scholarly journals Latest Geodetic Changes of Austre Lovénbreen and Pedersenbreen, Svalbard

2019 ◽  
Vol 11 (24) ◽  
pp. 2890 ◽  
Author(s):  
Songtao Ai ◽  
Xi Ding ◽  
Florian Tolle ◽  
Zemin Wang ◽  
Xi Zhao
Keyword(s):  
Mass Balance ◽  
Snow Depth ◽  
Spline Interpolation ◽  
Time Interval ◽  
Short Time Interval ◽  
Mass Balances ◽  
Glacier Surface ◽  
Elevation Changes ◽  
Rtk Gps ◽  
Geodetic Mass Balance

Geodetic mass changes in the Svalbard glaciers Austre Lovénbreen and Pedersenbreen were studied via high-precision real-time kinematic (RTK)-global positioning system (GPS) measurements from 2013 to 2015. To evaluate the elevation changes of the two Svalbard glaciers, more than 10,000 GPS records for each glacier surface were collected every year from 2013 to 2015. The results of several widely used interpolation methods (i.e., inverse distance weighting (IDW), ordinary kriging (OK), universal kriging (UK), natural neighbor (NN), spline interpolation, and Topo to Raster (TTR) interpolation) were compared. Considering the smoothness and accuracy of the glacier surface, NN interpolation was selected as the most suitable interpolation method to generate a surface digital elevation model (DEM). In addition, we compared two procedures for calculating elevation changes: using DEMs generated from the direct interpolation of the RTK-GPS points and using the elevation bias of crossover points from the RTK-GPS tracks in different years. Then, the geodetic mass balances were calculated by converting the elevation changes to their water equivalents. Comparing the geodetic mass balances calculated with and without considering snow depth revealed that ignoring the effect of snow depth, which differs greatly over a short time interval, might lead to bias in mass balance investigation. In summary, there was a positive correlation between the geodetic mass balance and the corresponding elevation. The mass loss increased with decreasing elevation, and the mean annual gradients of the geodetic mass balance along the elevation of Austre Lovénbreen and Pedersenbreen in 2013–2015 were approximately 2.60‰ and 2.35‰, respectively. The gradients at the glacier snouts were three times larger than those over the whole glaciers. Additionally, some mass gain occurred in certain high-elevation regions. Compared with a 2019 DEM generated from unmanned aerial vehicle measurement, the glacier snout areas presented an accelerating thinning situation in 2015–2019.

scholarly journals Geodetic Mass Balance of Haxilegen Glacier No. 51, Eastern Tien Shan, from 1964 to 2018

2022 ◽  
Vol 14 (2) ◽  
pp. 272
Author(s):  
Chunhai Xu ◽  
Zhongqin Li ◽  
Feiteng Wang ◽  
Jianxin Mu ◽  
Xin Zhang
Keyword(s):  
Mass Loss ◽  
Mass Balance ◽  
Laser Scanning ◽  
Mean Value ◽  
Tien Shan ◽  
Glacier Mass Balance ◽  
Topographic Map ◽  
Glacier Surface ◽  
Elevation Changes ◽  
Geodetic Mass Balance

The eastern Tien Shan hosts substantial mid-latitude glaciers, but in situ glacier mass balance records are extremely sparse. Haxilegen Glacier No. 51 (eastern Tien Shan, China) is one of the very few well-measured glaciers, and comprehensive glaciological measurements were implemented from 1999 to 2011 and re-established in 2017. Mass balance of Haxilegen Glacier No. 51 (1999–2015) has recently been reported, but the mass balance record has not extended to the period before 1999. Here, we used a 1:50,000-scale topographic map and long-range terrestrial laser scanning (TLS) data to calculate the area, volume, and mass changes for Haxilegen Glacier No. 51 from 1964 to 2018. Haxilegen Glacier No. 51 lost 0.34 km2 (at a rate of 0.006 km2 a−1 or 0.42% a−1) of its area during the period 1964–2018. The glacier experienced clearly negative surface elevation changes and geodetic mass balance. Thinning occurred almost across the entire glacier surface, with a mean value of −0.43 ± 0.12 m a−1. The calculated average geodetic mass balance was −0.36 ± 0.12 m w.e. a−1. Without considering the error bounds of mass balance estimates, glacier mass loss over the past 50 years was in line with the observed and modeled mass balance (−0.37 ± 0.22 m w.e. a−1) that was published for short time intervals since 1999 but was slightly less negative than glacier mass loss in the entire eastern Tien Shan. Our results indicate that Riegl VZ®-6000 TLS can be widely used for mass balance measurements of unmonitored individual glaciers.

scholarly journals Geometry, mass balance and thinning at Eklutna Glacier, Alaska: an altitude-mass-balance feedback with implications for water resources

2017 ◽  
Vol 63 (238) ◽  
pp. 343-354 ◽  
Author(s):  
LOUIS C. SASS ◽  
MICHAEL G. LOSO ◽  
JASON GECK ◽  
EVAN E. THOMS ◽  
DANIEL MCGRATH
Keyword(s):  
Mass Loss ◽  
Mass Balance ◽  
Mass Balances ◽  
Negative Mass ◽  
Short Term ◽  
Glacier Surface ◽  
Surface Mass ◽  
Accumulation Zone ◽  
Southcentral Alaska ◽  
Elevation Changes

ABSTRACTWe analyzed glacier surface elevations (1957, 2010 and 2015) and surface mass-balance measurements (2008–2015) on the 30 km2Eklutna Glacier, in the Chugach Mountains of southcentral Alaska. The geodetic mass balances from 1957 to 2010 and 2010 to 2015 are −0.52 ± 0.46 and −0.74 ± 0.10 m w.e. a−1, respectively. The glaciological mass balance of −0.73 m w.e. a−1from 2010 to 2015 is indistinguishable from the geodetic value. Even after accounting for loss of firn in the accumulation zone, we found most of the mass loss over both time periods was from a broad, low-slope basin that includes much of the accumulation zone of the main branch. Ice-equivalent surface elevation changes in the basin were −1.0 ± 0.8 m a−1from 1957 to 2010, and −0.6 ± 0.1 m a−1from 2010 to 2015, shifting the glacier hypsometry downward and resulting in more negative mass balances: an altitude-mass-balance feedback. Net mass loss from Eklutna Glacier accounts for 7 ± 1% of the average inflow to Eklutna Reservoir, which is entirely used for water and power by Anchorage, Alaska's largest city. If the altitude-mass-balance feedback continues, this ‘deglaciation discharge dividend’ is likely to increase over the short-term before it eventually decreases due to diminishing glacier area.

scholarly journals Long-range terrestrial laser scanning measurements of summer and annual mass balances for Urumqi Glacier No. 1, eastern Tien Shan, China

2018 ◽  
Author(s):  
Chunhai Xu ◽  
Zhongqin Li ◽  
Huilin Li ◽  
Feiteng Wang ◽  
Ping Zhou
Keyword(s):  
Mass Balance ◽  
Laser Scanning ◽  
Terrestrial Laser Scanning ◽  
Tien Shan ◽  
Surface Mass Balance ◽  
Mass Balances ◽  
Surface Mass ◽  
Elevation Changes ◽  
Geodetic Mass Balance

Abstract. The direct glaciological method typically provides in situ observations of annual or seasonal surface mass balance, but can only be implemented through a succession of intensive in situ measurements of measuring networks of stakes and snow pits. This has contributed to glacier surface mass-balance measurements being sparse and often discontinuous in the Tien Shan. Nevertheless, long-term glacier mass-balance measurements are the basis for understanding climate–glacier interactions and projecting future water availability for glacierized catchments in the Tien Shan. Riegl VZ®-6000 long-range terrestrial laser scanning (TLS), typically using class 3B laser beams, is exceptionally well suited for measuring snowy and icy terrain in repeated glacier mapping, and subsequently annual and seasonal geodetic mass balance can be determined. This paper introduces the applied TLS for monitoring summer and annual surface elevation and geodetic mass changes of Urumqi Glacier No. 1 (UG1) as well as delineating accurate glacier boundaries for two consecutive years (2015-17), and discusses the potential of such technology in glaciological applications. Three-dimensional changes of ice and firn/snow bodies and the corresponding densities were considered for the volume-to-mass conversion. UG1 showed pronounced thinning and mass loss for the four investigated periods; glacier-wide geodetic mass balance in the mass-balance year 2015-16 was slightly more negative than in 2016-17. The majority of TLS-derived geodetic elevation changes at individual stakes were slightly positive, but showed a close correlation with the glaciological elevation changes (changes in exposed stake height) of individual stakes (R2 ≥ 0.90). Statistical comparison shows that agreement between the glaciological and geodetic mass balances can be considered satisfying, indicating that the TLS system yields accurate results and has the potential to monitor remote and inaccessible glacier areas where no glaciological measurements are available.

scholarly journals Long-range terrestrial laser scanning measurements of annual and intra-annual mass balances for Urumqi Glacier No. 1, eastern Tien Shan, China

2019 ◽  
Vol 13 (9) ◽  
pp. 2361-2383 ◽  
Author(s):  
Chunhai Xu ◽  
Zhongqin Li ◽  
Huilin Li ◽  
Feiteng Wang ◽  
Ping Zhou
Keyword(s):  
Mass Balance ◽  
Long Range ◽  
Tien Shan ◽  
Glacier Mass Balance ◽  
Surface Mass Balance ◽  
Mass Balances ◽  
Surface Mass ◽  
Mass Conversion ◽  
Geodetic Mass Balance

Abstract. The direct glaciological method provides in situ observations of annual or seasonal surface mass balance, but can only be implemented through a succession of intensive in situ measurements of field networks of stakes and snow pits. This has contributed to glacier surface mass-balance measurements being sparse and often discontinuous in the Tien Shan. Nevertheless, long-term glacier mass-balance measurements are the basis for understanding climate–glacier interactions and projecting future water availability for glacierized catchments in the Tien Shan. Riegl VZ®-6000 long-range terrestrial laser scanner (TLS), typically using class 3B laser beams, is exceptionally well suited for repeated glacier mapping, and thus determination of annual and seasonal geodetic mass balance. This paper introduces the applied TLS for monitoring summer and annual surface elevation and geodetic mass changes of Urumqi Glacier No. 1 as well as delineating accurate glacier boundaries for 2 consecutive mass-balance years (2015–2017), and discusses the potential of such technology in glaciological applications. Three-dimensional changes of ice and firn–snow bodies and the corresponding densities were considered for the volume-to-mass conversion. The glacier showed pronounced thinning and mass loss for the four investigated periods; glacier-wide geodetic mass balance in the mass-balance year 2015–2016 was slightly more negative than in 2016–2017. Statistical comparison shows that agreement between the glaciological and geodetic mass balances can be considered satisfactory, indicating that the TLS system yields accurate results and has the potential to monitor remote and inaccessible glacier areas where no glaciological measurements are available as the vertical velocity component of the glacier is negligible. For wide applications of the TLS in glaciology, we should use stable scan positions and in-situ-measured densities of snow–firn to establish volume-to-mass conversion.

scholarly journals An optimized method to calculate the geodetic mass balance of mountain glaciers

2018 ◽  
Vol 64 (248) ◽  
pp. 917-931 ◽  
Author(s):  
RUBÉN BASANTES-SERRANO ◽  
ANTOINE RABATEL ◽  
CHRISTIAN VINCENT ◽  
PASCAL SIRGUEY
Keyword(s):  
Spatial Variability ◽  
Mass Balance ◽  
Mean Difference ◽  
Full Density ◽  
Elevation Change ◽  
Low Contrast ◽  
Mountain Glaciers ◽  
Elevation Changes ◽  
Geodetic Mass Balance ◽  
Similar Accuracy

ABSTRACTUnderstanding the effects of climate on glaciers requires precise estimates of ice volume change over several decades. This is achieved by the geodetic mass balance computed by two means: (1) the digital elevation model (DEM) comparison (SeqDEM) allows measurements over the entire glacier, however the low contrast over glacierized areas is an issue for the DEM generation through the photogrammetric techniques and (2) the profiling method (SePM) is a faster alternative but fails to capture the spatial variability of elevation changes. We present a new framework (SSD) that relies upon the spatial variability of the elevation change to densify a sampling network to optimize the surface-elevation change quantification. Our method was tested in two small glaciers over different periods. We conclude that the SePM overestimates the elevation change by ~20% with a mean difference of ~1.00 m (root mean square error (RMSE) = ~3.00 m) compared with results from the SeqDEM method. A variogram analysis of the elevation changes showed a mean difference of <0.10 m (RMSE = ~2.40 m) with SSD approach. A final assessment on the largest glacier in the French Alps confirms the high potential of our method to compute the geodetic mass balance, without going through the generation of a full-density DEM, but with a similar accuracy than the SeqDEM approach.

scholarly journals Application of a mass-balance model to a Himalayan glacier

1999 ◽  
Vol 45 (151) ◽  
pp. 559-567 ◽  
Author(s):  
Rijan Bhakta Kayastha ◽  
Tetsuo Ohata ◽  
Yutaka Ageta
Keyword(s):  
Mass Balance ◽  
Surface Albedo ◽  
Balance Model ◽  
Mass Balance Model ◽  
Mass Balances ◽  
Climatic Parameters ◽  
Glacier Surface ◽  
Temperature And Precipitation ◽  
Ice Surface ◽  
Good Agreement

AbstractA mass-balance model based on the energy balance at the snow or ice surface is formulated, with particular attention paid to processes affecting absorption of radiation. The model is applied to a small glacier, Glacier AX010 in the Nepalese Himalaya, and tests of its mass-balance sensitivity to input and climatic parameters are carried out. Calculated and observed area-averaged mass balances of the glacier during summer 1978 (June-September) show good agreement, namely -0.44 and -0.46 m w.e., respectively.Results show the mass balance is strongly sensitive to snow or ice albedo, to the effects of screening by surrounding mountain walls, to areal variations in multiple reflection between clouds and the glacier surface, and to thin snow covers which alter the surface albedo. In tests of the sensitivity of the mass balance to seasonal values of climatic parameters, the mass balance is found to be strongly sensitive to summer air temperature and precipitation but only weakly sensitive to relative humidity.

scholarly journals Comparison of direct and geodetic mass balances on a multi-annual time scale

2010 ◽  
Vol 4 (3) ◽  
pp. 1151-1194
Author(s):  
A. Fischer
Keyword(s):  
Mass Balance ◽  
Direct Method ◽  
Mean Difference ◽  
Published Data ◽  
Glacier Mass Balance ◽  
Mass Balances ◽  
Direct Data ◽  
The Mean ◽  
The Difference ◽  
Geodetic Mass Balance

Abstract. Glacier mass balance is measured with the direct or the geodetic method. In this study, the geodetic mass balances of six Austrian glaciers in 19 periods between 1953 and 2006 are compared to the direct mass balances in the same periods. The mean annual geodetic mass balance for all periods is −0.5 m w.e./year. The mean difference between the geodetic and the direct data is −0.7 m w.e., the minimum −7.3 m w.e. and the maximum 5.6 m w.e. The accuracy of geodetic mass balance resulting from the accuracy of the DEMs ranges from 2 m w.e. for photogrammetric data to 0.002 m w.e. for LIDAR data. Basal melt, seasonal snow cover and density changes of the surface layer contribute up to 0.7 m w.e. for the period of 10 years to the difference to the direct method. The characteristics of published data of Griesgletscher, Gulkana Glacier, Lemon Creek glacier, South Cascade, Storbreen, Storglaciären, and Zongo Glacier is similar to these Austrian glaciers. For 26 analyzed periods with an average length of 18 years the mean difference between the geodetic and the direct data is −0.4 m w.e., the minimum −7.2 m w.e. and the maximum 3.6 m w.e. Longer periods between the acquisition of the DEMs do not necessarily result in a higher accuracy of the geodetic mass balance. Specific glaciers show specific trends of the difference between the direct and the geodetic data according to their type and state. In conclusion, geodetic and direct mass balance data are complementary, but differ systematically.

scholarly journals Investigations on intra-annual elevation changes using multi-temporal airborne laser scanning data: case study Engabreen, Norway

2005 ◽  
Vol 42 ◽  
pp. 195-201 ◽  
Author(s):  
Thomas Geist ◽  
Hallgeir Elvehøy ◽  
Miriam Jackson ◽  
Johann Stötter
Keyword(s):  
Mass Balance ◽  
Laser Scanning ◽  
Laser Scanner ◽  
Remote Sensing Data ◽  
Control Area ◽  
Airborne Laser Scanning ◽  
Time Interval ◽  
Scanner Data ◽  
Glacier Surface ◽  
Airborne Laser

AbstractKey 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 (Δarea, Δvolume).

scholarly journals Changes of the tropical glaciers throughout Peru between 2000 and 2016 – Mass balance and area fluctuations

2019 ◽  
Author(s):  
Thorsten Seehaus ◽  
Philipp Malz ◽  
Christian Sommer ◽  
Stefan Lippl ◽  
Alejo Cochachin ◽  
...  
Keyword(s):  
Mass Balance ◽  
Landsat Imagery ◽  
Ratio Method ◽  
Time Interval ◽  
Temporal Region ◽  
Glacier Area ◽  
Mass Balances ◽  
Study Region ◽  
Tropical Glaciers ◽  
Glacier Changes

Abstract. Glaciers in tropical regions are very sensitive to climatic variations and thus strongly affected by climate change. The majority of the tropical glaciers worldwide are located in the Peruvian Andes, which have shown significant ice loss in the last century. Here, we present the first multi-temporal, region wide survey of geodetic mass balances and glacier area fluctuations throughout Peru covering the period 2000–2016. Glacier extents are derived from Landsat imagery by performing automatic glacier delineation based on a combination of the NDSI and band ratio method and final manual inspection and correction. A total glacier area loss of −548.5 ± 65.7 km2 (−29 %, −34.3 km2 a−1) is obtained for the study period. Using interferometric satellite SAR acquisitions, bi-temporal geodetic mass balances are derived. An average specific mass balance of −357 ± 43 kg m−2 a−1 is found throughout Peru for the period 2000–2016. However, there are strong regional and temporal differences in the mass budgets ranging from 68 ± 102 kg m−2 a−1 to −990 ± 476 kg m−2 a−1. The ice loss increased towards the end of the observation period. Between 2013 and 2016, a retreat of the glaciated area of −203.8 ± 65.7 km2 (− 16 %, −101.9 km2 a−1) is mapped and the average mass budget amounts to −836 ± 188 kg m−2 a−1. The glacier changes revealed can be attributed to changes in the climatic settings in the study region, derived from ERA-Interim reanalysis data and the Oceanic Niño Index. The intense El Niño activities in 2015/16 are most likely the trigger for the increased change rates in the time interval 2013–2016. Our observations provide fundamental information on the current dramatic glacier changes for local authorities and for the calibration and validation of glacier change projections.

scholarly journals Mass balances of Yala and Rikha Samba glaciers, Nepal, from 2000 to 2017

2021 ◽  
Vol 13 (8) ◽  
pp. 3791-3818
Author(s):  
Dorothea Stumm ◽  
Sharad Prasad Joshi ◽  
Tika Ram Gurung ◽  
Gunjan Silwal
Keyword(s):  
Mass Loss ◽  
Mass Balance ◽  
Water Resource Management ◽  
Important Variable ◽  
Glacier Mass Balance ◽  
Mass Balances ◽  
Monitoring Strategies ◽  
Length Changes ◽  
The Mean ◽  
Geodetic Mass Balance

Abstract. The glacier mass balance is an important variable to describe the climate system and is used for various applications like water resource management or runoff modelling. The direct or glaciological method and the geodetic method are the standard methods to quantify glacier mass changes, and both methods are an integral part of international glacier monitoring strategies. In 2011, we established two glacier mass-balance programmes on Yala and Rikha Samba glaciers in the Nepal Himalaya. Here we present the methods and data of the directly measured annual mass balances for the first six mass-balance years for both glaciers from 2011/2012 to 2016/2017. For Yala Glacier we additionally present the directly measured seasonal mass balance from 2011 to 2017, as well as the mass balance from 2000 to 2012 obtained with the geodetic method. In addition, we analysed glacier length changes for both glaciers. The directly measured average annual mass-balance rates of Yala and Rikha Samba glaciers are −0.80 ± 0.28 and −0.39 ± 0.32 m w.e. a−1, respectively, from 2011 to 2017. The geodetically measured annual mass-balance rate of Yala Glacier based on digital elevation models from 2000 and 2012 is −0.74 ± 0.53 m w.e. The cumulative mass loss for the period 2011 to 2017 for Yala and Rikha Samba glaciers is −4.80 ± 0.69 and −2.34 ± 0.79 m w.e., respectively. The mass loss on Yala Glacier from 2000 to 2012 is −8.92 ± 6.33 m w.e. The winter balance of Yala Glacier is positive, and the summer balance is negative in every investigated year. The summer balance determines the annual balance. Compared to regional mean geodetic mass-balance rates in the Nepalese Himalaya, the mean mass-balance rate of Rikha Samba Glacier is in a similar range, and the mean mass-balance rate of Yala Glacier is more negative because of the small and low-lying accumulation area. During the study period, a change of Yala Glacier's surface topography has been observed with glacier thinning and downwasting. The retreat rates of Rikha Samba Glacier are higher than for Yala Glacier. From 1989 to 2013, Rikha Samba Glacier retreated 431 m (−18.0 m a−1), and from 1974 to 2016 Yala Glacier retreated 346 m (−8.2 m a−1). The data of the annual and seasonal mass balances, point mass balance, geodetic mass balance, and length changes are accessible from the World Glacier Monitoring Service (WGMS, 2021), https://doi.org/10.5904/wgms-fog-2021-05.

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