scholarly journals Annual 30 m dataset for glacial lakes in High Mountain Asia from 2008 to 2017

2021 ◽  
Vol 13 (2) ◽  
pp. 741-766 ◽  
Author(s):  
Fang Chen ◽  
Meimei Zhang ◽  
Huadong Guo ◽  
Simon Allen ◽  
Jeffrey S. Kargel ◽  
...  
Keyword(s):  
Water Resources ◽  
Glacial Lake ◽  
High Mountain ◽  
Slight Reduction ◽  
Lake Area ◽  
Hydroelectric Power ◽  
Glacial Lakes ◽  
Proglacial Lakes ◽  
Area Increase ◽  
Proglacial Lake

Abstract. Atmospheric warming is intensifying glacier melting and glacial-lake development in High Mountain Asia (HMA), and this could increase glacial-lake outburst flood (GLOF) hazards and impact water resources and hydroelectric-power management. There is therefore a pressing need to obtain comprehensive knowledge of the distribution and area of glacial lakes and also to quantify the variability in their sizes and types at high resolution in HMA. In this work, we developed an HMA glacial-lake inventory (Hi-MAG) database to characterize the annual coverage of glacial lakes from 2008 to 2017 at 30 m resolution using Landsat satellite imagery. Our data show that glacial lakes exhibited a total area increase of 90.14 km2 in the period 2008–2017, a +6.90 % change relative to 2008 (1305.59±213.99 km2). The annual increases in the number and area of lakes were 306 and 12 km2, respectively, and the greatest increase in the number of lakes occurred at 5400 m elevation, which increased by 249. Proglacial-lake-dominated areas, such as the Nyainqêntanglha and central Himalaya, where more than half of the glacial-lake area (summed over a 1∘ × 1∘ grid) consisted of proglacial lakes, showed obvious lake-area expansion. Conversely, some regions of eastern Tibetan mountains and Hengduan Shan, where unconnected glacial lakes occupied over half of the total lake area in each grid, exhibited stability or a slight reduction in lake area. Our results demonstrate that proglacial lakes are a main contributor to recent lake evolution in HMA, accounting for 62.87 % (56.67 km2) of the total area increase. Proglacial lakes in the Himalaya ranges alone accounted for 36.27 % (32.70 km2) of the total area increase. Regional geographic variability in debris cover, together with trends in warming and precipitation over the past few decades, largely explains the current distribution of supraglacial- and proglacial-lake area across HMA. The Hi-MAG database is available at https://doi.org/10.5281/zenodo.4275164 (Chen et al., 2020), and it can be used for studies of the complex interactions between glaciers, climate and glacial lakes, studies of GLOFs, and water resources.

scholarly journals Annual 30-meter Dataset for Glacial Lakes in High Mountain Asia from 2008 to 2017

2020 ◽  
Author(s):  
Fang Chen ◽  
Meimei Zhang ◽  
Huadong Guo ◽  
Simon Allen ◽  
Jeffrey S. Kargel ◽  
...  
Keyword(s):  
Large Population ◽  
Tien Shan ◽  
Glacial Lake ◽  
High Mountain ◽  
Slight Reduction ◽  
Lake Area ◽  
Glacial Lakes ◽  
Proglacial Lake ◽  
Area Expansion ◽  
Lake Number

Abstract. Climate change is intensifying glacier melting and lake development in High Mountain Asia (HMA), which could increase glacial lake outburst flood hazards and impact water resource and hydroelectric power management. However, quantification of variability in size and type of glacial lakes at high resolution has been incomplete in HMA. Here, we developed a HMA Glacial Lake Inventory (Hi-MAG) database to characterize the annual coverage of glacial lakes from 2008 to 2017 at 30 m resolution using Landsat satellite imagery. It is noted that a rapid increase in lake number and moderate area expansion was influenced by a large population of small glacial lake (≤ 0.04 km2), and faster growth in lake number occurred above 5300 m elevation. Proglacial lake dominated areas showed significant lake area expansion, while unconnected lake dominated areas exhibited stability or slight reduction. Small glacial lakes accounted for approximately 15% of the lake area in Eastern Hindu Kush, Western Himalaya, Northern/Western Tien Shan, and Gangdise Mountains, but contributed > 50 % of lake area expansion in these regions over a decade. Our results demonstrate proglacial lakes are a main contributor while small glacial lakes are an overlooked element to recent lake evolution in HMA. Regional geographic variability of debris cover, together with trends in warming and precipitation over the past few decades, largely explain the current distribution of supra- and proglacial lake area across HMA. The Hi-MAG database are available at: https://doi.org/10.5281/zenodo.3700282, it can be used for studies on glacier-climate-lake interactions, glacio-hydrologic models, glacial lake outburst floods and potential downstream risks and water resources.

scholarly journals Spatially and Temporally Resolved Monitoring of Glacial Lake Changes in Alps During the Recent Two Decades

2021 ◽  
Vol 9 ◽  
Author(s):  
Jingsong Ma ◽  
Chunqiao Song ◽  
Yanjun Wang
Keyword(s):  
Glacial Lake ◽  
Water Volume ◽  
High Mountain ◽  
Lake Area ◽  
Glacial Lakes ◽  
Holistic View ◽  
Supraglacial Lakes ◽  
Different Types ◽  
The Alps ◽  
The Mean

Climate warming is intensifying the melting of glaciers and the growth of glacial lakes in the Alps, which has a profound impact on the management of water resources and high-mountain hydropower in this region. However, the research on the spatial distribution and temporal evolution of the Alps glacial lakes of various types still lacks a holistic view. In this study, we developed an inventory of Alps glacial lakes of different types and then obtained the annual areas of these lakes from 2000 to 2019 using JRC Global Surface Water and Global Land Analysis and Discovery data at a resolution of 30 m. A total of 498 glacial lakes (>0.01 km2) with the net area of 33.77 ± 6.94 km2 were identified in the Alps in 2019 and are mainly distributed in the western and central Alps. These Alps glacial lakes, with the area ranging 0.01–1.59 km2, are generally dominated by small-sized ones. The comparison of lakes of different types indicated that ice-uncontacted lakes are dominant in number and area, accounting for 59.4 and 58.4%, respectively. In terms of the elevation distribution, almost half of the lakes are concentrated at the altitude of 2,250–2,750 m (a.s.l.). Meanwhile, the mean altitude of small glacial lakes is higher than that of large lakes. The distribution of ice-contacted lakes and supraglacial lakes were more concentrated, and the mean altitude was higher. During the study period, the number, area, and water volume of glacial lakes were increasing, but the expansion varied between different periods. The changing trends of the glacial lake area and volume were consistent and presents in three stages, as the glacial lake expanded rapidly in the first 5 years and in the last 7 years and remained relatively stable between 2005 and 2012. The number and area of glacier-fed lakes increased rapidly, while the non-glacier-fed lakes were relatively stable. The area change rate of supraglacial lakes was the largest (+47%). This study provides a spatially-complete and temporally-consecutive picture of glacial lake changes in the Alps and can be greatly helpful for future research on climate-glacier-lake interactions, glacial lake outburst floods, and freshwater resources in this region.

scholarly journals Future glacial lakes in High Mountain Asia: an inventory and assessment of hazard potential from surrounding slopes

2021 ◽  
pp. 1-18
Author(s):  
Wilhelm Furian ◽  
David Loibl ◽  
Christoph Schneider
Keyword(s):  
Mass Movement ◽  
High Mountain ◽  
Lake Area ◽  
Glacial Lakes ◽  
Mountain Areas ◽  
Glacial Retreat ◽  
Proglacial Lakes ◽  
Outburst Floods ◽  
Glacial Lake Outburst Floods ◽  
Triggering Events

Abstract Bedrock overdeepenings exposed by continued glacial retreat can store precipitation and meltwater, potentially leading to the formation of new proglacial lakes. These lakes may pose threats of glacial lake outburst floods (GLOFs) in high mountain areas, particularly if new lakes form in geomorphological setups prone to triggering events such as landslides or moraine collapses. We present the first complete inventory for future glacial lakes in High Mountain Asia by computing the subglacial bedrock for ~100 000 glaciers and estimating overdeepening area, volume and impact hazard for the larger potential lakes. We detect 25 285 overdeepenings larger than 104 m2 with a volume of 99.1 ± 28.6 km3 covering an area of 2683 ± 773.8 km2. For the 2700 overdeepenings larger than 105 m2, we assess the lake predisposition for mass-movement impacts that could trigger a GLOF by estimating the hazard of material detaching from surrounding slopes. Our findings indicate a shift in lake area, volume and GLOF hazard from the southwestern Himalayan region toward the Karakoram. The results of this study can be used for anticipating emerging threats and potentials connected to glacial lakes and as a basis for further studies at suspected GLOF hazard hotspots.

scholarly journals Glacial Lake Area Change and Potential Outburst Flood Hazard Assessment in the Bhutan Himalaya

2021 ◽  
Vol 9 ◽  
Author(s):  
Sonam Rinzin ◽  
Guoqing Zhang ◽  
Sonam Wangchuk
Keyword(s):  
Dominant Role ◽  
Glacial Lake ◽  
High Mountain ◽  
Lake Area ◽  
Glacial Lakes ◽  
Lake Evolution ◽  
Glacier Melt ◽  
The 1960S ◽  
Very High ◽  
Sentinel 2

Against the background of climate change-induced glacier melting, numerous glacial lakes are formed across high mountain areas worldwide. Existing glacial lake inventories, chiefly created using Landsat satellite imagery, mainly relate to 1990 onwards and relatively long (decadal) temporal scales. Moreover, there is a lack of robust information on the expansion and the GLOF hazard status of glacial lakes in the Bhutan Himalaya. We mapped Bhutanese glacial lakes from the 1960s to 2020, and used these data to determine their distribution patterns, expansion behavior, and GLOF hazard status. 2,187 glacial lakes (corresponding to 130.19 ± 2.09 km2) were mapped from high spatial resolution (1.82–7.62 m), Corona KH-4 images from the 1960s. Using the Sentinel-2 (10 m) and Sentinel-1 (20 m × 22 m), we mapped 2,553 (151.81 ± 7.76 km2), 2,566 (152.64 ± 7.83 km2), 2,572 (153.94 ± 7.83 km2), 2,569 (153.97 ± 7.79 km2) and 2,574 (156.63 ± 7.95 km2) glacial lakes in 2016, 2017, 2018, 2019 and 2020, respectively. The glacier-fed lakes were mainly present in the Phochu (22.63%) and the Kurichu (20.66%) basins. A total of 157 glacier-fed lakes have changed into non-glacier-fed lakes over the 60 years of lake evolution. Glacier-connected lakes (which constitutes 42.25% of the total glacier-fed lake) area growth accounted for 75.4% of the total expansion, reaffirming the dominant role of glacier-melt water in expanding glacial lakes. Between 2016 and 2020, 19 (4.82 km2) new glacial lakes were formed with an average annual expansion rate of 0.96 km2 per year. We identified 31 lakes with a very-high and 34 with high GLOF hazard levels. These very-high to high GLOF hazard lakes were primarily located in the Phochu, Kurichu, Drangmechu, and Mochu basins. We concluded that the increasing glacier melt is the main driver of glacial lake expansion. Our results imply that extending glacial lakes studies back to the 1960s provides new insights on glacial lake evolution from glacier-fed lakes to non-glacier-fed lakes. Additionally, we reaffirmed the capacity of Sentinel-1 and Sentinel-2 data to determine annual glacial lake changes. The results from this study can be a valuable basis for future glacial lake monitoring and prioritizing limited resources for GLOF mitigation programs.

scholarly journals Inventory and classification of the post Little Ice Age glacial lakes in Svalbard

2022 ◽  
Author(s):  
Iwo Wieczorek ◽  
Mateusz Czesław Strzelecki ◽  
Łukasz Stachnik ◽  
Jacob Clement Yde ◽  
Jakub Małecki
Keyword(s):  
Little Ice Age ◽  
High Arctic ◽  
Ice Age ◽  
Aerial Photographs ◽  
Glacial Lake ◽  
High Mountain ◽  
Lake Area ◽  
Glacial Lakes ◽  
Mountain Areas ◽  
Outburst Floods

Abstract. Rapid changes of glacial lakes are among the most visible indicators of global warming in glacierized areas around the world. The general trend is that the area and number of glacial lakes increase significantly in high mountain areas and polar latitudes. However, there is a lack of knowledge about the current state of glacial lakes in the High Arctic. This study aims to address this issue by providing the first glacial lake inventory from Svalbard, with focus on the genesis and evolution of glacial lakes since the end of the Little Ice Age. We use aerial photographs and topographic data from 1936 to 2012 and satellite imagery from 2013 to 2020. The inventory includes the development of 566 glacial lakes (total area of 145.91 km2) that were in direct contact with glaciers in 2008–2012. From the 1990s to the end of the 2000s, the total glacial lake area increased by nearly a factor of six. A decrease in the number of lakes between 2012 and 2020 is related to two main processes: the drainage of 197 lakes and the merger of smaller reservoirs into larger ones. The changes of glacial lakes show how climate change in the High Arctic affect proglacial geomorphology by enhanced formation of glacial lakes, leading to higher risks associated with glacier lake outburst floods in Svalbard.

scholarly journals Simulation and Assessment of Future Glacial Lake Outburst Floods in the Poiqu River Basin, Central Himalayas

Water ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1376
Author(s):  
Taigang Zhang ◽  
Weicai Wang ◽  
Tanguang Gao ◽  
Baosheng An
Keyword(s):  
River Basin ◽  
Hazard Assessment ◽  
Glacial Lake ◽  
High Mountain ◽  
Glacial Lakes ◽  
Central Himalayas ◽  
Outburst Floods ◽  
Glacial Lake Outburst Floods ◽  
Social And Economic Development ◽  
Glacial Lake Outburst Flood

A glacial lake outburst flood (GLOF) is a typical glacier-related hazard in high mountain regions. In recent decades, glacial lakes in the Himalayas have expanded rapidly due to climate warming and glacial retreat. Some of these lakes are unstable, and may suddenly burst under different triggering factors, thus draining large amounts of water and impacting downstream social and economic development. Glacial lakes in the Poiqu River basin, Central Himalayas, have attracted great attention since GLOFs originating there could have a transboundary impact on both China and Nepal, as occurred during the Cirenmaco GLOF in 1981 and the Gongbatongshaco GLOF in 2016. Based on previous studies of this basin, we selected seven very high-risk moraine-dammed lakes (Gangxico, Galongco, Jialongco, Cirenmaco, Taraco, Beihu, and Cawuqudenco) to simulate GLOF propagation at different drainage percentage scenarios (i.e., 25%, 50%, 75%, and 100%), and to conduct hazard assessment. The results show that, when any glacial lake is drained completely or partly, most of the floods will enter Nepal after raging in China, and will continue to cause damage. In summary, 57.5 km of roads, 754 buildings, 3.3 km2 of farmland, and 25 bridges are at risk of damage due to GLOFs. The potentially inundated area within the Chinese part of the Poiqu River basin exceeds 45 km2. Due to the destructive impacts of GLOFs on downstream areas, appropriate and effective measures should be implemented to adapt to GLOF risk. We finally present a paradigm for conducting hazard assessment and risk management. It uses only freely available data and thus is easy to apply.

scholarly journals Recent Changes of Glacial Lakes in the High Mountain Asia and Its Potential Controlling Factors Analysis

2021 ◽  
Vol 13 (18) ◽  
pp. 3757
Author(s):  
Meimei Zhang ◽  
Fang Chen ◽  
Hang Zhao ◽  
Jinxiao Wang ◽  
Ning Wang
Keyword(s):  
Google Earth ◽  
Controlling Factors ◽  
Rapid Expansion ◽  
Expansion Rate ◽  
Glacial Lake ◽  
High Mountain ◽  
Glacial Lakes ◽  
Computing Platform ◽  
Glacier Ice ◽  
Landsat Satellite

The current glacial lake datasets in the High Mountain Asia (HMA) region still need to be improved because their boundary divisions in the land–water transition zone are not precisely delineate, and also some very small glacial lakes have been lost due to their mixed reflectance with backgrounds. In addition, most studies have only focused on the changes in the area of a glacial lake as a whole, but do not involve the actual changes of per pixel on its boundary and the potential controlling factors. In this research, we produced more accurate and complete maps of glacial lake extent in the HMA in 2008, 2012, and 2016 with consistent time intervals using Landsat satellite images and the Google Earth Engine (GEE) cloud computing platform, and further studied the formation, distribution, and dynamics of the glacial lakes. In total, 17,016 and 21,249 glacial lakes were detected in 2008 and 2016, respectively, covering an area of 1420.15 ± 232.76 km2 and 1577.38 ± 288.82 km2; the lakes were mainly located at altitudes between 4400 m and 5600 m. The annual areal expansion rate was approximately 1.38% from 2008 to 2016. To explore the cause of the rapid expansion of individual glacial lakes, we investigated their long-term expansion rates by measuring changes in shoreline positions. The results show that glacial lakes are expanding rapidly in areas close to glaciers and had a high expansion rate of larger than 20 m/yr from 2008 to 2016. Glacial lakes in the Himalayas showed the highest expansion rate of more than 2 m/yr, followed by the Karakoram Mountains (1.61 m/yr) and the Tianshan Mountains (1.52 m/yr). The accelerating rate of glacier ice and snow melting caused by global warming is the primary contributor to glacial lake growth. These results may provide information that will help in the understanding of detailed lake dynamics and the mechanism, and also facilitate the scientific recognition of the potential hazards associated with glacial lakes in this region.

scholarly journals GAN-GL: Generative Adversarial Networks for Glacial Lake Mapping

2021 ◽  
Vol 13 (22) ◽  
pp. 4728
Author(s):  
Hang Zhao ◽  
Meimei Zhang ◽  
Fang Chen
Keyword(s):  
Large Scale ◽  
Glacial Lake ◽  
Background Information ◽  
Generative Adversarial Networks ◽  
High Mountain ◽  
Landsat 8 ◽  
Glacial Lakes ◽  
Ancillary Data ◽  
Generative Adversarial Network ◽  
Adversarial Network

Remote sensing is a powerful tool that provides flexibility and scalability for monitoring and investigating glacial lakes in High Mountain Asia (HMA). However, existing methods for mapping glacial lakes are designed based on a combination of several spectral features and ancillary data (such as the digital elevation model, DEM) to highlight the lake extent and suppress background information. These methods, however, suffer from either the inevitable requirement of post-processing work or the high costs of additional data acquisition. Signifying a key advancement in the deep learning models, a generative adversarial network (GAN) can capture multi-level features and learn the mapping rules in source and target domains using a minimax game between a generator and discriminator. This provides a new and feasible way to conduct large-scale glacial lake mapping. In this work, a complete glacial lake dataset was first created, containing approximately 4600 patches of Landsat-8 OLI images edited in three ways—random cropping, density cropping, and uniform cropping. Then, a GAN model for glacial lake mapping (GAN-GL) was constructed. The GAN-GL consists of two parts—a generator that incorporates a water attention module and an image segmentation module to produce the glacial lake masks, and a discriminator which employs the ResNet-152 backbone to ascertain whether a given pixel belonged to a glacial lake. The model was evaluated using the created glacial lake dataset, delivering a good performance, with an F1 score of 92.17% and IoU of 86.34%. Moreover, compared to the mapping results derived from the global–local iterative segmentation algorithm and random forest for the entire Eastern Himalayas, our proposed model was superior regarding the segmentation of glacial lakes under complex and diverse environmental conditions, in terms of accuracy (precision = 93.19%) and segmentation efficiency. Our model was also very good at detecting small glacial lakes without assistance from ancillary data or human intervention.

scholarly journals Glacial lake evolution and glacier–lake interactions in the Poiqu River basin, central Himalaya, 1964–2017

2019 ◽  
Vol 65 (251) ◽  
pp. 347-365 ◽  
Author(s):  
GUOQING ZHANG ◽  
TOBIAS BOLCH ◽  
SIMON ALLEN ◽  
ANDREAS LINSBAUER ◽  
WENFENG CHEN ◽  
...  
Keyword(s):  
River Basin ◽  
Glacial Lake ◽  
Lake Area ◽  
Central Himalaya ◽  
Glacial Lakes ◽  
Elevation Change ◽  
Ice Flow ◽  
Entire Study ◽  
Lake Development ◽  
The Mean

ABSTRACTDespite previous studies, glacier–lake interactions and future lake development in the Poiqu River basin, central Himalaya, are still not well understood. We mapped glacial lakes, glaciers, their frontal positions and ice flow from optical remote sensing data, and calculated glacier surface elevation change from digital terrain models. During 1964–2017, the total glacial-lake area increased by ~110%. Glaciers retreated with an average rate of ~1.4 km2 a−1 between 1975 and 2015. Based on rapid area expansion (>150%), and information from previous studies, eight lakes were considered to be potentially dangerous glacial lakes. Corresponding lake-terminating glaciers showed an overall retreat of 6.0 ± 1.4 to 26.6 ± 1.1 m a−1 and accompanying lake expansion. The regional mean glacier elevation change was −0.39 ± 0.13 m a−1 while the glaciers associated with the eight potentially dangerous lakes lowered by −0.71 ± 0.05 m a−1 from 1974 to 2017. The mean ice flow speed of these glaciers was ~10 m a−1 from 2013 to 2017; about double the mean for the entire study area. Analysis of these data along with climate observations suggests that ice melting and calving processes play the dominant role in driving lake enlargement. Modelling of future lake development shows where new lakes might emerge and existing lakes could expand with projected glacial recession.

scholarly journals Glaciers, glacial lakes and glacial lake outburst floods in the Mount Everest region, Nepal

2009 ◽  
Vol 50 (53) ◽  
pp. 81-86 ◽  
Author(s):  
Samjwal Ratna Bajracharya ◽  
Pradeep Mool
Keyword(s):  
Average Rate ◽  
Glacial Lake ◽  
High Mountain ◽  
Glacial Lakes ◽  
Mount Everest ◽  
The Past ◽  
Outburst Floods ◽  
Glacial Lake Outburst Floods ◽  
Himalayan Glaciers ◽  
Recent Climate

AbstractRecent climate changes have had a significant impact on the high-mountain glacial environment. Rapid melting of glaciers has resulted in the formation and expansion of moraine-dammed lakes, creating a potential danger from glacial lake outburst floods (GLOFs). Most lakes have formed during the second half of the 20th century. Glaciers in the Mount Everest (Sagamartha) region, Nepal, are retreating at an average rate of 10–59 ma–1. From 1976 to 2000, Lumding and Imja Glaciers retreated 42 and 34 ma–1, respectively, a rate that increased to 74 ma–1 for both glaciers from 2000 to 2007. During the past decade, Himalayan glaciers have generally been shrinking and retreating faster while moraine-dammed lakes have been proliferating. Although the number of lakes above 3500 m a.s.l. has decreased, the overall area of moraine-dammed lakes is increasing. Understanding the behaviour of glaciers and glacial lakes is a vital aspect of GLOF disaster management.

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