002 dtms are newly generated using digital photogrammetry the geodetic mass balance for 1968 85 is 2 6 0 8 m w e and for 1985 2002 it is 2 0 1 6 m w e the area of western svartisen decreased from 190 km 2 in 1968 to 187 km 2 in 1985 and to 184 km 2 in 2002 the outlet glacier flatisen in the southeast retreated 1700 m over the two periods the geodetic mass balance is also determined for engabreen drainage basin as 2 1 0 9 m w e for the first period and 0 3 2 4 m w e for the second the results for engabreen are compared to traditional mass balances and the large deviations cannot be explained from uncertainties determined for the geodetic method the assessed errors contributing to the uncertainty in the geodetic mass balance are elevation errors uncertainties from the applied melt correction and the use of sorge s law assuming constant snow thickness and density

widespread and accelerating glacier retreat on the lyngen peninsula northern norway since their little ice age maximum the recession of mountain glaciers worldwide is increasing global sea level and in many regions human activities will have to adapt to changes in surface hydrology thus it is important to provide up to date analyses of glacier change and the factors modulating their response to climate warming here we report changes in the extent of 120 glaciers on the lyngen peninsula northern norway where glacier runoff is utilised for hydropower and where glacial lake outburst floods have occurred glaciers covered at least 114 km2 in 1953 and we compare this inventory with those from 1988 2001 and a new one from 2014 and previously dated little ice age lia limits results show a steady reduction in area 0 3 a 1 between their lia maximum 1915 and 1988 consistent with increasing summer air temperatures but recession paused between 1988 and 2001 coinciding with increased winter precipitation air temperatures increased 0 5 c per decade from the 1990s and the rate of recession accelerated to 1 a 1 between 2001 and 2014 when glacier area totalled 95 7 km2 small glaciers 0 05 km2 with low maximum elevations 1400 m experienced the largest percentage losses and if warming continues several glaciers may disappear within the next two decades

langfjordjokelen a rapidly shrinking glacier in northern norway in this paper we document changes of langfjordjokelen a small ice cap in northern norway surface mass balance measurements have been carried out on an east facing part 3 2 km 2 o f the ice cap since 1989 measurements reveal a strong thinning the balance year 2008 09 was the 13th successive year with significant negative annual balance 0 30 m w e the average annual deficit was 0 9 m w e over 1989 2009 the recent thinning of langfjordjokelen is stronger than observed for any other glacier in mainland norway maps from 1966 1994 and 2008 show that the whole ice cap is shrinking the total volume loss over 1966 2008 was 0 264 km 3 the east facing part has been greatly reduced in volume 46 area 38 and length 20 for this part over 1994 2008 the cumulative direct mass balance 14 5 m w e is less negative than the geodetic mass balance 17 7 m w e a surface mass balance model using upper air meteorological data was used to reconstruct annual balances back to 1948 and to reconstruct unmeasured years 1994 and 1995 sensitivity of annual balance to 18c warming is 0 76 m w e and to 10 increase in precipitation is 0 20 m w e

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

glacier change in norway since the 1960s an overview of mass balance area length and surface elevation changes in this paper we give an overview of changes in area length surface elevation and mass balance of glaciers in mainland norway since the 1960s frontal advances have been recorded in all regions except the northernmost glaciers in troms and finnmark storsteinsfjellbreen lyngen and langfjordjokelen more than half of the observed glaciers 27 of 49 had marked advances in the 1990s the glaciological mass balance values for the period 1962 2018 where 43 glaciers have been measured show great inter annual variability the results reveal accelerated deficit since 2000 the most negative decade being 2001 2010 some years with a positive mass balance or less negative after 2010s can be attributed to variations in large scale atmospheric circulation a surface elevation change and geodetic mass balance were calculated for a sample of 131 glaciers covering 817 km 2 in the 1960s and 734 km 2 in the 2010s giving an area reduction of 84 km 2 or 10 the sample covers many of the largest glaciers in norway and they had an overall change in surface elevation of 15 5 m for the 50 year period converted to a geodetic mass balance this gives a mean mass balance of 0 27 0 05 m w e a 1

photogrammetric reconstruction of glacier mass balance using a kinematic ice flow model a 20 year time series on grubengletscher swiss alps the kinematic boundary condition at the glacier surface can be used to provide glacier mass balance at individual points if changes in surface elevation horizontal and vertical surface velocities and surface slope are known vertical ice velocity can in turn be estimated from basal slope basal ice velocity and surface strain this relation is applied to reconstruct a 20 year mass balance curve of grubengletscher swiss alps largely using repeated aerial photogrammetry but only a minimum of field work for individual years the mass balance distribution on the glacier tongue was modelled with an accuracy of about 0 9 m a 1 ice mechanical assumptions and errors in glacier bed geometry markedly affect discrete mass balance patterns but are eliminated to a major extent when calculating year to year mass balance changes the resulting curve for the grubengletscher tongue 1973 1992 shows reasonable consistency with meteorological data and other glaciologically derived mass balance series large changes in measured ice speed on the glacier tongue 50 significantly governed the long term variability of ice thickness over the observational period

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

extracting a climate signal from 169 glacier records i constructed a temperature history for different parts of the world from 169 glacier length records using a first order theory of glacier dynamics i related changes in glacier length to changes in temperature the derived temperature histories are fully independent of proxy and instrumental data used in earlier reconstructions moderate global warming started in the middle of the 19th century the reconstructed warming in the first half of the 20th century is 0 5 kelvin this warming was notably coherent over the globe the warming signals from glaciers at low and high elevations appear to be very similar

mass balance of glaciers and ice caps consensus estimates for 1961 2004 1 working with comprehensive collections of directly measured data on the annual mass balance of glaciers other than the two ice sheets we combine independent analyses to show that there is broad agreement on the evolution of global mass balance since 1960 mass balance was slightly below zero around 1970 and has been growing more negative since then excluding peripheral ice bodies in greenland and antarctica global average specific balance for 1961 1990 was 219 112 kg m 2 a 1 representing 0 33 0 17 mm sle sea level equivalent a 1 for 2001 2004 the figures are 510 101 kg m 2 a 1 and 0 77 0 15 mm sle a 1 including the smaller greenland and antarctic glaciers global total balance becomes 0 38 0 19 mm sle a 1 for 1961 1990 and 0 98 0 19 mm sle a 1 for 2001 2004 for 1991 2004 the glacier contribution 0 77 0 26 mm sle a 1 is 20 30 of a recent estimate of 3 2 0 4 mm a 1 of total sea level rise for 1993 2005 while our error estimates are not rigorous we believe them to be liberal as far as they go but we also discuss several unquantified biases of which any may prove to be significant

stable carbon isotope record of terrestrial organic materials for the last 450 ma yr abstract the timing and magnitude of carbon isotope excursions is essential for understanding the global transfer of carbon among the oceansland and atmosphere numerous studies have focused on data collection of stable carbon isotopes 13c from marine sediments and by extension to the atmosphere but many fewer systematic studies have been conducted on land plants over long time intervals we pursued three approaches to determining stable carbon isotope trends for the past 450 ma yr from c3 plants 13cp in 5 ma yr time steps first a compilation of 6888 13cp values from ten carbon sources from the literature average 24 6 1 7 isoorg data base the second approach assumes the 13cp is controlled primarily by the 13c of atmospheric co2 13ca and subsequent isotopic fractionation from diffusion and carboxylation during photosynthesis mod1 the third approach assumes changes in atmospheric co2 concentration pco2 causes physiological driven isotopic fractionation during photosynthesis when pco2 is greater than average holocene conditions mod2 compared to isoorg and mod1 mod2 reveals lower 13cp by up to 6 during periods when pco2 is elevated as secular governors of 13cp the 13ca and pco2 are most influential when they are directional and amplify the isotopic signal despite potential influences from local and regional environmental conditions and averaging the 13cp of multiple plant sources in many of the 5 ma yr age bins ten positive carbon isotopic excursions pcies are identified in isoorg of this study most of the excursions occurred during cool to glacial conditions or ocean anoxic events one prominent negative isotopic excursion ensued from 260 to 240 ma yr which may have been a response to oxidation of light c methane outbursts volcanic eruptions or bolide impact

centreline and cross glacier air temperature variability on an alpine glacier assessing temperature distribution methods and their influence on melt model calculations the spatio temporal distribution of air temperature over mountain glaciers can demonstrate complex patterns yet it is often represented simplistically using linear vertical temperature gradients vtgs extrapolated from off glacier locations we analyse a network of centreline and lateral air temperature observations at tsanteleina glacier italy during summer 2015 on average vtgs are steep 1 but they are shallow under warm ambient conditions when the correlation between air temperature and elevation becomes weaker published along flowline temperature distribution methods explain centreline observations well including warming on the lower glacier tongue but cannot estimate lateral temperature variability application of temperature distribution methods improves simulation of melt rates rmse in an energy balance model by up to 36 compared to the environmental lapse rate extrapolated from an off glacier station however results suggest that model parameters are not easily transferable to glaciers with a small fetch without recalibration such methods have potential to improve estimates of temperature across a glacier but their parameter transferability should be further linked to the glacier and atmospheric characteristics furthermore cold spots which can be 2 c cooler than expected for their elevation whose occurrence is not predicted by the temperature distribution models are identified at one quarter of the measurement sites

modelling 60 years of glacier mass balance and runoff for chhota shigri glacier western himalaya northern india glacier mass balance and runoff are simulated from 1955 to 2014 for the catchment 46 glacier cover containing chhota shigri glacier western himalaya using gridded data from three regional climate models 1 the rossby centre regional atmospheric climate model v 4 rca4 2 the regional atmosphere model remo and 3 the weather research and forecasting model wrf the input data are downscaled to the simulation grid 300 m and calibrated with point measurements of temperature and precipitation additional input is daily potential global radiation calculated using a dem at a resolution of 30 m the mass balance model calculates daily snow accumulation melt and runoff the model parameters are calibrated with available mass balance measurements and results are validated with geodetic measurements other mass balance model results and run off measurements simulated annual mass balances slightly decreased from 0 3 m w e a 1 1955 99 to 0 6 m w e a 1 for 2000 14 for the same periods mean runoff increased from 2 0 m 3 s 1 1955 99 to 2 4 m 3 s 1 2000 14 with glacier melt contributing about one third to the runoff monthly runoff increases are greatest in july due to both increased snow and glacier melt whereas slightly decreased snowmelt in august and september was more than compensated by increased glacier melt

life history of a cyclonic ring detached from the kuroshio extension as seen by the geosat altimeter the sea surface dynamic topography ssdt sea surface height relative to the geoid is approximately estimated by combining the temporal fluctuation of ssdt determined from altimetry data with the climatological mean ssdt calculated from hydrographic data this approximated ssdt or composite ssdt is obtained in the area southeast of japan for the first year 1986 1987 of the geosat exact repeat mission variations in the kuroshio current system are well described by the composite ssdt in particular a complete life history of a cyclonic ring is observed for the first time in this region namely westward propagation of a southward meander of the kuroshio extension its pinching off to form a cyclonic ring the ring s westward movement its coalescence with the kuroshio and its eastward advection all available hydrographic data and cloud free satellite infrared images support the existence of this series of phenomena

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

a distributed surface energy balance model for complex topography and its application to storglaciaren sweden a grid based surface energy balance mass balance model has been developed to simulate snow and ice melt in mountainous regions with an hourly resolution the model is applied to storglaciaren a valley glacier in sweden using a 30 m resolution digital elevation model emphasis is directed towards computing the radiation components these are modelled individually considering the effects of slope angle aspect and effective horizon a new parameterization for snow albedo is suggested modifying the albedo of the preceding hour as a function of time after snowfall air temperature and cloudiness the model is used to provide the meltwater input for discharge modelling and to assess the influence of the individual components on melt results are validated by means of observed melt rates patterns of snow line retreat and proglacial discharge in general simulations are in good agreement with observations in particular the diurnal and seasonal fluctuations of discharge are simulated remarkably well

conventional versus reference surface mass balance glacier surface mass balance evaluated over the actual glacier geometry depends not only on climatic variations but also on the dynamic adjustment of glacier geometry therefore it has been proposed that reference surface balances calculated over a constant glacier hypsometry are better suited for climatic interpretation here we present a comparison of 82 year modelled time series 1926 2008 of conventional and reference surface balance for 36 swiss glaciers over this time period the investigated glaciers have lost 22 of their area and ice surface elevation close to the current glacier terminus has decreased by 78 m on average conventional balance in the last decade at 0 91 m w e a 1 is 0 14 m w e a 1 less negative than the reference surface balance about half of the negative stabilizing feedback on mass balance due to glacier terminus retreat is compensated by more negative mass balances due to surface lowering short term climatic variability is clearly reflected in the conventional mass balance series however the magnitude of the long term negative trend is underestimated compared to that found in the reference surface balance series both conventional and reference surface specific balances show large spatial variability among the 36 glaciers

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

reconstruction of mass balance of glaciers in southern norway back to 1948 a model using upper air meteorological variables in the us national centers for environmental prediction and us national center for atmospheric research ncep ncar re analysis database is used to extend net balance bn back to 1948 for seven glaciers in southern norway the observational record of another glacier storbreen began in 1948 over the observational record of each of the seven glaciers correlation with storbreen estimates bn more accurately than the upper air model does for four of them and less accurately for three in all seven cases however an average of the model and the storbreen correlation is more accurate than either alone so the average is used to reconstruct bn for years when it was not observed for the seven glaciers other than storbreen a combined series is formed from observations during their period of record and from reconstructed values prior to then back to 1948 there are three distinct sections in all eight bn series prior to 1989 1989 1995 when the north atlantic oscillation index was strongly positive and after 1995 the 1989 95 mean bn was anomalously positive because of both decreased ablation and especially increased accumulation the mean bn since 1995 has been anomalously negative because of increased ablation whilst accumulation has been nearly the same as over 1948 88 the first principal component of the eight 1949 2005 bn series explains 78 of the total variance and the second explains 12 over 1949 88 there were no substantial shifts in bn or in either winter balance bw or summer balance bs at any of the seven glaciers where observations began after 1948 nor were there in the storbreen record there is a distinction between the three glaciers that gained mass over 1948 2005 and the five that lost mass each of the three that gained had accumulation area ratio aar 0 64 and 0 7 of its areas in the lowest tenth of its altitude range while the five that lost had aar 0 46 and 1 9 s 4 4 because of these hypsometries the five glaciers that lost mass now have an especially large ablation area