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1.
Tons basin has the maximum share of glaciers, more than 50 glaciers, as well as glacierised area in Uttarakhand and Himachal Pradesh and the majority of the glaciers are of valley type. One of the important features of the glaciers of Tons valley is the presence of a thick mantle of supraglaciers moraine cover which can be attributed to the terrain characteristics, besides, the avalanche fed nature of the glaciers. The present study is the extraction of Glacio-geomorphological unit of Tons River basin based on the visual interpretation of remote sensing data. It was very much difficult in field, to extract all glacio-geomorphological units in glaciated area, but based on the remote sensing data, it becomes easy to identify. With the help of glacio-geomorphological map it has been found that four most important glaciers which fed the Tons River are Bandarpunch Glacier, Jaundar Bamak glacier, Jhajju Bamak and Tilku glacier. The tributaries of Tons River i.e. Harkidun Gad, Rupin Nadi and Supin Nadi are mainly fed by the mountain glaciers, valley glaciers and glacier lakes. The erosional terraces, glacio-fluvial terraces, open ??U?? shaped valleys, proglacial lake, lateral moraines, terminal moraines, palaeo-cirque and debris/talus cones are well developed in this glaciated regions. Glacio-geomorphic features are very much significant for palaeo-climatic reconstruction, showing variations, temporally and spatially. At the same time, these landforms, which are also altered by processes prevailing during interglacial period, helps in the geo-environment studies and glacier related problems like avalanches, global warming and cloudburst etc.  相似文献   

2.
The study of advancement and recession of the glaciers in the Himalayas is essential due to their contrasting response towards climatic change. In the present study, Survey of India (SOI) topographical maps of 1962, IRS: LISS-III image of 2001 and LANDSAT-5: TM (Thematic Mapper) image of 2009 were used to analyze the glacier fluctuations in a part of Zanskar valley. The analysis carried out on 212 glaciers indicated decrease of 57 km2 (8 %) of glacier area over many glacier which was partly compensated with area increase by 42 km2 (6 %) in other glaciers, resulting an overall glacier area decrease by only 15 km2 (2 %) from 1962–2001. Due to glacier fragmentation the number of glaciers increased from 212 in 1962 to 238 by 2001. Although majority of glaciers (88 %) exhibited retreat (up to 13 my?1), minor advancement (<15 my?1) also took place in few glaciers during this period. Advancement took place mainly in larger glaciers (2–5 km2 and >5 km2) located over wider altitudinal range (700 m–1,000 m) whereas smaller glaciers (<2 km2) with narrow altitudinal range (100 m–500 m) exhibited retreat. The supraglacial debris analysis indicated that percentage of debris cover over glaciers ranges from 1.43 % to 18.15 %. Smaller glaciers (<2 km2) were debris free in comparison to the larger glaciers (>5 km2). During 2001–2009 majority of the glaciers were apparently stable in terms of their area and snout position indicating less impact of climate forcing in parts of Zanskar valley as compared to other parts of the Himalaya.  相似文献   

3.
The Himalayas has one of the largest concentrations of glaciers outside the Polar Regions. Various reports suggest that significant number of mountain glaciers is shrinking due to climatic variations. Monitoring of these glaciers is important to assess future availability of water resources in the Himalayan region. However, Himalayan glaciers are normally difficult to monitor due to the rugged, mountainous terrain. Therefore, images of Indian Remote Sensing Satellite were used to monitor glaciers in the Baspa basin. Investigations have shown the presence of 30 glaciers in the basin, with areal extent of 167 km2. Out of these, 19 glaciers, with areal extent of 140 km2 were selected to estimate retreat. Investigation suggests that almost all glaciers are retreating in the study basin and overall 19% deglaciation has been observed from 1962 to 2001. In general, altitude distribution appears to have significant influence on glacial retreat. Glaciers located around 5000 m altitude range are showing 24% loss as compared to 14% by glaciers located in altitude range higher than 5400 m. In addition, mean altitude of glacier terminus is shifted upward by 88 m, i.e. from 4482 to 4570 m in last 39 years. The glacial volumes were estimated using regression relationship between area and depth. The investigations have suggested that 19.10 km3 of glacial water stored in the 19 glaciers in 1962, has been reduced to 14.71 km3 in 2001, respectively, an overall loss of 23 percent in a period between 1962 and 2001. These investigations suggest that all glaciers in the Baspa Basin are reducing and in long term, such reducing trend can create scarcity of water in the region.  相似文献   

4.
Himalayas possess one of the largest resources of snow, ice and glaciers that act as a huge freshwater reservoir. Monitoring the glaciers is important to assess the overall reservoir health of the Himalayas. Samudra Tapu is one of the largest glaciers in Chandra basin of district Lahaul and Spiti, Himachal Pradesh. Based on the field investigations and the remote sensing techniques. features such as accumulation area, ablation area snowline/equilibrium line, moraine-dammed lakes and permanent snowfields were mapped. The glacial terminus was identified using moraine-dammed lake, as lake is located at down streamside of the terminus. The total recession of glacier during the period of 38 years (1962–2000) is about 742 m with an average rate of 19.5 m/yr. In addition, glacial extent is reduced from 73 to 65 km2 between 1962 and 2000. suggesting overall deglaciation of 11%. During field investigation. three stages of glaciation using terminal moraine were identified. These moraines were mapped by merging LISS-II1 and PAN data. At the peak of glaciation. the glacial terminus was extended 3.18 km downstream of terminus position in year 2000. Total area during peak of glaciation period has been observed to be 77.67 km2, which is 12.67 km2 higher than the present glacier extent.  相似文献   

5.
Snow physical properties, snow cover and glacier facies are important parameters which are used to quantify snowpack characteristics, glacier mass balance and seasonal snow and glacier melt. This study has been done using C-band synthetic aperture radar (SAR) data of Indian radar imaging satellite, radar imaging satellite-1 (RISAT)-1, to estimate the seasonal snow cover and retrieve snow physical properties (snow wetness and snow density), and glacier radar zones or facies classification in parts of North West Himalaya (NWH), India. Additional SAR data used are of Radarsat-2 (RS-2) satellite, which was used for glacier facies classification of Smudra Tapu glacier in Himachal Pradesh. RISAT-1 based snow cover area (SCA) mapping, snow wetness and snow density retrieval and glacier facies classification have been done for the first time in NWH region. SAR-based inversion models were used for finding out wet and dry snow dielectric constant, dry and wet SCA, snow wetness and snow density. RISAT-1 medium resolution scan-SAR mode (MRS) in HV polarization was used for first time in NWH for deriving time series of SCA maps in Beas and Bhagirathi river basins for years 2013–2014. The SAR-based inversion models were implemented separately for RISAT-1 quad pol. FRS2, for wet snow and dry snow permittivity retrieval. Masks for layover and shadow were considered in estimating final snow parameters. The overall accuracy in terms of R2 value comes out to be 0.74 for snow wetness and 0.72 for snow density based on the limited ground truth data for subset area of Manali sub-basin of Beas River up to Manali for winter of 2014. Accuracy for SCA was estimated to be 95 % when compared with optical remote sensing based SCA maps with error of ±10 %. The time series data of RISAT-1 MRS and hybrid data in RH/RV mode based decompositions were also used for glacier radar zones classification for Gangotri and Samudra Tapu glaciers. The various glaciers radar zones or facies such as debris covered glacier ice, clean or bare glacier ice radar zone, percolation/refreeze radar zone and wet snow, ice wall etc., were identified. The accuracy of classified maps was estimated using ground truth data collected during 2013 and 2014 glacier field work to Samudra Tapu and Gangotri glaciers and overall accuracy was found to be in range of 82–90 %. This information of various glacier radar zones can be utilized in marking firn line of glaciers, which can be helpful for glacier mass balance studies.  相似文献   

6.
随着全球气候变暖,中亚地区大部分冰川逐渐变薄。高海拔山地冰川的变化会影响到周边地区的水资源和海平面变化,因此,我们需要高精度的地表高程观测数据来监测冰面高程变化。本文以喜马拉雅山脉西段的纳木那尼冰川为例,基于CryoSat-2卫星雷达高度计SARIn模式数据,修改了伪重复轨平面拟合方法,并计算了从2010年8月至2016年7月的冰面高程变化。纳木那尼冰面平均高程变化率为-0.47±0.44 m/year,整体呈现变薄趋势,与前人文献的结果基本一致,表明CryoSat-2数据在山地冰川使用伪重复轨平面方法估算高程变化有效可行。  相似文献   

7.
An attempt has been made to study variations in the glacier extent over a period of time using digital elevation model (DEM) and orthoimages derived from IRS-1C PAN stereo pairs of 1997–98 and topographical map surveyed during 1962–63. DEM and orthoimages have been generated using integrated software developed for processing of IRSIC/ID panchromatic stereo data using the softcopy photogrammetric workstation. Case studies of two glaciers, i.e. the Janapa garang and Shaune garang glaciers of the Basapa basin, a sub-basin of Satluj River in India, have been presented here. Generation of DEM has been followed by the estimation of its accuracy. PAN images were interpreted for identification of the snout of the glaciers. The geographical locations of the snouts on the images were compared with the location as mapped on the topographical map of the study area. To verify satellite observations, field investigations were carried out at Shaune garang glacier area. The Janapa garang and the Shaune garang are observed to have retreat of 596m and 923 m respectively. Reduction in the thickness of ice in the deglaciated part of the Shaune garang glacier was estimated on the basis of change in the elevations of the glacial surface from 1963 to 1998.  相似文献   

8.
受全球气候变化的影响,近年来中国藏东南及横断山脉多数冰川物质持续亏损、运动速度减缓,导致泥石流、滑坡等灾害频发。为突破光学遥感受气候条件制约的瓶颈,联合卫星合成孔径雷达（synthetic aperture radar,SAR）和地基SAR两种技术手段,选取海螺沟冰川作为典型研究区域,开展时序监测分析。基于对近11 a间获取的38景PALSAR系列影像的像素偏移统计表明,海螺沟1号冰川粒雪盆和冰瀑布上沿区域整体运动最快,最大速度超过2 m/d;在海拔2 900~3 900 m的冰舌区,冰川运动趋缓,速度降至0.1~0.4 m/d;随着季节更替,海螺沟冰川运动速度呈周期性波动,积累区的夏冬两季差异为25%~35%,而冰舌段的差异则高达4倍。在年际变化方面,海螺沟1号冰川的运动速度平均减缓率为每年7.27%,消融区内减缓率高达每年15.57%。同时,使用像素偏移追踪和Stacking-InSAR（interferometric SAR）方法在海螺沟U型谷北坡探明了多处不稳定滑坡体,统计分析表明,此类滑坡运动与冰川消融具有强相关性,滑移速度于每年夏季达到峰值,2018年度最大滑移速度为南北向100 mm/d、东西向50 mm/d。进一步分析地基雷达的高频实时监测数据,确定该滑坡体的滑移速度在2018-07-09达到峰值（150 mm/d）,并于随后失稳垮塌,详细展现了整个蠕变致灾过程。相关研究数据及监测结果可为冰冻圈及山地灾害研究提供参考。  相似文献   

9.
Glaciers are widely recognized as key indicators of climate change, and melt water obtained from them is an important source of fresh water and for hydropower generation. Regular monitoring of a large number of Himalayan glaciers is important for improving our knowledge of glacier response to climate change. In the present study, Survey of India topographical maps (1966) and Landsat datasets as ETM+ (2000, 2006) and TM (2011) have been used to study glacier fluctuations in Tirungkhad basin. A deglaciation of 26.1% (29.1?km2) in terms of area from 1966 to 2011 was observed. Lower altitude small glaciers (area?<?1?km2) lost more ice (34%), while glaciers with an area <10?km2 lost less (20%). The percentage of change in glacier length was 26% (31.9?km) from 1966 to 2011. The south-facing glaciers showed high percentages of loss. From 2000 to 2011, debris cover has increased by 1.34%. The analysis of the trend in meteorological data collected from Kalpa and Purbani stations was carried out by Mann Kendall non-parametric method. During the last two decades, the mean annual temperature (Tmax and Tmin) has increased significantly, accompanied with a fall in snow water equivalent (SWE) and rainfall. The increasing trend in temperature and decreasing trend in SWE were significant at 95% confidence level. This observation shows that the warming of the climate is probably one of the major reasons for the glacier change in the basin.  相似文献   

10.
针对青藏高原冰川高程变化研究较少的问题,该文提出一种大范围区域的冰川高程变化监测方法。基于ICESat激光高度计数据,联合利用SRTM DEM数据,计算念青唐古拉山脉冰川的高程变化,进而反演冰川的冰量变化。结果显示,念青唐古拉山冰川高程在2003—2009年间平均减薄速率为(0.53±0.47)(m·a~(-1)),估算得到冰量年均减少(0.32±0.28)km~3,总体呈逐年减少趋势,证明冰川一直处于消融状态。拉萨和当雄气象站的资料表明,冰川消融主要是由于当地气温升高。  相似文献   

11.
Dokriani Glacier is regarded as one of the important glaciers of Bhagirathi River basin, which fed river Ganges. The length of the glacier is about 4.6 km, and snout elevation is about 4028 m m.s.l. The mass balance of this glacier was calculated using field-based measurements for few years during 1994 to 2000. However, due to remote and poor accessibility, the field-based measurements could not continue; thus, remote sensing-based methods become useful tool to estimate the long-term mass balance of the glacier. In this study, glacier mass balance has been determined using accumulation area ratio (AAR) method. Remote sensing data sets, e.g. Landsat TM, ETM?+?and OLI, have been used to estimate AAR for different years from 1994 to 2014. An attempt has also been made to develop a mathematical relationship between remote sensing-derived AAR and field-observed mass balance data of the glacier. Further, this relationship has been used to estimate mass balance of the glacier for different years using remote sensing-derived AAR. Estimated mass balance was validated from ground-observed mass balance for few years. The field-observed and remote sensing-derived mass balance data are compared and showed high correlation. It has been observed that AAR for the Dokriani Glacier varies from 0.64 to 0.71. Mass balance of the glacier was observed between ??15.54 cm and ??50.95 cm during the study period. The study highlights the application of remote sensing in mass balance study of the glaciers and impact of climate change in glaciers of Central Indian Himalaya.  相似文献   

12.
A total of 125 glaciers covering an area of 1896 sq. km. were mapped on 1:250,000 scale in Himachal Pradesh using satellite images. The areal extent obtained from satellite images was found to be comparable with that from field estimates for eight glaciers for which data are available. This suggests that remote sensing can provide glacial areal extent similar to ground-based methods. Depth of an individual glacier was inferred indirectly by using its relationship with areal extent and geomorphological characteristics, as suggested by Muller (1970). These characteristics were estimated by using satellite images. The analysis suggests that the water equivalent of the glaciers in Himachal Pradesh is about 165 cu km. It is seventeen times more than the storage capacity of the Govind Sagar. This estimate will get revised when other snow/ice features as permanent snow field, ice apron, hanging glaciers and rocky glaciers are mapped. Mapping on larger scale, say 1:50,000, will lead to a further revision as many smaller glaciers and other features will get mapped.  相似文献   

13.
The importance of mass wasting in glacier environments and its impacts on glacier dynamics is not fully understood. This is the first occurrence of a debris avalanche event onto a Himalayan glacier through satellite data analysis. The analysis of various factors indicates the slide was a climate-driven hill-slope event activated in 2009 masking the Miyar glacier surface up to ~1.5% including its both lateral moraines and medial moraines. Due to this addition the glacier had neither advance nor retreat from 2009 to 2014. Eventually the debris will contribute to the supraglacial and englacial debris of the glacier. This showcases the way of mass wasting an important contribution to the debris budget of the Himalayan glaciers.  相似文献   

14.
Peri-glacial studies of the Samudra Tapu glacier reveal three stages of well preserved moraines which are also marked by fluvial overprinting. The signatures of fluvial outwashes over the otherwise morainal deposits have been utilized in estimating the extent of palaeo-lake in the valley of Samudra Tapu glacier of the Chandra basin. Distance and thickness of snout of the glacier and its morainal deposits is estimated by the Laser Range Finder. With the change in the position of the snout there is a change in the extent and orientation of the lake. Recent expedition to the glacier confirms this process to be continuing. The study is important in reconstructing formation of the lake with respect to snout position of the glacier. Based on ground truth, fast melting of the snout is confirmed from year 2004 onwards, with the development of fresh end/terminal moraine. The study reveals that the snout region of the Samudra Tapu glacier is thinning and retreating at an alarming rate and is enlarging the lake extent. The development of fresh terminal moraine has the potential to impound the fast melting glacial waters which in turn can pose serious threat to the downstream regions of the Chandra valley.  相似文献   

15.
Countries like Iran, which are geographically situated in a rather arid and warm regions, will suffer more from global warming than countries located in humid and semi-humid regions. In such environments, analyzing the variations of mountain glaciers can reveal several aspects of climate change patterns more efficiently in comparison to the other geo-indicators. The present study reports some evidence of changes for Alamkouh glacier between 1955 and 2010 based on several mediums to high-resolution satellite images. Considering that most part of the Alamkouh glacier is covered by debris and delineating its actual area is not possible, planimetric change analysis was restricted to the clean-ice regions. The object-oriented classification approach was used to estimate the clean ice areas. This technique takes into account the shapes of the features along with their spectral patterns. Results revealed that clean ice regions of Alamkouh glacier shrank since 1955 with an overall area reduction of about 59 %. Although the general observed trend is a clean ice area reduction, some advancement was detected over the period from 2000 to 2010. During 1992–2000, the maximum reduction in the clean ice area was observed (0.08 km2.a?1). However, clean ice area of the case study has partially increased about 0.028 km2.a?1 from 2000 to 2010. Supra-glacial lake change analysis illustrated that at the surface of the glacier, lakes have been enlarged remarkably in the past 55 years (about 4.75 times greater). In addition, clean ice area and the surface area of supra-glacial lakes oscillated in compliance with each other. The findings revealed that the maximum expansion of supra-glacial lake occurred during 1992–2000, which demonstrate the glacier maximum reduction during this period. This shrinkage in the Alamkouh glacier caused an extensive glacial lake outburst flood in Jun 2011. The results of this study agree with documented changes in other mountain glaciers located in arid and semi-arid environments and they also confirm the application of mountain glaciers in climate variations monitoring over such regions.  相似文献   

16.
高山冰川遥感提取方法研究   总被引：1，自引：0，他引：1  
遥感的应用使得对冰川大尺度全覆盖、多时相变化的监测成为可能,然而冰川信息遥感提取方法的误差大等难题成为影响冰川监测的障碍。本文综合分析比较了目前已有的多种冰川提取方法的有效性,得出提取冰川范围精度最高的是面向对象的目视判读方法,其次是最大似然法监督分类、面向对象的自动分类、比值阈值法、雪盖指数法等。各自动方法提取冰川面积均有较大误差,且误差主要出现在冰舌末端、阴影区、薄冰区和云层遮盖范围等区域。本文将面向对象的目视判读法应用于冰川提取中,在保证信息提取精度的同时提高了传统解译的效率。  相似文献   

17.
Moraine-dammed lakes are normally formed near glacier terminus. These lakes can burst due to excessive melting and can cause floods in the valleys. Many such floods have been reported in the Himalayas and other parts of the World. In this paper, an inventory of these lakes in the Satluj and the Chenab basins has been reported. During the investigation, 22 lakes in the Satluj and 31 lakes in the Chenab basin were mapped. In the Chenab basin, two lakes are of very large size, their areal extent is 105 and 55 ha, located in toposheet number 52 HI 1 and 52H02, respectively. These lakes were selected for detail monitoring. The lake near the Geepang glacier, is located in toposheet number 52H 02 and its area was 27 ha in 1976. Using the satellite data, areal extent of the lake was monitored. The lake area was almost doubled to 55 ha in 2001. This suggested that, lake size is constantly increasing and it can cause outburst flood. The maximum possible depth of lake was estimated by taking the average difference of maximum and minimum height of moraine dam from the Survey of India toposheet. By considering the average depth, the volume of the lake water and the instantaneous discharge of 350 mVsec were estimated. This is large discharge for a small stream like the Geepang Gath and it can damage many civilian and defense establishments. Therefore, further detail field investigations of this lake are needed to assess threat potential and to develop strategy to avoid this flash flood.  相似文献   

18.
Himalayan region has high concentrations of mountain glaciers. Large extent of this region is covered by seasonal snow during winter. Runoff generates from melting of these snow and glaciers is one of the important sources of water for the Himalayan Rivers. Glaciers and snowfields are distributed throughout the Himalayas and form a source of numerous streams. Due to steep slopes, all such streams have potential sites for hydropower generation. If this potential is fully utilized, it will help in generating power from environmentally friendly Run-of-River (RoR) hydropower stations. Considering these aspects, a stream flow simulation model was developed for small streams. This will help in estimation of average seasonal unrestricted hydropower potential of snow and glaciated streams for winter, summer, monsoon and autumn seasons. Information generated through remote sensing technique as glacier, permanent snow cover, seasonal snow cover, altitude of snow and glaciers were used in conjunction with daily maximum and minimum temperature, rainfall and discharge. The model was developed for Malana nala located in Parbati River basin near Kullu in Himachal Pradesh. It was validated at adjacent Tosh nala in the same basin. Seasonal runoff computed from the model is comparable with observed data for all seasons except Monsoon. Good results in autumn, winter and summer seasons demonstrates usefulness of runoff model to assess hydropower potential of snow and glaciated streams and therefore, the model was applied to ungauged Sorang Gad and Kirang Khad. In winter runoff was estimated as 1.8 and 1.69 cumecs for Kirang Khad and Sorang Gad, respectively. This is important, as viability of hydropower station depends upon winter stream runoff. These results suggest that the model is useful tool to assess initial estimate of hydropower potential for large number of snow and glaciated streams, for which no hydrological data is available.  相似文献   

19.
Glaciers are natural reservoirs of fresh water in frozen state and sensitive indicators of climate change. Among all the mountainous glaciated regions, glaciers of Himalayas form one of the largest concentrations of ice outside the Polar Regions. Almost all the major rivers of northern India originate from these glaciers and sustain perennial flow. Therefore, in view of the importance and role of the glaciers in sustaining the life on the Earth, monitoring the health of glaciers is necessary. Glacier??s health is monitored in two ways (i) by mapping the change in extent of glaciers (ii) by finding variation in the annual mass balance. This paper has been discussed the later approach for monitoring the health of glaciers of Warwan and Bhut basins. Mass balance of glaciers of these two basins was determined based on the extraction of snow line at the end of ablation season. A series of satellite images of AWiFS sensor were analysed for extraction of snowline on the glaciers for the period of 2005, 2006 and 2007. The snow line at the end of ablation season is used to compute accumulation area ratio (AAR = Accumulation area/Glacier area) for each glacier of basins. An approach based on relationship of AAR to specific mass balance (computed in field) for glaciers of Basapa basin was employed in the present study. Mean of specific mass balance of individual glacier for the year 2005, 2006 and 2007 of Warwan basin was found to be ?ve 0.19?m, ?ve 0.27?m and ?ve 0.2?m respectively. It is 0.05?m, ?ve 0.11?m and ?ve 0.19?m for Bhut basin. The analysis suggests a loss of 4.3 and 0.83?km3 of glacier in the monitoring period of 3?years for Warwan and Bhut basins respectively. The overall results suggest that the glaciers of Warwan basin and Bhut basins have suffered more loss of ice than gain in the monitoring period of 3?years.  相似文献   

20.
控制点布设对冰川区无人机摄影测量精度的影响   总被引：2，自引：0，他引：2  
冰川监测是冰冻圈科学研究中的一项重要基础内容,获取高质量冰川DEM和DOM数据是研究的基础。随着无人机技术的兴起,给冰川监测提供了全新的技术手段,然而冰川区开展无人机摄影测量时,地面控制点的布设与测量成为能否获取高精度数据产品的关键,而山地冰川往往伴随着地形复杂,行走困难,野外实地测量难以全面实施等不利因素。本研究中以位于祁连山西段大雪山地区的老虎沟12号冰川末端部分为研究区域,设计实施了多种控制点布设方案,使用低空微型无人机飞行3个架次,获取研究区航摄影像。通过对比控制点在不同分布情况及数量情况下,DEM和DOM数据检查点的精度,评价不同控制点布设方案的可行性。对比结果显示,在航飞过程中使用单格网模式即可获取高精度的影像数据;实施地面控制作业时,使用5—7个控制点均匀分布在测量区即可获取较高精度的图像数据;当冰川区不能满足均匀布设控制点时,可沿冰川主流线布设足够数量的控制点,所得图像精度也可以满足冰川学研究要求;若只能在冰川中下部或者中上部布设控制点,则控制点应覆盖冰面起伏较大的区域。  相似文献   

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