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1.
Glacier flow is a key factor in understanding the nature of glaciers, and it is also one of the main research contents of glacier dynamics, which can provide basic support for rational utilization of glacier resources and early warning of glacier disasters. There are many mountain glaciers located in the west of China. The study on the spatiotemporal variation of surface velocity of glaciers also has great significance for the social and economic development of the western China. Koxkar Baxi Glacier, locates on the southern slopes of the Tomur Peak, is a typical dendritic glacier. In order to obtain the conditions of Koxkar Baxi Glacier’flow rates and its variation to further reveal the future of the variation of glacier, the spatiotemporal variability of glacier velocity was surveyed using correlation(COSI-Corr)method on Landsat imagery from 2014 to 2020. The results show that: (1)The average annual flow velocity of the Koxkar Baxi Glacier was 0. 04~0. 05 m·d-1 during 2014 to 2020. (2)The glacier reaches its maximum flow velocity near the center part, and the velocity decreased towards both lateral margins. In a longitudinal profile, ice flow velocity in the accumulation area increased down to the equilibrium line, while decreased towards the glacier terminal. The maximum velocity with 0. 17~ 0. 20 m·d-1 was found near the equilibrium line altitude. (3)The glacier flow velocity in warm seasons were 16. 67% faster than that in cold seasons. (4)The glacier flow velocity from 2014 to 2020 showed a slight decreasing trend, and the average flow velocity decreased 0. 01 m·d-1. (5)Temperature and precipitation had certain influence on the seasonal fluctuation and interannual variation of the flow velocity of the glacier. © 2022 Science Press (China). All rights reserved.  相似文献   

2.
Under the background of significant climate warming since the 1980s,the glaciers in China's monsoonal temperate glacier region respond to the warming intensely.Based on the glaciohy-drological observations at some typical glaciers from Mts.Yulong(玉龙) and Gongga(贡嘎) of Heng-duan(横断) Mountains Range in the southeastern Tibetan plateau,the glaciohydrological changes in the temperate glacier region since the 1980s were investigated.First,the glacier terminus exhibited an accelerating retreat.Second,as the glaci...  相似文献   

3.
The study of spatial and temporal covariances of glaciers and lakes would help us to understand the impact of climate change within a basin in Tibet. This study focuses on glacier and lake variations in the Mapam Yumco(玛旁雍错)Basin (covering 7 786.44 km2)by Integrationg series of spatial data from topographic maps and digital satellite images at four different times 1974, 1990, 1999,and 2003. The results indicate that (1) decreased lakes, retreated glaciers, enlarged lakes and advanced glaciers co-exist in the basin during the last 30 years; (2) glacier recession was accelerated in recent years due to the warmer climate; (3) lake areas in the basin are both reduced and enlarged by an accelerated speed with more water supplies from speeding melt glaciers or frozen ground in the last three decades.  相似文献   

4.
王凯  孙永玲  孙世金  刘晓 《冰川冻土》2022,44(3):971-983
Skamri Glacier is the largest glacier in China, and it is a surge-type glacier. The study on the charac⁃ teristics of glacial movement is of great significance for early warning of glacial disasters caused by glacier surge. In this paper, 20 pairs of Landsat-8 images from 2018 to 2021 were selected to extract the surface veloci⁃ ty of Skamri Glacier using optical image feature tracking method, analyze the uncertainty of velocity, and ana⁃ lyze the temporal and spatial changes characteristics of velocity of the glacier. The results show that there are ob⁃ vious spatial differences in the surface velocity of Skamri Glacier. During the period from January 2018 to June 2019, the velocity of the south tributary of Skamri Glacier is much greater than that of its north tributary(west), while during the period from June 2019 to November 2021, it presents completely opposite spatial characteris⁃ tics, which is mainly due to the sudden increase of the velocity of the north tributary(west)in June 2019. Ac⁃ cording to the results of velocity changes from 2018 to 2021, it is found that the north tributary(west)surges in June 2019 and is still in the surge period until November 2021. The north tributary(west)glacier terminus will advance about 320 m towards the main glacier from August 2020 to September 2021;The velocity of the south tributary has been very large during the study period, and the maximum velocity reaches 441 m·a-1;The veloci⁃ ty of the north tributary(east)of Skamri Glacier increased sharply in July 2021, and the tributary may surge;The velocity of the main glacier of Skamri Glacier increased significantly after the confluence of the south tribu⁃ tary and the surge of the two north tributaries. In addition, there are temporal and spatial differences in the eleva⁃ tion distribution of the maximum velocity of the main glacier and its tributaries in this area. © 2022 Science Press (China). All rights reserved.  相似文献   

5.
Foreword     
China has 46 377 glaciers with a total area of 59 425 km2, which accounts for 11%-14.5% of the total area of mountain glaciers in the world. As one of the largest mountain ranges in Central Asia and Northwest China, the Tianshan contains 15 935 gla-ciers with a total area of 15 416 km2. These glaciers are a vital source of water for more than 100 million people and for wildlife ecosystems in this vast arid and semi-arid land. Urumqi Glacier No. 1, the best monitored glacier in China, is located at the h...  相似文献   

6.
Glaciological mass balance(MB)is considered the most direct,undelayed and unfiltered response of the glaciers to climatic perturbations.However,it may inherit errors associated with stake underrepresentation,averaging over the entire glacier and human bias.Therefore,proper validation of glaciological MB with geodetic MB is highly recommended by the World Glacier Monitoring Service(WGMS).The present study focuses on the Dokriani Glacier,central Himalaya which is one of the bench-mark glaciers in the region and has glaciological MB records from 1993 to 2013 with intermittent gaps.In the present study,firstly the glaciological MB series is extended to 2014 i.e.,field-based MB for one more year is computed and,to compare with it,the geodetic MB is computed for the 1999–2014 period using high resolution Cartosat-1 digital elevation model(DEM)and SRTM DEM.Finally,the study assesses the regional representation of the Dokriani Glacier in terms of MB and evaluates the influence of the MB regime on its morphological evolution.Results show that the average glaciological MB(-0.34±0.2 m water equivalent(w.e.)y-1)is more negative than the geodetic MB(-0.23±0.1 m w.e.y-1)for the 1999–2014 period.This is likely because of the partial representation of glacier margins in the glaciological MB,where melting is strikingly low owing to thick debris cover(>30 cm).In contrast,geodetic MB considers all marginal pixels leading to a comparatively low MB.A comparative assessment shows that the MB of Dokriani Glacier is less negative(possibly due to its huge accumulation area)than most other glacier-specific and regional MBs,restricting it to be a representative glacier in the region.Moreover,continuous negative MB has brought a peculiar change in the epiglacial morphology in the lower tongue of the glacier as differential debris thickness-induced differential melting has turned the glacier surface into a concave one.This concavity has led to development of a large(10–20 m deep)supraglacial channel which is expanding incessantly.The supraglacial channel is also connected with the snout wall and accelerates terminus disintegration.Given the total thickness of about 30–50 m in the lower glacier tongue,downwasting at its current pace,deepening/widening of supraglacial channel coupled with rapid terminus retreat may lead to the complete vanishing of the lower one km glacier tongue.  相似文献   

7.
Zircon and apatite fission-track dating indicates that the exhumation of the Dabie Mountains tended to be accelerated in the Cenozoic and that the exhumation of the eastern Dabie Mountains was more and more intense from south to north, which is in accordance with the more and more intense dissection from south to north, as is reflected by the modern geomorphologic features of the Dabie Mountains. The accelerated exhumation during the Cenozoic was related to the high elevation of the Dabie Mountains resulting from Late Cretaceous-Palaeogene detachment faulting and subsequent fault-block uplift and subsidence. The average elevation at that time was at least about 660 m higher than that at the present. The intense exhumation lagged behind intense uplift.  相似文献   

8.
How to effectively identify glacial sediments, especially Quaternary moraine, has been in dispute for decades. The traditional methods, e.g., sedimentary and geomorphologic ones, are facing challenge in eastern China where controversial moraine deposits are dominatingly distributed. Here, for the first time, we introduce the acoustic emission (AE) stress measurement, a kind of historical stress measurement, to identify Quaternary moraine. The results demonstrate that it can be employed to reconstruct stress information of glaciation remaining in gravels, and may shed light on the identification of Quaternary moraine in eastern China. First, we measured the AE stress of gravels of glacial origin that are underlying the Xidatan Glacier, eastern Kunlun Mountains in western China. Second, we calculated the stress according to the actual thickness of the glacier. The almost identical stress values suggest that the glacial gravels can memorize and preserve the overlying glacier-derived aplomb stress. And then we introduce this new approach to the controversial moraine in Mount Lushan, eastern China. The results indicate that the stress is attributed to the Quaternary glacier, and the muddy gravels in the controversial moraine in Mount Lushan are moraine deposits but not others.  相似文献   

9.
The Working Group I report of the Sixth Assessment Report(AR6)of the Intergovernmental Panel on Climate Change(IPCC)was released in August 2021. Base on updated and expanding data, AR6 presented the improved assessment of past changes and processes of cryosphere. AR6 also predicted the future changes us⁃ ing the models in CMIP6. The components of cryosphere were rapid shrinking under climate warming in the last decade. There were decreasing trends in Arctic sea-ice area and thickness. Sea-ice loss was significant. The Greenland Ice Sheet, the Antarctic Ice Sheet and all glaciers lost more mass than in any other decade. Global warming over the last decades had led to widespread permafrost warming, active layer thickness increasing and subsea permafrost extent reducing. Snow cover extent in the Northern Hemisphere also decreased significantly. However, the variations of snow depth and snow water equivalent showed great spatial heterogeneity. The rapid shrinking of the cryosphere accelerated the global mean sea level rise. The impact of human activities on cryo⁃ sphere will become more significant in the future. The Arctic sea-ice area will decrease, and the Arctic Ocean will likely become practically sea ice-free. The Greenland Ice Sheet, the Antarctic Ice Sheet and glaciers will continue to lose mass throughout this century. Permafrost and Northern Hemisphere snow cover extent will con⁃ tinue to decrease as global climate continues to warm. In addition, there are still uncertainties in the prediction of cryosphere due to the absence of observations, the poor sensitivity of models to the components and processes of cryosphere, and the inexplicit represent of the mechanism of light-absorbing impurities. More attentions should be paid on these issues in the future. © 2022 Science Press (China). All rights reserved.  相似文献   

10.
The cryosphere constitutes an important subset of the hydrosphere.The Himalayan cryosphere is a significant contributor to the hydrological budget of a large river system such as the Ganges.Basic data on the cryosphere in the Himalaya is inadequate and also has large uncertainties.The data on glacial melt component in the Himalayan rivers of India also shows high variability.The Gangotri glacier which constitutes nearly a fifth of the glacierized area of the Bhagirathi basin represents one of the fastest receding,large valley glaciers in the region which has been surveyed and monitored for over sixty years.The availability of measurement over a long period and relatively small glacier-fed basin for the Bhagirathi river provides suitable constraints for the measurement of the glacial melt fraction in a Himalayan river.Pre- and post-monsoon samples reveal a decreasing trend Of depletion of δ~(18)O in the river water from glacier snout(Gaumukh) to the confluence of the Bhagirathi river with the Alaknanda river near Devprayag.Calculations of existing glacial melt fraction(~ 30%at Rishikesh) are not consistent with the reported glacial thinning rates.It is contended that the choice of unsuitable end-members in the three component mixing model causes the overestimation of glacial melt component in the river discharge.Careful selection of end members provides results(~11%at Devprayag) that are consistent with the expected thinning rates.  相似文献   

11.
研究冰川面积变化对气温变化的响应模式,对于冰川资源的保护和利用具有重要意义。利用Landsat MSS、TM和OLI影像,采用比值阈值法结合目视修正,提取了阿尔金山地区1973—2020年8个时期的冰川边界信息,分析了冰川的时空变化特征,并结合距离阿尔金山较近的且末、若羌、茫崖和冷湖等四个气象站点的气象数据,分析了冰川变化对气温变化的响应规律。主要结论如下:1973—2020年阿尔金山地区冰川整体处于退缩状态,面积减少了(64.89±12.36) km2(19.21%±2.90%);1973—1990年冰川退缩较快,年均退缩率为(0.49±0.07)%·a-1;1990—1995年和1995—2000年这两个时期冰川退缩最快,年均退缩率分别为(1.07±0.08)%·a-1和(1.08±0.08)%·a-1;2000年后,冰川退缩速率较慢,比较稳定,年均退缩率均低于0.2%·a-1。气温是影响阿尔金山地区1973—2020年冰川变化的主要气候因子。阿尔金山地区冰川对不同气温变化阶段的响应模式为:气温升高阶段,冰川消融,冰川面积减少;气温稳定阶段,冰川逐渐进入新的动态均衡状态,冰川面积也相对稳定;气温降低阶段,因冰川运动的滞后性,冰川面积在短时间内无明显变化。  相似文献   

12.
基于Landsat系列卫星遥感影像、 SRTM DEM和TanDEM-X DEM对喀喇昆仑山中部Shigar流域不同类型冰川的面积变化、 物质平衡进行了分析。结果表明: 1993—2016年间Shigar流域内有25条跃动冰川(面积增加1.30 km2), 68条前进冰川(面积增加0.86 km2), 50条退缩冰川(面积减少3.48 km2), 376条稳定冰川(面积减少1.34 km2)。跃动冰川的冰川长度和规模均集中在较大范围内, 前进冰川的规模略高于退缩冰川, 退缩冰川多为小规模冰川, 特大规模冰川保持稳定状态; 不同类型冰川的空间分布差异较大, 且不同海拔带内水热组合条件不一致也影响冰川运动状态。2000—2013年间, 流域内跃动冰川物质平衡为(+0.17±0.03) m w.e.·a-1, 前进冰川物质平衡为(-0.01±0.03) m w.e.·a-1, 退缩冰川物质平衡为(-0.22±0.03) m w.e.·a-1, 稳定冰川物质平衡为(-0.01±0.03) m w.e.·a-1。四类冰川表面高程变化随归一化冰川长度的变化模式以及不同海拔带内和不同坡度区间的冰川表面高程变化显示: 跃动冰川主要特征是积累区物质积累量大; 前进冰川上部物质积累并且向下运动推动冰川末端前进; 退缩冰川消融区物质亏损量大使得冰川末端退缩。  相似文献   

13.
2008—2018年中国冰川变化分析   总被引:5,自引:3,他引:2  
调查冰川资源的分布与变化,对区域乃至全球的自然环境与经济社会发展都具有十分重要的意义。基于315景Landsat 8 OLI遥感影像,结合中国第二次冰川编目数据与Google Earth软件,通过人工目视解译等方法调查了2018年中国冰川的分布与变化。结果表明:中国现存冰川53 238条,总面积为(47 174.21±19.93) km2,72%的冰川面积<0.5 km2,规模在1~32 km2的冰川的面积占中国冰川总面积的60%。2008—2018年,中国冰川总面积减少1 393.97 km2,面积变化率为-0.43%?a-1。冰川面积变化率表现出明显的空间差异,面积退缩最快的是冈底斯山,达-1.07%?a-1;最慢的是羌塘高原,为-0.05%?a-1。坡度上,各山系之间的冰川面积变化率差异较为明显。超过70%的山系位于正东和东南方向的冰川面积退缩快,2008—2018年退缩率为-5.0%;正北方向的冰川面积退缩相对缓慢,同时期退缩率为-3.8%。气温和降水变化率差异以及海拔、坡度、坡向等地形差异,共同影响中国冰川的变化。  相似文献   

14.
西藏阿里地区大、小昂龙冰川变化观测研究   总被引:1,自引:1,他引:0  
在西藏阿里地区狮泉河上游的大、小昂龙冰川开展了连续2年(2014—2016年)的冰川变化地面观测,主要包括冰川表面物质平衡与差分GPS高程变化同步观测,以及冰川表面流速观测,冰川末端观测和冰川雷达测厚。观测结果表明:大、小昂龙冰川表面物质平衡与同期差分GPS观测结果之间存在差异。冰川表面物质平衡结果显示,2014—2016年间,大、小昂龙冰川分别以每年72 mm w.e.和219 mm w.e.的速率减薄。差分GPS观测结果显示,同期大、小昂龙冰川分别以每年(442±90) mm w.e.和(265±90) mm w.e.的速率减薄;在2015/2016年,大、小昂龙冰川表面平均流速分别为4.4 m·a-1和2.3 m·a-1,其中大昂龙冰川表面平均流速较上一物质平衡年增加了10.5%;2014—2016年间,小昂龙冰川先是前进了11 m,之后又退缩了34 m,两年内平均每年退缩11.5 m;大昂龙冰川平均冰厚为67.9 m,实测最大厚度为216 m,根据雷达测厚数据插值计算的冰川储量为0.452 km3;小昂龙冰川实测最大厚度为190 m。  相似文献   

15.
1970—2016年阿尔金山冰川长度变化   总被引:2,自引:1,他引:1  
长度是冰川的重要几何参数,对于认识冰川动态特征和模拟冰川厚度具有重要价值。基于阿尔金山第一次和第二次冰川编目数据及Landsat OLI遥感影像,利用冰川中流线方法提取了阿尔金山1970年、2010年和2016年的冰川长度数据,并结合气象资料分析了冰川长度对气候变化的响应。结果表明:2016年阿尔金山共有冰川507条,面积272.95 km2,平均长度为1.02 km,长度为2~5 km和0.2~1 km的冰川分别构成了该山系冰川面积和数量的主体。1970—2016年阿尔金山冰川面积减少了53.07 km2(变化速率为-1.15 km2·a-1),冰川长度平均缩短了0.26 km(变化速率为-5.65 m·a-1),其中西段冰川长度相对变化速率明显快于东段,且2010—2016年冰川退缩速率明显快于1970—2010年,气温升高是导致阿尔金山冰川退缩的主要原因。冰川长度与冰川面积、周长有较强的相关性,冰川长度变化与冰川消融区面积变化及末端海拔上升有较强的正相关关系,即冰川消融区面积减少越多,冰川末端海拔上升越高,冰川末端长度的减少值也越大。  相似文献   

16.
祁连山冰川融水是维系我国西北地区生态平衡的重要因素。为评估祁连山冰川在全球气候变暖背景下的状态, 利用Landsat-TM、 ETM+、 OLI等遥感影像, 基于波段比值阈值法提取1987 - 2018年共计7期冰川边界进行时序变化分析。结果显示: 近31年来祁连山冰川面积从2 080.39 km2退缩到1 442.09 km2, 年均退缩率达0.99%, 相比1956 - 1990年间的退缩率(0.58%)大幅增加; 近31年来冰川物质平衡线高度稳步上升; 冰川主要分布在海拔4 700 ~ 5 100 m之间, 冰川退缩随海拔降低而增加; 约93%的冰川的面积小于2.0 km2, 小于0.1 km2的冰川的总数和总面积呈增加态势; 0.5 ~ 1.0 km2的冰川退缩最快, 年均退缩率达1.53%, 而大于10.0 km2的冰川退缩最慢, 年均退缩率为0.59%; 祁连山冰川退缩主要由夏季均温升高引起, 且最近十年间冰川呈现出加速退缩的态势。  相似文献   

17.
利用2000年的Landsat5遥感数据、1970年和2009年的冰川编目数据, 对天山中段南坡开都河流域和北坡玛纳斯河流域的冰川变化进行了对比分析, 并结合地面气象站点数据分析了冰川对气候变化的响应及南北坡冰川变化的差异性. 研究表明: 1970-2009年间, 两流域冰川面积减少了494.33 km2, 占总面积的26.8% (0.8%·a-1); 冰川储量减少了32.73 km3, 占总储量的27.9% (0.8%·a-1). 其中, 2000-2009年冰川面积和冰储量年退缩率(1.3%·a-1)比1970-2000年(0.6%·a-1)大; 冰储量减少的速率略大于面积缩小的速率, 说明冰川面积缩小的同时, 其厚度在迅速减薄. 1970-2000年和2000-2009年间, 玛纳斯河流域的冰川年均面积退缩率分别为0.5%·a-1和1.4%·a-1, 开都河流域的冰川年均面积退缩率为0.9%·a-1和1.1%·a-1, 显示出玛纳斯河流域冰川在2000年后呈加速萎缩趋势. 影响研究区冰川变化的主因是气温, 而夏季升温幅度及降水的不同是造成南北坡冰川差异性变化的重要原因.  相似文献   

18.
以长江源各拉丹冬为研究区,针对该地区地物特点,选取了1986—2015年间云量较少、成像质量较高的相关卫星影像作为数据源,在充分了解环境特征与影像特点的基础上,基于“波段阈值比值法”,通过人机交互调整阈值,对大范围冰川区域进行快速边界提取,并基于提取结果,结合数字高程数据、气象数据等相关数据展开了分析。结果表明:1986—2015年间研究区冰川面积减小92.06 km2,减少速率为0.33%·a-1;其中1986—1994年、1994—2001年、2001—2009年、2009—2015年分别减少32.95 km2、27.37 km2、13.11 km2和18.63 km2,减少速率分别为0.47%·a-1、0.41%·a-1、0.17%·a-1和0.34%·a-1。同时,依据空间组织方式进行了研究区冰川变化的分区分析,结果表明在不同分区、不同规模上该地区冰川变化呈现出不同的趋势;部分区域内冰川的降级、分裂现象较为明显,对不同等级规模冰川的变化趋势有一定影响。研究区冰川面积的坡向变化以东南向退缩最剧烈,西向增加最多。典型冰川方面,岗陇加玛冰川2001—2009年为面积退缩最为剧烈,1994—2001年面积略有增加。研究时段内冬季降水量逐年减少,不足以弥补因为气温升高导致的快速消融。  相似文献   

19.
利用SRTM DEM和ASTER立体像对数据获取的DEM分析了2000—2020年兴都库什东部的冰川物质平衡,并结合CRU TS 4.04气象数据探讨了气温、降水、地形和冰湖对南、北冰川区物质平衡空间差异的影响。结果表明:2000—2020年兴都库什东部冰川区物质平衡为(-0.02±0.04) m w.e.·a-1,冰川整体呈现微弱的负物质平衡状态。从坡向来看,南坡以正物质平衡冰川居多,北坡以负物质平衡冰川居多。从南、北两个子区域来看,北部冰川区物质平衡为(0.07±0.04) m w.e.·a-1,南部冰川区物质平衡为(-0.32±0.04) m w.e.·a-1。北部冰川面积规模大,所处海拔区间高,南部则相反。北部冰川区处于较高的海拔区间且冬季气温较低,导致夏季升温所产生的冰川消融的影响被削弱,冰川物质平衡的分布与降水分布在空间上具有一致性。南部冰川区出现的强烈物质亏损主要是由于夏季气温的急剧升高和冰川处于较低的海拔区间。南、北区域冰前湖和冰面湖面积不断扩大的空间差异性,也在一定程度上加剧了该地区冰川物质平衡的空间差异。  相似文献   

20.
深入了解全球变暖背景下青藏高原东南部海洋型冰川的变化趋势及其对气候变化的响应,对认识不同类型冰川对气候变化的响应方式有重要意义。根据Landsat系列遥感影像和数字高程等数据提取了青藏高原东南部雀儿山地区1987—2016年期间多年的冰川边界,并对其变化过程和特征进行了分析。结果表明:1987—2016年雀儿山地区冰川面积持续减小,变化率为(-1.69±0.87)%·a-1,为青藏高原众多山系中变化最大的之一。研究区冰川消融主要发生在规模<1 km2的小型冰川及海拔5 200 m以下的冰川消融区,其中西南方向的冰川退缩速率最大。气象数据分析结果显示,1987—2016年雀儿山地区夏季平均气温总体上升了1.58 ℃,平均升温速率为0.33 ℃?(10a)-1。由于夏季平均气温与冰川变化过程有显著的相关性,而同期年降水量无明显变化,由此推测,夏季平均气温的上升是雀儿山地区冰川快速退缩的主因。此外,相对于单纯基于光谱特征提取冰川信息,结合地形阴影模拟数据进行遥感冰川分类在一定程度上可以提高分类精度。  相似文献   

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