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1.
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   

2.
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   

3.
Himalayan glaciers and their mass balance are poorly sampled through direct mass balance measurements. Thus, based on Landsat datasets of ETM+ (2000), ETM+ (2006) and TM (2011), mass balance studies of 32 glaciers was carried out using accumulation area ratio (AAR) method in the Tirungkhad river basin, a tributary of Satluj River, located in western Himalayan region. The overall specific mass balance was negative varying from ?27 cm (2000) to ?41 cm (2011). Out of 32 glaciers, 27 glaciers (81.2 %) showed negative mean mass balance and 5 glaciers (18.7 %) showed positive mean mass balance. Mean of specific mass balance for the year 2000, 2006 and 2011 was found to be ?48 cm, ?55 cm and ?0.61 cm respectively, in case of glaciers with negative mass balance while in case of glaciers with positive mass balance, it was 0.67 cm (2000), 0.56 cm (2006) and 0.47 cm (2011). The investigations suggested a loss of ?0.034 km3 of glacial ice for 2000, 0.036 km3 for 2006 and 0.038 km3 for 2011 respectively. The negative mass balance of the glaciers since 2000 correlates well with the increasing trend of annual mean temperature and decreasing trend of precipitation (snow water equivalent (SWE) and rainfall). Based on Mann Kendall test the temperature and SWE trends were significant at 95 % confidence level, however, the rainfall trend was insignificant.  相似文献   

4.
Detailed inventory of glacial lakes in a Glacial Lake Outburst Flood (GLOF) prone area is vital for disaster mitigation. Availability of cheaper high resolution satellite data from Indian remote sensing satellites enables us to create up-to-date inventory for use in prioritisation of glacial lakes for GLOF risk assessment. Earlier inventories show presence of more glacial lakes in Brahmaputra basin in Indian Himalaya. Teesta River is one of the tributary of Brahmaputra and previous studies have shown that the inventory of glacial lakes in Teesta basin varies from 143 to 320. In the present study, the inventory carried out using satellite data of years 2000, 2007 and 2014 show presence of 301 (25.789 km2), 302 (26.081 km2) and 644 (29.706 km2) glacial lakes in Teesta basin respectively. The steep increase in number of lakes in the latest inventory is primarily due to the finer spatial resolution of satellite data used. Analysis of water spread area of glacial lakes at different altitudes shows that most of the lakes in the higher altitudes are small in size. It is observed that more than 66% of lakes are in the altitude beyond 4500 m and of size less than 50,000 sqm (5 ha). Out of 301 glacial lakes inventoried during 2000, water spread area of 6 lakes have decreased in 2014 and 31 lakes have shown increase in area. Out of these 31 lakes, 17 lakes are classified as end moraine dammed lakes and among them, 14 are located in Upper Teesta sub-basin and in higher altitudes (beyond 5000 m). The prioritisation of these lakes for GLOF risk needs to be carried out with detailed field investigation.  相似文献   

5.
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   

6.
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   

7.
To account for the variable response of the Himalayan glaciers towards climatic warming during the recent past, an attempt has been made in the present study to evaluate the changes in glacier area and shift in glacier snout position of selected glaciers in a part of the Greater Himalayan Range (GHR), Jammu & Kashmir (J&K), India. Multi-temporal satellite images of different years viz. 1975, 1989, 1992, 2001 and 2007 were used for mapping the boundaries of glaciers. Among the three observation periods (1975–1989/1992, 1989/1992–2001 and 2001–2007), during 1989/1992–2001 the majority of the glaciers exhibited considerable decrease in area. In contrast during 2001–2007, some glaciers exhibited increase in area indicating comparatively cooler climatic conditions as compared to the previous period. With reference to snout retreat, all the glaciers had a fluctuating trend of retreat during the observation periods although the retreat rate was higher during 1989/1992–2001 in some glaciers.  相似文献   

8.
Using high-resolution Google EarthTM images in conjunction with Landsat images, the glaciers and lakes in the Baspa basin are classified to explore the recent changes. A total number of 109 glaciers (187 ± 3.7 km2) are mapped and subsequently classified as compound valley glaciers, simple valley glaciers, cirques, niches, glacieretes and ice aprons. The compound and simple valley glaciers contribute 67.1 ± 1.3% and 19.8 ± 0.3% to the total glacier cover of the basin. Similarly, a total number of 129 glacial lakes (0.360 ± 0.007 km2) are identified. From 1976 to 2011, the compound valley glaciers have lost a small area of 10.3 ± 0.03% at a rate of 0.41 ± 0.002 km2 a-1, whereas the niche glaciers have lost higher area of 40.1 ± 0.001% at a rate of 0.04 ± 0.0001 km2 a-1. Change detection of two benchmark glacial lakes revealed a progressive expansion during recent decades. The Baspa Bamak proglacial lake has expanded from 0.020 ± 0.0004 km2 (2000) to 0.069 ± 0.001 km2 (2011). Due to the complete loss of source ice, another glacial lake has expanded from 0.09 ± 0.001 km2 (1994) to 0.10 ± 0.002 km2 (2011). During the study period, the mean annual temperature that is Tavg, Tmin and Tmax have increased significantly at the 95% confidence level by 1.5 oC (0.070 °C a-1), 1.8 oC (0.076 °C a-1) and 1.6 oC (0.0071 °C a-1) from 1985 to 2008. However, the precipitation has decreased significantly from 1976 and 1985 to 2008.  相似文献   

9.
Abstract

This paper documents ongoing glacier retreat in the eastern part of the Granatspitz Mountains (Hohe Tauern Range, Austrian Alps) for the time period 2003–2009 using aerial photogrammetry. Aerial photographs of 2003, 2006, and 2009 were made available by the Hydrological Service of the Regional Government of Salzburg, the Federal Office of Metrology, Surveying and Mapping, Vienna, and the Regional Government of the Tyrol, respectively. High resolution multi-temporal digital elevation models and digital orthophotos of the area of interest were derived using digital photogrammetric methods to provide a sound basis for glaciological research. Glacier outlines of the three glacial stages were mapped interactively. Temporal change in area and surface height of the glaciers mapped clearly document glacier retreat. Glacier mass balance based on the geodetic method was calculated for Stubacher Sonnblickkees (Glacier). Mean annual specific net balance amounts to ?656 mm w.e. for the time period 2003–2009, with a mass balance gradient of 324 mm w.e. (100 m)?1 and an equilibrium-line altitude of 2995 m a.s.l. Digital orthophoto maps and other thematic maps, e.g. showing surface height change, were prepared to support further data interpretation. Both the study area and its spatio-temporal change were visualized with special emphasis on the glaciers in a computer generated video film. Another film (exposure 29 August 2011) shows the lower part of Stubacher Sonnblickkees and its surroundings for reasons of comparison.  相似文献   

10.
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   

11.
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   

12.
Seasonal snow melt in the Wind River Range, Wyoming, has been ending earlier over the last several decades leaving the region to rely more on supplemental melt water from mountain glaciers. This leads to the necessity of understanding recent glacial changes. This study uses elevation data from 1966, 2006 and 2011 to calculate surface elevation and volume changes that have occurred on Continental Glacier. Results indicate a mean volume change of ?0.034 ± 0.02 km3 and surface elevation change of ?0.36 ± 0.19 m y?1 between 1966 and 2006. Detailed spatial analysis shows that the glacier is divided into two sections which are thinning at different rates (lower section: ?0.06±0.19 m y?1; upper section: ?0.51 ± 0.19 m y?1). The upper section has experienced 97% of the thinning (or 742.5 × 103 m3 of melt water equivalent per year) and increased its rate since 2006 by 27.5%.  相似文献   

13.
Abstract

This paper presents the first measurement of multi-decadal thickness and volume changes (1969–2000) of the Dongkemadi Ice Field (DIF) in the Tanggula Mountains, central Qinghai-Tibetan Plateau, China, using multi-source remote sensing data. These include the Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM) acquired in February, 2000, a DEM generated by digitising analogue topographic maps from 1969, and Landsat ETM+ imagery from 2000. Digital glacier outlines and GIS-based processing were used to calculate an elevation difference map to evaluate the relative elevation error of these two DEMs over ice-free areas. This method was also used to identify regions of glacier elevation thinning and thickening corresponding to glacier mass loss and gain. Analysis of 67,520 points on flat grass and rock terrain surrounding the DIF, with a slope less than 25°, showed a mean elevation difference of –0.90 m and a standard deviation of 5.58 m. A thickness change error within ±6 m was estimated. Between 1969 and 2000, 76.51% of the whole DIF area appeared to be thinning while 23.49% showed thickening. The average glacier surface thinning was –12.58 m with a standard deviation of 18.29 m and the estimated volume loss was 1.17 km3. The standard deviation of volume change was 0.0006 km3 over the DIF. A thinning rate up to 0.41±0.194 m a?1 or 0.038 km3 a?1 for the volume loss was observed for the whole ice field, which seems to be evidence for the ongoing retreat of glaciers on the Qinghai-Tibetan Plateau. It was found that the spatial thickness change pattern derived from the remote sensing method was consistent with the thickness change results of the Small Dongkemadi Glacier (SDG) from field measurements. The estimated error of the annual thickness change rate was on the order of 5%. The relationship between elevation change and absolute glacier elevation over typical glaciers was also analysed, showing considerable variability. These changes have possibly resulted from increased temperature and decreased precipitation in this region.  相似文献   

14.
Himalayan region has one of the largest concentrations of mountain glaciers whose areal extent is changing due to global warming. In order to assess future changes in glacier extent due to global warming, information about glacier depth and debris cover is important. In this paper, application of ground penetrating radar (GPR) is discussed to assess glacier depth and debris cover. This investigation was carried out at Patseo and Samudratapu glaciers in Himachal Pradesh (West Himalaya). Antennas of frequency 50 and 100 MHz have been used for glacier depth and 500 MHz for moraine depth estimation. GPR signatures of glaciers were collected and further analyzed using velocities of electromagnetic waves in different media. The depth of Patseo glacier was estimated as 40 m. However, depth of the larger Samudra Tapu glacier could not be estimated using 50 and 100 MHz antennas. The depth of moraines was estimated using 500 MHz antenna and it varies from 0.35 cm to 0.85 cm for medial and around 1–2 m for lateral moraine at the experimental site.  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.
In the current study, the shuttle radar topography mission (SRTM) data, with～90 m horizontal resolution, were used to delineate the paleodrainage system and their mega basin extent in the East Sahara area. One mega-drainage basin has been detected, covering an area of 256 000 km2. It is classified into two sub mega basins. The Uweinate sub mega basin, which is composed of four main tributaries, collected water from a vast catchment region and drained eastward from the north, west, and southwest, starting at...  相似文献   

17.
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18.
Satellite Remote Sensing, with both optical and SAR instruments, can provide distributed observations of snow cover over extended and inaccessible areas. Both instruments are complementary, but there have been limited attempts at combining their measurements. We describe a novel approach to produce monthly maps of dry and wet snow areas through application of data fusion techniques to MODIS fractional snow cover and Sentinel-1 wet snow mask, facilitated by Google Earth Engine. The method is demonstrated in a 55,000 km2 river basin in the Indian Himalayan region over a period of ∼2.5 years, although it can be applied to any areas of the world where Sentinel-1 data are routinely available. The typical underestimation of wet snow area by SAR is corrected using a digital elevation model to estimate the average melting altitude. We also present an empirical model to derive the fractional cover of wet snow from Sentinel-1. Finally, we demonstrate that Sentinel-1 effectively complements MODIS as it highlights a snowmelt phase which occurs with a decrease in snow depth but no/little decrease in snowpack area. Further developments are now needed to incorporate these high resolution observations of snow areas as inputs to hydrological models for better runoff analysis and improved management of water resources and flood risk.  相似文献   

19.
以洪水坝河流域为例,利用1956年的地形图和2003年的ASTER遥感影像及数字高程模型,在GIS的支持下对两期数据进行统计分析,结果表明:近47年来,洪水坝河流域冰川面积减少了14.04%,长度退缩了17.28%,储量减少了2.26%。研究认为,气温显著升高是洪水坝河流域冰川快速萎缩的主要原因。在和祁连山地区、西藏以及天山地区的冰川进行对比后,发现研究区冰川消融的速率介于三地之间,初步推测是由研究区所在区域的气候和自身属性共同作用的结果。  相似文献   

20.
Haryana-Punjab plain (Yamuna-Sutlej interfluve) is part of the Indo-Gangetic foreland basin and makes the eastern part of the Indus River system. It is characterized by southwestern regional slope and is made up of sediments derived from the Himalayan front. The southern part of the Haryana-Punjab plain has a narrow northeast sloping surface, made up of sediments derived from the Rajasthan craton, making the peripheral bulge of the basin. The area of interaction of these two opposing slopes is marked by a rather flat region of poor drainage with a number of water bodies. This interactive zone of the two slopes has a constricted belt of westerly outlet merging in the Indus alluvial plain. The excessive sediments derived from the Himalayan front formed mega-fans, which in Late Pleistocene, extended down to 200 m altitude close to the southern limit of Haryana-Punjab plain. There are geomorphic evidence of punctuations in reduction in fan building activity during Late Quaternary with terminations at 225 and 300 m altitude, prominently seen in satellite imagery and Digital Elevation Model (DEM). The Haryana-Punjab plain also exhibits undulations with prominent highgrounds around Bhatinda, Hissar, and Sonipat-Jind. During the Late Quaternary, the streams of Yamuna-Sutlej interfluve region, viz., Dangri (sometimes referred as Tangri), Ghaggar-Saraswati, Markanda and Chautang, drastically reduced their carrying capacity due to reduced monsoon activity and neotectonic block movements. These streams abort within their terminal fans. Yamuna River is confined within its valley having prominent flood plain (T0) and well-developed Newer Alluvial plain (T1); as such it has not been a part of Indus system, at least during Holocene.  相似文献   

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