This article reports modeled ice thickness distribution and total ice volume of the 65 selected glaciers(>0.5 km^2)of Chandra basin,located in the Western Himalayas.This is a first-of-its-kind study that gives deta...This article reports modeled ice thickness distribution and total ice volume of the 65 selected glaciers(>0.5 km^2)of Chandra basin,located in the Western Himalayas.This is a first-of-its-kind study that gives detailed insights about the current ice thickness distribution at an individual glacier level in the Western Himalayas.The estimates are obtained using an optimally parameterized Glab Top2_IITB[Glacier Bed Topography Indian Institute of Technology Bombay(IITB)version]model with highresolution Digital Elevation Model(DEM)as an input.The total estimated volume of all the 65 selected glaciers is about 55.32 km^3 covering a total area of about 591.03 km^2.Using hypsometric analysis,it is found that the maximum amount of ice volume,i.e.,about 12.79 km^3,is currently residing at the elevation range of 5200–5400 m a.s.l.Ice thickness estimates obtained in the current study are compared with the ensemble estimates obtained in the Global Glacier Thickness Initiative(G2TI)project for three large glaciers,namely,Bada Shigri,Samudra Tapu,and Gepang Gath glaciers.The obtained results indicate that the difference between both the studies is marginal in terms of mean ice thickness and maximum ice thickness estimates except Samudra Tapu glacier.Moreover,the uncertainty of the estimated glacier ice volume from this study is about±15%whereas,from the G2TI project,it is about 25%.The main reasons for the difference could be the quality of the inputs used,model structure,model parameterization as well as the time stamp of the input used.The obtained results from this study indicate that the use of appropriate shape factor and better DEM would result in more reliable glacier ice thickness estimates even by using a simple slopedependent model like Glab Top2_IITB.展开更多
40~30 ka BP在过去被认为是末次冰期的间冰阶,温度稍高,但仍在冰期内.20世纪90年代西昆仑山古里雅冰芯记录研究首次指出,当时气温可能高出现代4℃,即为以前所不知的间冰期.追踪同期湖泊沉积,孢粉与古生物,黄土与沙漠地区古土壤,石灰岩...40~30 ka BP在过去被认为是末次冰期的间冰阶,温度稍高,但仍在冰期内.20世纪90年代西昆仑山古里雅冰芯记录研究首次指出,当时气温可能高出现代4℃,即为以前所不知的间冰期.追踪同期湖泊沉积,孢粉与古生物,黄土与沙漠地区古土壤,石灰岩洞穴中石笋,古河道,滨海地区海相沉积等多种记录,集成研究表明,当时青藏高原与西北干旱区有许多淡水大湖,降水量远比现代丰沛,导致外流水系扩大,如青海境内的黄河上游水系形成.暖湿的气候条下,森林分布区向北向西大范围扩展,华南热带喜湿热的陆均松(Dacrydiumsp.)北界移至22°~24°N,表明当时热带气温高于现代2℃左右,降水量也有较大增加.长江下游石笋资料和北方半干旱、半湿润区的植物、古土壤、河道沉积资料均表示降水增加,森林覆盖度大.由于冰川和极地冰盖萎缩,海平面上升,给合若干地区地面沉降,海河下游、长江三角洲和珠江三角洲均出现相当规模的海侵.上述涉及全中国的特殊暖湿环境的形成与地球轨道运行岁差周期变化导致中低纬度日射增强,致使温度升高,季风区与西风带降水量都有显著增加关系密切,而植被改善又对温度和湿度有正反馈作用.展开更多
文摘蓝冰钻(BID,Blue Ice Drill)是一款大直径、便携式钻机系统,由美国麦迪逊-威斯康辛大学冰钻设计与操作团队研发,可以从近地面的钻点快速获取直径241 mm、无污染的冰芯样品.蓝冰钻的主要组成部分如下:1)下井电机/齿轮减速器:带动冰芯钻刀和外管内的芯管旋转,以便高效运送切割下来的固态冰;2)变频驱动器及配套的控制箱,管理钻机的输入电源;3)安装在反扭杆两侧的把手,在地面以上时起到反扭作用;4)冰芯回收工具:回收冰芯不是通过钻头上的卡刀,而是由独立的冰芯回收工具完成;5)其他附属设备:所有的下井设备通过在绞车上运行的绳索,悬挂在一个可折叠的三脚架上.蓝冰钻系统最少可由两个人操作,并已成功在南极Taylor冰川蓝冰区完成两个工作季.本款钻机系统的升级版本——深蓝冰钻(BID-Deep),目前已经完成设计,获取冰芯深度可至200 m.
基金the funding support provided by the Indian Institute of Technology Bombay,Centre of Excellence in Climate Studies(IITB-CECS)project of the Department of Science and Technology(DST),New Delhi,India。
文摘This article reports modeled ice thickness distribution and total ice volume of the 65 selected glaciers(>0.5 km^2)of Chandra basin,located in the Western Himalayas.This is a first-of-its-kind study that gives detailed insights about the current ice thickness distribution at an individual glacier level in the Western Himalayas.The estimates are obtained using an optimally parameterized Glab Top2_IITB[Glacier Bed Topography Indian Institute of Technology Bombay(IITB)version]model with highresolution Digital Elevation Model(DEM)as an input.The total estimated volume of all the 65 selected glaciers is about 55.32 km^3 covering a total area of about 591.03 km^2.Using hypsometric analysis,it is found that the maximum amount of ice volume,i.e.,about 12.79 km^3,is currently residing at the elevation range of 5200–5400 m a.s.l.Ice thickness estimates obtained in the current study are compared with the ensemble estimates obtained in the Global Glacier Thickness Initiative(G2TI)project for three large glaciers,namely,Bada Shigri,Samudra Tapu,and Gepang Gath glaciers.The obtained results indicate that the difference between both the studies is marginal in terms of mean ice thickness and maximum ice thickness estimates except Samudra Tapu glacier.Moreover,the uncertainty of the estimated glacier ice volume from this study is about±15%whereas,from the G2TI project,it is about 25%.The main reasons for the difference could be the quality of the inputs used,model structure,model parameterization as well as the time stamp of the input used.The obtained results from this study indicate that the use of appropriate shape factor and better DEM would result in more reliable glacier ice thickness estimates even by using a simple slopedependent model like Glab Top2_IITB.
文摘40~30 ka BP在过去被认为是末次冰期的间冰阶,温度稍高,但仍在冰期内.20世纪90年代西昆仑山古里雅冰芯记录研究首次指出,当时气温可能高出现代4℃,即为以前所不知的间冰期.追踪同期湖泊沉积,孢粉与古生物,黄土与沙漠地区古土壤,石灰岩洞穴中石笋,古河道,滨海地区海相沉积等多种记录,集成研究表明,当时青藏高原与西北干旱区有许多淡水大湖,降水量远比现代丰沛,导致外流水系扩大,如青海境内的黄河上游水系形成.暖湿的气候条下,森林分布区向北向西大范围扩展,华南热带喜湿热的陆均松(Dacrydiumsp.)北界移至22°~24°N,表明当时热带气温高于现代2℃左右,降水量也有较大增加.长江下游石笋资料和北方半干旱、半湿润区的植物、古土壤、河道沉积资料均表示降水增加,森林覆盖度大.由于冰川和极地冰盖萎缩,海平面上升,给合若干地区地面沉降,海河下游、长江三角洲和珠江三角洲均出现相当规模的海侵.上述涉及全中国的特殊暖湿环境的形成与地球轨道运行岁差周期变化导致中低纬度日射增强,致使温度升高,季风区与西风带降水量都有显著增加关系密切,而植被改善又对温度和湿度有正反馈作用.
