Glacier surface elevation changes in Rongbuk Catchment of the Central Himalayas in the last four decades

2020 ◽  
Author(s):  
Qinghua Ye ◽  
Wei Nie ◽  
Yimin Chen ◽  
Gang Li ◽  
lide Tian ◽  
...  
Keyword(s):  
Climate Modeling ◽  
Melting Rate ◽  
Surface Elevation ◽  
High Mountain ◽  
Glacier Surface ◽  
Important Indicator ◽  
Central Himalayas ◽  
Glacier Melting ◽  
Elevation Changes ◽  
Thinning Rate

<p>Glaciers in the central Himalayas are important water resources for the downstream habitants, and accelerating melting of the high mountain glaciers speed up with continuous warming. We summerized the geodetic glacier surface elevation changes (Dh) by 6 data sets at different time periods during 1974-2016 in RongbukCatchment(RC) on the northern slope of Mt. Qomolangma (Mt. Everest) in the Central Himalayas. The result showed that glacier Dh varied with altitude and time, from -0.29 ± 0.03m a<sup>-1</sup> in 1974-2000, to -0.47 ±0.24 m a<sup>-1</sup> in 1974-2006,and -0.48 ±0.16 m a<sup>-1</sup> in 1974-2012. Dh increased to -0.60 ± 0.20 m a<sup>-1</sup> in 2000-2012, then decreased to-0.46 ± 0.24 m a<sup>-1</sup> in 2000-2014, and by -0.49 ± 0.08 m a<sup>-1</sup> in 2000-2016, showing a diverse rate being up - down- a little up. However, it generally presented a similar glacier thinning rate by -0.46~-0.49 m a<sup>-1</sup> in the last four decades since 1970s in RC according to Dh<sub>1974-2006</sub>, Dh<sub>1974-2012</sub>, Dh<sub>2000-2014</sub>, and Dh<sub>2000-2016</sub>. Local meteorological observations revealed that, to a first order, the glacier thinning rate was kept the same pace with the number of annual melting days (MD). In spite of the obviously arising summer air temperature (T<sub>S</sub>) in 2000-2014, a slowdown glacier melting rate by -391 mm w.e.a<sup>-1</sup> occurred in 2000-2014 because of less melting days with more precipitation and less annual mean temperature(T<sub>m</sub>). It shows that MD is another important indicator and controlling factor to evaluate or to estimate glacier melting trend, especially in hydrological or climate modeling.</p>

scholarly journals Fifty Years of Tidewater Glacier Surface Elevation and Retreat Dynamics along the South-East Coast of Spitsbergen (Svalbard Archipelago)

2022 ◽  
Vol 14 (2) ◽  
pp. 354
Author(s):  
Jan Kavan ◽  
Guy D. Tallentire ◽  
Mihail Demidionov ◽  
Justyna Dudek ◽  
Mateusz C. Strzelecki
Keyword(s):  
East Coast ◽  
Aerial Images ◽  
Surface Elevation ◽  
Glacier Surface ◽  
Svalbard Archipelago ◽  
Tidewater Glaciers ◽  
Air Temperatures ◽  
Frontal Zones ◽  
Elevation Changes ◽  
Norwegian Polar Institute

Tidewater glaciers on the east coast of Svalbard were examined for surface elevation changes and retreat rate. An archival digital elevation model (DEM) from 1970 (generated from aerial images by the Norwegian Polar Institute) in combination with recent ArcticDEM were used to compare the surface elevation changes of eleven glaciers. This approach was complemented by a retreat rate estimation based on the analysis of Landsat and Sentinel-2 images. In total, four of the 11 tidewater glaciers became land-based due to the retreat of their termini. The remaining tidewater glaciers retreated at an average annual retreat rate of 48 m year−1, and with range between 10–150 m year−1. All the glaciers studied experienced thinning in their frontal zones with maximum surface elevation loss exceeding 100 m in the ablation areas of three glaciers. In contrast to the massive retreat and thinning of the frontal zones, a minor increase in ice thickness was recorded in some accumulation areas of the glaciers, exceeding 10 m on three glaciers. The change in glacier geometry suggests an important shift in glacier dynamics over the last 50 years, which very likely reflects the overall trend of increasing air temperatures. Such changes in glacier geometry are common at surging glaciers in their quiescent phase. Surging was detected on two glaciers studied, and was documented by the glacier front readvance and massive surface thinning in high elevated areas.

scholarly journals Examining geodetic glacier mass balance in the eastern Pamir transition zone

2020 ◽  
Vol 66 (260) ◽  
pp. 927-937
Author(s):  
Mingyang Lv ◽  
Duncan J. Quincey ◽  
Huadong Guo ◽  
Owen King ◽  
Guang Liu ◽  
...  
Keyword(s):  
Mass Balance ◽  
Statistical Difference ◽  
Mass Gain ◽  
High Mountain ◽  
Glacier Mass Balance ◽  
Negative Mass ◽  
Glacier Surface ◽  
Digital Elevation ◽  
Elevation Changes ◽  
Individual Scale

AbstractGlaciers in the eastern Pamir have reportedly been gaining mass during recent decades, even though glaciers in most other regions in High Mountain Asia have been in recession. Questions still remain about whether the trend is strengthening or weakening, and how far the positive balances extend into the eastern Pamir. To address these gaps, we use three different digital elevation models to reconstruct glacier surface elevation changes over two periods (2000–09 and 2000–15/16). We characterize the eastern Pamir as a zone of transition from positive to negative mass balance with the boundary lying at the northern end of Kongur Tagh, and find that glaciers situated at higher elevations are those with the most positive balances. Most (67% of 55) glaciers displayed a net mass gain since the 21st century. This led to an increasing regional geodetic glacier mass balance from −0.06 ± 0.16 m w.e. a−1 in 2000–09 to 0.06 ± 0.04 m w.e. a−1 in 2000–15/16. Surge-type glaciers, which are prevalent in the eastern Pamir, showed fluctuations in mass balance on an individual scale during and after surges, but no statistical difference compared to non-surge-type glaciers when aggregated across the region.

scholarly journals Influence of recent warming and ice dynamics on glacier surface elevations in the Canadian High Arctic, 1995–2014

2018 ◽  
Vol 64 (245) ◽  
pp. 450-464 ◽  
Author(s):  
COLLEEN A. MORTIMER ◽  
MARTIN SHARP ◽  
WESLEY VAN WYCHEN
Keyword(s):  
Land Surface ◽  
High Arctic ◽  
Surface Elevation ◽  
Surface Velocity ◽  
Glacier Surface ◽  
Ice Dynamics ◽  
Thickness Change ◽  
Near Surface ◽  
Elevation Changes ◽  
Moderate Resolution Imaging Spectroradiometer

ABSTRACTRepeat airborne laser altimetry measurements show widespread thinning (surface lowering) of glaciers in Canada's Queen Elizabeth Islands since 1995. Thinning rates averaged for 50 m elevation bins, were more than three times higher during the period 2005/06 to 2012/14 pentad than during the previous two pentads. Strongly negative thickness change (dh/dt) anomalies from 2005/06 to 2012/14, relative to the 1995–2012/14 mean, suggest that most of the measured thinning occurred during the most recent 5–6 year period when mean summer land surface temperatures (LSTs) were anomalously high and the mean summer black-sky shortwave broadband albedos (BSA) were anomalously low, relative to the 2000/01–15/16 period, and upper-air (700 hPa) and near surface (2 m) air temperatures were between 0.8°C and 1.5°C higher than 1995–2012 mean. Comparisons of dh/dt with mean summer LST and BSA measurements from the Moderate Resolution Imaging Spectroradiometer and with surface longitudinal strain rates computed from surface velocity fields derived from RADARSAT 1/2 and Landat-7 ETM + data suggest that surface elevation changes were driven mainly by changes in climate. An exception to this occurs along many fast-flowing outlet glaciers where ice dynamics appear also to have played an important role in surface elevation changes.

Occurrence and characteristics of ice-debris landforms in Poiqu basin (central Himalaya)

2020 ◽  
Author(s):  
Tobias Bolch ◽  
Philipp Rastner ◽  
Jan Bouke Pronk ◽  
Atanu Bhattacharya ◽  
Lin Liu ◽  
...  
Keyword(s):  
Surface Elevation ◽  
High Mountain ◽  
Central Himalaya ◽  
Digital Elevation ◽  
Debris Transport ◽  
Elevation Changes ◽  
Movement Field ◽  
Rock Glaciers ◽  
Southern Tibetan Plateau ◽  
Satellite Radar

<p>Rock glaciers and other ice-debris landforms (I-DLs) are an important part of the debris-transport system in high mountains and their internal ice could provide a relevant contribution to water supply especially in dry regions. Recent research has shown that I-DLs are abundant in High Mountain Asia, but knowledge about their occurrence and characteristics is still limited.</p><p>We are therefore investigating I-DLs in the Poiqu basin (~28°17´N, 85°58´E) – central Himalaya/southern Tibetan Plateau using remote sensing aided by field observations. We use very high-resolution stereo Pleiades data from the contemporary period and stereo Corona and Hexagon data from the 1970s to generate digital elevation models, applied satellite radar interferometry based on ALOS-1 PALSAR and Sentinel-1 SAR data and feature tracking using Sentinel-2 and the Pleiades data. Generated DEMs allowed us to create a hillshade to support identification, to derive their topographical parameters and to investigate surface elevation changes. I-DLs were identified and classified based on their characteristic shape, their surface structure and surface movement. Field observationssupported the identification of the landforms.</p><p>We found abundant occurrence of rock glaciers (with typical characteristics like lobate-shaped forms, ridges and furrows as well as steep fronts) but also significant movements of both former lateral moraines and debris-slopes in permafrost area. Preliminary results revealed the occurrence of more than 350 rock glaciers covering an area of about 21 km<sup>2</sup>. About 150 of them are active. The largest rock glacier has an area of 0.5 km<sup>2</sup> and three have an area of more than 0.3 km<sup>2</sup>. The rock glaciers are located between ~3715 m and ~5850 m with a mean altitude of ~5075 m a.s.l.. The mean slope of all rock glaciers is close to 17.5° (min. 6.8°, max. 37.6°). Most of the rock glaciers face towards the Northeast (19%) and West (18.5%). Surface elevation changes between the 1970s and 2018 show no significant changes but indicate slight elevation gain at the front of active rock glaciers caused by their downward movements.</p><p>Work will be continued to generate an inventory of all I-DLs in the study area including information about their activity and surface elevation changes.</p>

Interannual Rock Glacier Surface Elevation Changes using UAS in Great Basin National Park, Nevada.

2020 ◽  
Author(s):  
Nischay Soni ◽  
Bryan Mark ◽  
Forrest Schoessow ◽  
Scott Reinemann ◽  
James DeGrand ◽  
...  
Keyword(s):  
Great Basin ◽  
National Park ◽  
Surface Elevation ◽  
Rock Glacier ◽  
Glacier Surface ◽  
Elevation Changes ◽  
Great Basin National Park

Multi-decadal ice-velocity and elevation changes of a monsoonal maritime glacier: Hailuogou glacier, China

2010 ◽  
Vol 56 (195) ◽  
pp. 65-74 ◽  
Author(s):  
Yong Zhang ◽  
Koji Fujita ◽  
Shiyin Liu ◽  
Qiao Liu ◽  
Xin Wang
Keyword(s):  
Thermal Emission ◽  
Surface Elevation ◽  
Aerial Photographs ◽  
Differential Gps ◽  
Glacier Surface ◽  
Ablation Area ◽  
Glacier Terminus ◽  
Digital Elevation ◽  
Elevation Changes ◽  
Ice Velocity

AbstractDigital elevation models (DEMs) of the ablation area of Hailuogou glacier, China, produced from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data obtained in 2009, differential GPS (DGPS) data surveyed in 2008 and aerial photographs acquired in 1966 and 1989 are differenced to estimate long- and short-term glacier surface elevation change (dh/dt). The mean dh/dt of the ablation area over 43 years (1966–2009) is −1.1 ± 0.4 m a−1. Since 1989 the thinning has accelerated significantly. Ice velocities measured by DGPS at 28 fixed stakes implanted in the ablation area increase with distance from the glacier terminus, ranging from 41.0 m a−1 approaching the glacier terminus to a maximum of 205.0 m a−1 at the base of an icefall. Our results reveal that the overall average ice velocity in the ablation area has undergone significant temporal variability over the past several decades. Changes in glacier surface elevation in the ablation area result from the combined effects of climate change and glacier dynamics, which are driven by different factors for different regions and periods.

scholarly journals Use of historical elevation data to calculate surface-elevation and volume changes of Ha-Iltzuk Icefield, southwest British Columbia, Canada, 1970 to mid-1980s

2011 ◽  
Vol 52 (59) ◽  
pp. 109-115 ◽  
Author(s):  
Jeffrey A. VanLooy ◽  
Richard R. Forster
Keyword(s):  
British Columbia ◽  
Average Rate ◽  
Meteorological Data ◽  
Surface Elevation ◽  
Volume Changes ◽  
Digital Elevation ◽  
Elevation Data ◽  
Elevation Changes ◽  
Elevation Model ◽  
Thinning Rate

AbstractInvestigations into glacial changes, including understanding variations in the rates of glacial volume and surface-elevation changes, have increased over the past decade. This study uses historical glacier elevation data in the form of topographic maps from 1970 and a digital elevation model from the mid-1980s to calculate surface-elevation and volume changes for Ha-Iltzuk Icefield, southwest British Columbia, Canada. Results indicate that the icefield thinned at an average rate of 0.76±0.25 ma–1 during this period. A previous study of Ha-Iltzuk Icefield also using the geodetic method found a thinning rate of 1.0±0.20ma–1 between the mid-1980s and 1999, indicating a slight increase in the amount of icefield thinning. Within the ablation zone, thinning increased with decreasing elevation at a rate of 1.9±0.68 ma–1 km–1 between these two periods (1970 to mid-1980s versus mid-1980s to 1999). Analysis of meteorological data suggests that increases in both temperature and rainfall, as well as decreases in snowfall, likely contributed to the increased thinning rate.

scholarly journals LiDAR snow cover studies on glacier surface: significance of snow- and ice dynamical processes

2013 ◽  
Vol 7 (2) ◽  
pp. 1787-1832 ◽  
Author(s):  
K. Helfricht ◽  
M. Kuhn ◽  
M. Keuschnig ◽  
A. Heilig
Keyword(s):  
Spatial Distribution ◽  
Standard Deviation ◽  
Snow Cover ◽  
Snow Depth ◽  
Laser Scanning ◽  
Snow Accumulation ◽  
Surface Elevation ◽  
High Mountain ◽  
Dynamical Processes ◽  
Elevation Changes

Abstract. The storage of water within the seasonal snow cover is a substantial source for runoff in high mountain catchments. Information about the spatial distribution of snow accumulation is necessary for calibration and validation of hydro-meteorological models. Generally only a small number of precipitation measurements deliver precipitation input for modeling in remote mountain areas. The spatial interpolation and extrapolation of measurements of precipitation is still difficult. Multi-temporal application of Light Detecting And Ranging (LiDAR) techniques from aircraft, so-called airborne laser scanning (ALS), enables to derive surface elevations changes even in inaccessible terrain. Within one snow accumulation season these surface elevation changes can be interpreted as snow depths as a first assumption for snow hydrological studies. However, dynamical processes in snow, firn and ice are contributing to surface elevation changes on glaciers. To evaluate the magnitude and significance of these processes on alpine glaciers in the present state, ALS derived surface elevation changes were compared to converted snow depths from 35.4 km of ground penetrating radar (GPR) profiles on four glaciers in the high alpine region of Ötztal Alps. LANDSAT data were used to distinguish between firn and ice areas of the glaciers. In firn areas submerging ice flow and densification of firn and snow are contributing to a mean relative deviation of ALS surface elevation changes from actually observed snow depths of −20.0% with a mean standard deviation of 17.1%. Deviations between ALS surface elevation changes and GPR snow depth are small along the profiles on the glacier tongues. At these areas mean absolute deviation of ALS surface elevation changes and GPR snow depth is 0.004 m with a mean standard deviation of 0.27 m. Emergence flow leads to distinct positive deviations only at the very front of the glacier tongues. Snow depths derived from ALS deviate less from actually measured snow depths than expected errors of in-situ measurements of solid precipitation. Hence, ALS derived snow depths are an important data source for both, spatial distribution and total sum of the snow cover volume stored on the investigated glaciers and in the corresponding high mountain catchments at the end of an accumulation season.

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