remote sensing estimates of glacier mass balances in the himachal pradesh western himalaya india abstract although they correspond to an important fraction of the total area of mountain glaciers 33 000 km2 out of 546 000 km2 himalayan glaciers and their mass balance are poorly sampled for example between 1977 and 1999 the average area surveyed each year on the field was 6 8 km2 only no direct mass balance measurement is available after 1999 to contribute to fill this gap we use remote sensing data to monitor glacier elevation changes and mass balances in the spiti lahaul region 32 2 n 77 6 e himachal pradesh western himalaya india our measurements are obtained by comparing a 2004 digital elevation model dem to the 2000 srtm shuttle radar topographic mission topography the 2004 dem is derived from two spot5 satellite optical images without any ground control points this is achieved thanks to the good on board geolocation of spot5 scenes and using srtm elevations as a reference on the ice free zones before comparison on glaciers the two dems are analyzed on the stable areas surrounding the glaciers where no elevation change is expected two different biases are detected a long wavelength bias affects the spot5 dem and is correlated to an anomaly in the roll of the spot5 satellite a bias is also observed as a function of altitude and is attributed to the srtm dataset both biases are modeled and removed to permit unbiased comparison of the two dem on the 915 km2 ice covered area digitized from an aster image on most glaciers a clear thinning is measured at low elevations even on debris covered tongues between 1999 and 2004 we obtain an overall specific mass balance of 0 7 to 0 85 m a water equivalent depending on the density we use for the lost or gained material in the accumulation zone this rate of ice loss is twice higher than the long term 1977 to 1999 mass balance record for himalaya indicating an increase in the pace of glacier wastage to assess whether these ice losses are size dependant all glaciers were classified into three samples according to their areal extent all three samples show ice loss the loss being higher for glaciers larger than 30 km2 in the case of the benchmark chhota shigri glacier a good agreement is found between our satellite observations and the mass balances measured on the field during hydrological years 2002 2003 and 2003 2004 future studies using a similar methodology could determine whether similar ice losses have occurred in other parts of the himalaya and may allow evaluation of the contribution of this mountain range to ongoing sea level rise

aerodynamic roughness of fixed sandy beds the nature of interactions between surface winds and sand surfaces that can be characterized by aerodynamic roughness length has important implications for aeolian sediment transport here we report the wind tunnel results of systematic tests of the aerodynamic roughness lengths of different sized fixed sand beds at different free stream wind velocities the results suggest that there are complex variations of aerodynamic roughness length wind is an active factor in determining the aerodynamic roughness length of fixed sand beds the so called 1 30 law in aeolian research proposed by bagnold more than a half century ago for sand surfaces is found to suffer some limitations some multivariate models relating aerodynamic roughness length and other factors are provided the differences between the aerodynamic roughness of fixed and mobile beds are discussed and it is implied that mobile surfaces adapt to the wind by changing roughness the similarities between aerodynamic roughness and hydraulic roughness are compared aerodynamic roughness is divided into aerodynamically smooth transitional and completely rough regimes

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

a freshwater old carbon offset in lake baikal siberia and problems with the radiocarbon dating of archaeological sediments evidence from the sagan zaba ii site abstract lake baikal in eastern siberia is one of the largest and deepest freshwater lakes in the world and its diverse fauna were extensively utilized by local human populations over many millennia the regional culture history models primarily are based on radiocarbon dates on human skeletal remains and in some cases also on dates on sediments from habitation sites analyses of a set of 113 radiocarbon dates from the sagan zaba holocene hunter gatherer and pastoralist habitation site 52 6825 n 106 4760 e on the western coast of lake baikal demonstrates two critical problems in the dating of these sets of materials first comparison of ams radiocarbon dates on terrestrial mammal and baikal seal bones from sagan zaba reveals the existence of a freshwater radiocarbon offset in the seal remains of at least 700 radiocarbon years radiocarbon dates on skeletal remains from humans who consumed the aquatic fauna also should be expected to carry an old carbon offset second comparison of radiocarbon dates made on sediment samples with those made on terrestrial mammal bones demonstrates major inconsistencies the primary problem with these samples is that the carbon being dated in them is of unclear relationship to human activities of interest at the site therefore the still common practice in this region of radiocarbon dating sediments to establish archaeological chronologies should be abandoned the ams radiocarbon dating of bone from species which clearly fed outside of lake baikal s aquatic environments should provide more reliable age estimates for human activities at archaeological sites

slip along the sultanhani fault in central anatolia from deformed pleistocene shorelines of palaeo lake konya and implications for seismic hazards in low strain regions

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

from balance to imbalance a shift in the dynamic behaviour of chhota shigri glacier western himalaya india mass balance and dynamic behaviour of chhota shigri glacier have been investigated between 2002 and 2010 and compared to data collected in 1987 1989 during the period 2002 2010 the glacier experienced a negative glacier wide mass balance of 0 67 0 40 m a w e between 2003 and 2010 elevation and ice flow velocities are slowly decreasing in the ablation area leading to a 24 to 37 reduction in ice fluxes an expected response of the glacier dynamics to its recent negative mass balances the reduced ice fluxes still remain far larger than the balance fluxes calculated from the year 2002 to 2010 average surface mass balances therefore further slow down thinning and terminus retreat of chhota shigri glacier are expected over the next years conversely the 2003 2004 ice fluxes are in good agreement with ice fluxes calculated assuming that the glacier wide mass balance is zero given the limited velocity change between 1987 1989 and 2003 2004 and the small terminus change between 1988 and 2010 we suggest that the glacier has experienced a period of near zero or slightly positive mass balance in the 1990s before shifting to a strong imbalance in the 21st century this result challenges the generally accepted idea that glaciers of western himalaya have been shrinking rapidly for the last decades

temperature reconstruction from glacier length fluctuations in the himalaya a temperature reconstruction in the glacierized himalaya over the past centuries using glacial length fluctuation records is challenging due to the abundance of debris covered glaciers and a scarcity of glacial length fluctuation data using idealized flowline model simulations we show that supraglacial debris cover significantly alters the length fluctuations only when the debris cover is very thick an expanded database of length fluctuation records for 43 glaciers in the himalaya and karakoram is compiled and a standard linear inversion procedure is applied to a subset of 34 glaciers in this database the reconstructed temperature anomaly during 1860 2010 indicates a continued warming of the region with a total temperature change of 1 6 k a close resemblance of the regional temperature anomaly to global trends is seen

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

chronology of a sedimentary sequence from the land ocean interaction zone in the north jiangsu basin abstract the north jiangsu basin njb located in the western part of the north jiangsu south yellow sea basin is a critical region providing invaluable archives about the evolution processes of the land ocean interchange and climatic environments in a coastal zone chronology is of crucial importance to reconstruct the timing of sea level eustacy and shoreline changes as well as the evolution of the regional environment by means of numerical dating to determine the age of sedimentary strata in the sea land interaction zone of the njb however sediment dating in the njb remains controversial due to limitations in the quantity and quality of chronological data therefore the sediments in the jianhu gangxi gx profile of the njb were analyzed in this study by applying both fine grained quartz optically stimulated luminescence osl dating and 14c dating the results were used to discuss the processes of regional environment evolution the osl dating of fine grained quartz components in sediments was found to be a reliable method to determine deposition ages of sediments in the land sea interaction zone in the njb the combination of osl and accelerator mass spectrometry 14c dating techniques allowed a reliable and high resolution chronological framework for the gx profile since the last glaciation the sedimentary environment in the eastern portion of the njb changed significantly in particular 1 between 13 and 7 25 ka b p the area of interest was dominated by lacustrine deposition within a stable sedimentary environment with low deposition rates 2 from 7 25 to 6 45 ka b p marine transgression events occurred and the deposition rate increased rapidly in an area of land sea interaction 3 after 6 45 ka b p a regression event occurred and the study area transformed into a lowland lake environment

application of 34s analysis for elucidating terrestrial marine and freshwater ecosystems evidence of animal movement husbandry practices in an early viking community around lake mývatn iceland carbon and nitrogen stable isotope ratios 13c and 15n have been used widely in archaeology to investigate palaeodiet sulphur stable isotope ratios 34s have shown great promise in this regard but the potential of this technique within archaeological science has yet to be fully explored here we report 34s 13c and 15n values for 129 samples of animal bone collagen from skutusta ir an early viking age landnam settlement in north east iceland this dataset represents the most comprehensive study to date of its kind on archaeological material and the results show a clear offset in 34s values between animals deriving their dietary resources from terrestrial mean 5 6 2 8 freshwater mean 2 7 1 4 or marine mean 15 9 1 5 reservoirs with the three food groups being significantly different at 2 this offset allows reconstruction of the dietary history of domesticated herbivores and demonstrates differences in husbandry practices and animal movement trade which would be otherwise impossible using only 13c and 15n values for example several terrestrial herbivores displayed enriched bone collagen 34s values compared to the geology of the lake m vatn region indicating they may have been affected by sea spray whilst being pastured closer to the coast before being traded inland additionally the combination of heavy 15n values coupled with light 34s values within pig bone collagen suggests that these omnivores were consuming freshwater fish as a significant portion of their diet arctic foxes were also found to be consuming large quantities of freshwater resources and radiocarbon dating of both the pigs and foxes confirmed previous studies showing that a large freshwater radiocarbon 14c reservoir effect exists within the lake overall these stable isotope and 14c data have important implications for obtaining a fuller reconstruction of the diets of the early viking settlers in iceland and may allow a clearer identification of the marine and or freshwater 14c reservoir effects that are known to exist in human bone collagen

time variable ice loss in asian high mountains from satellite gravimetry abstract substantial amount of glacial ice is considered to be melting in the asian high mountains gravimetry by grace satellite during 2003 2009 suggests the average ice loss rate in this region of 47 12 gigaton gt yr 1 equivalent to 0 13 0 04 mm yr 1 sea level rise this is twice as fast as the average rate over 40 years before the studied period and agrees with the global tendency of accelerating glacial loss such ice loss rate varies both in time and space mass loss in himalaya is slightly decelerating while those in northwestern glaciers show clear acceleration uncertainty still remains in the groundwater decline in northern india and proportion of almost isostatic e g tectonic uplift and non isostatic e g glacial isostatic adjustment portions in the current uplift rate of the tibetan plateau if gravity increase associated with ongoing glacial isostatic adjustment partially canceled the negative gravity trend the corrected ice loss rate could reach 61 gt yr 1

a comparison of empirical and physically based glacier surface melt models for long term simulations of glacier response we investigate the performance of five glacier melt models over a multi decadal period in order to assess their ability to model future glacier response the models range from a simple degree day model based solely on air temperature to more sophisticated models including the full shortwave radiation balance in addition to the empirical models the performance of a physically based energy balance eb model is examined the melt models are coupled to an accumulation and a surface evolution model and applied in a distributed manner to rhonegletscher switzerland over the period 1929 2012 at hourly resolution for calibration seasonal mass balance measurements 2006 12 are used decadal ice volume changes for six periods in the years 1929 2012 serve for model validation over the period 2006 12 there are almost no differences in performance between the models except for eb which is less consistent with observations likely due to lack of meteorological in situ data however simulations over the long term 1929 2012 reveal that models which include a separate term for shortwave radiation agree best with the observed ice volume changes indicating that their melt relationships are robust in time and thus suitable for long term modelling in contrast to more empirical approaches that are oversensitive to temperature fluctuations

radiocarbon reservoir effects in human bone collagen from northern iceland human bone collagen from a series of icelandic human pagan graves was radiocarbon 14c dated to aid understanding of early settlement landnam chronologies in northern iceland these individuals potentially consumed marine protein the 14c age of samples containing marine carbon requires a correction for the marine 14c reservoir effect the proportion of non terrestrial sample carbon was quantified via measurement of carbon stable isotopes 13c using a simple mixing model based on 13c measurements of archaeofaunal samples non terrestrial carbon was also quantified in six pig bones from the archaeofaunal dataset assuming all non terrestrial carbon in human and pig bone collagen was marine derived calibrated age ranges calculated using a mixed intcal09 marine09 calibration curve were consistent with an early settlement date close to landnam but several samples returned pre landnam age ranges measurements of nitrogen stable isotopes 15n strongly suggest that many of the human bone collagen samples contain freshwater diet derived carbon icelandic freshwater systems frequently display large freshwater 14c reservoir effects of the order of 10 000 14c years and we suggest that the presence of freshwater carbon is responsible for the anomalously early ages within our dataset in pig samples the majority of non terrestrial carbon is freshwater in origin but in human samples the proportion of freshwater carbon is within the error of the marine component 10 this presents a major obstacle to assessing temporal patterns in the ages of human remains from sampled graves although the majority of grave ages are within the same broad calibrated range

meteorological controls on glacier mass balance in high asia the aim of this study is to investigate spatial and temporal variations of meteorological variables known to control glacier mass balance processes and to demonstrate their relevance in high asia the study uses the ncep ncar reanalysis database us national centers for environmental prediction and us national center for atmospheric research which is global and continuous since 1 january 1948 a positive degree day pdd model of annual glacier wide summer surface balance bs uses upper air temperatures at ncep ncar gridpoints near each of six glaciers between 40 and 458 n and between 71 and 878 e and two others near 508 n 878 e model error ranged between 0 19 and 0 41 m w e comparable with the observational accuracy of bs sensitivity to temperature change dbs dt ranges between 0 5 and 0 2 m w e a 1 8c 1 for these glaciers

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

implications of a freshwater radiocarbon reservoir correction for the timing of late holocene settlement of the elk hills kern county california abstract uncertainties regarding the magnitude of freshwater radiocarbon reservoir effects can introduce random errors into dates on archaeological freshwater carbonates as a result many archaeologists avoid dating freshwater shells unless no other datable materials are available the chronology of prehistoric occupation of the former naval petroleum reserve no 1 npr 1 at elk hills kern county has been established with 50 radiocarbon dates on freshwater mussels gonidea and anodonta sp characterization of any freshwater radiocarbon reservoir effect is crucial for the accurate interpretation of inferred settlement and subsistence changes on the elk hills paired charcoal and freshwater mussels sampled from closely associated contexts were dated to identify a freshwater reservoir effect paired anodonta and gonidea sp shells were dated to investigate interspecific differences in fractionation results indicate that a 340 20 14 c yr correction should be applied to conventional 14 c dates on freshwater carbonates in the buena vista basin before calendar calibration evidence of interspecific differences is inconclusive dates recalibrated with the reservoir correction indicate that widespread occupation of the elk hills is correlated with increasing precipitation towards the end of the medieval climatic anomaly and during the little ice age suggesting that slough resource exploitation may have been driven by regional population pressure rather than drought related declines in aquatic productivity

mediaeval lead pollution in the river ouse at york england the city of york in northern england has a long history of being flooded by the river ouse excavations of a 9 m sedimentary profile were carried out by the york archaeological trust on the site of a pumping station associated with a flood prevention scheme at north street on the south west bank of the river ouse this profile records evidence of human activity and episodic river sedimentation over a period from the 2nd to the 14th century ad anthropogenic materials in the profile include waterfront timber and wattle structures and dumps of organic domestic debris and industrial waste evidence of historic floods is preserved in interleaved alluvial deposits this study reports on the degree of lead pb contamination at the site from roman to mediaeval times and the sources of both alluvial and manufactured lead deposited in the profile archaeological sedimentological geochemical and mineralogical evidence suggest that yorkshire dales mining activity during the 9th 13th centuries ad may have both directly and indirectly caused lead contamination of the alluvial deposits at north street

application of inventory data for estimating characteristics of and regional climate change effects on mountain glaciers a pilot study with the european alps a parameterization scheme using simple algorithms for unmeasured glaciers is being applied to glacier inventory data to estimate the basic glaciological characteristics of the inventoried ice bodies and simulate potential climate change effects on mountain glaciers for past and potential climate scenarios glacier changes for assumed mass balance changes are calculated as step functions between steady state conditions for time intervals that approximately correspond to the characteristic dynamic response time a few decades of the glaciers in order to test the procedure a pilot study was carried out in the european alps where detailed glacier inventories had been compiled around the mid 1970s total glacier volume in the alps is estimated at about 130 km3 for the mid 1970s strongly negative mass balances are likely to have caused a loss of about 10 20 of this total volume during the decade 1980 90 backward calculation of glacier length changes using a mean annual mass balance of 0 25m w e a 1 since the end of the little ice age around 1850 ad gives considerable scatter but satisfactory overall results as compared with long term observations the total loss of alpine surface ice mass since 1850 can be estimated at about half the original value an acceleration of this development with annual mass losses of around 1 m a 1 or more as anticipated from ipcc scenario a for the coming century could eliminate major parts of the presently existing alpine ice volume within decades

sensitivity of mass balance and equilibrium line altitude to climate change in the french alps assessment of the sensitivity of surface mass balance and equilibrium line altitude ela to climate change is crucial for simulating the future evolution of glaciers such an assessment has been carried out using an extensive dataset comprising numerous measurements of snow accumulation and snow and ice ablation made on four french glaciers over the past 16 years winter mass balance shows a complicated pattern with respect to altitude with no clear linear relationship although the ratios of winter mass balance to valley precipitation differ considerably from site to site they are relatively constant over time relationships between snow ice ablation and temperature are stable with no link with altitude the mean snow and ice positive degree day pdd factors are 0 003 and 0 0061 m w e c 1 d 1 this analysis shows that at a given site ablation depends mainly on the amount of snow precipitation and on cumulative pdds the sensitivity of annual ablation to temperature change increases almost linearly from 0 25 m w e c 1 at 3500 m to 1 55 m w e c 1 at 1650 m ela sensitivity to temperature change was found to range from 50 to 85 m c 1

geodetic and direct mass balance measurements comparison and joint analysis this paper describes a new compilation of both direct and geodetic mass balance measurements develops a procedure to reduce diverse balance measurements over different time spans to common time spans and presents updated estimates of global average balance of small glaciers based on the enlarged compilation although geodetic measurements are fewer than direct measurements they cover four times as many balance years direct and geodetic measurements are unbiased with respect to one another but differences are often substantial the statistical procedure can be understood by imagining that an n year balance measurement is an average of a series of 1 year measurements the series is hypothetical but we can calculate the uncertainty of each of its elements if in addition to its measured average we can also estimate its standard deviation for this claim to be valid the annual series must be stationary and normally distributed with independent roughly uncorrelated elements for which there is reasonable evidence the need to know the standard deviation means that annual direct measurements from a nearby glacier or equally reliable information about variability are indispensable given this information the new methodology results in moderately more negative balances this is probably because tidewater glaciers are better represented in the geodetic data in any case the most recent published estimate of global average balance 0 8 1 0 mm a 1 of sea level equivalent for 2001 04 is now increased substantially to 1 1 1 4 mm a 1 for 2001 05

freshwater reservoir effect and the radiocarbon chronology of the cemetery in ząbie poland in the 3rd millennium bc an island on the anskie lake in north eastern poland was seasonally settled by a group of people practicing a syncretic burial ritual exhibiting indigenous and foreign patterns they left behind a small cemetery consisting of at least six graves 14c dates made for samples of human bones until 2009 did not coincide with the expected age of the graves under a new pilot program in 2010 2013 a series of radiocarbon measurements was made for the human bones and an artefact of red deer antler along with analyses of the stable isotopes ratios of carbon 13c and nitrogen 15n in the collagen the results indicate a significant proportion of freshwater food in the diet which caused the radiocarbon dates to be too old due to the freshwater reservoir effect fre based on the dating of the antler unaffected by fre and comparative analysis the reservoir offset for one of the graves was estimated to 740 radiocarbon years the results although limited by a low number of investigated humans and animals indicate indirectly a specialization in the exploitation of local water resources such an economic strategy seems to be characteristic for the societies inhabiting the coasts of the baltic sea and littoral zones of large lakes in the final neolithic and at the beginning of the early bronze age

understanding the variability in freshwater radiocarbon reservoir offsets a cautionary tale abstract freshwater resources in past diets can lead to inaccuracies when attempts are made to ascertain their radiocarbon ages or those of the consumers radiocarbon reservoir effects may lead to significant age offsets when the bones or other tissues of these consumers are radiocarbon dated a number of recent studies have investigated freshwater reservoir offsets however no study thus far has satisfactorily obtained a ubiquitous freshwater reservoir correction due to variability in the ecosystems analysed this study tests the possibility of predicting freshwater reservoir effects from the carbonate alkalinity of the water with measurements on modern fish bone and water samples a predictive capability would be especially valuable in the absence of well preserved archaeological fish bone we surveyed samples from lakes and rivers in varying geological settings in britain and ireland modern fish bone and water samples were analysed to investigate modern radiocarbon offsets from the atmosphere archaeological fish bone was also analysed to examine past reservoir offsets at selected sites stable carbon and nitrogen isotope values were measured to aid in interpretation of any variability in the offsets large freshwater reservoir offsets were measured in some modern and archaeological samples maximum offset 1638 14 c years the freshwater reservoir offsets in the fish bone were highly correlated with alkalinity of water in modern lake sites analysed however a high amount of variation within and between fish species was also evident in the results precluding the possibility of providing regional corrections for freshwater reservoir offsets from alkalinity although this still may provide a general guideline the variability is thought to be due to differences in the diet of individual fish

marine or estuarine radiocarbon reservoir corrections for mollusks a case study from a medieval site in the south of england abstract mollusk shells are frequently radiocarbon dated and provide reliable calibrated age ranges when the regional marine reservoir correction is well established for mollusks from an estuarine environment the reservoir correction may be significantly different than the regional marine reservoir correction due to the input of bedrock or soil derived carbonates some mollusk species such as oysters are tolerant of a significant range of salinities which makes it difficult to determine which reservoir correction is appropriate a case study is presented of an anomalous radiocarbon age for an oyster shell paint dish found in the fabric of the ruined nave walls of st mary s church shoreham by sea west sussex england stable isotopes 18 o and 13 c were used to establish the type of environment in which the oyster had lived paired marine and terrestrial samples from a nearby medieval site were radiocarbon dated to provide an appropriate reservoir correction

freshwater radiocarbon reservoir age in the lower yellow river floodplain during the late holocene the radiocarbon concentration of the dissolved inorganic carbon dic pool of most freshwater bodies such as lakes and rivers tends to be depleted with respect to that of the contemporaneous atmosp

using remote sensing data to determine equilibrium line altitude and mass balance time series validation on three french glaciers 1994 2002 alpine glaciers are very sensitive to climate fluctuations and their mass balance can be used as an indicator of regional scale climate change here we present a method to calculate glacier mass balance using remote sensing data snowline measurements from remotely sensed images recorded at the end of the hydrological year provide an effective proxy of the equilibrium line mass balance can be deduced from the equilibrium line altitude ela variations three well documented glaciers in the french alps where the mass balance is measured at ground level with a stake network were selected to assess the accuracy of the method over the 1994 2002 period eight mass balance cycles results obtained by ground measurements and remote sensing are compared and show excellent correlation r 2 0 89 both for the ela and for the mass balance indicating that the remote sensing method can be applied to glaciers where no ground data exist on the scale of a mountain range or a given climatic area the main differences can be attributed to discrepancies between the dates of image acquisition and field measurements cloud cover and recent snowfalls constitute the main restrictions of the image based method

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

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

the randolph glacier inventory a globally complete inventory of glaciers the randolph glacier inventory rgi is a globally complete collection of digital outlines of glaciers excluding the ice sheets developed to meet the needs of the fifth assessment of the intergovernmental panel on climate change for estimates of past and future mass balance the rgi was created with limited resources in a short period priority was given to completeness of coverage but a limited uniform set of attributes is attached to each of the 198 000 glaciers in its latest version 3 2 satellite imagery from 1999 2010 provided most of the outlines their total extent is estimated as 726 800 34 000 km 2 the uncertainty about 5 is derived from careful single glacier and basin scale uncertainty estimates and comparisons with inventories that were not sources for the rgi the main contributors to uncertainty are probably misinterpretation of seasonal snow cover and debris cover these errors appear not to be normally distributed and quantifying them reliably is an unsolved problem combined with digital elevation models the rgi glacier outlines yield hypsometries that can be com bined with atmospheric data or model outputs for analysis of the impacts of climatic change on glaciers the rgi has already proved its value in the generation of significantly improved aggregate estimates of glacier mass changes and total volume and thus actual and potential contributions to sea level rise

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

an enhanced temperature index glacier melt model including the shortwave radiation balance development and testing for haut glacier d arolla switzerland an enhanced temperature index glacier melt model incorporating incoming shortwave radiation and albedo is presented the model is an attempt to combine the high temporal resolution and accuracy of physically based melt models with the lower data requirements and computational simplicity of empirical melt models represented by the degree day method and its variants the model is run with both measured and modelled radiation data to test its applicability to glaciers with differing data availability five automatic weather stations were established on haut glacier d arolla switzerland between may and september 2001 reference surface melt rates were calculated using a physically based energy balance melt model the performance of the enhanced temperature index model was tested at each of the four validation stations by comparing predicted hourly melt rates with reference melt rates predictions made with three other temperature index models were evaluated in the same way for comparison the enhanced temperature index model offers significant improvements over the other temperature index models and accounts for 90 95 of the variation in the reference melt rate the improvement is lower but still significant when the model is forced by modelled shortwave radiation data thus offering a better alternative to existing models that require only temperature data input

spatial variability of 14c reservoir effects in tibetan plateau lakes abstract radiocarbon dating of lake sediments is often hampered by the presence of a lake reservoir effect lre also dead carbon or old carbon effect especially in dry and cold regions with a sparse plant cover in the catchment the tibetan plateau became a hotspot of the palaeoenvironmental and climate research community in recent years and the assessment of present day lres is a crucial prerequisite for the establishment of reliable radiocarbon age depth relationships for lake sediment cores this paper examines the spatial variability of lres within individual lakes through a discussion of new data for lake donggi cona and a compilation of previously published data for five additional lakes where lre data are available for different sites lake reservoir effects for lake donggi cona on the northeastern tibetan plateau were determined for shells of aquatic snails collected alive close to the lake s shore the largest determined lre of 20 000 14 c years is significantly larger than previously reported lres from the central part of the lake and larger than any previously published lre for the tibetan plateau relatively low lres in the central regions of lakes higher lres towards the margins and high lres in tributaries and spring waters are apparently a common pattern of tibetan plateau lakes the differences in lres within individual lakes or catchment areas are attributed to the more prolonged exchange of the lake water s dissolved inorganic carbon with the atmospheric co 2 in central lake regions on the one hand and the increasing influence of 14 c free or poor stream and groundwater due to the dissolution of carbonaceous basement rocks towards its margins generally higher lres were recorded in the three tectonically active lake regions of the six examined catchments and it is speculated that rising crustal co 2 further contributes to the lres in these catchments in addition to these observations and inferences elevated 14 c levels of the atmosphere as a result of nuclear bomb testing are often ignored if lres for modern materials are reported by convention relative to the atmospheric 14 c activity of the year 1950 lre data reported in this way represent unrealistic minimum estimates

an assessment of basin scale glaciological and hydrological sensitivities in the hindu kush himalaya glacier responses to future climate change will affect hydrology at sub basin scales the main goal of this study is to assess glaciological and hydrological sensitivities of sub basins throughout the hindu kush himalaya region we use a simple geometrical analysis based on a full glacier inventory and digital elevation model to estimate sub basin equilibrium line altitudes elas from assumptions of steady state accumulation area ratios the ela response to an increase in temperature is expressed as a function of mean annual precipitation derived from a range of high altitude studies changes in glacier contributions to streamflow in response to increased temperatures are examined for scenarios of both static and adjusted glacier geometries on average glacier contributions to streamflow increase by 50 for a 1 k warming based on a static geometry large decreases 60 on average occur in all basins when glacier geometries are instantaneously adjusted to reflect the new ela finally we provide estimates of sub basin glacier response times that suggest a majority of basins will experience declining glacier contributions by 2100

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

discovering anomalous dynamics and disintegrating behaviour in glaciers of chandra bhaga sub basins part of western himalaya using dinsar abstract glacier velocity is one of the important parameters to know about glacier dynamics its mass and health understanding glacier velocity also assists in the analysis of ice thickness ice flux and mass balance furthermore basin sub basin wise studies are helpful to understand the climate change over that region instead of monitoring individual glaciers in the current study the spatial distribution of glacier velocity is generated for the entire chandra and bhaga sub basins in the lahaul spiti district of himachal pradesh india using advanced land observing satellite 2 phased array type l band synthetic aperture radar 2 alos 2 palsar 2 differential interferometry pair images with a 14 days temporal gap the glaciers in chandra sub basin are found to have a high flow rate as compared to the glaciers in bhaga sub basin local slope and ice thickness which decrease towards the terminus in general control the movement of valley glaciers and lower movement rate is observed for most of glaciers towards the terminus frontal area however a few glaciers of bhaga sub basin demonstrate an accelerated movement in their frontal areas this irregular behaviour is also studied in this work and it is discovered that terrain slope and influx of melting water from adjacent glaciers are the major causes for such behaviour of these glaciers they are therefore prone to accelerated mass loss compared to other glaciers in the sub basin another key finding of the anomalous glacier dynamics study is the disintegrating behaviour of glaciers which is also identified by interpreting the responses of physical scattering mechanisms retrieved from glaciers using fully polarimetric alos 2 palsar 2 warming temperatures are expected to cause glacier retreat and separation of tributary glaciers from the main glacier body melt water from tributary glaciers can further accelerate glacier flow and ice melt in lower part of glacier trunk this can lead to formation of dead ice zones and disintegration of himalayan glaciers which are supported by numerous tributary glaciers therefore we expect that the loss in glacier area due to warming will be larger than the present prediction where mass loss is considered from conventional way