understanding the interrelationships among mass balance meteorology discharge and surface velocity on chhota shigri glacier over 2002 2019 using in situ measurements

regionally differentiated contribution of mountain glaciers and ice caps to future sea level rise the contribution to sea level rise from mountain glaciers and ice caps has grown over the past decades a projection of their melting during the twenty first century based on temperature and precipitation projections from ten climate models suggests that by 2100 these glaciers will lose about 21 of their total global volume

mass balance of trambau glacier rolwaling region nepal himalaya in situ observations long term reconstruction and mass balance sensitivity we conducted a mass balance study of debris free trambau glacier in the rolwaling region nepal himalaya which is accessible to 6000 m a s l to better understand mass balance processes and the effect of precipitation on these processes on high elevation himalayan glaciers continuous in situ meteorological and mass balance observations that spanned the three melt seasons from may 2016 are reported an energy and mass balance model is also applied to evaluate its performance and sensitivity to various climatic conditions glacier wide mass balances ranging from 0 34 0 38 m w e in 2016 to 0 82 0 53 m w e in 2017 18 are obtained by combining the observations with model results for the areas above the highest stake the estimated long term glacier mass balance which is reconstructed using the era interim data calibrated with in situ data is 0 65 0 39 m w e a 1 for the 1980 2018 period a significant correlation with annual precipitation r 0 77 p

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

the status and decadal change of glaciers in bhutan from the 1980s to 2010 based on satellite data in order to monitor changes in the glaciers in the bhutan himalaya a repeat decadal glacier inventory was carried out from landsat images of 1977 78 1980 1990 2000 and 2010 the base map of glaciers was obtained by the object based image classification method using the multispectral landsat images of 2010 this method is used separately to delineate clean ice and debriscovered glaciers with some manual editing glacier polygons of 2000 1990 and 1980 were obtained by manual editing on 2010 by separately overlaying respective years the 2010 inventory shows 885 glaciers with a total area of 642 16 1 km the glacier area is 1 6 of the total land cover in bhutan the result of a repeat inventory shows 23 3 0 9 glacial area loss between 1980 and 2010 with the highest loss 11 6 1 2 between 1980 and 1990 and the lowest 6 7 0 1 between 2000 and 2010 the trend of glacier area change from the 1980s to 2010 is 6 4 1 6 loss of glacier area was mostly observed below 5600ma s l and was greater for clean ice glaciers the equilibrium line altitude has shifted upward from 5170 110ma s l to 5350 150ma s l in the years 1980 2010

effect of precipitation seasonality on climatic sensitivity of glacier mass balance abstract numerical calculations are described aimed at evaluating the influence of precipitation seasonality and seasonality concentration on climatic sensitivity of glacier mass balance equilibrium line altitudes elas are modeled using idealized meteorological variables and then a warming test 1 c is performed which revealed that the effects of latitude and the annual precipitation amount are less than those of precipitation seasonality and its concentration calculation shows higher sensitivities for the glaciers located in a summer precipitation climate than for those located within a winter precipitation climate difference due to seasonality is enhanced with the seasonality concentration the present study suggests that the earlier parameterization of glacier mass balance with annual precipitation amount is insufficient to describe the response of glaciers to climate change distribution of precipitation seasonality and its concentration suggest that many parts of the world have a summer precipitation climate but their seasonality concentration is not significant worldwide on the other hand an extensive region of asia and part of the andes are located in the highly concentrated summer precipitation climate this suggests the high sensitivity of glacier mass balance in these regions to climate change

analyzing the evolution of the tessina landslide using aerial photographs and digital elevation models abstract evolution of the tessina landslide near belluno italy from 1954 to the present situation has been documented using multitemporal landslide maps the maps were produced through the interpretation of sequential aerial photographs and direct field mapping of the landslide in 1998 and 1999 the interpretations were converted to large scale multitemporal topographical maps and digitized resulting in detailed geomorphological maps of the tessina landslide for the following periods 1954 1961 1969 1980 1991 1993 1998 and 1999 a quantitative volumetric analysis was also carried out using a series of digital elevation models derived from the available 1 5000 scale digital contour maps with 5 m contour interval for 1948 1964 1980 1991 and 1993 the total volume of material removed and accumulated was calculated for the entire tessina landslide for the different time steps available results indicate that the tessina landslide existed prior to its main reactivation in 1960 after which the landslide reduced in activity from 1991 however very large reactivations have taken place and the landslide continues to be active although the landslide has reached the lateral boundaries of the old pre 1960 landslide it is now expanding upslope where it may still mobilize large amounts of material

performance of aster and srtm dems and their potential for assessing glacial lakes in the lunana region bhutan himalaya to assess the potential volume of a glacial lake outburst flood glof more precisely than in previous studies we analyze ground survey data and remote sensing digital elevation models dems around glacial lakes in the lunana region bhutan based on a dem generated from differential gps ground surveys we first evaluate the relative accuracies of dems produced by the advanced spaceborne thermal emission and reflection radiometer aster and the shuttle radar topography mission srtm root mean square errors of the altitudinal difference between these dems and ground survey data were 11 0 m for aster and 11 3 m for srtm these errors are similar to those of previous studies we show that a topographical classification allows a better estimate of elevation on lakes ponds riverbeds and glaciers due to their flat surfaces while the relative accuracy is worse over moraines and hill slopes due to their narrow ridges and steep slopes using the optical satellite images and the ground survey data we re evaluate the glof volume in 1994 as 17 2 5 3 10 6 m 3 we show glof related information such as distance altitudinal difference and gradient at possible outburst points where the lake level is higher than the neighboring riverbed and or glacial lake

preliminary results of mass balance observations of yala glacier and analysis of temperature and precipitation gradients in langtang valley nepal monitoring the glacier mass balance of summer accumulation type himalayan glaciers is critical to not only assess the impact of climate change on the volume of such glaciers but also predict the downstream water availability and the global sea level change in future to better understand the change in meteorological parameters related to glacier mass balance and runoff in a glacierized basin and to assess the highly heterogeneous glacier responses to climate change in the nepal himalaya and nearby ranges the cryosphere monitoring project cmp carries out meteorological observations in langtang valley and mass balance measurements on yala glacier a debris free glacier in the same valley a negative annual mass balance of 0 89 m w e and the rising equilibrium line altitude of yala glacier indicate a continuation of a secular trend toward more negative mass balances lower temperature lapse rate during the monsoon the effect of convective precipitation associated with mesoscale thermal circulation in the local precipitation and the occurrence of distinct diurnal cycles of temperature and precipitation at different stations in the valley are other conclusions of this comprehensive scientific study initiated by cmp which aims to yield multi year glaciological hydrological and meteorological observations in the glacierized langtang river basin

mass balance and a glacier surge of guliya ice cap in the western kunlun shan between 2005 and 2015 abstract contemporary estimates of glacier changes are necessary to assess the impact of climate change associated hazards and water resources management glaciers in high mountain asia hma are mostly retreating except the karakoram and western kunlun shan confirmed by remote sensing measurements however ground validation with precise measurements of these mass balance estimates are scarce this study selected guliya ice cap in the western kunlun shan to observe its recent changes regarding surface dynamics and mass balance using aster dem of 2005 and 2015 our findings indicate that one of the north facing glaciers surged with no previous surging history during july and early november 2015 advancing at about 8 m per day on average the mass balance shows a balance condition 0 01 0 02 m w e a 1 the icesat data 2004 2008 at selected locations compared to dgps data collected in the field during 2015 indicating a minute difference of 0 03 0 05 m a 1 with aster data in the same area our findings suggest that guliya ice cap in the western kunlun shan is in equilibrium state following a similar pattern mass gain or stable conditions as observed previously

climate science himalayan glaciers in the balance a measurement by satellite altimetry shows the himalayan glaciers to be losing mass at only moderate rates but raises broader questions about other methods for estimating mass balance see letter p 495

effect of summer accumulation on glacier mass balance on the tibetan plateau revealed by mass balance model the characteristics and sensitivities of a cold based glacier on the tibetan plateau where the summer monsoon provides most of the mass input to glaciers are discussed using an energy balance model incorporating the process of water refreezing the model accurately represents the observational results related to the mass balance of xiao dongkemadi glacier on the central plateau during 1992 93 our data revealed that the mass balance of cold glaciers cannot simply be described by the surface mass heat balances because about 20 of infiltrated water is refrozen and thus does not run off from the glacier model calculations demonstrate that glaciers in an arid environment can maintain their mass since the monsoon provides precipitation during the melting season snowfall in summer keeps surface albedo high and largely restrains ablation nevertheless the calculations also make clear that glaciers on the plateau are more vulnerable than those of other regions because of summer accumulation in the monsoon climate warming would cause not only a decrease in accumulation but also a drastic increase in ablation in combination with surface albedo lowering therefore although glaciers on and around the plateau can be sustained by summer accumulation they are more vulnerable to warming than winter accumulation type glaciers

the sustainability of water resources in high mountain asia in the context of recent and future glacier change high mountain asia contains the largest volume of glacier ice outside the polar regions and contain the headwaters of some of the largest rivers in central asia these glaciers are losing mass at a mean rate of between 0 18 and 0 5 m water equivalent per year while glaciers in the himalaya are generally shrinking those in the karakoram have experienced a slight mass gain both changes have occurred in response to rising air temperatures due to northern hemisphere climate change in the westerly influenced indus catchment glacier meltwater makes up a large proportion of the hydrological budget and loss of glacier mass will ultimately lead to a decrease in water supplies in the monsoon influenced ganges and brahmaputra catchments the contribution of glacial meltwater is relatively small compared to the indus and the decrease in annual water supplies will be less dramatic therefore enhanced glacier melt will increase river flows until the middle of the twenty first century but in the longer term into the latter part of this century river flows will decline as glaciers shrink declining meltwater supplies may be compensated by increases in precipitation but this could exacerbate the risk of flooding

elevation changes of glaciers revealed by multitemporal digital elevation models calibrated by gps survey in the khumbu region nepal himalaya 1992 2008 due to remoteness and high altitude only a few ground based glacier change studies are available in high mountain areas in the himalaya however digital elevation models based on remotely sensed data rs dems provide feasible opportunities to evaluate how fast himalayan glaciers are changing here we compute elevation changes in glacier surface total area 183 3 km in the khumbu region nepal himalaya for the period 1992 2008 using multitemporal rs dems and a map derived dem calibrated with differential gps survey data in 2007 elevation change is calculated by generating a weighted least squares linear regression model our method enables us to provide the distribution of uncertainty of the elevation change debris covered areas show large lowering rates the spatial distribution of elevation change shows that the different wastage features of the debris covered glaciers depend on their scale slope and the existence of glacial lakes the elevation changes of glaciers in the eastern khumbu region are in line with previous studies the regional average mass balance of 0 40 0 25mw e a for the period 1992 2008 is consistent with a global value of about 0 55mw e a for the period 1996 2005

the potential of 3d gully monitoring with gis using high resolution aerial photography and a digital photogrammetry system although gully erosion is generally considered a major process of land degradation its contribution to total soil loss by erosion has recently been a subject of much discussion the lack of adequate methods for the documentation and monitoring of gullies resulted in the shortage of quantitative data therefore a high resolution remote sensing system for aerial surveys by blimp or kite has been developed which meets spatial and temporal image resolutions required for short term gully monitoring the objective of this paper is to examine the potential of a method using non metric digital photogrammetry and gis for gully surface modelling and monitoring two bank gullies representing different morphological types of gullies v shaped and u shaped were chosen from a dataset of gully systems in semi arid spain the considerable relief energy and complex topography of the gullies in a natural vegetated landscape were found to be a challenge to digital photogrammetric techniques introducing errors which inhibit fully automated dem generation using a hybrid method combining stereomatching for mass point extraction with manual 3d editing and digitizing high resolution dems 5 and 7 5 cm pixel size were created for the study sites gis analysis of the dems for different monitoring periods 2 to 4 years allowed the computation of gully area and volume as well as their changes with an accuracy and detail sufficient to represent the geomorphological forms and processes involved furthermore the spatially continuous survey of the entire form offered the possibility of distinguishing different zones of activity both at the gully rim and within the gully interior identifying patterns of erosion and deposition which indicate the limited use of headcut retreat rates for the assessment of sediment production on a short term basis

monitoring landslides from optical remotely sensed imagery the case history of tessina landslide italy collecting information on landslide occurrence and activity over wide areas is a crucial task for landslide hazard assessment field techniques despite being very precise are usually not sufficient to achieve this goal since they mostly provide pointbased measurements mainly because of its synoptic view and its capability for repetitive observations optical visible infrared remotely sensed imagery acquired at different dates and at high spatial resolution can be considered as an effective complementary tool for field techniques to derive such information an image processing method to map and monitor landslide activity using multitemporal optical imagery is proposed the method entails automatic change detection of suitably pre processed geometrically registered and radiometrically normalised sequential images followed by thresholding into landslide related change pixels subsequent filtering based on the degree of rectangularity of regions can also be considered to eliminate pixel clusters corresponding to man made land use changes the application of this method is illustrated in the complex tessina landslide in the eastern italian alps it has focused on discriminating the effects of a major reactivation that occurred in 1992 hence inferring the dynamics of the landslide at that time although the method has been devised for optical remote sensing imagery in general in the absence of high resolution satellite imagery covering that period digital images derived by scanning existing aerial photograph diapositives at 1 m pixel size have been used the method is able to classify image pixels according to landslide activity conditions d 2003 elsevier science b v all rights reserved

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

limestone biopitting in coastal settings a spatial morphometric sem and molecular microbiology sequencing study in the mallorca rocky coast balearic islands western mediterranean abstract biological agency on rock coasts has been widely recognised over recent decades this study deals with the distribution and morphometric characteristics of microforms features developed by cyanobacteria rivularia sp on coastal limestone outcrops these coastal microforms known as biopits have a small rounded basin shape a few millimetres in size environmental and geological data were collected from 100 random rock surface spots from punta des farallo cape mallorca western mediterranean from which major controls on the spatial distribution of biopits were established additionally morphological data on 382 biopits determined the diagnostic morphometry of these features and their enlargement mechanisms the results indicated that biopits exhibit a preferential location in shaded exposures and sheltered areas from prevailing winds and waves avoiding direct insolation and desiccation other major controls on these microforms location and development were variables such as the rock surface slope and the distance to the coast i e influence of splash and spray shadow spots displayed higher biopits density than other locations according to the patterns determined by environmental and geomorphological factors at the study site morphometric analyses showed that biopits have a width twice their depth the average width of the microforms was 6 49 2 40 mm and the average depth 2 46 1 09 mm most frequently the width depth ratio was 2 or larger this characteristic shape ratio was an additional factor that plays a role in maintaining the necessary humidity for microorganisms associated with biopits

a low cost landslide displacement activity assessment from time lapse photogrammetry and rainfall data application to the tessina landslide site abstract acquiring useful and reliable displacement data from a complex landslide site is often a problem because of large localized and scattered erosive processes and deformations the inaccessibility of the site the high cost of instrumentation and maintenance however these data are of fundamental importance not only to hazard assessments but also to understanding the processes at the basis of slope evolution in this framework time lapse photogrammetry can represent a good compromise the low accuracy is compensated for by the wide ranging and dense spatial displacement information that can be obtained with inexpensive equipment nevertheless when large displacement monitoring data sets become available the problem becomes the choice of the most suitable statistical model to describe the probability of movement and adequately simplify the complexity of a scattered intermittent and spatially inhomogeneous displacement field in this paper an automated displacement detection method which is based on the absolute image differences and digital correlations from a sequence of photos was developed and applied to a photographic survey activity at the head of the tessina landslide northeastern italy the method allowed us to simplify and binarize the displacement field and to recognize the intermittent activity and the peculiar behaviours of different parts of the landslide which were identified and classified by combining geomorphological and geological information moreover for the first time sliding correlations between these areas were quantitatively estimated using time series based binary logistic regression and the definition of a probability based directed graph of displacement occurrence that connected the source zones to the lower depletion basin and the main collector channel using rainfall data event based logistic and poisson regression models were applied to the upper zones of the landslide to estimate the probability of movement of each scarp and the persistence of the displacement as a result of certain rainfall events the results of these statistical analyses highlighted the capability of this approach to quantitatively evaluate the pattern of displacement occurrences and to assess the evolution of a landslide site to gain insight into geomorphological processes

first in situ record of decadal glacier mass balance 2003 2014 from the bhutan himalaya this study presents the first decadal mass balance record of a small debris free glacier in the bhutan himalaya where few in situ measurements have been reported to date since 2003 we have measured the mass balance of gangju la glacier which covers an area of 0 3km 2 and extends from 4900 to 5200ma s l using both differential gps surveys geodetic method and stake measurements direct method the observed mass balance ranged from 1 12 to 2 04mw e a 1 between 2003 and 2014 the glacier exhibited much greater mass loss than neighbouring glaciers in the eastern himalaya and southeastern tibet which are expected to be sensitive to climate change due to the monsooninfluenced humid climate observed mass balance profiles suggest that the equilibrium line altitude has been higher than gangju la glacier since 2003 implying that the entire glacier has experienced net ablation for at least the past decade

slight mass gain of karakoram glaciers in the early twenty first century the mass balance of hindu kush karakoram himalaya glaciers has been debated partly because of a severe lack of observations from the region an analysis of the regional mass balance of karakoram glaciers by comparison of digital elevation models from 1999 to 2008 reveals a small glacier mass gain in the area

structure from motion photogrammetry a low cost effective tool for geoscience applications abstract high resolution topographic surveying is traditionally associated with high capital and logistical costs so that data acquisition is often passed on to specialist third party organisations the high costs of data collection are for many applications in the earth sciences exacerbated by the remoteness and inaccessibility of many field sites rendering cheaper more portable surveying platforms i e terrestrial laser scanning or gps impractical this paper outlines a revolutionary low cost user friendly photogrammetric technique for obtaining high resolution datasets at a range of scales termed structure from motion sfm traditional softcopy photogrammetric methods require the 3 d location and pose of the camera s or the 3 d location of ground control points to be known to facilitate scene triangulation and reconstruction in contrast the sfm method solves the camera pose and scene geometry simultaneously and automatically using a highly redundant bundle adjustment based on matching features in multiple overlapping offset images a comprehensive introduction to the technique is presented followed by an outline of the methods used to create high resolution digital elevation models dems from extensive photosets obtained using a consumer grade digital camera as an initial appraisal of the technique an sfm derived dem is compared directly with a similar model obtained using terrestrial laser scanning this intercomparison reveals that decimetre scale vertical accuracy can be achieved using sfm even for sites with complex topography and a range of land covers example applications of sfm are presented for three contrasting landforms across a range of scales including an exposed rocky coastal cliff a breached moraine dam complex and a glacially sculpted bedrock ridge the sfm technique represents a major advancement in the field of photogrammetry for geoscience applications our results and experiences indicate sfm is an inexpensive effective and flexible approach to capturing complex topography

landslide monitoring by using ground based sar interferometry an example of application to the tessina landslide in italy abstract an innovative technique based on radar interferometry and implemented using ground based instrumentation has been applied for monitoring the tessina landslide italy belluno the technique has allowed us to derive multitemporal surface deformation maps of the entire depletion zone of the landslide with a high spatial resolution and accuracy the portable device used in this application is known as linear sar lisa and it is able to provide measurements at 17 ghz with a synthetic aperture of up to 2 8 m the results have been validated by comparing the recorded pixel displacements with independent measurements carried out by a motorized theodolite and electronic distance meter edm on two benchmarks

topographic controls on the debris cover extent of glaciers in the eastern himalayas regional analysis using a novel high resolution glacier inventory abstract to better understand the influence of topography on the formation of himalayan debris covered glaciers we manually digitized 5301 glaciers covering an area of 5691 893 km2 from high resolution advanced land observing satellite imagery and identified 842 debris covered glaciers with a debris covered area of 3839 753 km2 this estimation of the debris covered area of these glaciers is a novel approach in the eastern himalayas we investigated the relationship between the debris covered area and the corresponding potential debris supply pds slopes for the debris covered glaciers across the region the pds slopes on the southern side show better correlation with their debris covered area formation than those situated on the northern side of the himalayan barrier with this correlation weakening toward the western massifs further investigation showed that pds slopes oriented se to w exert a stronger control on the formation of debris covered areas which is related to the diurnal freeze thaw cycle on the southern slope of the mountain barrier

using global positioning system techniques in landslide monitoring the precise determination of point coordinates with conventional global positioning system gps techniques often required observation times of one to several hours in the last few years new gps methods have been developed among them the fast static and real time kinematic with higher productivity and good theoretical precision the main objective of this paper is to ascertain the performance of these methods in landslide monitoring practice we present first of all the basic principles of the gps the equipment and working procedures we discuss afterwards the applicability of the gps to the monitoring of landslide surface displacements compared with the classical surveying methods the gps allows a larger coverage and productivity with similar accuracy furthermore it can work in all kinds of weather conditions and a direct line of sight between stations is not required finally we present an example of the performance of the gps equipment in the landslide of vallcebre eastern pyrenees spain this landslide has been periodically monitored since 1987 with terrestrial photogrammetry and geodetic measurements theodolite electronic distance metres edm the movement extends over an area of 0 8 km2 and has experienced displacements as large as 1 6 m during the period 1996 1997 14 campaigns over a period of 26 months using both static and kinematic gps methods have been carried out the gps measurements have been compared with the results obtained with the edm inclinometers and wire extensometers and checked against fixed stable points the precision achieved with the gps measurements is 12 to 16 mm in the horizontal plane and 18 to 24 mm in elevation 2000 elsevier science b v all rights reserved