Sweta

Bio: Sweta is an academic researcher from National Remote Sensing Centre. The author has contributed to research in topics: Drainage basin & Glacial period. The author has an hindex of 1, co-authored 2 publications receiving 5 citations.

Updated Glacial Lake Inventory of Indus River Basin based on High-Resolution Indian Remote Sensing Satellite Data

Abstract: A comprehensive updated inventory of glacial lakes in the Indus River basin (up to the Indian administrative boundary) has been carried out using 157 high-resolution Indian Remote Sensing satellite images, mostly covering mountainous region of the Western Himalayas and Karakoram Ranges. Glacial lakes are classified in ten different types depending upon dam type, process of lake formation, topographic feature, and geographical position. Distribution of glacial lakes has been studied in terms of area, type, area versus type, elevation, elevation versus type, and area versus elevation at basin and subbasin levels, along with Indian administrative and transboundary region level. A total of 5335 glacial lakes ≥ 0.25 ± 0.06 ha has been inventoried in the Indus River basin covering a total water spread area of 17395.03 ± 1013.28 ha. About 4633 (86.84%) glacial lakes are with < 5 ha in size, whereas remaining lakes, i.e. 702 (13.16%), are with ≥ 5 ha in size, contributing to 34.04 ± 1.63% and 65.96 ± 1.63% of total lake area, respectively. Other glacial erosion types of lake are found to be the maximum with 2516 in number (47.16%) occupying a total lake extent of 8247.44 ± 499.21 ha at 47.42% in the basin. More than half (i.e. 52.43%) of the lakes are situated in the high altitude range of 4001–5000 m amsl and dominated by other glacial erosion type of lakes, i.e. 58.17%. Glacial lakes are majorly distributed in the Gilgit subbasin (18.95%) followed by Indus Upper subbasin (18.78%) with a total lake extent of 19.43 ± 0.03% and 19.93 ± 0.01%, respectively. A total of 4280 (80.22%) glacial lakes lies within Indian region covering 79.26 ± 0.02%, whereas remaining 19.78% of lakes are located in transboundary region with a 20.74 ± 0.02% total lake area. Within India, majority of lakes are situated in Ladakh (UT) with 75.21% of lake count covering a total water spread area of 72.28 ± 0.15%.

Different glacier status with atmospheric circulations in Tibetan Plateau and surroundings

Abstract: Glacial melting in the Tibetan Plateau affects the water resources of millions of people. This study finds that—partly owing to changes in atmospheric circulations and precipitation patterns—the most intensive glacier shrinkage is in the Himalayan region, whereas glacial retreat in the Pamir Plateau region is less apparent.

An inventory of glacial lakes in the Third Pole region and their changes in response to global warming

Abstract: article i nfo No glacial lake census exists for the Third Pole region, which includes the Pamir-Hindu Kush-Karakoram- Himalayas and the Tibetan Plateau. Therefore, comprehensive information is lacking about the distribution of and changes in glacial lakes caused by current global warming conditions. In this study, the first glacial lake in- ventories for the Third Pole were conducted for ~1990, 2000, and 2010 using Landsat TM/ETM+ data. Glacial lake spatial distributions, corresponding areas and temporal changes were examined. The significant results are as follows. (1) There were 4602, 4981, and 5701 glacial lakes (N0.003 km 2 ) covering areas of 553.9 ± 90, 581.2 ± 97, and 682.4 ± 110 km 2 in ~1990, 2000, and 2010, respectively; these lakes are primarily located in the Brahmaputra (39%),Indus (28%), and AmuDarya (10%) basins. (2) Small lakes (b0.2 km 2 ) are more sensitive to climate changes. (3) Lakes closer to glaciers and at higher altitudes, particularly thoseconnected to glacier ter- mini, have undergone larger area changes. (4) Glacier-fed lakes are dominant in both quantity and area (N70%) and exhibit faster expansion trends overall compared to non-glacier-fed lakes. We conclude that glacier meltwa- ter may play a dominant role in the areal expansion of most glacial lakes in the Third Pole. In addition, the pat- terns of the glacier-fed lakes correspond well with warming temperature trends and negative glacier mass balance patterns. This paper presents an important database of glacial lakes and provides a basis for long-term monitoring and evaluation of outburst flood disasters primarily caused by glacial lakes in the Third Pole.

Contrasted evolution of glacial lakes along the Hindu-Kush Himalaya mountain range between 1990 and 2009

Abstract: In this study, we present a first regional assessment of glacial lake distribution and evolution in the Hindu Kush Himalaya (HKH). Seven sites have been selected between Bhutan and Afghanistan, to capture the climatic variability along the 2000-km long mountain range. For each site, glacial lakes have been mapped with LANDSAT satellite imagery acquired in 1990, 2000 and 2009, using an automatic classification. In the East (India, Nepal and Bhutan), glacial lakes are bigger and more numerous than in the West (Pakistan, Afghanistan), and have grown continuously between 1990 and 2009 by 20% to 65%. On the other hand, during the same period, the glacial lake coverage has shrunk in the Hindu Kush (−50%) and the Karakorum (−30%). This east/west pattern of lake changes seems in agreement with sparse glaciological measurements that suggest less (or even no) ice loss in the western part of the HKH.

High resolution inventory and hazard assessment of potentially dangerous glacial lakes in upper Jhelum basin, Kashmir Himalaya, India

Abstract: Abstract In the Himalayan Mountain region, a large number of glacial lakes have developed in the recent past due to glacier recession under the influence of climate change. In this study, we used high resolution satellite data such as Indian Remote Sensing (IRS) LISS-IV (5.8 m) and Google earth images supplemented with field survey to generate an updated glacial lake inventory of Upper Jhelum Basin (UJB) of Kashmir Himalaya. The Sentinel-2A (10 m), Landsat-OLI (30 m) and MSS (60 m), and Cartosat-DEM (30 m) were additional data sources used for glacial lake mapping and change detection analysis. A total of 393 glacial lakes covering an area of 21.55 ± 3.8 km2 were identified, mapped and inventoried. The lake inventory includes 102 proglacial lakes, 13 supraglacial lakes and 278 unconnected glacial lakes. Using the weighted index-based method, 21 glacial lakes were found as Potentially Dangerous Glacial Lakes (PDGLs). Out of these, 7 lakes were classified as High, 9 as Medium and 5 as Low hazard glacial lakes as per the hazard assessment. Change detection analysis of PDGLs from 1980 to 2020 revealed an increase in area from 5.92 km2 to 8.46 km2 thereby, indicating a growth of 2.51 ±0.9 km2(30%) at a rate of 0.063 km2/year. The formation and growth of glacial lakes in this area is attributed to continuous glacier recession under the warming trend of temperature and declining nature of precipitation. In this study, the findings showed that Tavg and Tmin are rising significantly at a rate of 0.004ºC/year and 0.013ºC/year respectively. This study provides an important database for future GLOF studies in the region.

Glacial Lake Expansion in the Central Himalayas By Landsat Images, 1990-2010

Abstract: Glacial lake outburst flood (GLOF) is a serious hazard in high, mountainous regions. In the Himalayas, catastrophic risks of GLOFs have increased in recent years because most Himalayan glaciers have experienced remarkable downwasting under a warming climate. However, current knowledge about the distribution and recent changes in glacial lakes within the central Himalaya mountain range is still limited. Here, we conducted a systematic investigation of the glacial lakes within the entire central Himalaya range by using an object-oriented image processing method based on the Landsat Thematic Mapper (TM) or Enhanced Thematic Mapper (ETM) images from 1990 to 2010. We extracted the lake boundaries for four time points (1990, 2000, 2005 and 2010) and used a time series inspection method combined with a consistent spatial resolution of Landsat images that consistently revealed lake expansion. Our results show that the glacial lakes expanded rapidly by 17.11% from 1990 to 2010. The pre-existing, larger glacial lakes, rather than the newly formed lakes, contributed most to the areal expansion. The greatest expansions occurred at the altitudinal zones between 4800 m and 5600 m at the north side of the main Himalayan range and between 4500 m and 5600 m at the south side, respectively. Based on the expansion rate, area and type of glacial lakes, we identified 67 rapidly expanding glacial lakes in the central Himalayan region that need to be closely monitored in the future. The warming and increasing amounts of light-absorbing constituents of snow and ice could have accelerated the melting that directly affected the glacial lake expansion. Across the main central Himalayas, glacial lakes at the north side show more remarkable expansion than those at the south side. An effective monitoring and warning system for critical glacial lakes is urgently needed.