Glacier changes in the Garhwal Himalaya, India, from 1968 to 2006 based on remote sensing
01 Aug 2011-Journal of Glaciology (International Glaciological Society)-Vol. 57, Iss: 203, pp 543-556
TL;DR: In this article, the authors mapped the upper Bhagirathi and Saraswati/Alaknanda basins of the Garhwal Himalaya using Corona and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) satellite images acquired in 1968 and 2006, respectively.
Abstract: Glacier outlines are mapped for the upper Bhagirathi and Saraswati/Alaknanda basins of the Garhwal Himalaya using Corona and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) satellite images acquired in 1968 and 2006, respectively. A subset of glaciers was also mapped using Landsat TM images acquired in 1990. Glacier area decreased from 599.9 ± 15.6 km2 (1968) to 572.5 ± 18.0 km2 (2006), a loss of 4.6 ± 2.8%. Glaciers in the Saraswati/Alaknanda basin and upper Bhagirathi basin lost 18.4 ± 9.0 km2 (5.7 ± 2.7%) and 9.0 ± 7.7 km2 (3.3 ± 2.8%), respectively, from 1968 to 2006. Garhwal Himalayan glacier retreat rates are lower than previously reported. More recently (1990–2006), recession rates have increased. The number of glaciers in the study region increased from 82 in 1968 to 88 in 2006 due to fragmentation of glaciers. Smaller glaciers ( 50 km2) which lost 2.8 ± 2.7% (0.074 ± 0.071 % a−1). From 1968 to 2006, the debris-covered glacier area increased by 17.8 ± 3.1% (0.46 ± 0.08% a−1) in the Saraswati/Alaknanda basin and 11.8 ± 3.0% (0.31 ± 0.08% a−1) in the upper Bhagirathi basin. Climate records from Mukhim (∼1900 m a.s.l.) and Bhojbasa (∼3780 m a.s.l.) meteorological stations were used to analyze climate conditions and trends, but the data are too limited to make firm conclusions regarding glacier–climate interactions.
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TL;DR: The contemporary evolution of glaciers in the Himalayan region is reviewed, including those of the less well sampled region of the Karakoram to the Northwest, in order to provide a current, comprehensive picture of how they are changing.
Abstract: Himalayan glaciers are a focus of public and scientific debate. Prevailing uncertainties are of major concern because some projections of their future have serious implications for water resources. Most Himalayan glaciers are losing mass at rates similar to glaciers elsewhere, except for emerging indications of stability or mass gain in the Karakoram. A poor understanding of the processes affecting them, combined with the diversity of climatic conditions and the extremes of topographical relief within the region, makes projections speculative. Nevertheless, it is unlikely that dramatic changes in total runoff will occur soon, although continuing shrinkage outside the Karakoram will increase the seasonality of runoff, affect irrigation and hydropower, and alter hazards.
1,561 citations
TL;DR: Satellite laser altimetry and a global elevation model are used to show widespread glacier wastage in the eastern, central and south-western parts of the HKKH during 2003–08 and show indirect evidence of a complex pattern of glacial responses in reaction to heterogeneous climate change signals.
Abstract: Glaciers are among the best terrestrial climate indicators, an important water resource in mountains1,2 and a major contributor to global sea level rise3,4. In the Hindu Kush - Karakoram - Himalaya region (HKKH), a paucity of appropriate glacier data has prevented a comprehensive assessment of current regional mass balance5. However, there are indirect evidences of a complex pattern of glacial responses5-8 in reaction to heterogeneous climate change signals9. Here, we provide the first coherent data set of detailed glacier thickness changes over the HKKH during 2003-2009 by combining satellite laser altimetry and a global elevation model. In the eastern, central and south-western parts of the HKKH, glacier wastage is widespread with regional thinning rates up to 0.66 ± 0.09 m a-1 in the Jammu-Kashmir region. Conversely, in the Karakoram, glaciers are close to balance with only a slight thinning of 0.07 ± 0.04 m a-1. Regionally averaged thinning rates under debris-mantled ice are similar to those of clean ice despite insulation by debris covers. The 2003-2008 specific mass balance for our HKKH study region is -0.21 ± 0.05 m a-1 water equivalent (WE), significantly less negative than the global average of ~ -0.7 m a-1 WE for glaciers and ice caps4,10. This difference is mainly an effect of the balanced glacier mass budget in the Karakoram. The corresponding HKKH sea level contribution is +0.035 ± 0.009 mm a-1 amounting to 1% of the present-day sea level rise11. Our 2003-2008 mass budget of -12.8 ± 3.5 Gt a-1 is more negative than recent satellite gravimetry based estimates of -5 ± 6 Gt a-1 over 2003-2010 (ref. 12). For the mountain catchments of the Indus and Ganges basins13, the glacier imbalance contributes ~3.5% and ~2.0%, respectively, to the annual average river discharge13, and up to ~10% for the Upper Indus basin14.
961 citations
TL;DR: In this article, the authors present a time series of mass changes for ten glaciers covering an area of about 50 km2 south and west of Mt. Everest, using stereo Corona spy imagery (years 1962 and 1970), aerial images and recent high resolution satellite data (Cartosat-1).
Abstract: . Mass loss of Himalayan glaciers has wide-ranging consequences such as changing runoff distribution, sea level rise and an increasing risk of glacial lake outburst floods (GLOFs). The assessment of the regional and global impact of glacier changes in the Himalaya is, however, hampered by a lack of mass balance data for most of the range. Multi-temporal digital terrain models (DTMs) allow glacier mass balance to be calculated. Here, we present a time series of mass changes for ten glaciers covering an area of about 50 km2 south and west of Mt. Everest, Nepal, using stereo Corona spy imagery (years 1962 and 1970), aerial images and recent high resolution satellite data (Cartosat-1). This is the longest time series of mass changes in the Himalaya. We reveal that the glaciers have been significantly losing mass since at least 1970, despite thick debris cover. The specific mass loss for 1970–2007 is 0.32 ± 0.08 m w.e. a−1, however, not higher than the global average. Comparisons of the recent DTMs with earlier time periods indicate an accelerated mass loss. This is, however, hardly statistically significant due to high uncertainty, especially of the lower resolution ASTER DTM. The characteristics of surface lowering can be explained by spatial variations of glacier velocity, the thickness of the debris-cover, and ice melt due to exposed ice cliffs and ponds.
386 citations
Cites background from "Glacier changes in the Garhwal Hima..."
...Corona and Hexagon data are also of high value for mapping glaciers and investigating area changes (Bhambri et al., 2011; Bolch et al., 2010; Narama et al., 2010)....
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University of Calgary1, ETH Zurich2, Cooperative Institute for Research in Environmental Sciences3, Swiss Federal Institute for Forest, Snow and Landscape Research4, University of Washington5, University of Zurich6, University of Potsdam7, United States Geological Survey8, University of Minnesota9, University of Graz10, University of Natural Resources and Life Sciences, Vienna11, University of Toulouse12, University of Utah13, Heidelberg University14, University of Geneva15, University of Leeds16, Simon Fraser University17, Newcastle University18, University of Dayton19, University of Oslo20, Planetary Science Institute21, University of Alberta22, University of Grenoble23, University of Sheffield24, Indian Institute of Technology Indore25, University of Dundee26, UNESCO27, Jawaharlal Nehru University28, Stockholm International Water Institute29, University of British Columbia30, University of Exeter31, Kathmandu32, Wadia Institute of Himalayan Geology33, University of Kashmir34, University of Delhi35, Utrecht University36, International Centre for Integrated Mountain Development37, University of Chile38, Northumbria University39
TL;DR: In this paper, an analysis of satellite imagery, seismic records, numerical model results, and eyewitness videos reveals that ~27x106 m3 of rock and glacier ice collapsed from the steep north face of Ronti Peak.
Abstract: On 7 Feb 2021, a catastrophic mass flow descended the Ronti Gad, Rishiganga, and Dhauliganga valleys in Chamoli, Uttarakhand, India, causing widespread devastation and severely damaging two hydropower projects. Over 200 people were killed or are missing. Our analysis of satellite imagery, seismic records, numerical model results, and eyewitness videos reveals that ~27x106 m3 of rock and glacier ice collapsed from the steep north face of Ronti Peak. The rock and ice avalanche rapidly transformed into an extraordinarily large and mobile debris flow that transported boulders >20 m in diameter, and scoured the valley walls up to 220 m above the valley floor. The intersection of the hazard cascade with downvalley infrastructure resulted in a disaster, which highlights key questions about adequate monitoring and sustainable development in the Himalaya as well as other remote, high-mountain environments.
201 citations
TL;DR: In this paper, the authors present a new glacier inventory for the western Himalayas, compiled from Landsat ETM+ scenes acquired between 2000 and 2002, coherence images from ALOS PALSAR image pairs, the SRTM digital elevation model (DEM) and the ASTER Global DEM (GDEM).
185 citations
Cites background or methods from "Glacier changes in the Garhwal Hima..."
...7b) shows the typical patterns of mountain glaciers in mid-latitudes (e.g. Paul et al., 2011; Andreassen et al., 2008; Bhambri et al., 2011): In this region, 86% of all analyzed glaciers are smaller than 1 km(2), but they share only 20....
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...A number of glaciological studies in this region are focusing on individual glaciers or on glacier inventories of smaller sub-basins (e.g., Kulkarni et al., 2007; Bhambri et al., 2011)....
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...7b) shows the typical patterns of mountain glaciers in mid-latitudes (e.g. Paul et al., 2011; Andreassen et al., 2008; Bhambri et al., 2011): In this region, 86% of all analyzed glaciers are smaller than 1 km2, but they share only 20.2% of the total area....
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...Mapping of debris-covered glacier parts Editing of debris-covered glacier parts is one of the most time-consuming tasks in the compilation of a glacier inventory and highly error prone (e.g. Bolch et al., 2008; Racoviteanu et al., 2008; Bhambri et al., 2011)....
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...Declassified imagery of spy sensors from the 60s like Corona or Hexagon provide a valuable alternative for such change assessment and were already successfully applied in the study region by Bhambri et al. (2011)....
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References
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TL;DR: It is shown that meltwater is extremely important in the Indus basin and important for the Brahmaputra basin, but plays only a modest role for the Ganges, Yangtze, and Yellow rivers, indicating a huge difference in the extent to which climate change is predicted to affect water availability and food security.
Abstract: More than 1.4 billion people depend on water from the Indus, Ganges, Brahmaputra, Yangtze, and Yellow rivers. Upstream snow and ice reserves of these basins, important in sustaining seasonal water availability, are likely to be affected substantially by climate change, but to what extent is yet unclear. Here, we show that meltwater is extremely important in the Indus basin and important for the Brahmaputra basin, but plays only a modest role for the Ganges, Yangtze, and Yellow rivers. A huge difference also exists between basins in the extent to which climate change is predicted to affect water availability and food security. The Brahmaputra and Indus basins are most susceptible to reductions of flow, threatening the food security of an estimated 60 million people.
2,754 citations
TL;DR: The SNOMAP algorithm as discussed by the authors was developed to map global snow cover using Earth Observing System (EOS) Moderate Resolution Imaging Spectroradiometer (MODIS) data beginning at launch in 1998.
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TL;DR: In this paper, an analysis of remotely sensed frontal changes and surface velocities from glaciers in the greater Himalaya between 2000 and 2008 shows large regional variability in the responses of Himalayan glaciers to climate change.
Abstract: The present state and future evolution of Himalayan glaciers has been controversial. An analysis of remotely sensed frontal changes and surface velocities from glaciers in the greater Himalaya between 2000 and 2008 shows large regional variability in the responses of Himalayan glaciers to climate change.
843 citations
TL;DR: In the late 1990s widespread evidence of glacier expansion was found in the central Karakoram, in contrast to a worldwide decline of mountain glaciers as mentioned in this paper, and the expansions were almost exclusively in glacier basins from the highest parts of the range and developed quickly after decades of decline.
Abstract: In the late 1990s widespread evidence of glacier expansion was found in the central Karakoram, in contrast to a worldwide decline of mountain glaciers. The expansions were almost exclusively in glacier basins from the highest parts of the range and developed quickly after decades of decline. Exceptional numbers of glacier surges were also reported. Unfortunately, there has been no on-going measurement of climatic or glaciological variables at these elevations. The present article examines possible explanations for this seemingly anomalous behavior, using evidence from short-term monitoring programs, low-altitude weather stations, and the distinctive environmental characteristics of the region. The latter involve interactions between regional air mass climatology, its seasonality, topoclimate or ‘verticality’ effects on glaciers with extreme altitudinal range, climatic sensitivities of heavy versus thin supraglacial debris, and complex temperature distributions in ice masses with ice falls through...
672 citations
"Glacier changes in the Garhwal Hima..." refers background in this paper
...However, some glaciers (e.g. Raikot Glacier in Nanga Parbat, Punjab Himalaya) have been stable during recent decades (Schmidt and Nüsser, 2009) and others have advanced (e.g. tributaries of Panmah and Liligo Glaciers in the Karakoram region of Pakistan) (Hewitt, 2005; Belò and others, 2008)....
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...This advance could be attributed to surging (Hewitt, 2005, 2007)....
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TL;DR: In this article, a semi-automated method extracted glacier extents from Landsat Thematic Mapper (TM) scenes for 2005 and 2000 using a band ratio (TM3/TM5).
489 citations