The last deglaciation, a key period for understanding present and future climate changes, has long been the hot topic for palaeoclimatological study. The Qinghai-Tibetan Plateau（QTP） is often a target study area for...The last deglaciation, a key period for understanding present and future climate changes, has long been the hot topic for palaeoclimatological study. The Qinghai-Tibetan Plateau（QTP） is often a target study area for understanding hemispheric, or even global environment changes. The glacial landforms on the QTP provide a unique perspective for its climate change. In order to investigate the onset of the last deglaciation at the QTP and its regional correlation, the terrestrial cosmogenic nuclides（TCN） 10 Be and 26 Al surface exposure dating was chosen to date the roche moutonnée, the polished surface and the moraine debris located at the palaeo-Daocheng Ice Cap（pDIC）, southeastern QTP. Our results show that the onset of the last deglaciation is at about 19 ka, followed by another warming event occurring around 15 ka in the p-DIC area. These timings agree well with other records, e.g. equivalent with a rapid sea level rise at 19 ka and the onset of B？lling warming event at about 15 ka. Thus, our new data can provide good reveal constraint on the climate evolution at the QTP.展开更多
The glacial landforms of the Qinghai-Tibetan Plateau （QTP） provide a unique opportunity to research hemispheric and global environmental changes. In this study, we focus on the glacial history of the palaeo-Daocheng...The glacial landforms of the Qinghai-Tibetan Plateau （QTP） provide a unique opportunity to research hemispheric and global environmental changes. In this study, we focus on the glacial history of the palaeo-Daocheng Ice Cap （p-DIC） in the southeastern QTP during the last glacial cycle. Based on field investigations, morphostratigraphy, and surface exposure dating of roche moutonnée, polished surface and moraine debris through the terrestrial cosmogenic nuclides （TCN） ^10Be and ^26Al. We identify glacial deposits of the last deglaciation, with minimum ages of 14.9±1.3-18.7±1.7 ka, the Last Glacial Maximum （LGM） of 24.7±2.2 ka, and the early part of the last glacial period （marine oxygen isotope stage （MIS） 3） of 37.1±3.4-45.2±3.9 ka. Our results show that in this region, the extent of the glacial advance during MIS 3 was larger than that during the traditional LGM （MIS 2）. These ages are consistent with prior chronologies, and the ^10Be age is consistent with the ^26Al age for the same sample. Thus, these data provide reliable constraints on climate change in the QTP, during the last glaciation.展开更多
emperature measurements in boreholes show that ice is of temperate state in accumulation area and of cold state in ablation area in Collins Ice Cap. Ice temperature of active layer is significantly influenced by seaso...emperature measurements in boreholes show that ice is of temperate state in accumulation area and of cold state in ablation area in Collins Ice Cap. Ice temperature of active layer is significantly influenced by seasonal variations of air temperature.The warming of ice by the melt water infiltration is remarkable. Snow cover also noticeably affects thermal regimes of the Collins Ice Cap. The measurements also reveal that temperature below the active layer is approximate to the melting point in the majority of the glacier except in the vicinity of the Little Dome,where ice temperature varies sharply within a surface distance of more than 10 metres. Significant water oozing from ice cores was observed at a depth of 30 m during the drilling near the Little Dome, which is probably caused by the combined effects such as internal runoffs,differential movement and high salinity of the glacier.展开更多
Glacier forming material shows no difference of oxygen isotope for different heights above sea level on Big Dome of Collins Ice Cap. δ 18 O variations of surface firn with depth(time) are extremely similar. ...Glacier forming material shows no difference of oxygen isotope for different heights above sea level on Big Dome of Collins Ice Cap. δ 18 O variations of surface firn with depth(time) are extremely similar. Owing to the material and energy exchange between different annual layers, homogeneity of oxygen isotope arises and leads to no avail of δ 18 O ice core dating on Big Dome Summit of Collins Ice Cap. Affected by seasonal variations of temperature, oxygen isotope composition of winter layer is distinctly different from that of summer layer whose δ 18 O value is higher and variation coefficient is smaller. By means of direct comparison oxygen isotope/temperature gradient of Collins Ice Cap is defined as 0.74‰/℃ in use of annual mean temperature and δ 18 O value on Big Dome Summit and Small Dome Top of Collins Ice Cap.展开更多
Based on detailed measurements of density and a numerous data on temperature in shallow boreholes (about 20m deep), the thermal properties and temperature distribution of snow / firn layer on the Law Dome ice cap, Ant...Based on detailed measurements of density and a numerous data on temperature in shallow boreholes (about 20m deep), the thermal properties and temperature distribution of snow / firn layer on the Law Dome ice cap, Antarctica, are discussed. According to a review of works on thermal properties of snow by Yen (1981), a relationship between thermal conductivity (K) and density (ρ) is proposed to be expressed by a formula, K=0.0784+2.697/ρ2. Then an eqation of heat transfer in a deformed ununiform medium is applied and solved analytically by two approaches. Comparison of calculated and measured temperatures indicates that the difference is mainly dependent on the determination of boundary donditions.展开更多
Measurements carried out for the upper 10m firn/ice obtained at the main dome of Collins Ice Cap, King George Island, Antarctica revealed the direct relation of soluble impurities of snow mass to the composition of at...Measurements carried out for the upper 10m firn/ice obtained at the main dome of Collins Ice Cap, King George Island, Antarctica revealed the direct relation of soluble impurities of snow mass to the composition of atmosphere aerosols. It was indicated that sea salt source dominates the atmosphere aerosol around Collins Ice Cap.The simultaneous variation shown by the concentration profiles of Na+ , K+ , Mg2+ , Ca2+, SO42-, Cl- , Br- and very close EF values (≈1) suggested their common marine source and similar deposition process. Besides the possible surface contamination,NH4+ varied uniformly along deeper part of the core in concentration, which could be considered as background value of ammonium. A satisfactory explanation for NO3- concentration profile has not reached at present.展开更多
Carrying dry and wet deposition records of aerosols in the mid-to upper-troposphereabove northwestern Qinghai-Xizang Plateau, the Guliya Ice Core extracted in 1992 at the el-evation of 6 400m on Guliya Ice Cap of west...Carrying dry and wet deposition records of aerosols in the mid-to upper-troposphereabove northwestern Qinghai-Xizang Plateau, the Guliya Ice Core extracted in 1992 at the el-evation of 6 400m on Guliya Ice Cap of western Kunlun Mt. has provided a uniqueopportunity to improve our understanding of atmospheric emvironment in this area. Onthe basis of studies on firn-ice transition of the ice cap, depositional processes展开更多
During 1991/1992 Chinese Antarctic Expedition, a full-year glacial investigations on the small dome of Coffins Ice Cap were carried out, the data from investigations showed that vertical temperature gradients on small...During 1991/1992 Chinese Antarctic Expedition, a full-year glacial investigations on the small dome of Coffins Ice Cap were carried out, the data from investigations showed that vertical temperature gradients on small dome were about 0. 79℃/100m and 0. 66℃/100m in the summer and in the winter separately. LOwer summer temperature in this area is one Of most important conditions for glacial development. In 1991/1992 the small dome was a weak positive balance year with a mass balance difference of 163 mm, annual ELA was 140m, mass balance gradient was 8.4mm/m and mass balance level was 928mm. Mass balance fluctuations on small dome in 1971-1992 were calculated by a new method, the results revealed that the small dome of Coffins Ice Cap was relatively stable over 21 years.展开更多
In the age of rapidly growing global population and escalating energy demands,the pursuit of sustainable,zero-emission energy sources has become critical.This article explores the interplay between environmental conce...In the age of rapidly growing global population and escalating energy demands,the pursuit of sustainable,zero-emission energy sources has become critical.This article explores the interplay between environmental concerns,such as global warming and the greenhouse effect,and the need for innovative energy solutions.The melting polar ice caps exemplify the urgent need for reducing carbon emissions.ARCs(advanced reactor concepts)in both fission and fusion technologies offer promising paths to zero-emission energy.Advanced fission reactors,including SMRs(small modular reactors)and Generation IV reactors,provide improved safety,efficiency,and waste management.Fusion energy,despite being in the experimental stage,holds potential as a nearly limitless clean energy source.AI(artificial intelligence)significantly enhances these technologies by optimizing design,operations,maintenance,safety,and grid integration.AI-driven innovations are pivotal in accelerating the development and deployment of ARC technologies,ensuring they are safe,reliable,and efficient.The article underscores the vital role of policy support,global cooperation,and strategic investments in shaping a sustainable energy future that can mitigate the effects of climate change,support economic growth,and protect our planet.展开更多
Poly-and perfluoroalkyl substances(PFASs)are important environmental contaminants globally and in the early 2000s they were shown to be ubiquitous contaminants in Arctic wildlife.Previous reviews by Butt et al.and Let...Poly-and perfluoroalkyl substances(PFASs)are important environmental contaminants globally and in the early 2000s they were shown to be ubiquitous contaminants in Arctic wildlife.Previous reviews by Butt et al.and Letcher et al.have covered studies on levels and trends of PFASs in the Arctic that were available to 2009.The purpose of this review is to focus on more recent work,generally published between 2009 and 2018,with emphasis on PFASs of emerging concern such as perfluoroalkyl carboxylates(PFCAs)and short-chain perfluoroalkyl sulfonates(PFSAs)and their precursors.Atmospheric measurements over the period 2006e2014 have shown that fluorotelomer alcohols(FTOHs)as well as perfluorobutanoic acid(PFBA)and perfluoroctanoic acid(PFOA)are the most prominent PFASs in the arctic atmosphere,all with increasing concentrations at Alert although PFOA concentrations declined at the Zeppelin Station(Svalbard).Results from ice cores show generally increasing deposition of PFCAs on the Devon Ice cap in the Canadian arctic while declining fluxes were found in a glacier on Svalbard.An extensive dataset exists for long-term trends of long-chain PFCAs that have been reported in Arctic biota with some datasets including archived samples from the 1970s and 1980s.Trends in PFCAs over time vary among the same species across the North American Arctic,East and West Greenland,and Svalbard.Most long term time series show a decline from higher concentrations in the early 2000s.However there have been recent(post 2010)increasing trends of PFCAs in ringed seals in the Canadian Arctic,East Greenland polar bears and in arctic foxes in Svalbard.Annual biological sampling is helping to determine these relatively short term changes.Rising levels of some PFCAs have been explained by continued emissions of long-chain PFCAs and/or their precursors and inflows to the Arctic Ocean,especially from the North Atlantic.While the effectiveness of biological sampling for temporal trends in long-chain PFCAs and PFSAs has been demonstrated,this does not apply to the C4eC8ePFCAs,perfluorobutane sulfonamide(FBSA),or perfluorobutane sulfonate(PFBS)which are generally present at low concentrations in biota.In addition to air sampling,sampling abiotic media such as glacial cores,and annual sampling of lake waters and seawater would appear to be the best approaches for investigating trends in the less bioaccumulative PFASs.展开更多
The Hengduan Mountains is in the transitional zone between the Qinghai-Tibet Plateau(QTP)and the YunnanGuizhou Plateau in China,and a key area for elucidating the Quaternary environmental changes in Asia.The paleo-Dao...The Hengduan Mountains is in the transitional zone between the Qinghai-Tibet Plateau(QTP)and the YunnanGuizhou Plateau in China,and a key area for elucidating the Quaternary environmental changes in Asia.The paleo-Daocheng ice cap was located on the Shaluli Hilly Plateau in the northeastern Hengduan Mountains,the oldest moraines in the Hengduan Mountains region were found in the ice cap area.Such glacial landforms provide key evidence to study the timing when this area entered the cryosphere with the uplift of the QTP.However,it is difficult to collect suitable glacial boulders from these moraines for traditional terrestrial in-situ cosmogenic nuclide(TCN)exposure dating because of long-term severe moraine degradation.Here,we collected clast samples from the moraine surface and depth profile to constrain the age of the oldest moraine in Kuzhaori(moraine E)using TCN^(10)Be dating technique.The minimum^(10)Be ages of five clast samples from the moraine surface range from 187.4±1.5 to 576.8±4.3 ka,implying that the moraine has been seriously degraded since deposition.Based on the TCN^(10)Be concentrations of the samples from a depth profile and simulations,the exposure-erosion-inheritance history of the profile was obtained.By fitting to the profile^(10)Be concentrations using the chi-square test,the simulations yielded a reliable age of 626.0±52.5 ka for the moraine.Therefore,the oldest moraine(moraine E)in Kuzhaori was most likely formed at about 0.63Ma ago,corresponding to the marine isotope stage(MIS)16.This glaciation represents the maximum Quaternary glaciation after the QTP was elevated into the cryosphere by the Kunlun-Yellow River Tectonic Movement.展开更多
Based on a two-dimensional energy balance model, the studies on some climatic issues such as the re- lationship between ice cap latitude and solar constant, desertifieation, and the warming effect of carbon dioxide, h...Based on a two-dimensional energy balance model, the studies on some climatic issues such as the re- lationship between ice cap latitude and solar constant, desertifieation, and the warming effect of carbon dioxide, have been reviewed and discussed. The phenomenon that a fixed solar constant might correspond to different equilibrium ice cap latitudes is determined by the continuity of albedo distribution. The disconti- nuity in albedo distribution increases the number of equilibrium ice cap latitudes. Desert would expand both northward and southward when desert surface albedo is increasing. This would deteriorate the ecological environment in border regions, and then threaten the existence of local inhabitants. Melting of the polar ice would not be accelerated, with increasing carbon dioxide concentration. The ice cap latitude would move northward slowly, with some “hiatus” periods, under the slowly increasing global average surface tempera- ture. According to the current research, future development of the two-dimensional energy balance model and possible progress are also forecasted.展开更多
基金supported by the National Excellent Doctoral Dissertation cultivation project of Nanjing Normal University (Grant No. 2012BS0005)the National Natural Science Foundation of China (Grant No. 40572097)the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘The last deglaciation, a key period for understanding present and future climate changes, has long been the hot topic for palaeoclimatological study. The Qinghai-Tibetan Plateau（QTP） is often a target study area for understanding hemispheric, or even global environment changes. The glacial landforms on the QTP provide a unique perspective for its climate change. In order to investigate the onset of the last deglaciation at the QTP and its regional correlation, the terrestrial cosmogenic nuclides（TCN） 10 Be and 26 Al surface exposure dating was chosen to date the roche moutonnée, the polished surface and the moraine debris located at the palaeo-Daocheng Ice Cap（pDIC）, southeastern QTP. Our results show that the onset of the last deglaciation is at about 19 ka, followed by another warming event occurring around 15 ka in the p-DIC area. These timings agree well with other records, e.g. equivalent with a rapid sea level rise at 19 ka and the onset of B？lling warming event at about 15 ka. Thus, our new data can provide good reveal constraint on the climate evolution at the QTP.
基金supported by the National Natural Science Foundation of China (Grant No.40572097)the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD) (Grant No.164320H116)by the Yulong Mountain tourism development and management committee special project
文摘The glacial landforms of the Qinghai-Tibetan Plateau （QTP） provide a unique opportunity to research hemispheric and global environmental changes. In this study, we focus on the glacial history of the palaeo-Daocheng Ice Cap （p-DIC） in the southeastern QTP during the last glacial cycle. Based on field investigations, morphostratigraphy, and surface exposure dating of roche moutonnée, polished surface and moraine debris through the terrestrial cosmogenic nuclides （TCN） ^10Be and ^26Al. We identify glacial deposits of the last deglaciation, with minimum ages of 14.9±1.3-18.7±1.7 ka, the Last Glacial Maximum （LGM） of 24.7±2.2 ka, and the early part of the last glacial period （marine oxygen isotope stage （MIS） 3） of 37.1±3.4-45.2±3.9 ka. Our results show that in this region, the extent of the glacial advance during MIS 3 was larger than that during the traditional LGM （MIS 2）. These ages are consistent with prior chronologies, and the ^10Be age is consistent with the ^26Al age for the same sample. Thus, these data provide reliable constraints on climate change in the QTP, during the last glaciation.
文摘emperature measurements in boreholes show that ice is of temperate state in accumulation area and of cold state in ablation area in Collins Ice Cap. Ice temperature of active layer is significantly influenced by seasonal variations of air temperature.The warming of ice by the melt water infiltration is remarkable. Snow cover also noticeably affects thermal regimes of the Collins Ice Cap. The measurements also reveal that temperature below the active layer is approximate to the melting point in the majority of the glacier except in the vicinity of the Little Dome,where ice temperature varies sharply within a surface distance of more than 10 metres. Significant water oozing from ice cores was observed at a depth of 30 m during the drilling near the Little Dome, which is probably caused by the combined effects such as internal runoffs,differential movement and high salinity of the glacier.
文摘Glacier forming material shows no difference of oxygen isotope for different heights above sea level on Big Dome of Collins Ice Cap. δ 18 O variations of surface firn with depth(time) are extremely similar. Owing to the material and energy exchange between different annual layers, homogeneity of oxygen isotope arises and leads to no avail of δ 18 O ice core dating on Big Dome Summit of Collins Ice Cap. Affected by seasonal variations of temperature, oxygen isotope composition of winter layer is distinctly different from that of summer layer whose δ 18 O value is higher and variation coefficient is smaller. By means of direct comparison oxygen isotope/temperature gradient of Collins Ice Cap is defined as 0.74‰/℃ in use of annual mean temperature and δ 18 O value on Big Dome Summit and Small Dome Top of Collins Ice Cap.
文摘Based on detailed measurements of density and a numerous data on temperature in shallow boreholes (about 20m deep), the thermal properties and temperature distribution of snow / firn layer on the Law Dome ice cap, Antarctica, are discussed. According to a review of works on thermal properties of snow by Yen (1981), a relationship between thermal conductivity (K) and density (ρ) is proposed to be expressed by a formula, K=0.0784+2.697/ρ2. Then an eqation of heat transfer in a deformed ununiform medium is applied and solved analytically by two approaches. Comparison of calculated and measured temperatures indicates that the difference is mainly dependent on the determination of boundary donditions.
文摘Measurements carried out for the upper 10m firn/ice obtained at the main dome of Collins Ice Cap, King George Island, Antarctica revealed the direct relation of soluble impurities of snow mass to the composition of atmosphere aerosols. It was indicated that sea salt source dominates the atmosphere aerosol around Collins Ice Cap.The simultaneous variation shown by the concentration profiles of Na+ , K+ , Mg2+ , Ca2+, SO42-, Cl- , Br- and very close EF values (≈1) suggested their common marine source and similar deposition process. Besides the possible surface contamination,NH4+ varied uniformly along deeper part of the core in concentration, which could be considered as background value of ammonium. A satisfactory explanation for NO3- concentration profile has not reached at present.
文摘Carrying dry and wet deposition records of aerosols in the mid-to upper-troposphereabove northwestern Qinghai-Xizang Plateau, the Guliya Ice Core extracted in 1992 at the el-evation of 6 400m on Guliya Ice Cap of western Kunlun Mt. has provided a uniqueopportunity to improve our understanding of atmospheric emvironment in this area. Onthe basis of studies on firn-ice transition of the ice cap, depositional processes
文摘During 1991/1992 Chinese Antarctic Expedition, a full-year glacial investigations on the small dome of Coffins Ice Cap were carried out, the data from investigations showed that vertical temperature gradients on small dome were about 0. 79℃/100m and 0. 66℃/100m in the summer and in the winter separately. LOwer summer temperature in this area is one Of most important conditions for glacial development. In 1991/1992 the small dome was a weak positive balance year with a mass balance difference of 163 mm, annual ELA was 140m, mass balance gradient was 8.4mm/m and mass balance level was 928mm. Mass balance fluctuations on small dome in 1971-1992 were calculated by a new method, the results revealed that the small dome of Coffins Ice Cap was relatively stable over 21 years.
文摘In the age of rapidly growing global population and escalating energy demands,the pursuit of sustainable,zero-emission energy sources has become critical.This article explores the interplay between environmental concerns,such as global warming and the greenhouse effect,and the need for innovative energy solutions.The melting polar ice caps exemplify the urgent need for reducing carbon emissions.ARCs(advanced reactor concepts)in both fission and fusion technologies offer promising paths to zero-emission energy.Advanced fission reactors,including SMRs(small modular reactors)and Generation IV reactors,provide improved safety,efficiency,and waste management.Fusion energy,despite being in the experimental stage,holds potential as a nearly limitless clean energy source.AI(artificial intelligence)significantly enhances these technologies by optimizing design,operations,maintenance,safety,and grid integration.AI-driven innovations are pivotal in accelerating the development and deployment of ARC technologies,ensuring they are safe,reliable,and efficient.The article underscores the vital role of policy support,global cooperation,and strategic investments in shaping a sustainable energy future that can mitigate the effects of climate change,support economic growth,and protect our planet.
基金We thank the Arctic Monitoring and Assessment Programme(AMAP)and the national programs in the circumpolar countries for their funding and support of this work.We are especially grateful to Simon Wilson,Cynthia de Wit,and the reviewers that read the chapter on PFASs in the original AMAP assessment.We are thankful to the northern communities in circumpolar regions for their cooperation and collection of biological samples that yielded the data reviewed here.DCGM was supported by the King Carl XVI Gustaf Professorship in Environmental Science at the Dept of Environmental Science and Analytical Chemistry,Stockholm University during 2018-19.
文摘Poly-and perfluoroalkyl substances(PFASs)are important environmental contaminants globally and in the early 2000s they were shown to be ubiquitous contaminants in Arctic wildlife.Previous reviews by Butt et al.and Letcher et al.have covered studies on levels and trends of PFASs in the Arctic that were available to 2009.The purpose of this review is to focus on more recent work,generally published between 2009 and 2018,with emphasis on PFASs of emerging concern such as perfluoroalkyl carboxylates(PFCAs)and short-chain perfluoroalkyl sulfonates(PFSAs)and their precursors.Atmospheric measurements over the period 2006e2014 have shown that fluorotelomer alcohols(FTOHs)as well as perfluorobutanoic acid(PFBA)and perfluoroctanoic acid(PFOA)are the most prominent PFASs in the arctic atmosphere,all with increasing concentrations at Alert although PFOA concentrations declined at the Zeppelin Station(Svalbard).Results from ice cores show generally increasing deposition of PFCAs on the Devon Ice cap in the Canadian arctic while declining fluxes were found in a glacier on Svalbard.An extensive dataset exists for long-term trends of long-chain PFCAs that have been reported in Arctic biota with some datasets including archived samples from the 1970s and 1980s.Trends in PFCAs over time vary among the same species across the North American Arctic,East and West Greenland,and Svalbard.Most long term time series show a decline from higher concentrations in the early 2000s.However there have been recent(post 2010)increasing trends of PFCAs in ringed seals in the Canadian Arctic,East Greenland polar bears and in arctic foxes in Svalbard.Annual biological sampling is helping to determine these relatively short term changes.Rising levels of some PFCAs have been explained by continued emissions of long-chain PFCAs and/or their precursors and inflows to the Arctic Ocean,especially from the North Atlantic.While the effectiveness of biological sampling for temporal trends in long-chain PFCAs and PFSAs has been demonstrated,this does not apply to the C4eC8ePFCAs,perfluorobutane sulfonamide(FBSA),or perfluorobutane sulfonate(PFBS)which are generally present at low concentrations in biota.In addition to air sampling,sampling abiotic media such as glacial cores,and annual sampling of lake waters and seawater would appear to be the best approaches for investigating trends in the less bioaccumulative PFASs.
基金supported by the National Natural Science Foundation of China(Grant Nos.41971009&41503054)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDA2000300)。
文摘The Hengduan Mountains is in the transitional zone between the Qinghai-Tibet Plateau(QTP)and the YunnanGuizhou Plateau in China,and a key area for elucidating the Quaternary environmental changes in Asia.The paleo-Daocheng ice cap was located on the Shaluli Hilly Plateau in the northeastern Hengduan Mountains,the oldest moraines in the Hengduan Mountains region were found in the ice cap area.Such glacial landforms provide key evidence to study the timing when this area entered the cryosphere with the uplift of the QTP.However,it is difficult to collect suitable glacial boulders from these moraines for traditional terrestrial in-situ cosmogenic nuclide(TCN)exposure dating because of long-term severe moraine degradation.Here,we collected clast samples from the moraine surface and depth profile to constrain the age of the oldest moraine in Kuzhaori(moraine E)using TCN^(10)Be dating technique.The minimum^(10)Be ages of five clast samples from the moraine surface range from 187.4±1.5 to 576.8±4.3 ka,implying that the moraine has been seriously degraded since deposition.Based on the TCN^(10)Be concentrations of the samples from a depth profile and simulations,the exposure-erosion-inheritance history of the profile was obtained.By fitting to the profile^(10)Be concentrations using the chi-square test,the simulations yielded a reliable age of 626.0±52.5 ka for the moraine.Therefore,the oldest moraine(moraine E)in Kuzhaori was most likely formed at about 0.63Ma ago,corresponding to the marine isotope stage(MIS)16.This glaciation represents the maximum Quaternary glaciation after the QTP was elevated into the cryosphere by the Kunlun-Yellow River Tectonic Movement.
基金Supported by the National(Key)Basic Research and Development(973)Program of China(2014CB953903)Fundamental Research Funds for Central Universities(2013YB45)
文摘Based on a two-dimensional energy balance model, the studies on some climatic issues such as the re- lationship between ice cap latitude and solar constant, desertifieation, and the warming effect of carbon dioxide, have been reviewed and discussed. The phenomenon that a fixed solar constant might correspond to different equilibrium ice cap latitudes is determined by the continuity of albedo distribution. The disconti- nuity in albedo distribution increases the number of equilibrium ice cap latitudes. Desert would expand both northward and southward when desert surface albedo is increasing. This would deteriorate the ecological environment in border regions, and then threaten the existence of local inhabitants. Melting of the polar ice would not be accelerated, with increasing carbon dioxide concentration. The ice cap latitude would move northward slowly, with some “hiatus” periods, under the slowly increasing global average surface tempera- ture. According to the current research, future development of the two-dimensional energy balance model and possible progress are also forecasted.
