The author affiliation and the funding information in the Acknowledgement section of the online version of the original article was revised.One affiliation(the 8th affiliation)of the first author is added.The Acknowle...The author affiliation and the funding information in the Acknowledgement section of the online version of the original article was revised.One affiliation(the 8th affiliation)of the first author is added.The Acknowledgement section of the original article has been revised to:Acknowledgments:This research was funded by the National University of Mongolia under grant agreement P2023(grant number P2023-4578)and supported by the Chey Institute for Advanced Studies“International Scholarship Exchange Fellowship for the academic year of 2024-2025”,Republic of Korea,and the National University of Mongolia.We would like to acknowledge the National University of Mongolia and Soumik Das from the Center for the Study of Regional Development,Jawaharlal Nehru University,New Delhi-110067,for his valuable assistance in preparing the geological maps.展开更多
This paper presents a detailed study on the textural and geochemical characteristics of the proglacial sediments near the edge of modern Nelson Ice Cap, Antarctica. The grain size distributions of the proglacial sedim...This paper presents a detailed study on the textural and geochemical characteristics of the proglacial sediments near the edge of modern Nelson Ice Cap, Antarctica. The grain size distributions of the proglacial sediments are characteristic of glacigenic deposits, but very different from those of aeolian and lacustrine sediments. Moreover, the grain size distributions of the proglacial sediments are fractal with a dimension of about 2.9, and the fractal dimensions can be used as another summary statistical parameter for quantifying the relative amounts of coarse and fine materials. Correlations between the absolute element abundances of the proglacial sediments are very weak due to mineral partitioning and other effects of glacial processes, but correlations between the element/Rb ratios are statistically significant. This finding indicates that element/Rb ratios can be used to reduce or eliminate the effects of glacial processes, evaluate geochemical data and determine the sediment provenance in the foreland of Antarctic glacier. Comparisons on the element concentrations among different environments suggest that the proglacial sediments are derived predominantly from local bedrocks and appear to be natural in origin. Thus these natural sediments can be used to study chemical weathering in the proglacial foreland of modern glacier.展开更多
Glacier inventories serve as critical baseline data for understanding the impacts of climate change on glaciers.The present study maps the outlines of glaciers in the Chandra-Bhaga Basin(western Himalaya)for the years...Glacier inventories serve as critical baseline data for understanding the impacts of climate change on glaciers.The present study maps the outlines of glaciers in the Chandra-Bhaga Basin(western Himalaya)for the years 1993,2000,2010,and 2019 using Landsat Thematic Mapper(TM),Enhanced Thematic Mapper(ETM),and Operational Land Imager(OLI)datasets.A total of 251 glaciers,each having an area above 0.5 km^(2),were identified,which include 216 clean-ice and 35 debris-covered glaciers.Area changes are estimated for three periods:1993-2000,2000-2010,and 2010-2019.The total glacierized area was 996±62 km^(2) in 1993,which decreased to 973±70 km^(2) in 2019.The mean rate of glacier area loss was higher in the recent decade(2010-2019),at 0.036 km^(2),compared to previous decades(0.029 km^(2) in 2000-2010 and 0.025 km^(2) in 1993-2000).Supraglacial debris cover changes are also mapped over the period of 1993 and 2019.It is found that the supraglacial debris cover increased by 14.12±2.54 km^(2)(15.2%)during 1993-2019.Extensive field surveys on Chhota Shigri,Panchi II,Patsio,Hamtah,Mulkila,and Yoche Lungpa glaciers were carried out to validate the glacier outlines and supraglacial debris cover estimated using satellite datasets.Controls of various morphological parameters on retreat were also analyzed.It is observed that small,clean ice,south oriented glaciers,and glaciers with proglacial lakes are losing area at faster rates than other glaciers in the basin.展开更多
This study investigates the glacial lake outburst flood(GLOF)hazards in the Tsambagarav mountain range in Western Mongolia,focusing on the Khukhnuruu Valley and its interconnected proglacial lakes.Over the last 30 yea...This study investigates the glacial lake outburst flood(GLOF)hazards in the Tsambagarav mountain range in Western Mongolia,focusing on the Khukhnuruu Valley and its interconnected proglacial lakes.Over the last 30 years,significant glacier retreats,driven by rising temperatures and changing precipitation patterns,have led to the formation and expansion of several proglacial lakes.Fieldwork combined with satellite data and meteorological analysis was used to assess the dynamics of glacier and lake area changes,with particular focus on the flood events of July 2021.The research reveals a substantial reduction in glacier area,particularly in the Khukhnuruu E complex,where glacier area decreased by 19.3%.The study highlights the influence of increasing temperatures and summer precipitation,which have accelerated ice melt,contributing to the expansion and eventual breaching of lakes.Additionally,lake area changes were influenced by the steepness of the terrain,with steeper slopes exacerbating peak discharge during floods.Of the studied seven lakes(Lake 1 to Lake 7),Lake 1 experienced the most dramatic reduction,with a decrease in area by 73.51%and volume by 84.84%,followed by Lake 7.This study underscores the region's vulnerability to climate-induced hazards and stresses the need for a comprehensive early warning system and disaster preparedness measures to mitigate future risks.展开更多
Accelerated glacier melt driven by global warming is increasing nitrate(NO_(3)^(-)) fluxes to downstream ecosystems,thereby attracting wide attention to nitrogen cycling in glacial-fed regions.Proglacial lakes are clo...Accelerated glacier melt driven by global warming is increasing nitrate(NO_(3)^(-)) fluxes to downstream ecosystems,thereby attracting wide attention to nitrogen cycling in glacial-fed regions.Proglacial lakes are closely connected to glaciers,and glacier-derived NO_(3)^(-)plays a critical role in regulating lake water NO_(3)^(-)concentrations.However,the relative contributions of glacier runoff(GR) versus in-lake biogeochemical processes to lake water NO_(3)^(-)remain poorly understood.This study uses measurements of NO_(3)^(-)concentrations and isotopic compositions(δ^(15)O-NO_(3)^(-),δ^(18)O-NO_(3)^(-),and Δ^(17)O-NO_(3)^(-))from the Qiangyong Glacier watershed on the Tibetan Plateau,combined with the MixSIAR model,to quantify the relative contributions of different NO_(3)^(-)sources.The results showed that GR was the dominant source to lake water NO_(3)^(-)during the melting season,accounting for 83%±5%,followed by in-lake microbial nitrification(MN) contributing 15%±4% and direct atmospheric deposition contributing 2%±2%.Further analysis reve aled that both GR input and internal lake processes controlled the seasonal variations of NO_(3)^(-)concentrations.During the early melt season,GR and enhanced in-lake nitrification increase NO_(3)^(-)concentrations,while sediment-mediated physical adsorption may contribute to their subsequent decrease.In contrast,during the non-melt season,NO_(3)^(-)concentrations gradually declined through microbial removal processes,such as denitrification and assimilation.This study quantified the relative contributions of GR and in-lake MN to lake NO_(3)^(-),highlighting that proglacial lakes are hotspots for nitrogen transformation.展开更多
The glaciers on the Tibetan Plateau(TP)constitute critical sources of water for the proglacial lakes and many rivers found downstream.To better understand the evolution of glaciers and the impact of this on proglacial...The glaciers on the Tibetan Plateau(TP)constitute critical sources of water for the proglacial lakes and many rivers found downstream.To better understand the evolution of glaciers and the impact of this on proglacial lakes,seven glaciers corresponding to continenṅtal,sub-continental,and marine climate types that are influenced by wester-lies and the Indian summer monsoon were selected for study.The evolution of the edges of these glaciers and their associated progla-cial lakes were identified based on the visual interpretation of Landsat TM/ETM+/OLI images.A dataset covering the period 1976-2020 that included the glacier and proglacial lake edge vectors was then created.The relative errors in the areas of the individual glaciers were less than 3%,and for the proglacial lakes these errors were in the range 0%-7%.The dataset was used to effectively compare the changes in glaciers and proglacial lakes that have occurred over the past four decades.The most striking changes that were found were the retreat of glaciers and the formation of small proglacial lakes.This dataset could also be used as a proxy to support research on changes in mountain glaciers,particularly their response to climate change and water resources.This response is of great scientific significance and is important in many applications,including assessments of the ecological problems caused by melting glaciers.The dataset can be downloaded from http://doi.org/10.57760/sciencedb.j00076.00131.展开更多
High-altitude glacier-lake systems in the eastern Pamir Plateau,Tajikistan,are highly sensitive elements of Central Asia’s cryosphere and are vital for sustaining regional water resources.The Yashilkul Lake is locate...High-altitude glacier-lake systems in the eastern Pamir Plateau,Tajikistan,are highly sensitive elements of Central Asia’s cryosphere and are vital for sustaining regional water resources.The Yashilkul Lake is located within a tectonic depression dammed by an ancient rockslide,forming a large alpine lake.This lake is currently impacted by intensified warming,glacier retreat,and poorly quantified hydrological shift.The primary objective of this study is to assess multi-decadal changes in the Yashilkul and Bulunkul lakes and their surrounding cryosphere between 1994 and 2024.The changes were analyzed using multitemporal Landsat imagery and unmanned aerial vehicle (UAV) surveys,complemented by in situ meteorological observations from the Bulunkul meteorological station spanning the period from 1990 to 2024.Glacier and lake boundaries were extracted from Landsat data,primarily by applying the normalized difference water index,supplemented by manual delineation.UAV photogrammetry characterized dam morphology and adjacent ponds,and climate trends were evaluated with the modified Mann-Kendall test.A significant warming trend of 0.096℃/a and pronounced interannual precipitation variability have driven persistent glacier retreat and lake surface area fluctuations.The Yashilkul Lake’s surface area decreased from 36.40 (±1.15) km^(2) in 2010 to 31.94 (±0.54) km^(2) in 2020 and partially rebounded to 33.99 (±0.60) km^(2) in 2024,while the Bulunkul Lake’s surface area remained nearly stable owing to limited glacial influence.Additionally,UAV surveys conducted in 2022 and 2024 revealed main features of the Yashilkul Lake:rockslidedammed origin,perched ponds along the dam body,and an artificial canal regulating its outflow.Nearby glaciers,particularly Glacier No.369,exhibited strong frontal retreat and proglacial lake expansion.The proglacial lake expanded nearly fourfold from 0.08 (±0.01)km^(2) in 2000 to 0.33 (±0.02) km^(2) in 2024,raising concerns about potential glacial lake outburst floods that could impact the Yashilkul Lake and compromise the integrity of its natural dam.The findings highlight accelerating hydrological and cryospheric transformations in the Pamir Plateau,emphasizing the need for sustained monitoring of glacier-lake systems owing to their critical implications for water security,ecological stability,and downstream hazard management.展开更多
文摘The author affiliation and the funding information in the Acknowledgement section of the online version of the original article was revised.One affiliation(the 8th affiliation)of the first author is added.The Acknowledgement section of the original article has been revised to:Acknowledgments:This research was funded by the National University of Mongolia under grant agreement P2023(grant number P2023-4578)and supported by the Chey Institute for Advanced Studies“International Scholarship Exchange Fellowship for the academic year of 2024-2025”,Republic of Korea,and the National University of Mongolia.We would like to acknowledge the National University of Mongolia and Soumik Das from the Center for the Study of Regional Development,Jawaharlal Nehru University,New Delhi-110067,for his valuable assistance in preparing the geological maps.
基金The work was supported by the Nationa1 Natural ScienceFoundation of China(Grant No．40231002 and 40076032)the project of Chinese Academy of Sciences(Grant No．KZCX2-303)
文摘This paper presents a detailed study on the textural and geochemical characteristics of the proglacial sediments near the edge of modern Nelson Ice Cap, Antarctica. The grain size distributions of the proglacial sediments are characteristic of glacigenic deposits, but very different from those of aeolian and lacustrine sediments. Moreover, the grain size distributions of the proglacial sediments are fractal with a dimension of about 2.9, and the fractal dimensions can be used as another summary statistical parameter for quantifying the relative amounts of coarse and fine materials. Correlations between the absolute element abundances of the proglacial sediments are very weak due to mineral partitioning and other effects of glacial processes, but correlations between the element/Rb ratios are statistically significant. This finding indicates that element/Rb ratios can be used to reduce or eliminate the effects of glacial processes, evaluate geochemical data and determine the sediment provenance in the foreland of Antarctic glacier. Comparisons on the element concentrations among different environments suggest that the proglacial sediments are derived predominantly from local bedrocks and appear to be natural in origin. Thus these natural sediments can be used to study chemical weathering in the proglacial foreland of modern glacier.
基金the Space Application Center, Ahmedabad (ISRO) for providing field support under “Integrated studies of Himalayan Cryosphere” programthe Glaciology Group, Jawaharlal Nehru University for providing necessary support for this research+1 种基金the grants from SERB (CRG/2020/004877) and MOES/16/19/2017-RDEAS projectsthe support from ISRO/RES/4/690/21-22 project
文摘Glacier inventories serve as critical baseline data for understanding the impacts of climate change on glaciers.The present study maps the outlines of glaciers in the Chandra-Bhaga Basin(western Himalaya)for the years 1993,2000,2010,and 2019 using Landsat Thematic Mapper(TM),Enhanced Thematic Mapper(ETM),and Operational Land Imager(OLI)datasets.A total of 251 glaciers,each having an area above 0.5 km^(2),were identified,which include 216 clean-ice and 35 debris-covered glaciers.Area changes are estimated for three periods:1993-2000,2000-2010,and 2010-2019.The total glacierized area was 996±62 km^(2) in 1993,which decreased to 973±70 km^(2) in 2019.The mean rate of glacier area loss was higher in the recent decade(2010-2019),at 0.036 km^(2),compared to previous decades(0.029 km^(2) in 2000-2010 and 0.025 km^(2) in 1993-2000).Supraglacial debris cover changes are also mapped over the period of 1993 and 2019.It is found that the supraglacial debris cover increased by 14.12±2.54 km^(2)(15.2%)during 1993-2019.Extensive field surveys on Chhota Shigri,Panchi II,Patsio,Hamtah,Mulkila,and Yoche Lungpa glaciers were carried out to validate the glacier outlines and supraglacial debris cover estimated using satellite datasets.Controls of various morphological parameters on retreat were also analyzed.It is observed that small,clean ice,south oriented glaciers,and glaciers with proglacial lakes are losing area at faster rates than other glaciers in the basin.
基金funded by the National University of Mongolia under grant agreement P2023(grant number P2023-4578)。
文摘This study investigates the glacial lake outburst flood(GLOF)hazards in the Tsambagarav mountain range in Western Mongolia,focusing on the Khukhnuruu Valley and its interconnected proglacial lakes.Over the last 30 years,significant glacier retreats,driven by rising temperatures and changing precipitation patterns,have led to the formation and expansion of several proglacial lakes.Fieldwork combined with satellite data and meteorological analysis was used to assess the dynamics of glacier and lake area changes,with particular focus on the flood events of July 2021.The research reveals a substantial reduction in glacier area,particularly in the Khukhnuruu E complex,where glacier area decreased by 19.3%.The study highlights the influence of increasing temperatures and summer precipitation,which have accelerated ice melt,contributing to the expansion and eventual breaching of lakes.Additionally,lake area changes were influenced by the steepness of the terrain,with steeper slopes exacerbating peak discharge during floods.Of the studied seven lakes(Lake 1 to Lake 7),Lake 1 experienced the most dramatic reduction,with a decrease in area by 73.51%and volume by 84.84%,followed by Lake 7.This study underscores the region's vulnerability to climate-induced hazards and stresses the need for a comprehensive early warning system and disaster preparedness measures to mitigate future risks.
基金supported by the National Natural Science Foundation of China for Excellent Young Scientists Fund Program(Grant No.42222105)the National Natural Science Foundation of China(Grant No.42421001)+1 种基金the Global Ocean Negative Carbon Emission(Global ONCE) Progrmthe Fundamental Research Funds for the Central Universities(Grant Nos.lzujbky-2022-ey08 and lzujbky-2023-eyt01)。
文摘Accelerated glacier melt driven by global warming is increasing nitrate(NO_(3)^(-)) fluxes to downstream ecosystems,thereby attracting wide attention to nitrogen cycling in glacial-fed regions.Proglacial lakes are closely connected to glaciers,and glacier-derived NO_(3)^(-)plays a critical role in regulating lake water NO_(3)^(-)concentrations.However,the relative contributions of glacier runoff(GR) versus in-lake biogeochemical processes to lake water NO_(3)^(-)remain poorly understood.This study uses measurements of NO_(3)^(-)concentrations and isotopic compositions(δ^(15)O-NO_(3)^(-),δ^(18)O-NO_(3)^(-),and Δ^(17)O-NO_(3)^(-))from the Qiangyong Glacier watershed on the Tibetan Plateau,combined with the MixSIAR model,to quantify the relative contributions of different NO_(3)^(-)sources.The results showed that GR was the dominant source to lake water NO_(3)^(-)during the melting season,accounting for 83%±5%,followed by in-lake microbial nitrification(MN) contributing 15%±4% and direct atmospheric deposition contributing 2%±2%.Further analysis reve aled that both GR input and internal lake processes controlled the seasonal variations of NO_(3)^(-)concentrations.During the early melt season,GR and enhanced in-lake nitrification increase NO_(3)^(-)concentrations,while sediment-mediated physical adsorption may contribute to their subsequent decrease.In contrast,during the non-melt season,NO_(3)^(-)concentrations gradually declined through microbial removal processes,such as denitrification and assimilation.This study quantified the relative contributions of GR and in-lake MN to lake NO_(3)^(-),highlighting that proglacial lakes are hotspots for nitrogen transformation.
基金supported by the National Natural Science Foundation of China(Grant No.42061014)the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(grant no.2019QZKK0201 and no.2019QZKK0105)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(no.XDA19070201)the Chinese National Key Research and Development Program(no.2021YFE011004).
文摘The glaciers on the Tibetan Plateau(TP)constitute critical sources of water for the proglacial lakes and many rivers found downstream.To better understand the evolution of glaciers and the impact of this on proglacial lakes,seven glaciers corresponding to continenṅtal,sub-continental,and marine climate types that are influenced by wester-lies and the Indian summer monsoon were selected for study.The evolution of the edges of these glaciers and their associated progla-cial lakes were identified based on the visual interpretation of Landsat TM/ETM+/OLI images.A dataset covering the period 1976-2020 that included the glacier and proglacial lake edge vectors was then created.The relative errors in the areas of the individual glaciers were less than 3%,and for the proglacial lakes these errors were in the range 0%-7%.The dataset was used to effectively compare the changes in glaciers and proglacial lakes that have occurred over the past four decades.The most striking changes that were found were the retreat of glaciers and the formation of small proglacial lakes.This dataset could also be used as a proxy to support research on changes in mountain glaciers,particularly their response to climate change and water resources.This response is of great scientific significance and is important in many applications,including assessments of the ecological problems caused by melting glaciers.The dataset can be downloaded from http://doi.org/10.57760/sciencedb.j00076.00131.
基金funded by the Key Program of National Natural Science Foundation of China (42230708,42361144887)the Tianshan Talent Project of Xinjiang Uygur Autonomous Region,China (2022TSYCLJ0056)。
文摘High-altitude glacier-lake systems in the eastern Pamir Plateau,Tajikistan,are highly sensitive elements of Central Asia’s cryosphere and are vital for sustaining regional water resources.The Yashilkul Lake is located within a tectonic depression dammed by an ancient rockslide,forming a large alpine lake.This lake is currently impacted by intensified warming,glacier retreat,and poorly quantified hydrological shift.The primary objective of this study is to assess multi-decadal changes in the Yashilkul and Bulunkul lakes and their surrounding cryosphere between 1994 and 2024.The changes were analyzed using multitemporal Landsat imagery and unmanned aerial vehicle (UAV) surveys,complemented by in situ meteorological observations from the Bulunkul meteorological station spanning the period from 1990 to 2024.Glacier and lake boundaries were extracted from Landsat data,primarily by applying the normalized difference water index,supplemented by manual delineation.UAV photogrammetry characterized dam morphology and adjacent ponds,and climate trends were evaluated with the modified Mann-Kendall test.A significant warming trend of 0.096℃/a and pronounced interannual precipitation variability have driven persistent glacier retreat and lake surface area fluctuations.The Yashilkul Lake’s surface area decreased from 36.40 (±1.15) km^(2) in 2010 to 31.94 (±0.54) km^(2) in 2020 and partially rebounded to 33.99 (±0.60) km^(2) in 2024,while the Bulunkul Lake’s surface area remained nearly stable owing to limited glacial influence.Additionally,UAV surveys conducted in 2022 and 2024 revealed main features of the Yashilkul Lake:rockslidedammed origin,perched ponds along the dam body,and an artificial canal regulating its outflow.Nearby glaciers,particularly Glacier No.369,exhibited strong frontal retreat and proglacial lake expansion.The proglacial lake expanded nearly fourfold from 0.08 (±0.01)km^(2) in 2000 to 0.33 (±0.02) km^(2) in 2024,raising concerns about potential glacial lake outburst floods that could impact the Yashilkul Lake and compromise the integrity of its natural dam.The findings highlight accelerating hydrological and cryospheric transformations in the Pamir Plateau,emphasizing the need for sustained monitoring of glacier-lake systems owing to their critical implications for water security,ecological stability,and downstream hazard management.
