The Thwaites Glacier in western Antarctica(Fig. 1) keeps glaciologists and climate scientists awake at night. The 120 kmwide glacier loses about 45 billion tonnes of ice each year, accounting for about 4% of global se...The Thwaites Glacier in western Antarctica(Fig. 1) keeps glaciologists and climate scientists awake at night. The 120 kmwide glacier loses about 45 billion tonnes of ice each year, accounting for about 4% of global sea level rise [1]. If it melted completely, sea levels would climb 65 cm, and follow-on effects could lead to a 3 m increase [2]. But if some scientists' vision becomes reality, in 10–15 years construction crews will sail into the Amundsen Sea off Antarctica to begin building an 80 km long underwater curtain that will shield the glacier from the warm currents that are accelerating its decline [3].展开更多
As a highly sensitive indicator of climate change in the arid northwest region of China,glacier dynamics in the Kaidu-Konqi River Basin directly influence regional runoff patterns,thereby playing a crucial role in sha...As a highly sensitive indicator of climate change in the arid northwest region of China,glacier dynamics in the Kaidu-Konqi River Basin directly influence regional runoff patterns,thereby playing a crucial role in shapingregional hydrology and maintaining ecological stability.This study systematically assessed glacier distribution in2020 and analyzed glacier changes from 1972 to 2020 using the Chinese Glacier Inventory of Xinjiang in 2020(CGI-XJ2020),historical satellite imagery from 1972,and data from the Second Chinese Glacier Inventory.In2020,the basin contained 713 glaciers covering 313.99 km^(2),with an estimated glacier volume of 11.81 km^(3)(0.41%glacier coverage).Glaciers were predominantly clustered in the northern and southwestern mountains.Small glaciers(<0.5 km^(2))comprised 78%of the glacier count but only 3%of the total area,whereas glaciers≥0.5 km^(2)accounted for 97%of the total area and 83.6%of the glacier volume.From 1972 to 2020,the totalglacier area decreased by 42.28%(229.99 km^(2))and glacier volume by 49.51%(11.58 km^(3)),equating to meanannual rates of−0.88%and−1.03%,respectively.Glacier retreat drives temporary increases in meltwatersupply but threatens long-term regional runoff stability and ecological water security.The retreat rate variedover different periods,with a more pronounced decline observed between 1972 and 2007.These findingshighlight an accelerating glacier loss in the basin,underscoring the need for continued monitoring and assess-ment of its hydrological and ecological impacts.展开更多
Surge-type glaciers are widely developed in mountainous areas around the world.Understanding the trigger mechanism of glacier surge is a prerequisite for addressing their impacts on hydrological assessments,disentangl...Surge-type glaciers are widely developed in mountainous areas around the world.Understanding the trigger mechanism of glacier surge is a prerequisite for addressing their impacts on hydrological assessments,disentangling climate-glacier linkages,and mitigating downstream hazards.Most glacier surges occur in the compound glaciers;however,attention paid to the trigger mechanisms of such surges is minimal.This study confirmed two surges in the northern and southern branches of the Aru-4 glacier,respectively,in the Western Tibetan Plateau,using multisource remote sensing data.The northern branch of the Aru-4 glacier entered the active phase in 1999 and the active phase lasted for 6 years.The southern branch of the Aru-4 glacier entered the active phase in 2007 and the active phase lasted for 9 years.The southern branch of the Aru-4 glacier experienced a long period of retreat before the northern branch surged and their tongues were in a detached state.The northern branch surge carried a large amount of ice to the frontal area,blocking the downward transport of ice from the southern branch and initiated surge.Through the analysis of two surge processes of Aru-4 glacier,we found a new surge mechanism for compound glaciers.It was revealed that surges in such glaciers are not only triggered by the reduction in basal sliding resistance caused by the internal factors.These surges initiated in the upper part of the glacier then propagated to down glacier by intense compression force.Furthermore,surges can also be triggered by external intervention of blocking by other branches.This external trigger initiates the surge in the lower part of the glacier then propagated to the upper part by longitudinal traction force.In addition,comparing with the surge triggered by the internal factors,the surge triggered by the external intervention may have a more dramatic process.展开更多
Frequent glacier-related watershed geohazard chains are causing severe damage to life and infrastructure,reported consistently from the Eastern Himalayan Syntaxis.This paper presents a systematic method for researchin...Frequent glacier-related watershed geohazard chains are causing severe damage to life and infrastructure,reported consistently from the Eastern Himalayan Syntaxis.This paper presents a systematic method for researching geohazard,from regional to individual scale.The methodology includes the establishment of geological chain inventories,discrimination of geohazard chain modes,analyses of dynamics and dam breaches,and risk assessments.The following results were obtained:(1)In the downstream of Yarlung Zangbo River,175 sites were identified as high-risk for river blockage disasters,indicating the development of watershed geohazards.Five geohazard chain modes were summarized by incorporating geomorphological characteristics,historical events,landslide zoning,and materials.The risk areas of typical hazard were identified and assessed using InSAR data.(2)Glacier-related watershed geohazard chains are significantly different from traditional landslides.A detailed inversion analysis was conducted on the massive rock-ice avalanche in the Sedongpu gully in 2021.This particular event lasted roughly 300 seconds,with a maximum flow velocity of 77.2 m/s and a maximum flow height of 93 meters.By scrutinizing the dynamic processes and mechanical characteristics,mobility stages and phase transitions can be divided into four stages.(3)Watershed geohazard chains tend to block rivers.The peak breach discharge of the Yigong Landslide reached 12.4×10^(4) m^(3)/s,which is 36 times the volume of the seasonal flood discharge in the Yigong River.Megafloods caused by landslide dam breaches have significantly shaped the geomorphology.This study offers insights into disaster patterns and the multistaged movement characteristics of glacier-related watershed geohazard chains,providing a comprehensive method for investigations and assessments in glacial regions.展开更多
Owing to glacial retreat and associated future runoff variations,major concerns have been raised over the sustainability of water resources in the Qilian Mountains.Based on the Python Glacier Evolution Model,we presen...Owing to glacial retreat and associated future runoff variations,major concerns have been raised over the sustainability of water resources in the Qilian Mountains.Based on the Python Glacier Evolution Model,we present projections of the Qiyi glacier for shared socioeconomic pathways(SSPs)calibrated with the glaciological mass balance.The results indicate the air temperature as the dominant factor in the continuous mass loss of the Qiyi Glacier in the future.Glacier area and volume are projected to decline to 0.16±0.11 km2(6.4%±4.4%,relative to 2015)and 0.0023±0.0006 km3(2.1%±1.5%,relative to 2015),respectively,by 2100,for SSP1-2.6.For SSP5-8.5,the glacier will disappear by 2088.The mass loss of the Qiyi Glacier will accelerate before 2050 for all SSPs but will decelerate after 2050 for SSP1-2.6 and SSP2-4.5.The peak water of glacier runoff will occur between2034 and 2045,with the duration of high water from 7 to 18 years.Thereafter,the runoff will rapidly decline till 2070–2080 and remain low afterward.Compared with the existing projections,the present projections indicate that the Qiyi Glacier will experience more drastic shrinkage and ice loss in the coming decades.Finally,the glacier runoff is expected to reach its peak water earlier with a shorter duration of high water.展开更多
Glacier mass balance is a key indicator of glacier health and climate change sensitivity.Influencing factors include both climatic and nonclimatic elements,forming a complex set of drivers.There is a lack of quantitat...Glacier mass balance is a key indicator of glacier health and climate change sensitivity.Influencing factors include both climatic and nonclimatic elements,forming a complex set of drivers.There is a lack of quantitative analysis of these composite factors,particularly in climate-typical regions like the Tanggula Mountains on the central Tibetan Plateau.We collected data on various factors affecting glacier mass balance from 2000 to 2020,including climate variables,topographic variables,geometric parameters,and glacier dynamics.We utilized linear regression models,ensemble learning models,and Open Global Glacier Model(OGGM)to analyze glacier mass balance changes in the Tanggula Mountains.Results indicate that linear models explain 58%of the variance in glacier mass balance,with seasonal temperature and precipitation having significant impacts.Our findings show that ensemble learning models made the explanations 5.2%more accurate by including the impact of topographic and geometric factors such as the average glacier height,the slope of the glacier tongue,the speed of the ice flow,and the area of the glacier.Interpretable machine learning identified the spatial distribution of positive and negative impacts of these characteristics and the interaction between glacier topography and ice dynamics.Finally,we predicted the responses of glaciers of different sizes to future climate change based on the results of interpretable machine learning.It was found that relatively large glaciers(>1 km~2)are likely to persist until the end of this century under low emission scenarios,whereas small glaciers(<1 km~2)are expected to nearly disappear by 2080 under any emission scenario.Our research provides technical support for improving glacier change modeling and protection on the Tibetan Plateau.展开更多
The estimation of glacier flow velocity on a short-term scale is very important for further glacier dynamics research.In this study,10 Sentinel-1 ascending images and 10 Sentinel-1 descending images of Urumqi Glacier ...The estimation of glacier flow velocity on a short-term scale is very important for further glacier dynamics research.In this study,10 Sentinel-1 ascending images and 10 Sentinel-1 descending images of Urumqi Glacier No.1 in 2017 were used to calculate the glacier flow velocity in a high coherence period by DIn SAR technology and MAI technology,while the offset tracking technology was used to estimate the glacier flow velocity in a low coherence period.Then,the monthly three-dimensional flow velocity of the glacier was calculated by the Helmert variance component estimation method.Finally,the accuracy of the estimated glacier flow velocity on a monthly scale was evaluated.The results showed that:(1)the monthly scale motion velocity of Urumqi Glacier No.1 in May,June,July,and August 2017 was 0.273 m/month,0.657 m/month,0.582 m/month,and 0.392 m/month,respectively.(2)The accuracy of glacier surface velocity from May 2017 to August 2017 was 0.033 m/month,0.026 m/month,0.034 m/month and 0.037 m/month,respectively.(3)The accuracy of glacier surface flow velocity from May 2017 to August 2017 was 0.018 m/month,0.031 m/month,0.029 m/month and 0.030 m/month,respectively.Therefore,the research methodology based on the Sentinel-1 ascending and descending data and presented in this paper was applicable to the estimation of monthly-scale flow velocity of mountain glaciers.展开更多
The Ili River is a typical transboundary river between China and Kazakhstan,with glaciers within its basin serving as a crucial solid water resource.Recently,we compiled the Chinese Glacier Inventory of Xinjiang in 20...The Ili River is a typical transboundary river between China and Kazakhstan,with glaciers within its basin serving as a crucial solid water resource.Recently,we compiled the Chinese Glacier Inventory of Xinjiang in 2020(CGI-XJ2020)using high-resolution satellite imagery(<2 m),based on visual interpretation.This study presented the state of glaciers in the Ili River Basin in 2020 by utilizing the data from CGI-XJ2020.It quantified glacier changes in 1960s–2020 based on CGI-XJ2020 and revised datasets from the First and Second Chinese Glacier Inventories.The results indicated that in 2020,the Ili River Basin contained 2,177 glaciers,totaling 1,433.19 km^(2)in area.Among them,213 glaciers were covered by 57.43 km^(2)of debris.The total uncertainty in glacier area was 46.43 km^(2),accounting for approximately 3.2%of the total area.Mapped glacier areas varied from 0.003 to 74.67 km^(2),with an average area of 0.66 km^(2)and a median area of 0.15 km^(2).Glaciers<0.5 km^(2)in size dominated in numbers,accounting for 75.1%of the total.Glaciers in the basin have undergone significant retreat during 1960s–2020,with their total area decreasing by 589.38 km^(2)(29.15%).A total of 495 glaciers(with an area of 49.67 km^(2))disappeared.The average annual glacier area retreat rates for 1960s-2007 and 2007–2020 were 10.86 km^(2)/a(0.54%/a)and 9.41 km^(2)/a(0.61%/a),respectively,showing a continued acceleration in glacier shrinkage,despite a slight decrease in absolute retreat rates.展开更多
In contrast to glaciological studies in Mexico,periglacial studies are very recent and limited to the analysis of the general permafrost cover in the high mountains of the country.Although some of the studies on the r...In contrast to glaciological studies in Mexico,periglacial studies are very recent and limited to the analysis of the general permafrost cover in the high mountains of the country.Although some of the studies on the reconstruction of Pleistocene glaciers in Mexico mention the existence of rock glaciers,to date no work has been done to study their physical properties or determining their state of conservation.Since rock glaciers are the most important visible indicators of mountain permafrost(along with features such as gelifluction lobes and patterned ground)and given that the“Nevado”rock glacier is the main example of its kind in Mexico,this study analyzes its internal temperature and assesses its state of conservation.The investigation was carried out by drilling and thermal monitoring of rock profiles as well as air.The results indicate that at present,the“Nevado”seems to lack permafrost inside.Although there is evidence of surface freezing during the winter months in the upper part of the rock glacier,in the lower portion it is almost unnoticed;and in both parts the internal temperature shows a tendency towards positive values as depth increases,a situation that predominates throughout the year.In addition,according to the records of the climatological station located in the lower part of the rock glacier,although the annual rainfall regime could be favorable for the formation and feeding of interstitial or segregated ice,the air temperature conditions throughout the year prevent permanent freezing.The sum of the above determines that at present the“Nevado”could be considered as an inactive and relict-type rock glacier;the presence of vegetation on the surface of the debris that make it up corroborates its inactivity.展开更多
The Turpan−Hami Basin in Xinjiang is a resource−scarce area where glaciers are important water resources.Based on the data of the Chinese Glacier Inventory of Xinjiang in 2020(CGI-XJ2020),this study analyzed andexplai...The Turpan−Hami Basin in Xinjiang is a resource−scarce area where glaciers are important water resources.Based on the data of the Chinese Glacier Inventory of Xinjiang in 2020(CGI-XJ2020),this study analyzed andexplained the distribution characteristics of glaciers in the Turpan−Hami Basin in 2020.Additionally,by inte-grating the updated First and Second Chinese Glacier Inventories,the study examined changes within the basinfrom 1962 to 2020.It also assessed the specific impact of glacier changes in the Hami region on the runoff of fourtypical basins.The results indicated that in 2020,the Turpan−Hami Basin contained 354 glaciers,covering anarea of 155.82 km^(2)and an estimated ice volume of 5.81 km3.Small glaciers(<0.5 km^(2))were the most numerous,accounting for 78%of the total,while glaciers ranging from 2.0 to 5.0 km^(2)were the largest area,covering39.37 km^(2),which represents 25.3%of the total glacier area.From 1962 to 2020,the glacier area decreased by85.06 km^(2)(35.3%).Between 1962 and 2009,the area decreased by 72.53 km^(2)(30.11%),with an average annualretreat of 1.54 km^(2)/a(0.64%/a).From 2009 to 2020,the area decreased by 12.53 km^(2)(7.44%),and the averageannual retreat slowed to 1.14 km^(2)/a(0.68%/a).These results suggested that while the total glacier area con-tinues to decline,the rate of decrease in absolute terms has slowed,whereas the relative rate of change hasincreased,indicating an accelerating trend in glacier melt.Climate-driven glacier changes have significantly impacted river hydrology and water resources in Hami.In basins without glaciers,runoff has shown a decreasingtrend,suggesting that the positive effect of increased precipitation on runoff may not be sufficient to offset thenegative impact of rising temperatures.In basins with smaller glaciers,the'peak water'for glacier runoff likelyoccurred in the 1980s and 1990s,and water resources are expected to continue deteriorating.In contrast,basinswith larger glaciers have not yet reached a'peak water'and high flow is projected to persist for decades.展开更多
Temperate glaciers in the southeastern Tibetan Plateau have experienced significant mass loss and retreat in recent decades,yet detailed on-site observations remain limited.Here we present the measured records of surf...Temperate glaciers in the southeastern Tibetan Plateau have experienced significant mass loss and retreat in recent decades,yet detailed on-site observations remain limited.Here we present the measured records of surface mass balance,ice velocity and surface ice temperature of Baishui River Glacier No.1 in Yulong Snow Mountain from 2018 to 2022.Our observations reveal an annual mean mass balance of-1.29±0.16 m w.e.,demonstrating a significant seasonal imbalance between reduced accumulation(multi-year average of 0.51±0.07 m w.e.)and enhanced ablation(multi-year average of 1.80±0.26 m w.e.),which provides crucial evidence for explaining the long-term mass loss.The average annual ice velocity,predominantly controlled by monsoon season dynamics which contribute 69%–74%of the total movement,was measured at 26.91±2.76 m yr^(-1)and exhibited a decreasing trend of 1.73 m yr^(-1).The ice temperature fluctuated between-13.41℃to-0.04℃,with an average of-6.04℃.The ice temperature and air temperature synchronized well in the nonmonsoon period,while the temperature rise was not synchronized and slightly delayed in the monsoon period.展开更多
Based on China's high-resolution satellite imagery series(2 m resolution),the Chinese Glacier Inventory of Xinjiang in 2020(CGI-XJ2020)was compiled,with 2020 as the baseline year.CGI-XJ2020 has five key features:1...Based on China's high-resolution satellite imagery series(2 m resolution),the Chinese Glacier Inventory of Xinjiang in 2020(CGI-XJ2020)was compiled,with 2020 as the baseline year.CGI-XJ2020 has five key features:1)improved accuracy in glacier boundary delineation and optimized inventory attributes through highresolution satellite imagery and field validation of 38 glaciers;2)established an area-volume formula for Xinjiang glaciers using ground-penetrating radar(GPR)thickness data from 23 glaciers in the study region;3)the use of high-resolution satellite imagery has reduced the minimum glacier area threshold,enabling the identification of more small glaciers;4)enhanced accuracy in delineating supraglacial debris coverage;5)upgraded administrative division from prefecture-level(CGI-2)to county-level.According to CGI-XJ2020 data,Xinjiang contains 24,202 glaciers in 2020,covering 23,629.28 km^(2)with an average size of 0.98 km^(2)per glacier and a total ice volume of 1,608.94 km^(3).Among these,1,612 debris-covered glaciers occupy 1,163.32 km^(2)(4.9%of the total glacierized area).Glaciers larger than 10 km^(2)(296 in total)cover 9,881.69 km^(2)with a volume of 1,053.17 km^(3),accounting for 41.82%of total area and 65.46%of total ice volume,respectively.The Kunlun Mountains host the most glaciers,followed by the Tianshan Mountains.The Tarim river basin contains the largest concentration(15,860 glaciers,18,594.24 km^(2),1,347.17 km^(3)).The Hotan Prefecture has the highest glacier density.展开更多
The surface velocity is one of the most important characteristics of glaciers.Monitoring and mapping glacier movements are of great significance for the studies of sea-level rise,glacier mass balance and dynamics,glob...The surface velocity is one of the most important characteristics of glaciers.Monitoring and mapping glacier movements are of great significance for the studies of sea-level rise,glacier mass balance and dynamics,global warming,and the management of freshwater resources.It is also essential for the early warnings of hazards caused by ice avalanches.SAR imaging geodesy has been developed for measuring glacier velocity,especially the pixel-offset tracking method.This paper introduces some basic concepts of glaciology and principles of various SAR imaging geodesy methods,with a detailed presentation about the developments in the applications of the pixel-offset tracking method.Finally,the challenges and future prospects of SAR imaging geodesy in glacier monitoring are discussed.展开更多
Glacier ice thickness is a critical parameter for simulating glacier dynamics and estimating glacier volume.This study proposes a novel approach that integrates the laminar flow model with random cell interpolation to...Glacier ice thickness is a critical parameter for simulating glacier dynamics and estimating glacier volume.This study proposes a novel approach that integrates the laminar flow model with random cell interpolation to estimate glacier ice thickness with high efficiency and accuracy.A primary advantage of this method is that it avoids 0ver-reliance on central flowlines,a significant constraint in many traditional models that is difficult to accurately delineate glaciers with complex flow patterns.Furthermore,the integration of random cell interpolation allows the model to generate glacier cross-sections that are more consistent with idealized,physically plausible shapes,refining the raw thickness estimates.The effectiveness and accuracy of this approach were validated in the Western Kunlun main peak region.The results demonstrate the model's reliability,with the total estimated glacier volume falling between the results of the established H&F and Glab Top2 models.The RCGTI calibration,a key component of our method,is proved to be highly effective,reducing the overall volume overestimation by 8.9%from 490.02 to 446.57 km~3.Crucially,when compared to ground penetrating radar(GPR)measurements,our model shows a better match than other mainstream inversion methods.This study demonstrates that the proposed integrated model provides a robust and effective method for large-scale assessments of glacier storage.展开更多
Based on the Chinese Glacier Inventory of Xinjiang in 2020(CGI-XJ2020),we analyzed glacier distribution in theAksu River Basin and examined glacier changes using datasets from Chinese three-period inventories.In 2020,...Based on the Chinese Glacier Inventory of Xinjiang in 2020(CGI-XJ2020),we analyzed glacier distribution in theAksu River Basin and examined glacier changes using datasets from Chinese three-period inventories.In 2020,the basin contained 3,491 glaciers,covering 4,144.84 km^(2),and estimated their ice volume at 345.05 km3.Thelargest glacier areas appeared at elevations between 3,800 and 4,100 m(29.70%),and northern-oriented glaciersdominated both in number(33.73%)and area(35.68%).From 1963 to 2007,glacier area decreased by361.22 km^(2),with an annual retreat rate of 0.38%.From 2007 to 2020,the area decreased by 118.88 km^(2),showing a higher retreat rate of 0.51%,indicating accelerated melting.Glaciers shrank rapidly across all ori-entations,with the fastest reductions occurring in the southwest and the slowest in the northwest.The extent ofglacier area change was influenced by glacier area and debris.Debris-covered glaciers were widespread in theAksu River Basin,with larger glaciers showing an increase in debris.Debris reduced the rate of terminus retreatin large glaciers,while glaciers with thinner debris layers experienced more pronounced melting,with large icetongues at lower altitudes shrinking rapidly,while high-altitude regions remained relatively stable.展开更多
Abnormal glacier movement is likely to result in canyon-type hazards chain,such as the barrier lake of Yarlung Zangbo Grand Canyon formed by glacier debris flow in October 2018 in China.Glacier hazard usually evolves ...Abnormal glacier movement is likely to result in canyon-type hazards chain,such as the barrier lake of Yarlung Zangbo Grand Canyon formed by glacier debris flow in October 2018 in China.Glacier hazard usually evolves from the glacier surge and may occur in a regular cycle.Understanding the characteristics and process of glacier surge is important for early hazard recognition and hazard assessment.Based on field investigations,remote sensing interpretations and SAR offset-tracking surveys,this study confirms a typical glacier surge in the northeast Pamir,and presents its characteristics and processes."Black ice"mixed moraines choking uplift and overflowing lateral marine are the most important scenic characteristics,which were formed under the conditions of stagnant glacier downstream and abundant super-glacial moraine.Glacier movement event can be divided into a five-period cycle including quiescent,inoculation,initiation,fracture and decline.This surge event lasted for about 300 days,initiated in February 2015 developed extensive fracturing zone in spring and early summer at maximum velocity of 10±0.95 m/day,declined after August 2015 and recovered to quiescent status in October 2015 for the next inoculation.The average height of glacier"receiving"area increased by 20-40 m with 2.7-3.6×10^8 m^3 ice transferred from glacier"reservoir",and this volume accumulation again require 50-100 years for glacier mass balance which gives approximately 100 years frequency of the glacier surge.Nevertheless,long-period increase of precipitation and temperature were favorable for the occurrence,hydrological instability is the direct triggering mechanism,and while the Glacier Lake Outburst Flood(GLOF)hazards are unlikely to occur with this surge.展开更多
Recent changes occurred in terminus of the debris-covered Bilafond Glacier in the Karakoram Range in the Himalayas, Northern Pakistan was investigated in this research. Landsat MSS, TM and ETM+ images were used for th...Recent changes occurred in terminus of the debris-covered Bilafond Glacier in the Karakoram Range in the Himalayas, Northern Pakistan was investigated in this research. Landsat MSS, TM and ETM+ images were used for this study. Digital elevation models derived from ASTER GDEM and SRTM were also utilized. Visible, infrared and thermal infrared channels were utilized in order to get accurate glacier change maps. Three methods were tried to map this debris-covered glacier in this research. The glacier has been mapped successfully and the changes in the glacier terminus from 1978 to 2011 have been calculated. Manual, semi-automatic and thermal methods were found to give similar results. It was found that the glacier has undergone serious ablation during this period despite of the fact that many of the larger glaciers in the Hindu Kush and Karakoram mountain regions in the Upper Indus Basin were reported to be expanding. The terminus has been moved back about 600 meters during this period and there was an abrupt change in the glacier terminus during 1990-2002. We propose that debris thickness is not the only factor that influences the glacier ablation but the altitude of the debris-covered glacier as well. Many glaciers in the Karakoram region reported to be expanding were having higher altitudes compared to the study area.展开更多
Information on the thickness distribution and volume of glacier ice is highly important for glaciological applications;however,detailed measurements of the ice thickness of many glaciers in the Chinese Altay Mountains...Information on the thickness distribution and volume of glacier ice is highly important for glaciological applications;however,detailed measurements of the ice thickness of many glaciers in the Chinese Altay Mountains remain lacking.Burqin Glacier No.18 is a northeast-orientated cirque glacier located on the southern side of the Altay Mountains.This study used PulseEKKO®PRO 100A enhancement ground-penetrating radar(GPR)to survey the ice thickness and volume of Burqin Glacier No.18 in summer 2018.Together with GPR surveying,spatial distributed profiles of the GPR measurements were concurrently surveyed using the real-time kinematic(RTK)global navigation satellite system(GNSS,Unistrong E650).Besides,we used QuickBird,WorldView-2,and Landsat TM to delineate accurate boundary of the glacier for undertaking estimation of glacier ice volume.GPR measurements revealed that the basal topography of profile B1-B2 was flat,the basal topography of profile C1-C2 presented a V-type form,and the basal topography of profile D1-D2 had a typical U-type topographic feature because the bedrock near the central elevation of the glacier was relatively flat.The longitudinal profile A1-A2 showed a ladder-like distribution.Glacier ice was thin at the terminus and its thickness increased gradually from the elevation of approximately 2620 m a.s.l.along the main axis of the glacier tongue with an average value of 80(±1)m.The average ice thickness of the glacier was determined as 27(±2)m and its total ice volume was estimated at 0.031(±0.002)km3.Interpretation of remote sensing images indicated that during 1989–2016,the glacier area reduced from 1.30 to 1.17 km2(reduction of 0.37%/a)and the glacier terminus retreated at the rate of 8.48 m/a.The mean ice thickness of Burqin Glacier No.18 was less than that of the majority of other observed glaciers in China,especially those in the Qilian Mountains and Central Chinese Tianshan Mountains;this is probably attributable to differences in glacier type and climatic setting.展开更多
During a study of fungal diversity in the Puruogangri Glacier ecosystem on the Qinghai-Xizang Plateau,a strain was isolated from soil samples at the glacier forefields using the dilution plate method,and identified as...During a study of fungal diversity in the Puruogangri Glacier ecosystem on the Qinghai-Xizang Plateau,a strain was isolated from soil samples at the glacier forefields using the dilution plate method,and identified as Sinophaeosphaeria xizangensis gen.et sp.nov.Morphological analysis revealed that the fungus produced olive to olive-brown conidia on PDA medium.The conidia consist of two or more cells,arranged in curved or irregular chains.Some cells slightly swollen,forming distinctly prominent bulging regions or aggregating into dense,hammer-shaped structures.Phylogenetic analyses based on five genetic loci,including internal transcribed spacer(ITS),large subunit ribosomal DNA(LSU),small subunit ribosomal DNA(SSU),RNA polymeraseⅡsecond largest subunit(rpb2),and translation elongation factor 1-α(tef1-α),indicate that this fungus represents a previously undescribed lineage within the family Phaeosphaeriaceae.This genus is located at the base of a branch that includes Paraloratospora,Loratospora,Wingfieldomyces and Sulcispora,revealing its unique evolutionary position.展开更多
Temperate glaciers are highly sensitive to variations in climate and environmental conditions.Investigating the chemical composition of dissolved organic matter(DOM)in glacier snow is essential for understanding its c...Temperate glaciers are highly sensitive to variations in climate and environmental conditions.Investigating the chemical composition of dissolved organic matter(DOM)in glacier snow is essential for understanding its characteristics,sources,and transformation processes within glacial systems.This study aims to elucidate the chemical composition and transformation of DOM in snow environment by analyzing samples collected from snowpits,surface snow,and snow meltwater at Baishui Glacier No.1 on Mt.Yulong during May and June.The average concentrations of dissolved organic carbon(DOC)in snow meltwater collected in May(1.63±0.63 mg L^(-1))and June(1.54±0.35 mg L^(-1))were both significantly higher than those measured in snowpit samples from May(0.74±0.10 mg L^(-1))and June(0.54±0.10 mg L^(-1)),as well as in surface snow samples from May(0.65±0.31 mg L^(-1))and June(0.69±0.30 mg L^(-1)).However,the concentrations of DOC in samples from the same category did not show significant variation between May and June.Using excitation-emission matrix(EEM)fluorescence spectroscopy coupled with parallel factor(PARAFAC)analysis,three protein-like components(C_(1),C_(2),and C_(3))and one humic-like component(C_(4))were identified.The protein-like components accounted for more than 75%of the total DOM in all snow samples,indicating that the fluorescent DOM originated from biological or microbial sources.Significant differences in the relative proportions of the four fluorescent components were observed between snowpit samples from May and June,whereas no significant variations were noted in the other sample types.Furthermore,a clear transformation from protein-like to humic-like components was observed during the transition from snowpits to snow meltwater.Further analysis using Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR MS)revealed that DOM in these snow samples was predominantly composed of aliphatic and peptide-like compounds(30.9%-50.9%),suggesting a substantial microbial contribution.FT-ICR MS data also demonstrated compositional shifts in DOM among snowpit,surface snow,and meltwater samples.Specifically,aliphatic and peptide-like compounds were progressively transformed into unsaturated compounds with high oxygen content,polyphenolic species,and condensed aromatic compounds during their transition from snowpit to meltwater.Therefore,the relative contribution of terrestrial-derived DOM increased during the transition from snowpit to snowmelt.Furthermore,an increase in heteroatom content in the DOM of meltwater samples indicated continuous chemical transformations likely driven by biological activity and/or photochemical processes during snowmelt and leaching.展开更多
文摘The Thwaites Glacier in western Antarctica(Fig. 1) keeps glaciologists and climate scientists awake at night. The 120 kmwide glacier loses about 45 billion tonnes of ice each year, accounting for about 4% of global sea level rise [1]. If it melted completely, sea levels would climb 65 cm, and follow-on effects could lead to a 3 m increase [2]. But if some scientists' vision becomes reality, in 10–15 years construction crews will sail into the Amundsen Sea off Antarctica to begin building an 80 km long underwater curtain that will shield the glacier from the warm currents that are accelerating its decline [3].
基金supported by the Third Xinjiang Scientific Expedition Program(Grant Nos.2022xjkk0101,2022xjkk0802)the Second Qinghai-Tibet Scientific Expedition Program(Grant No.2019QZKK0201)+2 种基金the National Natural Science Foundation of China(Grant No.42301166)the China-Tajikistan intergovernmental Joint R&D Project(Grant No.2025YFE0102800)the Science and Technology Program of Gansu Province(Grant Nos.23ZDFA017,22ZD6FA005)
文摘As a highly sensitive indicator of climate change in the arid northwest region of China,glacier dynamics in the Kaidu-Konqi River Basin directly influence regional runoff patterns,thereby playing a crucial role in shapingregional hydrology and maintaining ecological stability.This study systematically assessed glacier distribution in2020 and analyzed glacier changes from 1972 to 2020 using the Chinese Glacier Inventory of Xinjiang in 2020(CGI-XJ2020),historical satellite imagery from 1972,and data from the Second Chinese Glacier Inventory.In2020,the basin contained 713 glaciers covering 313.99 km^(2),with an estimated glacier volume of 11.81 km^(3)(0.41%glacier coverage).Glaciers were predominantly clustered in the northern and southwestern mountains.Small glaciers(<0.5 km^(2))comprised 78%of the glacier count but only 3%of the total area,whereas glaciers≥0.5 km^(2)accounted for 97%of the total area and 83.6%of the glacier volume.From 1972 to 2020,the totalglacier area decreased by 42.28%(229.99 km^(2))and glacier volume by 49.51%(11.58 km^(3)),equating to meanannual rates of−0.88%and−1.03%,respectively.Glacier retreat drives temporary increases in meltwatersupply but threatens long-term regional runoff stability and ecological water security.The retreat rate variedover different periods,with a more pronounced decline observed between 1972 and 2007.These findingshighlight an accelerating glacier loss in the basin,underscoring the need for continued monitoring and assess-ment of its hydrological and ecological impacts.
基金funded by the Open Research Fund of TPESER(Grant No.TPESER202502)the National Key Research and Development Program of China(Grant No.2024YFF0810700)+3 种基金the Science and Technology Program Project of Gansu Province,China(Grant No.25JRRA138)the Hydraulic Science Experimental Research and Technology Extension Project of Gansu Province,China(Grant No.25GSLK094)the Open Foundation of MOE Key Laboratory of Western China's Environmental System,Lanzhou Universitythe Fundamental Research Funds for the Central Universities(Grant No.1zujbky-2025-jdzx02)。
文摘Surge-type glaciers are widely developed in mountainous areas around the world.Understanding the trigger mechanism of glacier surge is a prerequisite for addressing their impacts on hydrological assessments,disentangling climate-glacier linkages,and mitigating downstream hazards.Most glacier surges occur in the compound glaciers;however,attention paid to the trigger mechanisms of such surges is minimal.This study confirmed two surges in the northern and southern branches of the Aru-4 glacier,respectively,in the Western Tibetan Plateau,using multisource remote sensing data.The northern branch of the Aru-4 glacier entered the active phase in 1999 and the active phase lasted for 6 years.The southern branch of the Aru-4 glacier entered the active phase in 2007 and the active phase lasted for 9 years.The southern branch of the Aru-4 glacier experienced a long period of retreat before the northern branch surged and their tongues were in a detached state.The northern branch surge carried a large amount of ice to the frontal area,blocking the downward transport of ice from the southern branch and initiated surge.Through the analysis of two surge processes of Aru-4 glacier,we found a new surge mechanism for compound glaciers.It was revealed that surges in such glaciers are not only triggered by the reduction in basal sliding resistance caused by the internal factors.These surges initiated in the upper part of the glacier then propagated to down glacier by intense compression force.Furthermore,surges can also be triggered by external intervention of blocking by other branches.This external trigger initiates the surge in the lower part of the glacier then propagated to the upper part by longitudinal traction force.In addition,comparing with the surge triggered by the internal factors,the surge triggered by the external intervention may have a more dramatic process.
基金supported by the National Natural Science Foundation of China(Nos.U2244227,U2244226,42177172)the National Key R&D Program of China(No.2022YFC3004301)China Geological Survey Project(No.DD20230538)。
文摘Frequent glacier-related watershed geohazard chains are causing severe damage to life and infrastructure,reported consistently from the Eastern Himalayan Syntaxis.This paper presents a systematic method for researching geohazard,from regional to individual scale.The methodology includes the establishment of geological chain inventories,discrimination of geohazard chain modes,analyses of dynamics and dam breaches,and risk assessments.The following results were obtained:(1)In the downstream of Yarlung Zangbo River,175 sites were identified as high-risk for river blockage disasters,indicating the development of watershed geohazards.Five geohazard chain modes were summarized by incorporating geomorphological characteristics,historical events,landslide zoning,and materials.The risk areas of typical hazard were identified and assessed using InSAR data.(2)Glacier-related watershed geohazard chains are significantly different from traditional landslides.A detailed inversion analysis was conducted on the massive rock-ice avalanche in the Sedongpu gully in 2021.This particular event lasted roughly 300 seconds,with a maximum flow velocity of 77.2 m/s and a maximum flow height of 93 meters.By scrutinizing the dynamic processes and mechanical characteristics,mobility stages and phase transitions can be divided into four stages.(3)Watershed geohazard chains tend to block rivers.The peak breach discharge of the Yigong Landslide reached 12.4×10^(4) m^(3)/s,which is 36 times the volume of the seasonal flood discharge in the Yigong River.Megafloods caused by landslide dam breaches have significantly shaped the geomorphology.This study offers insights into disaster patterns and the multistaged movement characteristics of glacier-related watershed geohazard chains,providing a comprehensive method for investigations and assessments in glacial regions.
基金supported by the National Natural Science Foundation of China(Nos.42130516,42171139,41871053)the Second Tibetan Plateau Scientific Expedition and Research Program(No.2019QZKK020102)+1 种基金Natural Science Basic Research Program of Shaanxi Province(No.2023–JC–QN–0300)the Science and Technology Program of Gansu Province(24JRRG012)。
文摘Owing to glacial retreat and associated future runoff variations,major concerns have been raised over the sustainability of water resources in the Qilian Mountains.Based on the Python Glacier Evolution Model,we present projections of the Qiyi glacier for shared socioeconomic pathways(SSPs)calibrated with the glaciological mass balance.The results indicate the air temperature as the dominant factor in the continuous mass loss of the Qiyi Glacier in the future.Glacier area and volume are projected to decline to 0.16±0.11 km2(6.4%±4.4%,relative to 2015)and 0.0023±0.0006 km3(2.1%±1.5%,relative to 2015),respectively,by 2100,for SSP1-2.6.For SSP5-8.5,the glacier will disappear by 2088.The mass loss of the Qiyi Glacier will accelerate before 2050 for all SSPs but will decelerate after 2050 for SSP1-2.6 and SSP2-4.5.The peak water of glacier runoff will occur between2034 and 2045,with the duration of high water from 7 to 18 years.Thereafter,the runoff will rapidly decline till 2070–2080 and remain low afterward.Compared with the existing projections,the present projections indicate that the Qiyi Glacier will experience more drastic shrinkage and ice loss in the coming decades.Finally,the glacier runoff is expected to reach its peak water earlier with a shorter duration of high water.
基金funding from the National Key Research and Development Program of China(2023YFC3206300)the Gansu Provincial Science and Technology Program(22ZD6FA005)+2 种基金the Gansu Youth Science and Technology Fund(E4310103)the Gansu Postdoctoral Science Foundation(E339880112)the Tibet Science and Technology Program(XZ202301ZY0001G and XZ202401JD0007)。
文摘Glacier mass balance is a key indicator of glacier health and climate change sensitivity.Influencing factors include both climatic and nonclimatic elements,forming a complex set of drivers.There is a lack of quantitative analysis of these composite factors,particularly in climate-typical regions like the Tanggula Mountains on the central Tibetan Plateau.We collected data on various factors affecting glacier mass balance from 2000 to 2020,including climate variables,topographic variables,geometric parameters,and glacier dynamics.We utilized linear regression models,ensemble learning models,and Open Global Glacier Model(OGGM)to analyze glacier mass balance changes in the Tanggula Mountains.Results indicate that linear models explain 58%of the variance in glacier mass balance,with seasonal temperature and precipitation having significant impacts.Our findings show that ensemble learning models made the explanations 5.2%more accurate by including the impact of topographic and geometric factors such as the average glacier height,the slope of the glacier tongue,the speed of the ice flow,and the area of the glacier.Interpretable machine learning identified the spatial distribution of positive and negative impacts of these characteristics and the interaction between glacier topography and ice dynamics.Finally,we predicted the responses of glaciers of different sizes to future climate change based on the results of interpretable machine learning.It was found that relatively large glaciers(>1 km~2)are likely to persist until the end of this century under low emission scenarios,whereas small glaciers(<1 km~2)are expected to nearly disappear by 2080 under any emission scenario.Our research provides technical support for improving glacier change modeling and protection on the Tibetan Plateau.
基金funded by the Basic scientific research fund projects(Youth Project)of the Educational Department of Liaoning Province in 2023(Grants No.JYTQN2023451)Liaoning Institute of Science and Technology doctoral research initiation fund project in 2023(Grants No.2307B27)+2 种基金Basic Research Project of Higher Education Institutions of Liaoning Provincial Department of Education(Grants No.2024JYTYB-12)the Basic scientific research fund projects(Youth Project)of the Educational Department of Liaoning Province in 2023(Grants No.JYTQN2024-21)Liaoning Institute of Science and Technology doctoral research initiation fund project in 2023(Grants No.2307B26)。
文摘The estimation of glacier flow velocity on a short-term scale is very important for further glacier dynamics research.In this study,10 Sentinel-1 ascending images and 10 Sentinel-1 descending images of Urumqi Glacier No.1 in 2017 were used to calculate the glacier flow velocity in a high coherence period by DIn SAR technology and MAI technology,while the offset tracking technology was used to estimate the glacier flow velocity in a low coherence period.Then,the monthly three-dimensional flow velocity of the glacier was calculated by the Helmert variance component estimation method.Finally,the accuracy of the estimated glacier flow velocity on a monthly scale was evaluated.The results showed that:(1)the monthly scale motion velocity of Urumqi Glacier No.1 in May,June,July,and August 2017 was 0.273 m/month,0.657 m/month,0.582 m/month,and 0.392 m/month,respectively.(2)The accuracy of glacier surface velocity from May 2017 to August 2017 was 0.033 m/month,0.026 m/month,0.034 m/month and 0.037 m/month,respectively.(3)The accuracy of glacier surface flow velocity from May 2017 to August 2017 was 0.018 m/month,0.031 m/month,0.029 m/month and 0.030 m/month,respectively.Therefore,the research methodology based on the Sentinel-1 ascending and descending data and presented in this paper was applicable to the estimation of monthly-scale flow velocity of mountain glaciers.
基金supported by Third Xinjiang Scientific Expedition Program(Grant No.2022xjkk0101)Second Qinghai-Tibet Scientific Expedition Program(Grant No.2019 QZKK0201)+2 种基金Third Xinjiang Sci-entific Expedition Program(Grant No.2021xjkk0401)National Natural Science Foundation of China(Grant No.42301166)National Natural Science Foundation of China(Grant No.42371148)。
文摘The Ili River is a typical transboundary river between China and Kazakhstan,with glaciers within its basin serving as a crucial solid water resource.Recently,we compiled the Chinese Glacier Inventory of Xinjiang in 2020(CGI-XJ2020)using high-resolution satellite imagery(<2 m),based on visual interpretation.This study presented the state of glaciers in the Ili River Basin in 2020 by utilizing the data from CGI-XJ2020.It quantified glacier changes in 1960s–2020 based on CGI-XJ2020 and revised datasets from the First and Second Chinese Glacier Inventories.The results indicated that in 2020,the Ili River Basin contained 2,177 glaciers,totaling 1,433.19 km^(2)in area.Among them,213 glaciers were covered by 57.43 km^(2)of debris.The total uncertainty in glacier area was 46.43 km^(2),accounting for approximately 3.2%of the total area.Mapped glacier areas varied from 0.003 to 74.67 km^(2),with an average area of 0.66 km^(2)and a median area of 0.15 km^(2).Glaciers<0.5 km^(2)in size dominated in numbers,accounting for 75.1%of the total.Glaciers in the basin have undergone significant retreat during 1960s–2020,with their total area decreasing by 589.38 km^(2)(29.15%).A total of 495 glaciers(with an area of 49.67 km^(2))disappeared.The average annual glacier area retreat rates for 1960s-2007 and 2007–2020 were 10.86 km^(2)/a(0.54%/a)and 9.41 km^(2)/a(0.61%/a),respectively,showing a continued acceleration in glacier shrinkage,despite a slight decrease in absolute retreat rates.
文摘In contrast to glaciological studies in Mexico,periglacial studies are very recent and limited to the analysis of the general permafrost cover in the high mountains of the country.Although some of the studies on the reconstruction of Pleistocene glaciers in Mexico mention the existence of rock glaciers,to date no work has been done to study their physical properties or determining their state of conservation.Since rock glaciers are the most important visible indicators of mountain permafrost(along with features such as gelifluction lobes and patterned ground)and given that the“Nevado”rock glacier is the main example of its kind in Mexico,this study analyzes its internal temperature and assesses its state of conservation.The investigation was carried out by drilling and thermal monitoring of rock profiles as well as air.The results indicate that at present,the“Nevado”seems to lack permafrost inside.Although there is evidence of surface freezing during the winter months in the upper part of the rock glacier,in the lower portion it is almost unnoticed;and in both parts the internal temperature shows a tendency towards positive values as depth increases,a situation that predominates throughout the year.In addition,according to the records of the climatological station located in the lower part of the rock glacier,although the annual rainfall regime could be favorable for the formation and feeding of interstitial or segregated ice,the air temperature conditions throughout the year prevent permanent freezing.The sum of the above determines that at present the“Nevado”could be considered as an inactive and relict-type rock glacier;the presence of vegetation on the surface of the debris that make it up corroborates its inactivity.
基金supported by the Third Xinjiang Scientific Expedition Program(Grant No.2022xjkk0101)Second Qinghai-Tibet Scientific Expedition Program(Grant No.2019QZKK0201)+2 种基金National Natural Science Foundation of China(Grant No.42301166)National Science Foundation of Gansu Province(Grant No.23JRRA658)Xinjiang Key Laboratory of Water Cycle and Utilization in Arid Zone(XJYS0907-2024-yb-11)
文摘The Turpan−Hami Basin in Xinjiang is a resource−scarce area where glaciers are important water resources.Based on the data of the Chinese Glacier Inventory of Xinjiang in 2020(CGI-XJ2020),this study analyzed andexplained the distribution characteristics of glaciers in the Turpan−Hami Basin in 2020.Additionally,by inte-grating the updated First and Second Chinese Glacier Inventories,the study examined changes within the basinfrom 1962 to 2020.It also assessed the specific impact of glacier changes in the Hami region on the runoff of fourtypical basins.The results indicated that in 2020,the Turpan−Hami Basin contained 354 glaciers,covering anarea of 155.82 km^(2)and an estimated ice volume of 5.81 km3.Small glaciers(<0.5 km^(2))were the most numerous,accounting for 78%of the total,while glaciers ranging from 2.0 to 5.0 km^(2)were the largest area,covering39.37 km^(2),which represents 25.3%of the total glacier area.From 1962 to 2020,the glacier area decreased by85.06 km^(2)(35.3%).Between 1962 and 2009,the area decreased by 72.53 km^(2)(30.11%),with an average annualretreat of 1.54 km^(2)/a(0.64%/a).From 2009 to 2020,the area decreased by 12.53 km^(2)(7.44%),and the averageannual retreat slowed to 1.14 km^(2)/a(0.68%/a).These results suggested that while the total glacier area con-tinues to decline,the rate of decrease in absolute terms has slowed,whereas the relative rate of change hasincreased,indicating an accelerating trend in glacier melt.Climate-driven glacier changes have significantly impacted river hydrology and water resources in Hami.In basins without glaciers,runoff has shown a decreasingtrend,suggesting that the positive effect of increased precipitation on runoff may not be sufficient to offset thenegative impact of rising temperatures.In basins with smaller glaciers,the'peak water'for glacier runoff likelyoccurred in the 1980s and 1990s,and water resources are expected to continue deteriorating.In contrast,basinswith larger glaciers have not yet reached a'peak water'and high flow is projected to persist for decades.
基金supported by the Postdoctoral Fellowship Program of CPSF(Grant No.GZC20232951)the Science and Technology program of Gansu Province(Grant No.22ZD6FA005)Program of the State Key Laboratory of Cryospheric Science and Frozen Soil Engineering(Grant No.CSFSE-TZ-2403,2410)。
文摘Temperate glaciers in the southeastern Tibetan Plateau have experienced significant mass loss and retreat in recent decades,yet detailed on-site observations remain limited.Here we present the measured records of surface mass balance,ice velocity and surface ice temperature of Baishui River Glacier No.1 in Yulong Snow Mountain from 2018 to 2022.Our observations reveal an annual mean mass balance of-1.29±0.16 m w.e.,demonstrating a significant seasonal imbalance between reduced accumulation(multi-year average of 0.51±0.07 m w.e.)and enhanced ablation(multi-year average of 1.80±0.26 m w.e.),which provides crucial evidence for explaining the long-term mass loss.The average annual ice velocity,predominantly controlled by monsoon season dynamics which contribute 69%–74%of the total movement,was measured at 26.91±2.76 m yr^(-1)and exhibited a decreasing trend of 1.73 m yr^(-1).The ice temperature fluctuated between-13.41℃to-0.04℃,with an average of-6.04℃.The ice temperature and air temperature synchronized well in the nonmonsoon period,while the temperature rise was not synchronized and slightly delayed in the monsoon period.
基金supported by the Third Xinjiang Scientific Expedition Program(Grant No.2022xjkk0101)the Second Qinghai-Tibet Scientific Expedition Program(Grant No.2019QZKK0201).
文摘Based on China's high-resolution satellite imagery series(2 m resolution),the Chinese Glacier Inventory of Xinjiang in 2020(CGI-XJ2020)was compiled,with 2020 as the baseline year.CGI-XJ2020 has five key features:1)improved accuracy in glacier boundary delineation and optimized inventory attributes through highresolution satellite imagery and field validation of 38 glaciers;2)established an area-volume formula for Xinjiang glaciers using ground-penetrating radar(GPR)thickness data from 23 glaciers in the study region;3)the use of high-resolution satellite imagery has reduced the minimum glacier area threshold,enabling the identification of more small glaciers;4)enhanced accuracy in delineating supraglacial debris coverage;5)upgraded administrative division from prefecture-level(CGI-2)to county-level.According to CGI-XJ2020 data,Xinjiang contains 24,202 glaciers in 2020,covering 23,629.28 km^(2)with an average size of 0.98 km^(2)per glacier and a total ice volume of 1,608.94 km^(3).Among these,1,612 debris-covered glaciers occupy 1,163.32 km^(2)(4.9%of the total glacierized area).Glaciers larger than 10 km^(2)(296 in total)cover 9,881.69 km^(2)with a volume of 1,053.17 km^(3),accounting for 41.82%of total area and 65.46%of total ice volume,respectively.The Kunlun Mountains host the most glaciers,followed by the Tianshan Mountains.The Tarim river basin contains the largest concentration(15,860 glaciers,18,594.24 km^(2),1,347.17 km^(3)).The Hotan Prefecture has the highest glacier density.
文摘The surface velocity is one of the most important characteristics of glaciers.Monitoring and mapping glacier movements are of great significance for the studies of sea-level rise,glacier mass balance and dynamics,global warming,and the management of freshwater resources.It is also essential for the early warnings of hazards caused by ice avalanches.SAR imaging geodesy has been developed for measuring glacier velocity,especially the pixel-offset tracking method.This paper introduces some basic concepts of glaciology and principles of various SAR imaging geodesy methods,with a detailed presentation about the developments in the applications of the pixel-offset tracking method.Finally,the challenges and future prospects of SAR imaging geodesy in glacier monitoring are discussed.
基金supported by the National Natural Science Foundation of China(No.42374053)the Hunan Provincial Natural Science Foundation(No.2023JJ30656)+1 种基金the 4th Earth Observation Research Project of JAXA(No.ER4A2N154)the DLR Satellite Project(No.TXGEO3812)。
文摘Glacier ice thickness is a critical parameter for simulating glacier dynamics and estimating glacier volume.This study proposes a novel approach that integrates the laminar flow model with random cell interpolation to estimate glacier ice thickness with high efficiency and accuracy.A primary advantage of this method is that it avoids 0ver-reliance on central flowlines,a significant constraint in many traditional models that is difficult to accurately delineate glaciers with complex flow patterns.Furthermore,the integration of random cell interpolation allows the model to generate glacier cross-sections that are more consistent with idealized,physically plausible shapes,refining the raw thickness estimates.The effectiveness and accuracy of this approach were validated in the Western Kunlun main peak region.The results demonstrate the model's reliability,with the total estimated glacier volume falling between the results of the established H&F and Glab Top2 models.The RCGTI calibration,a key component of our method,is proved to be highly effective,reducing the overall volume overestimation by 8.9%from 490.02 to 446.57 km~3.Crucially,when compared to ground penetrating radar(GPR)measurements,our model shows a better match than other mainstream inversion methods.This study demonstrates that the proposed integrated model provides a robust and effective method for large-scale assessments of glacier storage.
基金supported by Third Xinjiang Scientific Expedition Program(Grant No.2022xjkk0101)Second Qinghai-Tibet Scientific Expedition Program(Grant No.2019QZKK0201)+2 种基金National Natural Science Foundation of China(Grant No.42301166)National Science Foundation of Gansu Province(Grant No.23JRRA658)Xinjiang Key Laboratory of Water Cycle and Utilization in Arid Zone(XJYS0907-2024-yb-11)
文摘Based on the Chinese Glacier Inventory of Xinjiang in 2020(CGI-XJ2020),we analyzed glacier distribution in theAksu River Basin and examined glacier changes using datasets from Chinese three-period inventories.In 2020,the basin contained 3,491 glaciers,covering 4,144.84 km^(2),and estimated their ice volume at 345.05 km3.Thelargest glacier areas appeared at elevations between 3,800 and 4,100 m(29.70%),and northern-oriented glaciersdominated both in number(33.73%)and area(35.68%).From 1963 to 2007,glacier area decreased by361.22 km^(2),with an annual retreat rate of 0.38%.From 2007 to 2020,the area decreased by 118.88 km^(2),showing a higher retreat rate of 0.51%,indicating accelerated melting.Glaciers shrank rapidly across all ori-entations,with the fastest reductions occurring in the southwest and the slowest in the northwest.The extent ofglacier area change was influenced by glacier area and debris.Debris-covered glaciers were widespread in theAksu River Basin,with larger glaciers showing an increase in debris.Debris reduced the rate of terminus retreatin large glaciers,while glaciers with thinner debris layers experienced more pronounced melting,with large icetongues at lower altitudes shrinking rapidly,while high-altitude regions remained relatively stable.
基金supported by the National Key R&D Program of China(2018YFC1505002)CGS Research Fund(JYYWF20181501)+1 种基金National Natural Science Foundation of China(41672359)Chinese Academy of Sciences President’s International Fellowship Initiative(grant No.2018PC0009)
文摘Abnormal glacier movement is likely to result in canyon-type hazards chain,such as the barrier lake of Yarlung Zangbo Grand Canyon formed by glacier debris flow in October 2018 in China.Glacier hazard usually evolves from the glacier surge and may occur in a regular cycle.Understanding the characteristics and process of glacier surge is important for early hazard recognition and hazard assessment.Based on field investigations,remote sensing interpretations and SAR offset-tracking surveys,this study confirms a typical glacier surge in the northeast Pamir,and presents its characteristics and processes."Black ice"mixed moraines choking uplift and overflowing lateral marine are the most important scenic characteristics,which were formed under the conditions of stagnant glacier downstream and abundant super-glacial moraine.Glacier movement event can be divided into a five-period cycle including quiescent,inoculation,initiation,fracture and decline.This surge event lasted for about 300 days,initiated in February 2015 developed extensive fracturing zone in spring and early summer at maximum velocity of 10±0.95 m/day,declined after August 2015 and recovered to quiescent status in October 2015 for the next inoculation.The average height of glacier"receiving"area increased by 20-40 m with 2.7-3.6×10^8 m^3 ice transferred from glacier"reservoir",and this volume accumulation again require 50-100 years for glacier mass balance which gives approximately 100 years frequency of the glacier surge.Nevertheless,long-period increase of precipitation and temperature were favorable for the occurrence,hydrological instability is the direct triggering mechanism,and while the Glacier Lake Outburst Flood(GLOF)hazards are unlikely to occur with this surge.
基金Rio Grande do Sul State Foundation for Research (FAPERGS), Brazil for financial support
文摘Recent changes occurred in terminus of the debris-covered Bilafond Glacier in the Karakoram Range in the Himalayas, Northern Pakistan was investigated in this research. Landsat MSS, TM and ETM+ images were used for this study. Digital elevation models derived from ASTER GDEM and SRTM were also utilized. Visible, infrared and thermal infrared channels were utilized in order to get accurate glacier change maps. Three methods were tried to map this debris-covered glacier in this research. The glacier has been mapped successfully and the changes in the glacier terminus from 1978 to 2011 have been calculated. Manual, semi-automatic and thermal methods were found to give similar results. It was found that the glacier has undergone serious ablation during this period despite of the fact that many of the larger glaciers in the Hindu Kush and Karakoram mountain regions in the Upper Indus Basin were reported to be expanding. The terminus has been moved back about 600 meters during this period and there was an abrupt change in the glacier terminus during 1990-2002. We propose that debris thickness is not the only factor that influences the glacier ablation but the altitude of the debris-covered glacier as well. Many glaciers in the Karakoram region reported to be expanding were having higher altitudes compared to the study area.
基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA20020102,XDA20060201)the Second Tibetan Plateau Scientific Expedition and Research(STEP)Program(2019QZKK0201)+1 种基金the National Natural Science Foundation of China(International cooperation and exchange projects)(41761134093)the National Natural Science Foundation of China(41771077)。
文摘Information on the thickness distribution and volume of glacier ice is highly important for glaciological applications;however,detailed measurements of the ice thickness of many glaciers in the Chinese Altay Mountains remain lacking.Burqin Glacier No.18 is a northeast-orientated cirque glacier located on the southern side of the Altay Mountains.This study used PulseEKKO®PRO 100A enhancement ground-penetrating radar(GPR)to survey the ice thickness and volume of Burqin Glacier No.18 in summer 2018.Together with GPR surveying,spatial distributed profiles of the GPR measurements were concurrently surveyed using the real-time kinematic(RTK)global navigation satellite system(GNSS,Unistrong E650).Besides,we used QuickBird,WorldView-2,and Landsat TM to delineate accurate boundary of the glacier for undertaking estimation of glacier ice volume.GPR measurements revealed that the basal topography of profile B1-B2 was flat,the basal topography of profile C1-C2 presented a V-type form,and the basal topography of profile D1-D2 had a typical U-type topographic feature because the bedrock near the central elevation of the glacier was relatively flat.The longitudinal profile A1-A2 showed a ladder-like distribution.Glacier ice was thin at the terminus and its thickness increased gradually from the elevation of approximately 2620 m a.s.l.along the main axis of the glacier tongue with an average value of 80(±1)m.The average ice thickness of the glacier was determined as 27(±2)m and its total ice volume was estimated at 0.031(±0.002)km3.Interpretation of remote sensing images indicated that during 1989–2016,the glacier area reduced from 1.30 to 1.17 km2(reduction of 0.37%/a)and the glacier terminus retreated at the rate of 8.48 m/a.The mean ice thickness of Burqin Glacier No.18 was less than that of the majority of other observed glaciers in China,especially those in the Qilian Mountains and Central Chinese Tianshan Mountains;this is probably attributable to differences in glacier type and climatic setting.
基金supported by the Second Xizang Plateau Scientific Expedition and Research Program(2024QZKK02010303)the Second Qinghai-Xizang Plateau Scientific Expedition and Research(STEP)Program(2019QZKK0503).
文摘During a study of fungal diversity in the Puruogangri Glacier ecosystem on the Qinghai-Xizang Plateau,a strain was isolated from soil samples at the glacier forefields using the dilution plate method,and identified as Sinophaeosphaeria xizangensis gen.et sp.nov.Morphological analysis revealed that the fungus produced olive to olive-brown conidia on PDA medium.The conidia consist of two or more cells,arranged in curved or irregular chains.Some cells slightly swollen,forming distinctly prominent bulging regions or aggregating into dense,hammer-shaped structures.Phylogenetic analyses based on five genetic loci,including internal transcribed spacer(ITS),large subunit ribosomal DNA(LSU),small subunit ribosomal DNA(SSU),RNA polymeraseⅡsecond largest subunit(rpb2),and translation elongation factor 1-α(tef1-α),indicate that this fungus represents a previously undescribed lineage within the family Phaeosphaeriaceae.This genus is located at the base of a branch that includes Paraloratospora,Loratospora,Wingfieldomyces and Sulcispora,revealing its unique evolutionary position.
基金supported by grants from the Sichuan Natural Science Foundation Project(2024NSFSC0793)Dagu Glacier Research Institute(Center)project of Aba Normal College(AS-DTPT 2023072)the support of Youth Innovation Promotion Association CAS(2021429)。
文摘Temperate glaciers are highly sensitive to variations in climate and environmental conditions.Investigating the chemical composition of dissolved organic matter(DOM)in glacier snow is essential for understanding its characteristics,sources,and transformation processes within glacial systems.This study aims to elucidate the chemical composition and transformation of DOM in snow environment by analyzing samples collected from snowpits,surface snow,and snow meltwater at Baishui Glacier No.1 on Mt.Yulong during May and June.The average concentrations of dissolved organic carbon(DOC)in snow meltwater collected in May(1.63±0.63 mg L^(-1))and June(1.54±0.35 mg L^(-1))were both significantly higher than those measured in snowpit samples from May(0.74±0.10 mg L^(-1))and June(0.54±0.10 mg L^(-1)),as well as in surface snow samples from May(0.65±0.31 mg L^(-1))and June(0.69±0.30 mg L^(-1)).However,the concentrations of DOC in samples from the same category did not show significant variation between May and June.Using excitation-emission matrix(EEM)fluorescence spectroscopy coupled with parallel factor(PARAFAC)analysis,three protein-like components(C_(1),C_(2),and C_(3))and one humic-like component(C_(4))were identified.The protein-like components accounted for more than 75%of the total DOM in all snow samples,indicating that the fluorescent DOM originated from biological or microbial sources.Significant differences in the relative proportions of the four fluorescent components were observed between snowpit samples from May and June,whereas no significant variations were noted in the other sample types.Furthermore,a clear transformation from protein-like to humic-like components was observed during the transition from snowpits to snow meltwater.Further analysis using Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR MS)revealed that DOM in these snow samples was predominantly composed of aliphatic and peptide-like compounds(30.9%-50.9%),suggesting a substantial microbial contribution.FT-ICR MS data also demonstrated compositional shifts in DOM among snowpit,surface snow,and meltwater samples.Specifically,aliphatic and peptide-like compounds were progressively transformed into unsaturated compounds with high oxygen content,polyphenolic species,and condensed aromatic compounds during their transition from snowpit to meltwater.Therefore,the relative contribution of terrestrial-derived DOM increased during the transition from snowpit to snowmelt.Furthermore,an increase in heteroatom content in the DOM of meltwater samples indicated continuous chemical transformations likely driven by biological activity and/or photochemical processes during snowmelt and leaching.
