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.

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 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.

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 Elevation changes measured on Svalbard glaciers and ice caps from airborne laser data

2005 ◽  
Vol 42 ◽  
pp. 202-208 ◽  
Author(s):  
Jonathan L. Bamber ◽  
William Krabill ◽  
Vivienne Raper ◽  
Julian A. Dowdeswell ◽  
J. Oerlemans
Keyword(s):  
Mass Balance ◽  
Elevation Change ◽  
Svalbard Archipelago ◽  
Ice Caps ◽  
Airborne Laser ◽  
Air Temperatures ◽  
Lower Elevation ◽  
Elevation Changes ◽  
The Mean ◽  
Negative Balance

AbstractPrecise airborne laser surveys were conducted during spring in 1996 and 2002 on 17 ice caps and glaciers in the Svalbard archipelago covering the islands of Spitsbergen and Nordaustlandet. We present the derived elevation changes. Lower-elevation glaciers in south Spitsbergen show the largest thinning rates of ∼ 0.5 m a-1, while some of the higher, more northerly ice caps appear to be close to balance. The pattern of elevation change is complex, however, due to several factors including glacier aspect, microclimatological influences and the high natural annual variability in local accumulation and ablation rates. Anomalous changes were observed on Fridtjovbreen, which started surging in 1996, at the start of the measurement period. On this glacier, thinning (of > 0.6 m a-1) was observed in the accumulation area, coincident with thickening at lower elevations. Asymmetric thinning was found on two ice caps on Nordaustlandet, with the largest values on the eastern side of Vestfonna but the western slopes of Vegafonna. The mean elevation change for all ice masses was -0.19 m a-1 w.e., which is 1.6 times the net mass-balance value determined for the last 30 years. Using mass-balance sensitivity estimates for Svalbard suggests that the implied increase in negative balance is linked to warmer air temperatures in the late 1990s. Multiple linear regression suggests that mass balance is most closely correlated with latitude, rather than mean altitude or longitude.

MAPPING ROCK GLACIER SURFACE ELEVATION CHANGES IN GREAT BASIN NATIONAL PARK, NEVADA

2018 ◽  
Author(s):  
Forrest Scott Schoessow ◽  
◽  
John-Morgan Manos ◽  
John-Morgan Manos ◽  
Bryan G. Mark ◽  
...  
Keyword(s):  
Great Basin ◽  
National Park ◽  
Surface Elevation ◽  
Rock Glacier ◽  
Glacier Surface ◽  
Elevation Changes ◽  
Great Basin National Park

scholarly journals Estimation of volume changes of mountain glaciers from ICESat data: an example from the Aletsch Glacier, Swiss Alps

2013 ◽  
Vol 7 (4) ◽  
pp. 3261-3291 ◽  
Author(s):  
J. Kropáček ◽  
N. Neckel ◽  
A. Bauder
Keyword(s):  
Mass Balance ◽  
Statistical Approach ◽  
Swiss Alps ◽  
Surface Elevation ◽  
Linear Change ◽  
Glacier Surface ◽  
Ablation Area ◽  
Mountain Glaciers ◽  
Ice Cloud ◽  
Elevation Changes

Abstract. Worldwide estimation of recent changes in glacier volume is challenging, but becomes more feasible with the help of present and future remote sensing missions. NASA's Ice Cloud and Elevation Satellite (ICESat) mission provides accurate elevation estimates derived from the two way travel time of the emitted laser pulse. In this study two different methods were employed for derivation of surface elevation changes from ICESat records on example of the Aletsch Glacier. A statistical approach relies on elevation differences of ICESat points to a reference DEM while an analytical approach compares spatially similar ICESat tracks. Using the statistical approach, in the upper and lower parts of the ablation area, the surface lowering was found to be from −2.1 ± 0.15 m yr−1 to −2.6 ± 0.10 m yr−1 and from −3.3 ± 0.36 m yr−1 to −5.3 ± 0.39 m yr−1, respectively, depending on the DEM used. Employing the analytical method, the surface lowering in the upper part of the ablation area was estimated as −2.5 ± 1.3 m yr−1 between 2006 and 2009. In the accumulation area both methods revealed no significant trend. The trend in surface lowering derived by the statistical method allows an estimation of the mean mass balance in the period 2003–2009 assuming constant ice density and a linear change of glacier surface lowering with altitude in the ablation area. The resulting mass balance was validated by a comparison to another geodetic approach based on the subtraction of two DEMs for the years 2000 and 2009. We conclude that ICESat data is a valid source of information on surface elevation changes and on mass balance of mountain glaciers.

scholarly journals Surface elevation changes on Lachman Crags ice caps (north-eastern Antarctic Peninsula) since 1979 indicated by DEMs and ICESat data

2019 ◽  
Vol 65 (251) ◽  
pp. 410-421 ◽  
Author(s):  
ZBYNĚK ENGEL ◽  
JAN KROPÁČEK ◽  
JANA SMOLÍKOVÁ
Keyword(s):  
20Th Century ◽  
Antarctic Peninsula ◽  
Surface Elevation ◽  
Aerial Photographs ◽  
Altimeter Data ◽  
Glacier Surface ◽  
Ice Caps ◽  
North Eastern ◽  
Elevation Changes ◽  
The Antarctic

ABSTRACTThe long-term warming on the Antarctic Peninsula in the second half of the 20th century prompted rapid retreat of glaciers on the peninsula and surrounding islands. Retreat accelerated until the beginning of the new millennium when the regional warming trend significantly decreased. The response of glaciers to the change in temperature trend has been observed around the northern part of the Antarctic Peninsula but the timing of the shift from the surface lowering to mass gain remains unclear. Using historical aerial photographs, DEMs and satellite altimeter data from ICESat, we estimate areal and surface elevation changes of two small ice caps in the northern part of James Ross Island over the last 39 years. The glacierized area on Lachman Crags decreased from 4.337 ± 0.037 to 3.581 ± 0.014 km2 (−17.4%) between 1979 and 2006 and then increased to 3.597 ± 0.047 km2 (0.4%) until 2016. Surface lowering observed on ice caps after 1979 continued at least until 2008 as indicated by the ICESat data. The change from the lowering trend to increase in glacier surface elevation probably occurred after the ablation season 2008/09, which ranks among the warmest summers in the north-eastern Antarctic Peninsula since the mid-20th century.

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