scholarly journals Glacier changes and surges over Xinqingfeng and Malan Ice Caps in the inner Tibetan Plateau since 1970 derived from Remote Sensing Data

2019 ◽  
Author(s):  
Zhen Zhang ◽  
Shiyin Liu ◽  
Zongli Jiang ◽  
Donghui Shangguan ◽  
Junfeng Wei ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Mass Loss ◽  
Accumulation Rate ◽  
Remote Sensing Data ◽  
Landsat 8 ◽  
Glacier Area ◽  
Mean Velocity ◽  
Ice Caps ◽  
Total Mass Loss ◽  
Year 2000

Abstract. The inner Tibetan Plateau region is a glacierised area with heterogeneous variations. However, the detailed glacier area and mass changes in this region prior to the year 2000 are scarce, and there are limited processes available to understand this heterogeneity. In this paper, we present an integrated view of the glacier area and its mass changes for Mt. Xinqingfeng and Mt. Malan of the inner Tibetan Plateau as derived from topographic maps, Landsat, ASTER, SRTM DEM, and TerraSAR-X/TanDEM-X for the period of 1970–2012 and 1970–2018, respectively. Our results show that the glaciers experienced weak shrinkage in area by 0.09 ± 0.03 % from 1970 to 2018, but there was a median mass loss at a rate of 0.22 ± 0.17 m w.e. a−1 and 0.29 ± 0.17 m w.e. a−1 during 1999–2012 in Mt. Xinqingfeng and Mt. Malan respectively. The glaciers of Mt. Malan have had a lower total mass loss of 0.19 ± 0.14 m w.e. a−1 during 1970–1999. The mean velocity of the glaciers during 2013–2018 was 0.16 m d−1, as demonstrated from the Global Land Ice Velocity Extraction from Landsat 8 (GoLIVE). The Monuomaha Glacier and Zu Glacier together with another 5 glaciers displayed the surging or advancing characteristics during the observation period. These glaciers showed have a long active period of time and comparatively low velocities, which suggests that thermal controls are important for the surge initiation and recession. The ablation area or accumulation area exhibited small slopes with velocities that were too slow to remain in balance with the accumulation rate; thus, they required surging to transport mass from the reservoir area down the glacier tongue.

scholarly journals Glacier Variations at Xinqingfeng and Malan Ice Caps in the Inner Tibetan Plateau Since 1970

2020 ◽  
Vol 12 (3) ◽  
pp. 421
Author(s):  
Zhen Zhang ◽  
Shiyin Liu ◽  
Zongli Jiang ◽  
Donghui Shangguan ◽  
Junfeng Wei ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Mass Loss ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Glacier Area ◽  
Srtm Dem ◽  
The West ◽  
Ice Caps ◽  
Total Mass Loss ◽  
Observation Period

The inner Tibetan Plateau is a glacierized region where glaciers show heterogeneous change. The Xinqingfeng and Malan ice caps are located in this region, and a transition zone exists with shifting influences between the westerlies and Indian summer monsoon. However, there is a lack of detailed information regarding glacier area and mass changes in this region before 2000. In the present study, we describe an integrated view of the glacier area and its mass changes for Mt. Xinqingfeng and Mt. Malan as derived from topographic maps, Landsat, ASTER, SRTM DEM, and TerraSAR-X/TanDEM-X from 1970 to 2012 and from 1970 to 2018, respectively. Our results show that the glaciers experienced a slight shrinkage in area by 0.09 ± 0.03% a−1 from 1970 to 2018 with a median mass loss rate of 0.22 ± 0.17 m w.e. a−1 and 0.29 ± 0.17 m w.e. a−1 between 1999 and 2012 at Mt. Xinqingfeng and Mt. Malan, respectively. The glaciers of Mt. Malan had a total mass loss of 0.19 ± 0.14 m w.e. a−1 during the period 1970–1999. A minimum of seven glaciers at Mt. Xinqingfeng and Mt. Malan showed heterogeneous variations with either surging or advancing during the observation period. Among them, the West Monuomaha Glacier, Monuomaha Glacier, and Zu Glacier were identified as surging glaciers, and the others may also be surging glaciers, although more evidence is required. These glaciers showed a long active period and low velocities. Therefore, we suggested that thermal controls are important for surge initiation and recession.

Changes in glacier extent and surface elevations in the Depuchangdake region of northwestern Tibet, China

2016 ◽  
Vol 85 (1) ◽  
pp. 25-33 ◽  
Author(s):  
Zhiguo Li ◽  
Lide Tian ◽  
Hongbo Wu ◽  
Weicai Wang ◽  
Shuhong Zhang ◽  
...  
Keyword(s):  
Mass Loss ◽  
Remote Sensing Data ◽  
Shuttle Radar Topography Mission ◽  
Thematic Mapper ◽  
Glacier Retreat ◽  
Maximum Temperature ◽  
Glacier Mass Balance ◽  
Laser Altimeter ◽  
Total Mass Loss ◽  
Elevation Model

Remote sensing data, including those from Landsat Thematic Mapper/Enhanced Thematic Mapper Plus (TM/ETM +), the Shuttle Radar Topography Mission Digital Elevation Model (SRTM4.1 DEM), and the Geoscience Laser Altimeter System Ice, Cloud, and Land Elevation Satellite (Glas/ICESat), show that from 1991 to 2013 the glacier area in the Depuchangdake region of northwestern Tibet decreased from 409 to 393 km2, an overall loss of 16 km2, or 3.9% of the entire 1991 glacial area. The mean glacier-thinning rate was − 0.40 ± 0.16 m equivalent height of water per year (w.e./yr), equating to a glacier mass balance of − 0.16 ± 0.07 km3 w.e./yr. Total mass loss from 2003 to 2009 was − 1.13 ± 0.46 km3. Glacier retreat likely reflects increases in annual total radiation, annual positive degree days, and maximum temperature, with concurrent increases in precipitation insufficient to replenish glacial mass loss. The rate of glacier retreat in Depuchangdake is less than that for Himalayan glaciers in Indian monsoon-dominated areas, but greater than that for Karakoram glaciers in mid-latitude westerly-dominated areas. Glacier type, climate zone, and climate change all impact on the differing degrees of long-term regional glacial change rate; however, special glacier distribution forms can sometimes lead to exceptional circumstances.

scholarly journals Glacier Retreat in Iceland Mapped from Space: Time Series Analysis of Geodata from 1941 to 2018

2021 ◽  
Author(s):  
Sarah Hauser ◽  
Andreas Schmitt
Keyword(s):  
Mass Loss ◽  
Negative Temperature ◽  
Winter Precipitation ◽  
Landsat 8 ◽  
Climate Data ◽  
Equilibrium Line Altitude ◽  
Ice Caps ◽  
Glacier Terminus ◽  
Landsat 7 ◽  
Normalized Difference Snow Index

AbstractIn recent decades, glaciers outside Greenland and Antarctica have shown increasingly rapid rates of mass loss and retreat of the ice front, which is associated with climatic and oceanic warming. Due to their maritime location, Icelandic glaciers are sensitive to short-term climate fluctuations and have shown rapid rates of retreat and mass loss over the last decade. In this study, historical maps (1941–1949) of the US Army Map Service (AMS series C762) and optical satellite imagery (Landsat 1, Landsat 5, Landsat 7, Landsat 8, and Sentinel-2) are used to study the Langjökull, Hofsjökull and Vatnajökull ice caps. By the help of the Normalized Difference Snow Index (NDSI), the glacier terminus fluctuations of the ice caps from 1973 to 2018 and the Equilibrium Line Altitude (ELA) from 1973 to 2018 are analyzed. The results are compared with climate data, especially with mean summer temperatures and winter precipitation. Due to the negative temperature gradient with increasing altitude, bivariate histograms are generated, showing the glaciated area per altitude zone and time, and providing a prediction of the future development until 2050 and beyond. The results indicate that Langjökull, Hofsjökull and Vatnajökull are retreating and advancing over the study period in correlation with the mean summer temperature, with a steady decrease over time being the clearest and most significant trend. The lower parts of the glaciers, thus, will probably disappear during the next decades. This behaviour is also evident by an exceptional increase of the ELA observed on all three glaciers, which leads to a reduction of the accumulation zone.

scholarly journals Glacier Facies Mapping Using a Machine-Learning Algorithm: The Parlung Zangbo Basin Case Study

2019 ◽  
Vol 11 (4) ◽  
pp. 452 ◽  
Author(s):  
Jingxiao Zhang ◽  
Li Jia ◽  
Massimo Menenti ◽  
Guangcheng Hu
Keyword(s):  
Machine Learning ◽  
Tibetan Plateau ◽  
Learning Algorithm ◽  
Remote Sensing Data ◽  
Landsat 8 ◽  
The Tibetan Plateau ◽  
Important Indicator ◽  
Very High Spatial Resolution ◽  
Multi Temporal ◽  
Elevation Model

Glaciers in the Tibetan Plateau are an important indicator of climate change. Automatic glacier facies mapping utilizing remote sensing data is challenging due to the spectral similarity of supraglacial debris and the adjacent bedrock. Most of the available glacier datasets do not provide the boundary of clean ice and debris-covered glacier facies, while debris-covered glacier facies play a key role in mass balance research. The aim of this study was to develop an automatic algorithm to distinguish ice cover types based on multi-temporal satellite data, and the algorithm was implemented in a subregion of the Parlung Zangbo basin in the southeastern Tibetan Plateau. The classification method was built upon an automated machine learning approach: Random Forest in combination with the analysis of topographic and textural features based on Landsat-8 imagery and multiple digital elevation model (DEM) data. Very high spatial resolution Gao Fen-1 (GF-1) Panchromatic and Multi-Spectral (PMS) imagery was used to select training samples and validate the classification results. In this study, all of the land cover types were classified with overall good performance using the proposed method. The results indicated that fully debris-covered glaciers accounted for approximately 20.7% of the total glacier area in this region and were mainly distributed at elevations between 4600 m and 4800 m above sea level (a.s.l.). Additionally, an analysis of the results clearly revealed that the proportion of small size glaciers (<1 km2) were 88.3% distributed at lower elevations compared to larger size glaciers (≥1 km2). In addition, the majority of glaciers (both in terms of glacier number and area) were characterized by a mean slope ranging between 20° and 30°, and 42.1% of glaciers had a northeast and north orientation in the Parlung Zangbo basin.

scholarly journals On the attribution of industrial-era glacier mass loss to anthropogenic climate change

2020 ◽  
Author(s):  
Gerard H. Roe ◽  
John Erich Christian ◽  
Ben Marzeion
Keyword(s):  
Climate Change ◽  
Mass Loss ◽  
Response Times ◽  
Full Range ◽  
Public Understanding ◽  
Slow Cooling ◽  
Ice Caps ◽  
Total Mass Loss ◽  
Wide Range ◽  
Anthropogenic Contribution

Abstract. Around the world, small ice caps and glaciers have been losing mass and retreating during the industrial era. Estimates are that this has contributed approximately 30 % of the observed sea-level rise over the same period. It is important to understand the relative importance of natural and anthropogenic components of this mass loss. One recent study concluded that the best estimate of the anthropogenic contribution over the industrial era was only 25 %, implying a predominantly natural cause. Here we show that the fraction of the anthropogenic contribution to the total mass loss of a given glacier depends only on the magnitudes and rates of the natural and anthropogenic components of climate change, and on the glacier's response time. We consider climate change over the past millennium using synthetic scenarios, paleoclimate reconstructions, numerical climate simulations, and instrumental observations. We use these climate histories to drive a glacier model that can represent a wide range of glacier response times to evaluate the anthropogenic contribution to glacier mass loss. The slow cooling over the preceding millennium, followed by the rapid anthropogenic warming of the industrial era means that, over the full range of response times for small ice caps and glaciers, the central estimate of the anthropogenic component of the mass loss is essentially 100 %. Our results bring assessments of attribution of glacier mass loss into alignment with assessments of others aspects of climate change, such as global-mean temperature. Furthermore, these results reinforce the scientific and public understanding of centennial-scale glacier retreat as an unambiguous consequence of human activity.

scholarly journals On the attribution of industrial-era glacier mass loss to anthropogenic climate change

2021 ◽  
Vol 15 (4) ◽  
pp. 1889-1905
Author(s):  
Gerard H. Roe ◽  
John Erich Christian ◽  
Ben Marzeion
Keyword(s):  
Climate Change ◽  
Mass Loss ◽  
Response Times ◽  
Full Range ◽  
Public Understanding ◽  
Slow Cooling ◽  
Ice Caps ◽  
Total Mass Loss ◽  
Global Mean Temperature ◽  
Wide Range

Abstract. Around the world, small ice caps and glaciers have been losing mass and retreating since the start of the industrial era. Estimates are that this has contributed approximately 30 % of the observed sea-level rise over the same period. It is important to understand the relative importance of natural and anthropogenic components of this mass loss. One recent study concluded that the best estimate of the magnitude of the anthropogenic mass loss over the industrial era was only 25 % of the total, implying a predominantly natural cause. Here we show that the anthropogenic fraction of the total mass loss of a given glacier depends only on the magnitudes and rates of the natural and anthropogenic components of climate change and on the glacier's response time. We consider climate change over the past millennium using synthetic scenarios, palaeoclimate reconstructions, numerical climate simulations, and instrumental observations. We use these climate histories to drive a glacier model that can represent a wide range of glacier response times, and we evaluate the magnitude of the anthropogenic mass loss relative to the observed mass loss. The slow cooling over the preceding millennium followed by the rapid anthropogenic warming of the industrial era means that, over the full range of response times for small ice caps and glaciers, the central estimate of the magnitude of the anthropogenic mass loss is essentially 100 % of the observed mass loss. The anthropogenic magnitude may exceed 100 % in the event that, without anthropogenic climate forcing, glaciers would otherwise have been gaining mass. Our results bring assessments of the attribution of glacier mass loss into alignment with assessments of others aspects of climate change, such as global-mean temperature. Furthermore, these results reinforce the scientific and public understanding of centennial-scale glacier retreat as an unambiguous consequence of human activity.

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