Notes on glaciation in central Yukon Territory
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Two clearly defined series of glacial limit features, readily correlated and traced from place to place are inferred to mark the limits of the last glacial advance in central Yukon. These are the McConnell Moraine and an earlier advance, the Reid Moraine. In addition, older glacial drift, till, erratics and modified landforms have been found beyond the clearly marked limits and perhaps record two earlier glaciations. These earlier features are referred to as the Klaza Drift (the younger) and the Nansen Drift (the older).The Himalayas has drawn a wide attention in the context of the changing climate.The expansion of glacial lakes shows the variation of climate changes and is of importance to understand the risks of glacial lake outburst flood.On the basis of large scale topographical maps,DEMs,ASTER,images,glacial lake area variation against elevation and the changes of distance between glacial lake and its parent glacier were analyzed and the climatic implications were discussed in the Chinese Himalaya.The results show that,in the past 30 years,(1) the survived glacial lake expansion was a dominant contributor to the increase of glacial lake area,accounting for about 67%,and new formed lakes contributed to the rest 33% of area increment;(2) glacial lake area was averagely increasing in all 100-m-elevation bands where the largest growth occurred at elevations of 5000-5300 m,indicating a vertical variety of climate changes;(3) the more closer the glacial lake is to its parent glacier,the greater the area increasing rate of the glacial lakes,and among 15 types of glacial lake-glacier distance variation,60% of net lake area increment was due to the lakes directly connected with parent glaciers in the 2000s in Chinese Himalaya.
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Abstract This study is perhaps the first attempt to use satellite data (1990–2018) to analyze spatiotemporal changes in glacial lakes over the Kashmir Himalayas supplemented by field studies. Landsat images were used to delineate the spatial extent of glacial lakes at four time points, i.e., 1990, 2000, 2010 and 2018. The total count of lakes as well as their spatial extent showed a discernible increase. The number increased from 253 in 1990 to 322 in 2018, with a growth rate of 21.4%. The area has increased from 18.84 Km 2 in 1990 to 22.11 Km 2 in 2018 with a growth rate of 14.7 percent. The newly formed glacial lakes, including supra glacial lakes, were greater in number than the lakes that disappeared over the study period. All glacial lakes are situated at elevations of 2700 m asl and 4500 m asl. More than 78% of lake expansion in the study region is largely due to the growth of existing glacial lakes. Through area change analysis, our findings reveal that certain lakes show rapid expansion needing immediate monitoring and observation. The analysis of the meteorological variables reveals that minimum and maximum temperatures in the Jhelum basin have shown an increasing trend. T max showed an increase of 1.1°C, whereas T min increased to 0.7°C from 1990 to 2018. On the other hand, precipitation has shown a decreasing trend, which can be attributed to one of the major causes of glacier recession and the expansion of glacial lakes in the Upper Jhelum basin. Consequently, this study could play a significant role in devising a comprehensive risk assessment plan for potential GLOFs and developing a mechanism for continuous monitoring and management of lakes in the study region.
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Recent evolutions and current status of glacial lakes in the central Chinese Himalayas were analyzed using Landsat satellite imagery acquired in 1990, 2000, and 2010. The datasets show that there are 604 glacial lakes with a total area of 85.17 km 2 in the central Chinese Himalayas in 2010, in which moraine-dammed lakes are the most represented typology (199 lakes, 54.92 km 2 ) in terms of area. From 1990 to 2010, the expansion rate of total glacial lake area was 0.57 km 2 /year in the central Chinese Himalayas and was significantly higher than in the Nepal-Bhutan and Western India-Pakistan-Afghanistan Himalayas (−0.08 to 0.45 km 2 /year ) between 1990 and 2009. Of all glacial lakes, moraine-dammed lakes experienced a rapid increase in size at a rate of 0.45 km 2 /year from 1990 to 2010, while the area of other types of glacial lakes grew more slowly with an expansion rate that did not exceed 0.05 km 2 /year (valley lakes at a rate of 0.003 km 2 /year and glacial erosion lakes at a rate of 0.006 km 2 /year ). In addition, 23 potentially dangerous glacial lakes (PDGLs) are identified and their area increased by 77.46% between 1990 and 2010 and the increase rate is higher than non-PDGLs (39%) in the same period.
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The northern Tien Shan Mountains are one of the most hazardous areas in Kyrgyzstan due to frequent glacial lake outburst floods (GLOFs). The current status of glacial lakes in this region has not been reported in recent years. Therefore, this study investigates the variations of glacial lakes in the Kyrgyz and Teskey ranges using Sentinel-2 and PlanetScope optical satellite images from 2017 to 2019. Results confirm that there are 800 glacial lakes, of which 351 were in the Kyrgyz and 449 were in the Teskey Range. We found seasonality in the character of glacial lakes, most of which have been found to be unstable during our observation period. 242 glacial lakes showed significant variations in area. We found 46 newly emerging glacial lakes, five of which have rapidly expanded in the year since they formed, while 18 were found to have vanished. Thirteen lakes were found to be short-lived or unstable. In this study, 14 lakes showed a significant expansion of area. Such large variations in the glacial lakes are closely linked to local geomorphological conditions, local climate and glacier melt. We also identified a significant shift in the number of glacial lakes at altitudes over 3,500 m asl. It is associated with the mountain permafrost zone and variations of the glacier terminus. The current study recommends detailed investigation of glacial lakes in each season with the use of remote sensing and field surveys.
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Global climate change is significantly triggering the dynamic evolution of high-mountain lakes which may pose a serious threat to downstream areas, warranting their systematic and regular monitoring. This study presents the first temporal inventory of glacial and high-altitude lakes in the Sikkim, Eastern Himalaya for four points in time i.e., 1975, 1991, 2000 and 2017 using Hexagon, TM, ETM+ and OLI images, respectively. First, a baseline data was generated for the year 2000 and then the multi-temporal lake changes were assessed. The annual mapping of SGLs was also performed for four consecutive years (2014-2017) to analyze their nature and occurrence pattern. The results show an existence of 463 glacial and high-altitude lakes (>0.003 km2) in 2000 which were grouped into four classes: supraglacial (SGL; 50) pro/peri glacial lake in contact with glacier (PGLC; 35), pro/peri glacial lake away from glacier (PGLA; 112) and other lakes (OL; 266). The mean size of lakes is 0.06 km2 and about 87% lakes have area 80%) are persistent in nature, followed by drain-out (15-20%) and recurring type lakes (7-8%). The new-formed lakes (9-17%) were consistently noticed in all the years (2014-2017). The results of this study underline that regional climate is accelerating the cryosphere thawing and if the current trend continues, further glacier melting will likely occur. Therefore, formation of new lakes and expansion of existing lakes is expected in the study area leading to increase in potential of glacial lake outburst floods. Thereby, persistent attention should be paid to the influences of climatic change in the region.
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Abstract This study is perhaps the first attempt to use satellite data (1990–2018) to analyze spatiotemporal changes in glacial lakes over the Kashmir Himalayas supplemented by field studies. Landsat images were used to delineate the spatial extent of glacial lakes at four time points, i.e., 1990, 2000, 2010 and 2018. The total count of lakes as well as their spatial extent showed a discernible increase. The number increased from 253 in 1990 to 322 in 2018, with a growth rate of 21.4%. The area has increased from 18.84 Km 2 in 1990 to 22.11 Km 2 in 2018 with a growth rate of 14.7 percent. The newly formed glacial lakes, including supra glacial lakes, were greater in number than the lakes that disappeared over the study period. All glacial lakes are situated at elevations of 2700 m asl and 4500 m asl. More than 78% of lake expansion in the study region is largely due to the growth of existing glacial lakes. Through area change analysis, our findings reveal that certain lakes show rapid expansion needing immediate monitoring and observation. The analysis of the meteorological variables reveals that minimum and maximum temperatures in the Jhelum basin have shown an increasing trend. T max showed an increase of 1.1°C, whereas T min increased to 0.7°C from 1990 to 2018. On the other hand, precipitation has shown a decreasing trend, which can be attributed to one of the major causes of glacier recession and the expansion of glacial lakes in the Upper Jhelum basin. Consequently, this study could play a significant role in devising a comprehensive risk assessment plan for potential GLOFs and developing a mechanism for continuous monitoring and management of lakes in the study region.
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The evolution of a glacial lake is a true reflection of glacial and climatic change. Currently, the study of glacial lakes in the Altai Mountains is mainly concerned with the application of high-resolution remote sensing images to monitor and evaluate the potential hazards of glacial lakes. At present, there is no rapid and large-scale method to monitor the dynamical variation in glacial lakes in the Altai Mountains, and there is little research on predicting its future tendency. Based on the supervised classification results obtained by Google Earth Engine (GEE), combined with an analysis of meteorological data, we analyzed the spatial and temporal variations in glacial lakes in the Altai Mountains between 2000 and 2020, and used the MCE-CA-Markov model to predict their changes in the future. According to the results, as of 2020, there are 3824 glacial lakes in the Altai Mountains, with an area of 682.38 km2. Over the entire period, the glacial lake quantity growth rates and area were 47.82% and 17.07%, respectively. The distribution of glacial lakes in this region showed a larger concentration in the north than in the south. Most glacial lakes had areas smaller than 0.1 km2, and there was minimal change observed in glacial lakes larger than 0.2 km2. Analyzing the regional elevation in 100 m intervals, the study found that glacial lakes were predominantly distributed at elevations from 2000 m to 3000 m. Interannual rainfall and temperature fluctuations in the Altai Mountains have slowed since 2014, and the trends for the area and number of glacial lakes have stabilized. The growth of glacial lakes in both number and surface area is expected to continue through 2025 and 2030, although the pace of change will slow. In the context of small increases in precipitation and large increases in temperature, in the future, glacial lakes with faster surface area growth rates will be located primarily in the southern Altai Mountains.
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Abstract This study is perhaps the first attempt to use satellite data (1990–2018) to analyze spatiotemporal changes in glacial lakes over the Kashmir Himalayas supplemented by field studies. Landsat images were used to delineate the spatial extent of glacial lakes at four-time points, i.e., 1990, 2000, 2010 and 2018. The total count of lakes as well as their spatial extent showed a discernible increase. The number increased from 253 in 1990 to 324 in 2018, with a growth rate of 21.4%. The area has increased from 18.84 ± 0.1 km 2 in 1990 to 22.13 ± 0.12 km 2 in 2018 with a growth rate of 14.7%. The newly formed glacial lakes, including supraglacial lakes, were greater in number than the lakes that disappeared over the study period. All glacial lakes are situated at elevations of 2700 m asl and 4500 m asl. More than 78% of lake expansion in the study region is largely due to the growth of existing glacial lakes. Through area change analysis, our findings reveal that certain lakes show rapid expansion needing immediate monitoring and observation. The analysis of the meteorological variables reveals that minimum and maximum temperatures in the Jhelum basin have shown an increasing trend. T max showed an increase of 1.25 °C, whereas T min increased to 0.7 °C from 1980 to 2020. On the other hand, precipitation has shown a decreasing trend, which can be attributed to one of the major causes of glacier recession and the expansion of glacial lakes in the Upper Jhelum basin. Consequently, this study could play a significant role in devising a comprehensive risk assessment plan for potential Glacial Lake Outburst Floods (GLOFs) and developing a mechanism for continuous monitoring and management of lakes in the study region.
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