Research on changes in the redox conditions of bottom waters is essential for understanding deep water circulation,global ocean currents,climate change,and ecosystem health.Through sedimentary geological methods,a dee...Research on changes in the redox conditions of bottom waters is essential for understanding deep water circulation,global ocean currents,climate change,and ecosystem health.Through sedimentary geological methods,a deeper understanding of the complex relationships between various environmental changes can be achieved,providing detailed evidence and theoretical support for global climate change research.The Ross Sea in Antarctica plays a key role in the formation of Antarctic bottom water(AABW),and the complex climate changes since the last glacial maximum(LGM)make it particularly significant for study.This research analyzes core ANT32-RB16C from the Ross Sea using geochemical proxies such as major and trace elements,grain size,and redox-sensitive indicators like Mn/Ti,Co/Ti,Mo/Ti,Cd/Ti,U/Th,and Ni/Co molar concentration ratios.Combining this data with a previously established chronological framework,the study explores the evolution of redox conditions in the Ross Sea’s deep waters since the LGM.The results show that the deep waters have remained oxygen-rich since the LGM,with significant changes in four stages.Stage 1(24.7–15.7 cal ka BP):Strong oxidizing conditions,likely due to enhanced formation of Ross Sea bottom water(RSBW),increasing oxygen levels.Stage 2(15.7–4.5 cal ka BP):Weakened oxidizing conditions as temperatures rose and ice shelves retreated,increasing primary productivity and depleting oxygen.Stage 3(4.5–1.5 cal ka BP):Continued decline in oxidizing conditions,possibly linked to high primary productivity and oxygen consumption.Stage 4(1.5 cal ka BP to present):A rapid recovery of oxidizing conditions,likely driven by temperature drops,increased RSBW formation,and decreased productivity.展开更多
This study investigates the glacial lake outburst flood(GLOF)hazards in the Tsambagarav mountain range in Western Mongolia,focusing on the Khukhnuruu Valley and its interconnected proglacial lakes.Over the last 30 yea...This study investigates the glacial lake outburst flood(GLOF)hazards in the Tsambagarav mountain range in Western Mongolia,focusing on the Khukhnuruu Valley and its interconnected proglacial lakes.Over the last 30 years,significant glacier retreats,driven by rising temperatures and changing precipitation patterns,have led to the formation and expansion of several proglacial lakes.Fieldwork combined with satellite data and meteorological analysis was used to assess the dynamics of glacier and lake area changes,with particular focus on the flood events of July 2021.The research reveals a substantial reduction in glacier area,particularly in the Khukhnuruu E complex,where glacier area decreased by 19.3%.The study highlights the influence of increasing temperatures and summer precipitation,which have accelerated ice melt,contributing to the expansion and eventual breaching of lakes.Additionally,lake area changes were influenced by the steepness of the terrain,with steeper slopes exacerbating peak discharge during floods.Of the studied seven lakes(Lake 1 to Lake 7),Lake 1 experienced the most dramatic reduction,with a decrease in area by 73.51%and volume by 84.84%,followed by Lake 7.This study underscores the region's vulnerability to climate-induced hazards and stresses the need for a comprehensive early warning system and disaster preparedness measures to mitigate future risks.展开更多
In the context of global warming and intensified human activities,glacier instability in plateau regions has increased,and glacier debris flows have become active,which poses a significant threat to the lives and prop...In the context of global warming and intensified human activities,glacier instability in plateau regions has increased,and glacier debris flows have become active,which poses a significant threat to the lives and property of people and socioeconomic development.The mass movement process of glacier debris flows is extremely complex,so this paper uses the 2018 Sedongpu glacier debris flow event on the Qinghai-Tibet Plateau as an example and applies a numerical simulation method to invert the whole process of mass movement.In view of the interaction between phases in the process of motion,we use the fluid-solid coupling method to describe the mass movement.The granular-flow model and drift-flux model are employed in FLOW3D software to study the mass movement process of glacier debris flows and explore their dynamic characteristics.The results indicate that the glacier debris flow lasted for 700 s,and the movement process was roughly divided into four stages,including initiation,scraping,surging and deposition;the depositional characteristics calculated by the fluid-solid coupling model are consistent with the actual survey results and have good reliability;strong erosion occurs during the mass movement,the clear volume amplification effect,and the first wave climbs 17.8 m across the slope.The fluid-solid coupling method can better simulate glacier debris flows in plateau regions,which is helpful for the study of the mechanism and dynamic characteristics of such disasters.展开更多
Machine learning(ML)-based prediction models for mapping hazard(e.g.,landslide and debris flow)susceptibility have been widely developed in recent research.However,in some specific areas,ML models have limited applica...Machine learning(ML)-based prediction models for mapping hazard(e.g.,landslide and debris flow)susceptibility have been widely developed in recent research.However,in some specific areas,ML models have limited application because of the uncertainties in identifying negative samples.The Parlung Tsangpo Basin exemplifies a region prone to recurrent glacial debris flows(GDFs)and is characterized by a prominent landform featuring deep gullies.Considering the limitations of the ML model,we developed and compared two combined statistical models(FA-WE and FA-IC)based on factor analysis(FA),weight of evidence(WE),and the information content(IC)method.The final GDF susceptibility maps were generated by selecting 8 most important static factors and considering the influence of precipitation.The results show that the FA-IC model has the best performance.The areas with a very high susceptibility to GDFs are primarily located in the narrow valley section upstream,on both sides of the valley in the middle and downstream of the Parlung Tsangpo River,and in the narrow valley section of each tributary.These areas encompass 86 gullies and are characterized as"narrow and steep".展开更多
Ny-Ålesund,located in Arctic Svalbard,is one of the most sensitive areas on Earth to global warming.In recent years,accelerated glacier ablation has become remarkable in Ny-Ålesund.Glacial meltwaters dischar...Ny-Ålesund,located in Arctic Svalbard,is one of the most sensitive areas on Earth to global warming.In recent years,accelerated glacier ablation has become remarkable in Ny-Ålesund.Glacial meltwaters discharge a substantial quantity of materials to the ocean,affecting downstream ecosystems and adjacent oceans.In August 2015,various water samples were taken near Ny-Ålesund,including ice marginal meltwater,proglacial meltwater,supraglacial meltwater,englacial meltwater,and groundwater.Trace metals(Al,Cr,Mn,Fe,Co,Cu,Zn,Cd,and Pb),major ions,alkalinity,pH,dissolved oxygen,water temperature and electric conductivity were also measured.Major ions were mainly controlled by chemical weathering intensity and reaction types,while trace metals were influenced by both chemical weathering and physicochemical control upon their mobility.Indeed,we found that Brøggerbreen was dominated by carbonate weathering via carbonation of carbonate,while Austre Lovénbreen and Pedersenbreen were dominated by sulfide oxidation coupled with carbonate dissolution with a doubled silicate weathering.The higher enrichment of trace metals in supraglacial meltwater compared to ice marginal and proglacial meltwater suggested anthropogenic pollution from atmospheric deposition.In ice marginal and proglacial meltwater,principal component analysis indicated that trace metals like Cr,Al,Co,Mn and Cd were correlated to chemical weathering.This implies that under accelerated glacier retreat,glacier-derived chemical components are subjected to future changes in weathering types and intensity.展开更多
Modeling the earth's fluid and elastic response to the melting of the glaciers of the last ice age is the most direct way to infer the earth's radial viscosity profile.Here,we compare two methods for calculati...Modeling the earth's fluid and elastic response to the melting of the glaciers of the last ice age is the most direct way to infer the earth's radial viscosity profile.Here,we compare two methods for calculating the viscoelastic response to surface loading.In one,the elastic equation of motion is converted to a viscoelastic equation using the Correspondence Principle.In the other,elastic deformation is added to the viscous flow as isostatic adjustment proceeds.The two modeling methods predict adjustment histories that are different enough to potentially impact the interpretation of the observed glacial isostatic adjustment(GIA).The differences arise from buoyancy and whether fluid displacements are subjected to hydrostatic pre-stress.The methods agree if they use the same equations and boundary conditions.The origin of the differences is determined by varying the boundary conditions and pre-stress application.展开更多
Glaciers and glacial lakes are very sensitive to climate change,and studying their dynamics is important for revealing changes in global climate.In this study,we extracted the boundaries of glaciers and glacial lakes ...Glaciers and glacial lakes are very sensitive to climate change,and studying their dynamics is important for revealing changes in global climate.In this study,we extracted the boundaries of glaciers and glacial lakes in the Northern Tianshan Mountains based on Landsat TM/ETM+/OLI and Sentinel 2A/2B MSI remote sensing images and analyzed their dynamics and impacts over the past 30 years.The findings indicate that in 2020,the Northern Tianshan region exhibited a total of 3254 glaciers,with an area of 1670.55 km^(2) and a volume of 95.69 km^(3).The corresponding numbers,areas,and volumes of glacial lakes were 281,13.23 km^(2) and 210.49×10~6 m^(3),respectively.Over the past 30 years,glaciers and glacial lakes have exhibited opposite characteristics.The former decreased by 16,332.64 km^(2)(-0.60%·a^(–1)) and 18.36 km^(3)(-0.58%·a^(–1)),respectively,and the latter increased by 56 and2.48 km^(2)(0.82%·a^(–1)) and 38.88×10~6 m^(3)(0.79%·a^(–1)),respectively.Moreover,different glacier termination types cause differences in the glacier retreat rates.Lake-terminated glaciers retreated faster than land-terminated glaciers,and the type of glacier termination has a greater effect on the retreat rate than the size of the glacial area.展开更多
The accumulation processes of loess in northeastern(NE)China record the varying characteristics of the East Asian Monsoons(EAM)and the evolution of the local environment.In this study,grain size end-member analysis of...The accumulation processes of loess in northeastern(NE)China record the varying characteristics of the East Asian Monsoons(EAM)and the evolution of the local environment.In this study,grain size end-member analysis of the Dajiugang(DJG)section deposited since the Last Glacial in Chifeng City,NE China was used to reveal the dynamic depositional characteristics of loess and environmental evolution of NE China.Results showed that the Chifeng loess comprises three grain size end-members(EM),EM1(7.38μm),EM2(49.4μm)and EM3(90.00μm),indicating the three transport dynamics of dust delivered to the region.The EM1 represents atmospheric dust as the background.The EM2,mainly derived from relatively distant-sources deposition,and EM3,material transported over a short distance,correspond to the intensity of southwesterly winds and the East Asian Winter Monsoon(EAWM),respectively.Results of climate reconstruction,combined with other records,showed that the climate was generally cold and dry with a strong EAWM and a weak East Asian summer monsoon(EASM)during the stadial-period[Marine Isotope Stage(MIS)4 and MIS 2 stage].The climate was predominantly warm and humid,with weak EAWM and surface winds and strong EASM in interstadial-period(MIS 3 and MIS 1 stage).Comparisons between indicators,e.g.,EM3,the LR04 benthicδ18O stack and summer insolation at 65°N suggest that the strong EAWM is induced by increasing the Northern Hemisphere ice volume and reduced summer solar radiation.展开更多
Glacial lakes,intimately linked to glacier termini,are crucial landscape features of the Qinghai-Xizang Plateau(QXP,Qinghai-Tibet Plateau)and the Arctic.Climate warming has accelerated glacier retreat and the rapid ex...Glacial lakes,intimately linked to glacier termini,are crucial landscape features of the Qinghai-Xizang Plateau(QXP,Qinghai-Tibet Plateau)and the Arctic.Climate warming has accelerated glacier retreat and the rapid expansion of glacial lakes in both regions.Despite being typically considered harsh environments,these lakes serve as vital reservoirs for microbial biodiversity and carbon metabolism.In the face of climate change,glacial lake ecosystems over the QXP and the Arctic are undergoing unprecedentedtransformations.Thisopinioneditorial highlights the significance of conducting research and establishing long-term monitoring programs focused on microbial carbon metabolism in these glacial lakes.展开更多
In this article, we review the current knowledge of the glacial recession and related glacial lake development in the Andes of South America. Since the mid-1980 s, hundreds of glacial lakes either expanded or formed, ...In this article, we review the current knowledge of the glacial recession and related glacial lake development in the Andes of South America. Since the mid-1980 s, hundreds of glacial lakes either expanded or formed, and predictions show that additional hundreds of lakes will form throughout the 21 st century. However, studies on glacial lakes in the Andes are still relatively rare. Many glacial lakes pose a potential hazard to local communities, but glacial lake outburst floods(GLOFs) are understudied. We provide an overview on hazards from glacial lakes such as GLOFs and water pollution, and their monitoring approaches. In real-time monitoring, the use of unmanned aerial systems(UASs) and early warning systems(EWSs) is still extremely rare in the Andes, but increasingly authorities plan to install mitigation systems to reduce glacial lake risk and protect local communities. In support, we propose an international remote sensing-based observation initiative following the model of, for example, the Global Land Ice Measurements from Space(GLIMS) one, with the headquarters in one of the Andean nations.展开更多
Glaciers are one of the most important land covers in alpine regions and especially sensitive to global climate change. Remote sensing has proved to be the best method of investigating the extent of glacial variations...Glaciers are one of the most important land covers in alpine regions and especially sensitive to global climate change. Remote sensing has proved to be the best method of investigating the extent of glacial variations in remote mountainous areas. Using Landsat thematic mapping （TM） and multi-spectral-scanner （MSS） images from Mt. Qomolangma （Everest） National Nature Preserve （QNNP）, central high Himalayas for 1976, 1988 and 2006 we derived glacial extent for these three periods. A combination of object-oriented image interpretation methods, expert knowledge rules and field surveys were employed. Results showed that （1） the glacial area in 2006 was 2710.17 ＋ 0.011 km2 （about 7.41% of the whole study area）, and located mainly to the south and between 4700 m to 6800 m above sea level; （2） from 1976 to 2006, glaciers reduced by 501.91± 0.035 km2 and glacial lakes expanded by 36.88 ＋ 0.035 kin2; the rate of glacier retreat was higher in sub-basins on the southern slopes （16.79%） of the Himalayas than on the northern slopes （14.40%）; most glaciers retreated, and mainly occurred at an elevation of 4700-6400 m, and the estimated upper limit of the retreat zone is between 6600 m and 6700 m; （3） increase in temperature and decrease in precipitation over the study period are the key factors driving retreat.展开更多
Owing to the remoteness of the Longriba area and the lack of dating records,it is extremely challenging to reconstruct the chronology and extent of the paleoglaciers in this area.In this paper,we combined limited obse...Owing to the remoteness of the Longriba area and the lack of dating records,it is extremely challenging to reconstruct the chronology and extent of the paleoglaciers in this area.In this paper,we combined limited observational data with automated modelling for paleoglacial reconstructions.We first identified a broadly distributed paleoglacier from satellite imagery and field investigation based on the sediment-landform assemblage principle and dated it to 23.1±1.4~19.5±1.2 ka by ^(10)Be exposure dating,corresponding to the global Last Glacial Maximum(gLGM).Then,we reconstructed the extent and ice surface of 171 paleoglaciers formed during the similar period based on geomorphological evidence and‘ice surface profile’modelling.The results showed that the paleoglacial coverage was 426.5 km2,with an ice volume of 38.1 km^(3),in the Longriba area.The reconstructed equilibrium line altitudes(ELAs)based on modelled ice surfaces yielded an average of 4245±66 m above sea level(asl),~725±73 m lower than the present ELA(4970±29 m asl).The temperature was~5.51-6.68℃lower,and the precipitation was~30-34%less in Longriba,during the gLGM compared to the present day.This glacial advance was mainly driven by colder climate that was synchronous with Northern Hemisphere cooling events.展开更多
A series of sub-parallel linear glacial scours are identified on the crest of the Baoshi Seamount in the Northwind Abyssal Plain by compiling new multibeam data acquired during the 9 th Chinese Arctic Research Expedit...A series of sub-parallel linear glacial scours are identified on the crest of the Baoshi Seamount in the Northwind Abyssal Plain by compiling new multibeam data acquired during the 9 th Chinese Arctic Research Expedition(CHINARE-Arc9)in 2018 and previously published data.The new data reveal scours that developed at water depths of 850–1030 m with an orientation of about 75°/255°.The maximum water depth occurs in the southernmost scour and is deeper than that from previous investigations,which showed a maximum scouring depth of about 900 m on the seamount.The topographic and geomorphological characteristics suggest that these scours resulted from erosion by the ice shelf extending from the Chukchi margin and/or Laurentide Ice Sheet that grounded on the crest of the seamount and moved in a NE–SW direction.Other possibilities of their genesis include armadas of large icebergs/multi-keel icebergs calved from the Chukchi Shelf or the Laurentide Ice Sheet.The new data provide new constraints for assessing the extent and volume of the ice sheet in the Chukchi area during glacial maxima.展开更多
Despite being within the intertropical region of the planet,the Mexican territory still has glacier-covered mountains.In recent decades,important advances have been made in studies on glaciology and periglacial enviro...Despite being within the intertropical region of the planet,the Mexican territory still has glacier-covered mountains.In recent decades,important advances have been made in studies on glaciology and periglacial environment in Mexico both for current and past conditions.However,in spite of Cofre de Perote volcano(4200 m a.s.l.)being a strategically located mountain,it has not yet been studied in regards to the glacial and periglacial processes;in fact,those dynamics have modified the mountain massifs in the past.To complement the series of studies on glacial history in the high mountain environment of México,this study reconstructs the glacial cover and the periglacial environment of the volcano surface during the final stage of the Late Pleistocene based on climatic retrospective and through the identification of geomorphological features.The findings indicate the existence of a large glacier(ice cap)that covered the northern,western,and southern slopes of the mountain;while in the eastern sector there were two small glaciers,one being of cirque type,and the other of valley type.The current temperature conditions prevent the occurrence of permanent ice bodies;at the same time,it was found that the periglacial blockfields of the slopes is a legacy of the climatic conditions that prevailed at the end of Late Pleistocene.展开更多
Core D （21°23′02″N, 116°47′13″E, water depth 405 m） was sampled from the upper slope from the northeastern South China Sea （SCS） and applied to analyze the sedimentary environmental change in this se...Core D （21°23′02″N, 116°47′13″E, water depth 405 m） was sampled from the upper slope from the northeastern South China Sea （SCS） and applied to analyze the sedimentary environmental change in this sea area since the last glacial stage. The results of grain size analysis, diatom analysis and detrital mineral analysis were well matched. We divided the core D into two layers. The surface sand layer （0 - 2 cm） consisted of residual sediments, which might be originally the sediment in the late Pleistocene and later suffered from being transformed in the post glacial transgression. The lower layer （2 - 130 cm） was quite different from the surface one, which might mainly result from a neritic sedimentary environment in the last glacial stage. Two sedimentary cycles could be detected in the core D： regression during Marine isotope stage （MIS） 4 to transgression during MIS 3 and regression during MIS 2 to transgression during the post glacial.展开更多
The load of the continental ice caps of the Ice Ages deformed the bedrock, and when the ice melted in postglacial time, land rose. This process is known as glacial isostasy. The deformations are compensated either reg...The load of the continental ice caps of the Ice Ages deformed the bedrock, and when the ice melted in postglacial time, land rose. This process is known as glacial isostasy. The deformations are compensated either regionally or globally. Fennoscandian data indicate a regional compensation. Global sea level data support a regional, not global, compensation. Subtracting GIA corrections from satellite altimetry records brings—for the first time—different sea level indications into harmony of a present mean global sea level rise of 0.0 to 1.0 mm/yr.展开更多
The goal of this research study is to describe academic issues which have been debated in the field of Chinese geosciences for a century. In 1922, Jonquei S. Lee(Li Siguang) discovered Quaternary glacial relics at Tai...The goal of this research study is to describe academic issues which have been debated in the field of Chinese geosciences for a century. In 1922, Jonquei S. Lee(Li Siguang) discovered Quaternary glacial relics at Taihang Mountainin eastern China. In 1947, he published his research findings in the magazine Mount Lushan in Glacial Age. The research results had established three Ice Ages: Poyang(Gonzi), Dagu(Minde), and Lushan(Lisi). However, at that time, no Wurm glacial relics of the last Ice Age had been found in Lushan Mountain. Since then, the research team represented by Shi Yafeng, who is considered to be "the father of glaciers in China", questioned Jonquei S. Lee’s research results and concluded that "Professor Jonquei S. Lee’s Quaternary glacier research in Lushan Mountain having misread the debris flow". In 2005, the "middle-low mountains" in eastern China were finally defined as follows: "We clearly and unambiguously believe that there were no glacial activities in the middle-low mountainous areas of eastern China(east of 102° to 104°E;below 3,000 and 2,500 m) during the Quaternary Period". Currently, the long-standing academic debate appears to have come to a conclusion. As of 2015, the author and others began to investigate and study the Quaternary glacial relics in Mengshan Mountain(1,156 m above sea level), Shandong Province, one of the "middle-low mountains" of eastern China. The relics have been observed to posses the systematic features of glacial erosion, trough and valley striations, and moraine deposits. The applied dating method shave confirmed that there were not only glacial relics of the last Ice Age(Wurm), but also Holocene glacial relics in the Mengshan Mountain area. Therefore, in order to further establish the corresponding relationship between the glacier, loess, stream sediment series, and MIS in the Mengshan Mountain area, a large number of chronological studies have been carried out regarding the various types of sediments in the area, and 24 dating datahave been obtained using OSL, CRN, and 14 Cmethods.On this basis, the corresponding relationship between the sedimentary sequences and the MIS was established for the first time in eastern China, which in dicates the environmental changes which had occurred in eastern China since 80 ka. These discoveries s and chronological study results confirm the existence of the Last Ice Age, as well as Holocene glacial relics at Mengshan Mountain, there by confirming that Quaternary glaciation had occurred in the middle-low mountain areas of eastern China.展开更多
Glacial lakes are not only the important refresh water resources in alpine region, but also act as a trigger of many glacial hazards such as glacial lake outburst flood （GLOF） and debris flow. Therefore, glacial lak...Glacial lakes are not only the important refresh water resources in alpine region, but also act as a trigger of many glacial hazards such as glacial lake outburst flood （GLOF） and debris flow. Therefore, glacial lakes play an important role on the cryosphere, climate change and alpine hazards. In this paper, the issues of glacial lake were systematically discussed, then from the view of glacial lake inventory and glacial lake hazards study, the glacial lake was defined as natural water mainly supplied by modern glacial meltwater or formed in glacier moraine＇s depression. Furthermore, a complete classification system of glacial lake was proposed based on its formation mechanism, topographic feature and geographical position. Glacial lakes were classified as 6 classes and 8 subclasses, i.e., glacial erosion lake （including cirque lake, gla- cial valley lake and other glacial erosion lake）, moraine-dammed lake （including end mo- raine-dammed lake, lateral moraine-dammed lake and moraine thaw lake）, ice-blocked lake （including advancing glacier-blocked lake and other glacier-blocked lake）, supraglacial lake, subglacial lake and other glacial lake. Meanwhile, some corresponding features exhibiting on remote sensing image and quantitative indices for identifying different glacial lake types were proposed in order to build a universal and operational classification system of glacial lake.展开更多
The Early Holocene paleoclimate in Bosten Lake on the northern margin of the Tarim Basin, southern Xinjiang, is reconstructed through an analysis of a 953 cm long core （BSTC2000） taken from Bosten Lake. Multiple pro...The Early Holocene paleoclimate in Bosten Lake on the northern margin of the Tarim Basin, southern Xinjiang, is reconstructed through an analysis of a 953 cm long core （BSTC2000） taken from Bosten Lake. Multiple proxies of this core, including the mineral components of carbonate, carbonate content, stable isotopic compositions of carbonate, Ca/Sr, TOC and C/N and C/S of organic matter, are used to reconstruct the climatic change since 8500 a B.P. The chronology model is made by nine AMS 14C ages of leaves, seeds and organic matter contained in two parallel cores. The climate was cold and wet during 8500 to 8100 a B.P. Temperature increased from 8100 to 6400 a B.P., the climate was warm and humid, and the lake expanded. The lake level was highest during this stage. Then from 6400 to 5100 a B.P., the climate became cold and the lake level decreased slightly. During the late mid-Holocene, the climate was hot and dry from 5100 to 3100 a B.P., but there was a short cold period during 4400 to 3800 a B.P. At this temporal interval, a mass of ice and snow melting water supplied the lake at the early time and made the lake level rise. The second highest lake level stage occurred during 5200 to 3800 a B.P. The climate was cool and wet during 3100 to 2200 a B.P., when the lake expanded with decreasing evaporation. The lake had the last short-term high level during 3100 to 2800 a B.P. After this short high lake level period, the lake shrank because of the long-term lower temperature and reduced water supply. From 2200 to 1200 a B.P., the climate was hot and dry, and the lake shrank greatly. Although the temperature decreased somewhat from 1200 a B.P. to the present, the climate was warm and dry. The lake level began to rise a little again, but it did not reach the river bed altitude of the Konqi River, an outflow river of the Bosten Lake.展开更多
基金The National Key R&D Program of China under contract No. 2023YFC28 11305the Scientific Research Fund of the Second Institute of Oceanography,MNR under contract No. SZ2405the Impact and Response of Antarctic Seas to Climate Change under contract No. IRASCC
文摘Research on changes in the redox conditions of bottom waters is essential for understanding deep water circulation,global ocean currents,climate change,and ecosystem health.Through sedimentary geological methods,a deeper understanding of the complex relationships between various environmental changes can be achieved,providing detailed evidence and theoretical support for global climate change research.The Ross Sea in Antarctica plays a key role in the formation of Antarctic bottom water(AABW),and the complex climate changes since the last glacial maximum(LGM)make it particularly significant for study.This research analyzes core ANT32-RB16C from the Ross Sea using geochemical proxies such as major and trace elements,grain size,and redox-sensitive indicators like Mn/Ti,Co/Ti,Mo/Ti,Cd/Ti,U/Th,and Ni/Co molar concentration ratios.Combining this data with a previously established chronological framework,the study explores the evolution of redox conditions in the Ross Sea’s deep waters since the LGM.The results show that the deep waters have remained oxygen-rich since the LGM,with significant changes in four stages.Stage 1(24.7–15.7 cal ka BP):Strong oxidizing conditions,likely due to enhanced formation of Ross Sea bottom water(RSBW),increasing oxygen levels.Stage 2(15.7–4.5 cal ka BP):Weakened oxidizing conditions as temperatures rose and ice shelves retreated,increasing primary productivity and depleting oxygen.Stage 3(4.5–1.5 cal ka BP):Continued decline in oxidizing conditions,possibly linked to high primary productivity and oxygen consumption.Stage 4(1.5 cal ka BP to present):A rapid recovery of oxidizing conditions,likely driven by temperature drops,increased RSBW formation,and decreased productivity.
基金funded by the National University of Mongolia under grant agreement P2023(grant number P2023-4578)。
文摘This study investigates the glacial lake outburst flood(GLOF)hazards in the Tsambagarav mountain range in Western Mongolia,focusing on the Khukhnuruu Valley and its interconnected proglacial lakes.Over the last 30 years,significant glacier retreats,driven by rising temperatures and changing precipitation patterns,have led to the formation and expansion of several proglacial lakes.Fieldwork combined with satellite data and meteorological analysis was used to assess the dynamics of glacier and lake area changes,with particular focus on the flood events of July 2021.The research reveals a substantial reduction in glacier area,particularly in the Khukhnuruu E complex,where glacier area decreased by 19.3%.The study highlights the influence of increasing temperatures and summer precipitation,which have accelerated ice melt,contributing to the expansion and eventual breaching of lakes.Additionally,lake area changes were influenced by the steepness of the terrain,with steeper slopes exacerbating peak discharge during floods.Of the studied seven lakes(Lake 1 to Lake 7),Lake 1 experienced the most dramatic reduction,with a decrease in area by 73.51%and volume by 84.84%,followed by Lake 7.This study underscores the region's vulnerability to climate-induced hazards and stresses the need for a comprehensive early warning system and disaster preparedness measures to mitigate future risks.
基金supported by the National Natural Science Foundation of China(Nos.U20A20111,41977229)the Sichuan Youth Science and Technology Innovation Research Team Project(No.2020JDTD0006).
文摘In the context of global warming and intensified human activities,glacier instability in plateau regions has increased,and glacier debris flows have become active,which poses a significant threat to the lives and property of people and socioeconomic development.The mass movement process of glacier debris flows is extremely complex,so this paper uses the 2018 Sedongpu glacier debris flow event on the Qinghai-Tibet Plateau as an example and applies a numerical simulation method to invert the whole process of mass movement.In view of the interaction between phases in the process of motion,we use the fluid-solid coupling method to describe the mass movement.The granular-flow model and drift-flux model are employed in FLOW3D software to study the mass movement process of glacier debris flows and explore their dynamic characteristics.The results indicate that the glacier debris flow lasted for 700 s,and the movement process was roughly divided into four stages,including initiation,scraping,surging and deposition;the depositional characteristics calculated by the fluid-solid coupling model are consistent with the actual survey results and have good reliability;strong erosion occurs during the mass movement,the clear volume amplification effect,and the first wave climbs 17.8 m across the slope.The fluid-solid coupling method can better simulate glacier debris flows in plateau regions,which is helpful for the study of the mechanism and dynamic characteristics of such disasters.
基金funded by the National Natural Science Foundation of China(Grant Nos.42377170).
文摘Machine learning(ML)-based prediction models for mapping hazard(e.g.,landslide and debris flow)susceptibility have been widely developed in recent research.However,in some specific areas,ML models have limited application because of the uncertainties in identifying negative samples.The Parlung Tsangpo Basin exemplifies a region prone to recurrent glacial debris flows(GDFs)and is characterized by a prominent landform featuring deep gullies.Considering the limitations of the ML model,we developed and compared two combined statistical models(FA-WE and FA-IC)based on factor analysis(FA),weight of evidence(WE),and the information content(IC)method.The final GDF susceptibility maps were generated by selecting 8 most important static factors and considering the influence of precipitation.The results show that the FA-IC model has the best performance.The areas with a very high susceptibility to GDFs are primarily located in the narrow valley section upstream,on both sides of the valley in the middle and downstream of the Parlung Tsangpo River,and in the narrow valley section of each tributary.These areas encompass 86 gullies and are characterized as"narrow and steep".
基金The National Natural Science Foundation of China under contract Nos 42076227,41676175 and 41276202the Chinese Arctic and Antarctic Administration under contract No.CHINARE-YRS2015-21+1 种基金the Shanghai Pilot Program for Basic Re-search-Shanghai Jiao Tong University under contract No.21TQ1400201the Shanghai Frontiers Science Center of Polar Science(SCOPS).
文摘Ny-Ålesund,located in Arctic Svalbard,is one of the most sensitive areas on Earth to global warming.In recent years,accelerated glacier ablation has become remarkable in Ny-Ålesund.Glacial meltwaters discharge a substantial quantity of materials to the ocean,affecting downstream ecosystems and adjacent oceans.In August 2015,various water samples were taken near Ny-Ålesund,including ice marginal meltwater,proglacial meltwater,supraglacial meltwater,englacial meltwater,and groundwater.Trace metals(Al,Cr,Mn,Fe,Co,Cu,Zn,Cd,and Pb),major ions,alkalinity,pH,dissolved oxygen,water temperature and electric conductivity were also measured.Major ions were mainly controlled by chemical weathering intensity and reaction types,while trace metals were influenced by both chemical weathering and physicochemical control upon their mobility.Indeed,we found that Brøggerbreen was dominated by carbonate weathering via carbonation of carbonate,while Austre Lovénbreen and Pedersenbreen were dominated by sulfide oxidation coupled with carbonate dissolution with a doubled silicate weathering.The higher enrichment of trace metals in supraglacial meltwater compared to ice marginal and proglacial meltwater suggested anthropogenic pollution from atmospheric deposition.In ice marginal and proglacial meltwater,principal component analysis indicated that trace metals like Cr,Al,Co,Mn and Cd were correlated to chemical weathering.This implies that under accelerated glacier retreat,glacier-derived chemical components are subjected to future changes in weathering types and intensity.
文摘Modeling the earth's fluid and elastic response to the melting of the glaciers of the last ice age is the most direct way to infer the earth's radial viscosity profile.Here,we compare two methods for calculating the viscoelastic response to surface loading.In one,the elastic equation of motion is converted to a viscoelastic equation using the Correspondence Principle.In the other,elastic deformation is added to the viscous flow as isostatic adjustment proceeds.The two modeling methods predict adjustment histories that are different enough to potentially impact the interpretation of the observed glacial isostatic adjustment(GIA).The differences arise from buoyancy and whether fluid displacements are subjected to hydrostatic pre-stress.The methods agree if they use the same equations and boundary conditions.The origin of the differences is determined by varying the boundary conditions and pre-stress application.
基金The Third Xinjiang Scientific Expedition Program,No.2021xjkk0801National Natural Science Foundation of China,No.42161027。
文摘Glaciers and glacial lakes are very sensitive to climate change,and studying their dynamics is important for revealing changes in global climate.In this study,we extracted the boundaries of glaciers and glacial lakes in the Northern Tianshan Mountains based on Landsat TM/ETM+/OLI and Sentinel 2A/2B MSI remote sensing images and analyzed their dynamics and impacts over the past 30 years.The findings indicate that in 2020,the Northern Tianshan region exhibited a total of 3254 glaciers,with an area of 1670.55 km^(2) and a volume of 95.69 km^(3).The corresponding numbers,areas,and volumes of glacial lakes were 281,13.23 km^(2) and 210.49×10~6 m^(3),respectively.Over the past 30 years,glaciers and glacial lakes have exhibited opposite characteristics.The former decreased by 16,332.64 km^(2)(-0.60%·a^(–1)) and 18.36 km^(3)(-0.58%·a^(–1)),respectively,and the latter increased by 56 and2.48 km^(2)(0.82%·a^(–1)) and 38.88×10~6 m^(3)(0.79%·a^(–1)),respectively.Moreover,different glacier termination types cause differences in the glacier retreat rates.Lake-terminated glaciers retreated faster than land-terminated glaciers,and the type of glacier termination has a greater effect on the retreat rate than the size of the glacial area.
基金supported by the National Natural Science Foundation of China(No:41771245).
文摘The accumulation processes of loess in northeastern(NE)China record the varying characteristics of the East Asian Monsoons(EAM)and the evolution of the local environment.In this study,grain size end-member analysis of the Dajiugang(DJG)section deposited since the Last Glacial in Chifeng City,NE China was used to reveal the dynamic depositional characteristics of loess and environmental evolution of NE China.Results showed that the Chifeng loess comprises three grain size end-members(EM),EM1(7.38μm),EM2(49.4μm)and EM3(90.00μm),indicating the three transport dynamics of dust delivered to the region.The EM1 represents atmospheric dust as the background.The EM2,mainly derived from relatively distant-sources deposition,and EM3,material transported over a short distance,correspond to the intensity of southwesterly winds and the East Asian Winter Monsoon(EAWM),respectively.Results of climate reconstruction,combined with other records,showed that the climate was generally cold and dry with a strong EAWM and a weak East Asian summer monsoon(EASM)during the stadial-period[Marine Isotope Stage(MIS)4 and MIS 2 stage].The climate was predominantly warm and humid,with weak EAWM and surface winds and strong EASM in interstadial-period(MIS 3 and MIS 1 stage).Comparisons between indicators,e.g.,EM3,the LR04 benthicδ18O stack and summer insolation at 65°N suggest that the strong EAWM is induced by increasing the Northern Hemisphere ice volume and reduced summer solar radiation.
基金supported by Key Collaborative Research Program of the Alliance of International Science Organizations(Grant no.ANSO-CR-KP-2021-04)the Key Program of National Natural Science Foundation of China(Grant no.42330410)。
文摘Glacial lakes,intimately linked to glacier termini,are crucial landscape features of the Qinghai-Xizang Plateau(QXP,Qinghai-Tibet Plateau)and the Arctic.Climate warming has accelerated glacier retreat and the rapid expansion of glacial lakes in both regions.Despite being typically considered harsh environments,these lakes serve as vital reservoirs for microbial biodiversity and carbon metabolism.In the face of climate change,glacial lake ecosystems over the QXP and the Arctic are undergoing unprecedentedtransformations.Thisopinioneditorial highlights the significance of conducting research and establishing long-term monitoring programs focused on microbial carbon metabolism in these glacial lakes.
文摘In this article, we review the current knowledge of the glacial recession and related glacial lake development in the Andes of South America. Since the mid-1980 s, hundreds of glacial lakes either expanded or formed, and predictions show that additional hundreds of lakes will form throughout the 21 st century. However, studies on glacial lakes in the Andes are still relatively rare. Many glacial lakes pose a potential hazard to local communities, but glacial lake outburst floods(GLOFs) are understudied. We provide an overview on hazards from glacial lakes such as GLOFs and water pollution, and their monitoring approaches. In real-time monitoring, the use of unmanned aerial systems(UASs) and early warning systems(EWSs) is still extremely rare in the Andes, but increasingly authorities plan to install mitigation systems to reduce glacial lake risk and protect local communities. In support, we propose an international remote sensing-based observation initiative following the model of, for example, the Global Land Ice Measurements from Space(GLIMS) one, with the headquarters in one of the Andean nations.
基金supported by the National Natural Science Foundation of China[grant numbers 41931181 and 42075048]the Youth Innovation Promotion Association of the Chinese Academy of Sciences[grant number 2022075]。
基金The External Cooperation Program of the Chinese Academy of Sciences,No.GJHZ0954National Basic Research Program of China,No.2005CB422006Institutional Consolidation for the Coordinated and Integrated Monitoring of Natural Resources towards Sustainable Development and Environmental Conservation in the Hindu Kush-Karakoram-Himalaya Mountain Complex
文摘Glaciers are one of the most important land covers in alpine regions and especially sensitive to global climate change. Remote sensing has proved to be the best method of investigating the extent of glacial variations in remote mountainous areas. Using Landsat thematic mapping （TM） and multi-spectral-scanner （MSS） images from Mt. Qomolangma （Everest） National Nature Preserve （QNNP）, central high Himalayas for 1976, 1988 and 2006 we derived glacial extent for these three periods. A combination of object-oriented image interpretation methods, expert knowledge rules and field surveys were employed. Results showed that （1） the glacial area in 2006 was 2710.17 ＋ 0.011 km2 （about 7.41% of the whole study area）, and located mainly to the south and between 4700 m to 6800 m above sea level; （2） from 1976 to 2006, glaciers reduced by 501.91± 0.035 km2 and glacial lakes expanded by 36.88 ＋ 0.035 kin2; the rate of glacier retreat was higher in sub-basins on the southern slopes （16.79%） of the Himalayas than on the northern slopes （14.40%）; most glaciers retreated, and mainly occurred at an elevation of 4700-6400 m, and the estimated upper limit of the retreat zone is between 6600 m and 6700 m; （3） increase in temperature and decrease in precipitation over the study period are the key factors driving retreat.
基金supported by the National Science Foundation of China(NSFC 41771005 and 41230743)。
文摘Owing to the remoteness of the Longriba area and the lack of dating records,it is extremely challenging to reconstruct the chronology and extent of the paleoglaciers in this area.In this paper,we combined limited observational data with automated modelling for paleoglacial reconstructions.We first identified a broadly distributed paleoglacier from satellite imagery and field investigation based on the sediment-landform assemblage principle and dated it to 23.1±1.4~19.5±1.2 ka by ^(10)Be exposure dating,corresponding to the global Last Glacial Maximum(gLGM).Then,we reconstructed the extent and ice surface of 171 paleoglaciers formed during the similar period based on geomorphological evidence and‘ice surface profile’modelling.The results showed that the paleoglacial coverage was 426.5 km2,with an ice volume of 38.1 km^(3),in the Longriba area.The reconstructed equilibrium line altitudes(ELAs)based on modelled ice surfaces yielded an average of 4245±66 m above sea level(asl),~725±73 m lower than the present ELA(4970±29 m asl).The temperature was~5.51-6.68℃lower,and the precipitation was~30-34%less in Longriba,during the gLGM compared to the present day.This glacial advance was mainly driven by colder climate that was synchronous with Northern Hemisphere cooling events.
基金The National Natural Science Foundation of China under contract No.41976079the Chinese Polar Environment Comprehensive Investigation and Assessment Programmes under contract No.CHINARE-03-03。
文摘A series of sub-parallel linear glacial scours are identified on the crest of the Baoshi Seamount in the Northwind Abyssal Plain by compiling new multibeam data acquired during the 9 th Chinese Arctic Research Expedition(CHINARE-Arc9)in 2018 and previously published data.The new data reveal scours that developed at water depths of 850–1030 m with an orientation of about 75°/255°.The maximum water depth occurs in the southernmost scour and is deeper than that from previous investigations,which showed a maximum scouring depth of about 900 m on the seamount.The topographic and geomorphological characteristics suggest that these scours resulted from erosion by the ice shelf extending from the Chukchi margin and/or Laurentide Ice Sheet that grounded on the crest of the seamount and moved in a NE–SW direction.Other possibilities of their genesis include armadas of large icebergs/multi-keel icebergs calved from the Chukchi Shelf or the Laurentide Ice Sheet.The new data provide new constraints for assessing the extent and volume of the ice sheet in the Chukchi area during glacial maxima.
文摘Despite being within the intertropical region of the planet,the Mexican territory still has glacier-covered mountains.In recent decades,important advances have been made in studies on glaciology and periglacial environment in Mexico both for current and past conditions.However,in spite of Cofre de Perote volcano(4200 m a.s.l.)being a strategically located mountain,it has not yet been studied in regards to the glacial and periglacial processes;in fact,those dynamics have modified the mountain massifs in the past.To complement the series of studies on glacial history in the high mountain environment of México,this study reconstructs the glacial cover and the periglacial environment of the volcano surface during the final stage of the Late Pleistocene based on climatic retrospective and through the identification of geomorphological features.The findings indicate the existence of a large glacier(ice cap)that covered the northern,western,and southern slopes of the mountain;while in the eastern sector there were two small glaciers,one being of cirque type,and the other of valley type.The current temperature conditions prevent the occurrence of permanent ice bodies;at the same time,it was found that the periglacial blockfields of the slopes is a legacy of the climatic conditions that prevailed at the end of Late Pleistocene.
文摘Core D （21°23′02″N, 116°47′13″E, water depth 405 m） was sampled from the upper slope from the northeastern South China Sea （SCS） and applied to analyze the sedimentary environmental change in this sea area since the last glacial stage. The results of grain size analysis, diatom analysis and detrital mineral analysis were well matched. We divided the core D into two layers. The surface sand layer （0 - 2 cm） consisted of residual sediments, which might be originally the sediment in the late Pleistocene and later suffered from being transformed in the post glacial transgression. The lower layer （2 - 130 cm） was quite different from the surface one, which might mainly result from a neritic sedimentary environment in the last glacial stage. Two sedimentary cycles could be detected in the core D： regression during Marine isotope stage （MIS） 4 to transgression during MIS 3 and regression during MIS 2 to transgression during the post glacial.
文摘The load of the continental ice caps of the Ice Ages deformed the bedrock, and when the ice melted in postglacial time, land rose. This process is known as glacial isostasy. The deformations are compensated either regionally or globally. Fennoscandian data indicate a regional compensation. Global sea level data support a regional, not global, compensation. Subtracting GIA corrections from satellite altimetry records brings—for the first time—different sea level indications into harmony of a present mean global sea level rise of 0.0 to 1.0 mm/yr.
文摘The goal of this research study is to describe academic issues which have been debated in the field of Chinese geosciences for a century. In 1922, Jonquei S. Lee(Li Siguang) discovered Quaternary glacial relics at Taihang Mountainin eastern China. In 1947, he published his research findings in the magazine Mount Lushan in Glacial Age. The research results had established three Ice Ages: Poyang(Gonzi), Dagu(Minde), and Lushan(Lisi). However, at that time, no Wurm glacial relics of the last Ice Age had been found in Lushan Mountain. Since then, the research team represented by Shi Yafeng, who is considered to be "the father of glaciers in China", questioned Jonquei S. Lee’s research results and concluded that "Professor Jonquei S. Lee’s Quaternary glacier research in Lushan Mountain having misread the debris flow". In 2005, the "middle-low mountains" in eastern China were finally defined as follows: "We clearly and unambiguously believe that there were no glacial activities in the middle-low mountainous areas of eastern China(east of 102° to 104°E;below 3,000 and 2,500 m) during the Quaternary Period". Currently, the long-standing academic debate appears to have come to a conclusion. As of 2015, the author and others began to investigate and study the Quaternary glacial relics in Mengshan Mountain(1,156 m above sea level), Shandong Province, one of the "middle-low mountains" of eastern China. The relics have been observed to posses the systematic features of glacial erosion, trough and valley striations, and moraine deposits. The applied dating method shave confirmed that there were not only glacial relics of the last Ice Age(Wurm), but also Holocene glacial relics in the Mengshan Mountain area. Therefore, in order to further establish the corresponding relationship between the glacier, loess, stream sediment series, and MIS in the Mengshan Mountain area, a large number of chronological studies have been carried out regarding the various types of sediments in the area, and 24 dating datahave been obtained using OSL, CRN, and 14 Cmethods.On this basis, the corresponding relationship between the sedimentary sequences and the MIS was established for the first time in eastern China, which in dicates the environmental changes which had occurred in eastern China since 80 ka. These discoveries s and chronological study results confirm the existence of the Last Ice Age, as well as Holocene glacial relics at Mengshan Mountain, there by confirming that Quaternary glaciation had occurred in the middle-low mountain areas of eastern China.
基金National Natural Science Foundation of China,No.41261016,No.41561016Opening Foundation Projection of State Key Laboratory of Cryosphere Sciences,CAS,No.SKLCS-OP-2016-10+1 种基金Youth Scholar Scientific Capability Promoting Project of Northwest Normal University,No.NWNU-LKQN-14-4Geological Survey Project of China Geological Survey,No.DD2016034206
文摘Glacial lakes are not only the important refresh water resources in alpine region, but also act as a trigger of many glacial hazards such as glacial lake outburst flood （GLOF） and debris flow. Therefore, glacial lakes play an important role on the cryosphere, climate change and alpine hazards. In this paper, the issues of glacial lake were systematically discussed, then from the view of glacial lake inventory and glacial lake hazards study, the glacial lake was defined as natural water mainly supplied by modern glacial meltwater or formed in glacier moraine＇s depression. Furthermore, a complete classification system of glacial lake was proposed based on its formation mechanism, topographic feature and geographical position. Glacial lakes were classified as 6 classes and 8 subclasses, i.e., glacial erosion lake （including cirque lake, gla- cial valley lake and other glacial erosion lake）, moraine-dammed lake （including end mo- raine-dammed lake, lateral moraine-dammed lake and moraine thaw lake）, ice-blocked lake （including advancing glacier-blocked lake and other glacier-blocked lake）, supraglacial lake, subglacial lake and other glacial lake. Meanwhile, some corresponding features exhibiting on remote sensing image and quantitative indices for identifying different glacial lake types were proposed in order to build a universal and operational classification system of glacial lake.
基金co-supported by the National Natural Science Foundation of China (grant Nos.40773064,40331012 and 40041004)"973" Program of China (No.G1999043501)
文摘The Early Holocene paleoclimate in Bosten Lake on the northern margin of the Tarim Basin, southern Xinjiang, is reconstructed through an analysis of a 953 cm long core （BSTC2000） taken from Bosten Lake. Multiple proxies of this core, including the mineral components of carbonate, carbonate content, stable isotopic compositions of carbonate, Ca/Sr, TOC and C/N and C/S of organic matter, are used to reconstruct the climatic change since 8500 a B.P. The chronology model is made by nine AMS 14C ages of leaves, seeds and organic matter contained in two parallel cores. The climate was cold and wet during 8500 to 8100 a B.P. Temperature increased from 8100 to 6400 a B.P., the climate was warm and humid, and the lake expanded. The lake level was highest during this stage. Then from 6400 to 5100 a B.P., the climate became cold and the lake level decreased slightly. During the late mid-Holocene, the climate was hot and dry from 5100 to 3100 a B.P., but there was a short cold period during 4400 to 3800 a B.P. At this temporal interval, a mass of ice and snow melting water supplied the lake at the early time and made the lake level rise. The second highest lake level stage occurred during 5200 to 3800 a B.P. The climate was cool and wet during 3100 to 2200 a B.P., when the lake expanded with decreasing evaporation. The lake had the last short-term high level during 3100 to 2800 a B.P. After this short high lake level period, the lake shrank because of the long-term lower temperature and reduced water supply. From 2200 to 1200 a B.P., the climate was hot and dry, and the lake shrank greatly. Although the temperature decreased somewhat from 1200 a B.P. to the present, the climate was warm and dry. The lake level began to rise a little again, but it did not reach the river bed altitude of the Konqi River, an outflow river of the Bosten Lake.
