Snowfall in the Tianshan Mountains in China is frequent during winter;thus,avalanches have become a severe issue in snow-covered areas.Accumulation and metamorphosis,as well as hydrothermal exchanges with the environm...Snowfall in the Tianshan Mountains in China is frequent during winter;thus,avalanches have become a severe issue in snow-covered areas.Accumulation and metamorphosis,as well as hydrothermal exchanges with the environment,considerably affect the stability of snow on slopes.Therefore,a hydrothermal model of snow cover and its underlying surfaces must be developed on the basis of meteorological data to predict and help manage avalanches.This study adopted the conceptual model of snow as a porous medium and quantitatively analysed its internal physical processes on the basis of the thermal exchanges amongst its components.The effects of local meteorological factors on snow structure and the redistribution of energy and mass inside the snow cover in the Tianshan Mountains were simulated.Simulation results showed that deformation as a result of overlying snow and sublimation of snow cover at the bottom is the main cause of density variation in the vertical profile of snow cover.Temperature drives water movement in snow.The low-density area of the bottom snow is the result of temperature gradient.The simulation results of the long-term snow internal mass distribution obtained by the method established in this study are highly consistent with the actual observed trend of variation.Such consistency indicates an accurate simulation of the physical characteristics of snow cover in small and microscale metamorphism in the Tianshan Mountains during the stable period.展开更多
High-precision measuring of glacier evolution remains a challenge as the available global and regional remote sensing techniques cannot satisfactorily capture the local-scale processes of most small-and medium-sized m...High-precision measuring of glacier evolution remains a challenge as the available global and regional remote sensing techniques cannot satisfactorily capture the local-scale processes of most small-and medium-sized mountain glaciers.In this study,we use a high-precision local remote sensing technique,long-range terrestrial laser scanning(TLS),to measure the evolution of Urumqi Glacier No.1 at an annual scale.We found that the dense point clouds derived from the TLS survey can be used to reconstruct glacier surface terrain,with certain details,such as depressions,debris-covered areas,and supra-glacial drainages can be distinguished.The glacier experienced pronounced thickness thinning and continuous retreat over the last four mass-balance years(2015−2019).The mean surface slope of Urumqi Glacier No.1 gradually steepened,which may increase the removal of glacier mass.The glacier was deeply incised by two very prominent primary supra-glacial rivers,and those rivers presented a widening trend.Extensive networks of supra-glacial channels had a significant impact on accelerated glacier mass loss.High-precision measuring is of vital importance to understanding the annual evolution of this type of glacier.展开更多
The glacier is a crucial freshwater resource in arid and semiarid regions,and the vulnerability of the glacier change is intimately linked to regional ecological services and socio-economic sustainability.Taking the T...The glacier is a crucial freshwater resource in arid and semiarid regions,and the vulnerability of the glacier change is intimately linked to regional ecological services and socio-economic sustainability.Taking the Tianshan Mountains region in China as an example,a basic framework for studying the vulnerability of glacier change was constructed so as to address factors such as physical geography,population status,socio-economic level,agricultural development,and social services.The framework was based on key dimensions,that is,exposure,sensitivity,and adaptability,and this constituted a targeted evaluation index system.We examined the spatial structure and spatial autocorrelation of the glacier change vulnerability using ArcGIS and GeoDa software.The influence and interaction of natural,social,economic,population and other factors on glacier change adaptability was examined using the GeoDetector model.The results suggested the following:(1)The vulnerability level decreased from the western region to the eastern region with significant differences between the two regions.The eastern region had the lowest vulnerability,followed by the central region,and then western region which had the highest vulnerability.(2)Significant positive and negative correlations were found between exposure,sensitivity,and adaptability,indicating that the areas with high exposure and high sensitivity to glacier change tended to have a low adaptive capacity,which led to high vulnerability,and vice versa.(3)The spatial heterogeneity regarding the ability to cope with glacier change reflected the combined effects of the natural,social,economic,and demographic factors.Among them,factors such as the production value of secondary and tertiary industries,the urban population,urban fixed-asset investment,and the number of employees played major roles regarding the spatial heterogeneity of glacier change.展开更多
Hanging glaciers hold the absolute dominant number in West China and their changes had important influences on local hydrology,sea-level rise and natural hazards(snow/ice avalanches).However,logistic and operational d...Hanging glaciers hold the absolute dominant number in West China and their changes had important influences on local hydrology,sea-level rise and natural hazards(snow/ice avalanches).However,logistic and operational difficulties have resulted in the lack of in-situ-measured data,leaving us with poor knowledge of the changing behaviors of this type of glacier.Here,we presented the spatiotemporal pattern of seasonal and annual mass changes of a mid-latitude hanging glacier in the Tien Shan based on repeated terrestrial laser scanning(TLS)surveys during the period 2016-2018.The distributed glacier surface elevation changes exhibited highly spatiotemporal variability,and the winter elevation changes showed slight surface lowering at the upper elevations and weak thickening at the glacier terminus,which was contrary to altitudinal elevation changing patterns at the summer and annual scales.Mass balance processes of the hanging glacier mainly occurred during summer and the winter mass balance was nearly balanced(-0.10±0.15 m w.e.).The glacier exhibited more rapid mass loss than adjacent other morphological glacier and the estimated response time of the glacier to climate change was very short(6-9 years),indicating hanging glaciers will experience rapid wastage and disappearance in the future even with climate change mitigation.展开更多
Glaciers are a reliable freshwater resource in arid regions of West China and the vulnerability of its changes is closely related to regional ecosystem services and economic sustainable development. Here, we took the ...Glaciers are a reliable freshwater resource in arid regions of West China and the vulnerability of its changes is closely related to regional ecosystem services and economic sustainable development. Here, we took the Qilian Mountains as an example and analyzed the spatiotemporal characteristics of glacier changes from 1998 to 2018, based on remote sensing images and the Second Chinese Glacier Inventory. We estimated the basic organizational framework and evaluation index system of glacier change vulnerability from exposure, sensitivity and adaptability, which covered the factors of physical geography, population status and socio-economic level. We analyzed the spatial and temporal evolutions of glacier change vulnerability by using the vulnerability evaluation model. Our results suggested that:(1) Glacier area and volume decreased by 71.12±98.98 km^(2) and 5.59±4.41 km^(3), respectively, over the recent two decades, which mainly occurred at the altitude below 4800 m, with an area shrinking rate of 2.5%. In addition, glaciers in the northern aspect(northwest, north and northeast) had the largest area reduction. Different counties exhibited remarkable discrepancies in glacier area reduction, Tianjuan and Minle presented the maximum and minimum decrease, respectively.(2) Glacier change vulnerability level showed a decreasing trend in space from the central to the northwestern and southeastern regions with remarkable differences. Vulnerability level had increased significantly over time and was mainly concentrated in moderate, high and extreme levels with typical characteristics of phases and regional complexity. Our study can not only help to understand and master the impacts of recent glacier changes on natural and social aspects but also be conducive to evaluate the influences of glacier retreat on socio-economic developments in the future, thus providing references for formulating relevant countermeasures to achieve regional sustainable development.展开更多
Melt-albedo feedback on glaciers is recognized as important processes for understanding glacier behavior and its sensitivity to climate change.This study selected the Muz Taw Glacier in the Altai Mountains to investig...Melt-albedo feedback on glaciers is recognized as important processes for understanding glacier behavior and its sensitivity to climate change.This study selected the Muz Taw Glacier in the Altai Mountains to investigate the spatiotemporal variations in albedo and their linkages with mass balance,which will improve our knowledge of the recent acceleration of regional glacier shrinkage.Based on the Landsat-derived albedo,the spatial distribution of ablation-period albedo was characterized by a general increase with elevation,and significant east–west differences at the same elevation.The gap-filling MODIS values captured a nonsignificant negative trend of mean ablation-period albedo since 2000,with a total decrease of approximately 4.2%.From May to September,glacier-wide albedo exhibited pronounced V-shaped seasonal variability.A significant decrease in annual minimum albedo was found from 2000 to 2021,with the rate of approximately−0.30%yr−1 at the 99%confidence level.The bivariate relationship demonstrated that the change of ablation-period albedo explained 82%of the annual mass-balance variability.We applied the albedo method to estimate annual mass balance over the period 2000–2015.Combined with observed values,the average mass balance was−0.82±0.32 m w.e.yr−1 between 2000 and 2020,with accelerated mass loss.展开更多
基金supported by the 13th Five-year Informatization Plan of the Chinese Academy of Sciences,Grant No.XXH13506 and XXH13505-220Data sharing fundamental program for Construction of the National Science Technology Infrastructure Platform(Grant No.Y719H71006)。
文摘Snowfall in the Tianshan Mountains in China is frequent during winter;thus,avalanches have become a severe issue in snow-covered areas.Accumulation and metamorphosis,as well as hydrothermal exchanges with the environment,considerably affect the stability of snow on slopes.Therefore,a hydrothermal model of snow cover and its underlying surfaces must be developed on the basis of meteorological data to predict and help manage avalanches.This study adopted the conceptual model of snow as a porous medium and quantitatively analysed its internal physical processes on the basis of the thermal exchanges amongst its components.The effects of local meteorological factors on snow structure and the redistribution of energy and mass inside the snow cover in the Tianshan Mountains were simulated.Simulation results showed that deformation as a result of overlying snow and sublimation of snow cover at the bottom is the main cause of density variation in the vertical profile of snow cover.Temperature drives water movement in snow.The low-density area of the bottom snow is the result of temperature gradient.The simulation results of the long-term snow internal mass distribution obtained by the method established in this study are highly consistent with the actual observed trend of variation.Such consistency indicates an accurate simulation of the physical characteristics of snow cover in small and microscale metamorphism in the Tianshan Mountains during the stable period.
基金This study was supported by the National Natural Science Foundation of China(42001067)Natural Science Foundation of Gansu Province(21JR7RA059)+4 种基金National Cryosphere Desert Data Center(20D03)National Natural Science Foundation of China(41771077)the Strategic Priority Research Program of Chinese Academy of Sciences(XDA20020102)Second Tibetan Plateau Scientific Expedition and Research(STEP)program(2019QZKK0201)State Key Laboratory of Cryospheric Science(SKLCS-ZZ-2021).
文摘High-precision measuring of glacier evolution remains a challenge as the available global and regional remote sensing techniques cannot satisfactorily capture the local-scale processes of most small-and medium-sized mountain glaciers.In this study,we use a high-precision local remote sensing technique,long-range terrestrial laser scanning(TLS),to measure the evolution of Urumqi Glacier No.1 at an annual scale.We found that the dense point clouds derived from the TLS survey can be used to reconstruct glacier surface terrain,with certain details,such as depressions,debris-covered areas,and supra-glacial drainages can be distinguished.The glacier experienced pronounced thickness thinning and continuous retreat over the last four mass-balance years(2015−2019).The mean surface slope of Urumqi Glacier No.1 gradually steepened,which may increase the removal of glacier mass.The glacier was deeply incised by two very prominent primary supra-glacial rivers,and those rivers presented a widening trend.Extensive networks of supra-glacial channels had a significant impact on accelerated glacier mass loss.High-precision measuring is of vital importance to understanding the annual evolution of this type of glacier.
基金Strategic Priority Research Program of the Chinese Academy of Sciences,No.XDA20020102,No.XDA 20060201National Natural Science Foundation of China,No.41761134093,No.41471058,No.42001067+1 种基金The Second Tibetan Plateau Scientific Expedition and Research Program,No.2019QZKK0201National Cryosphere Desert Data Center,No.20D03。
文摘The glacier is a crucial freshwater resource in arid and semiarid regions,and the vulnerability of the glacier change is intimately linked to regional ecological services and socio-economic sustainability.Taking the Tianshan Mountains region in China as an example,a basic framework for studying the vulnerability of glacier change was constructed so as to address factors such as physical geography,population status,socio-economic level,agricultural development,and social services.The framework was based on key dimensions,that is,exposure,sensitivity,and adaptability,and this constituted a targeted evaluation index system.We examined the spatial structure and spatial autocorrelation of the glacier change vulnerability using ArcGIS and GeoDa software.The influence and interaction of natural,social,economic,population and other factors on glacier change adaptability was examined using the GeoDetector model.The results suggested the following:(1)The vulnerability level decreased from the western region to the eastern region with significant differences between the two regions.The eastern region had the lowest vulnerability,followed by the central region,and then western region which had the highest vulnerability.(2)Significant positive and negative correlations were found between exposure,sensitivity,and adaptability,indicating that the areas with high exposure and high sensitivity to glacier change tended to have a low adaptive capacity,which led to high vulnerability,and vice versa.(3)The spatial heterogeneity regarding the ability to cope with glacier change reflected the combined effects of the natural,social,economic,and demographic factors.Among them,factors such as the production value of secondary and tertiary industries,the urban population,urban fixed-asset investment,and the number of employees played major roles regarding the spatial heterogeneity of glacier change.
基金This research was supported by the National Natural Science Foundation of China(42001067)the Natural Science Foundation of Gansu Province(21JR7RA059)+3 种基金the National Cryosphere Desert Data Center(20D03)the State Key Laboratory of Cryospheric Science(SKLCS-ZZ-2021)the Second Tibetan Plateau Scientific Expedition and Research(STEP)program(2019QZKK0201)the National Natural Science Foundation of China(41771077).
文摘Hanging glaciers hold the absolute dominant number in West China and their changes had important influences on local hydrology,sea-level rise and natural hazards(snow/ice avalanches).However,logistic and operational difficulties have resulted in the lack of in-situ-measured data,leaving us with poor knowledge of the changing behaviors of this type of glacier.Here,we presented the spatiotemporal pattern of seasonal and annual mass changes of a mid-latitude hanging glacier in the Tien Shan based on repeated terrestrial laser scanning(TLS)surveys during the period 2016-2018.The distributed glacier surface elevation changes exhibited highly spatiotemporal variability,and the winter elevation changes showed slight surface lowering at the upper elevations and weak thickening at the glacier terminus,which was contrary to altitudinal elevation changing patterns at the summer and annual scales.Mass balance processes of the hanging glacier mainly occurred during summer and the winter mass balance was nearly balanced(-0.10±0.15 m w.e.).The glacier exhibited more rapid mass loss than adjacent other morphological glacier and the estimated response time of the glacier to climate change was very short(6-9 years),indicating hanging glaciers will experience rapid wastage and disappearance in the future even with climate change mitigation.
基金Second Tibetan Plateau Scientific Expedition and Research Program,No.2019QZKK0201Strategic Priority Research Program of the Chinese Academy of Sciences,No.XDA20020102,No.XDA20060201+2 种基金State Key Laboratory of Cryospheric Science,No.SKLCS-ZZ-2021National Natural Science Foundation of China,No.41721091,42001067National Cryosphere Desert Data Center,No.20D03。
文摘Glaciers are a reliable freshwater resource in arid regions of West China and the vulnerability of its changes is closely related to regional ecosystem services and economic sustainable development. Here, we took the Qilian Mountains as an example and analyzed the spatiotemporal characteristics of glacier changes from 1998 to 2018, based on remote sensing images and the Second Chinese Glacier Inventory. We estimated the basic organizational framework and evaluation index system of glacier change vulnerability from exposure, sensitivity and adaptability, which covered the factors of physical geography, population status and socio-economic level. We analyzed the spatial and temporal evolutions of glacier change vulnerability by using the vulnerability evaluation model. Our results suggested that:(1) Glacier area and volume decreased by 71.12±98.98 km^(2) and 5.59±4.41 km^(3), respectively, over the recent two decades, which mainly occurred at the altitude below 4800 m, with an area shrinking rate of 2.5%. In addition, glaciers in the northern aspect(northwest, north and northeast) had the largest area reduction. Different counties exhibited remarkable discrepancies in glacier area reduction, Tianjuan and Minle presented the maximum and minimum decrease, respectively.(2) Glacier change vulnerability level showed a decreasing trend in space from the central to the northwestern and southeastern regions with remarkable differences. Vulnerability level had increased significantly over time and was mainly concentrated in moderate, high and extreme levels with typical characteristics of phases and regional complexity. Our study can not only help to understand and master the impacts of recent glacier changes on natural and social aspects but also be conducive to evaluate the influences of glacier retreat on socio-economic developments in the future, thus providing references for formulating relevant countermeasures to achieve regional sustainable development.
基金supported by the National Natural Science Foundation of China[grant number 42001066]the Open-end Foundation for National Cryosphere Desert Data Center[grant number 20D05]+2 种基金the Foundation for Excellent Youth Scholars of NIEER,CAS[grant number FEYS2019003]State Key Laboratory of Cryospheric Science[grant number SKLCS-ZZ-2022]the Third Comprehensive Scientific Expedition of Xinjiang Uyghur Autonomous Region[grant number 2022xjkk0802,2022xjkk0701].
文摘Melt-albedo feedback on glaciers is recognized as important processes for understanding glacier behavior and its sensitivity to climate change.This study selected the Muz Taw Glacier in the Altai Mountains to investigate the spatiotemporal variations in albedo and their linkages with mass balance,which will improve our knowledge of the recent acceleration of regional glacier shrinkage.Based on the Landsat-derived albedo,the spatial distribution of ablation-period albedo was characterized by a general increase with elevation,and significant east–west differences at the same elevation.The gap-filling MODIS values captured a nonsignificant negative trend of mean ablation-period albedo since 2000,with a total decrease of approximately 4.2%.From May to September,glacier-wide albedo exhibited pronounced V-shaped seasonal variability.A significant decrease in annual minimum albedo was found from 2000 to 2021,with the rate of approximately−0.30%yr−1 at the 99%confidence level.The bivariate relationship demonstrated that the change of ablation-period albedo explained 82%of the annual mass-balance variability.We applied the albedo method to estimate annual mass balance over the period 2000–2015.Combined with observed values,the average mass balance was−0.82±0.32 m w.e.yr−1 between 2000 and 2020,with accelerated mass loss.