School Of Environment And Earth Sciences
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Item Evolution of Supraglacial Lakes from 1990 to 2020 in the Himalaya�Karakoram Region Using Cloud-Based Google Earth Engine Platform(Springer, 2023-10-27T00:00:00) Sahu, Rakesh; Ramsankaran, Raaj; Bhambri, Rakesh; Verma, Prateek; Chand, PritamEvolution of glacial lakes in the Himalayan and Karakoram (H�K) mountain ranges is an important indicator of glacier changes in response to climatic warming. The study utilized multi-temporal Landsat 4, 5, 7, and 8 images accessible in the cloud-based Google Earth Engine platform to analyse the spatiotemporal variations of the supraglacial lake (SGL) in the H�K regions from 1990 to 2020 at a decadal interval. It is observed that 61% (4.79�km2) of the SGL area increased from 1990 to 2020, while 223 new lakes formed in a similar time period. The most significant increase in the area of SGLs (30.15%; 2.93�km2) was observed between 2010 and 2020, while the slowest growth was observed between 1990 and 2000 (1.13%; 0.09�km2). The results indicate heterogeneity in SGL area changes in different regions. The region of Central Himalaya (CH) experienced the highest increase of 160% (3.8�km2) in the�SGL area from 1990 to 2020 with most of the rise in the�SGL area was observed in the Everest region, while a decrease of 9.4% (0.12�km2) was observed in the Eastern Himalaya (EH) region. During the study period, some SGLs converted into proglacial lakes in the EH region, which may be responsible for reducing the SGL area. The rise of SGL in the CH region can be attributed to higher mass loss, decreased glacier surface velocity, and increased rainfall in the�CH region. We also identified 15 glaciers that have SGLs near the terminus of the glaciers. If the same trend continues, these SGLs may soon be converted into proglacial lakes. The current inventory of SGL at a decadal scale shall be useful as baseline data for other hydro-glaciological models. � 2023, Indian Society of Remote Sensing.Item Heterogeneity in glacier thinning and slowdown of ice movement in the Garhwal Himalaya, India(Elsevier B.V., 2023-03-05T00:00:00) Bhambri, Rakesh; Schmidt, Susanne; Chand, Pritam; N�sser, Marcus; Haritashya, Umesh; Sain, Kalachand; Tiwari, Sameer K.; Yadav, Jairam SinghLimited ground-based surveys and extensive remote sensing analyses have confirmed glacier thinning in the Garhwal Himalaya. More detailed studies on specific glaciers and the drivers of reported changes are essential to comprehend small-scale differences in the effects of climatic warming on Himalayan glaciers. We computed elevation changes and surface flow distribution for 205 (?0.1 km2) glaciers in the Alaknanda, Bhagirathi, and Mandakini basins, all located in the Garhwal Himalaya, India. This study also investigates a detailed integrated analysis of elevation changes and surface flow velocities for 23 glaciers with varying characteristics to understand the impact of ice thickness loss on overall glacier dynamics. We observed significant heterogeneity in glacier thinning and surface flow velocity patterns using temporal DEMs and optical satellite images with ground-based verification. The average thinning rate was found to be 0.07 � 0.09 m a-1 from 2000 to 2015, and it increased to 0.31 � 0.19 m a-1 from 2015 to 2020, with pronounced differences between individual glaciers. Between 2000 and 2015, Gangotri Glacier thinned nearly twice as much as the neighbouring Chorabari and Companion glaciers, which have thicker supraglacial debris that protects the beneath ice from melting. The transitional zone between debris-covered and clean ice glaciers showed substantial flow during the observation period. However, the lower reaches of their debris-covered terminus areas are almost stagnant. These glaciers experienced a significant slowdown (~25 %) between 1993�1994 and 2020�2021, and only the Gangotri Glacier was active even in its terminus region during most observational periods. The decreasing surface gradient reduces the driving stress and causes slow-down surface flow velocities and an increase in stagnant ice. Surface lowering of these glaciers may have substantial long-term impacts on downstream communities and lowland populations, including more frequent cryospheric hazards, which may threaten future water and livelihood security. � 2023 Elsevier B.V.Item Frontal Changes of Gangotri Glacier, Garhwal Himalaya, between 1935 and 2022(Springer, 2023-02-07T00:00:00) Bhambri, Rakesh; Sain, Kalachand; Chand, Pritam; Srivastava, Deepak; Tiwari, Sameer K.; Yadav, Jairam SinghGangotri Glacier is one of the most thoroughly investigated glaciers in the Indian Himalaya in terms of terminus monitoring. This study aims to update the frontal retreat of Gangotri Glacier between 1935 and 2022 using a large scale Geological Survey of India map, remote sensing images, and repeated photography. Gangotri Glacier�s retreat rate varied significantly during the study period. This glacier receded by 1727 � 51m (19.8 � 0.2 m a?1) between 1935 and 2022. The retreat of Gangotri Glacier decreased from 2001 to 2006 (7.0 � 4.0 m a?1) compared to the previous observation (1980�2001; 21.0 � 1.2 m a?1) but increased about three times between 2006 and 2017 (21.9 � 1.9 m a?1). Furthermore, from 2017 to 2022, the frontal retreat accelerated by about 1.5 times (33.8 � 6.7 m a?1) compared to the period between 2006 and 2017. The findings of the present study are consistent with ground based survey conducted by the Geological Survey of India. � 2023, Geological Society of India, Bengaluru, India.Item Reassessing the Karakoram Through Historical Archives(Springer International Publishing, 2022-11-11T00:00:00) Bhambri, Rakesh; Chand, Pritam; N�sser, Marcus; Kawishwar, Prashant; Kumar, Amit; Gupta, Anil K.; Verma, Akshaya; Tiwari, Sameer K.The Karakoram region is an integral part of the Hindu Kush�Karakoram�Himalaya (HKH) mountain system and forms the great divide between the drainage of the Indus and Tarim basins. This region has a substantial geographical, historical, economical, cultural, and geopolitical importance owing to its location, rugged topography, distinct climate regime, and the presence of numerous glaciers. It acts as a water tower where its unique assemblage paved the way for developing ancient trade routes facilitating cultural exchange between Central Asia and the Indian subcontinent. It has attracted a large number of expeditions and scientific studies for more than 200 years, bringing significant advances in geographical knowledge. However, the spatial extent of the Karakoram in many studies particularly during the 2010s exhibits a large inconsistency. We, therefore, complied ?100 maps and vast literature to present the evolution of the geographical term �the Karakoram� and its spatial extent based on historical archives. We also provide a digital outline of the Karakoram region using GIS tools based on descriptive enumerations of the Royal Geographical Society (RGS) and the Survey of India (SoI) which we hope will provide new insight for a wide range of scientific disciplines, including geography, glaciology, geology, history, and cartography. � The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2022.Item Characteristics of surge-type tributary glaciers, Karakoram(Elsevier B.V., 2022-02-10T00:00:00) Bhambri, Rakesh; Hewitt, Kenneth; Haritashya, Umesh K.; Chand, Pritam; Kumar, Amit; Verma, Akshaya; Tiwari, Sameer Kumar; Rai, Santosh KumarThe Karakoram has a large concentration of surge-type glaciers, including 69 tributary glaciers, compared to 152 surge-type main or trunk glaciers. The paper addresses the interactions between tributary and trunk glaciers using digital elevation models (DEMs), surface displacement, field and archival reports. In particular, it explores the behavior and impacts of 13 tributary glacier surges on three trunk glaciers, namely the Hispar, Braldu and Panmah. Observations include five surge tributaries of Panmah, five of Braldu, and three of Hispar. We observed ASTER DEMs can help in some cases to detect surge signature where automated surface displacement does not detect the surge. We also observed substantial differences in surge dimensions, timing and histories of the main trunk glacier and their tributaries. East Braldu III tributary surged between 2000 and 2003, whereas East Braldu IV surged from 2003 to 2006, but in these periods, no other tributary shows surge signature. Between 2013 and 2016, Braldu trunk Glacier surged along with four tributaries out of five except West Braldu I. Volumes and geometry of ice transferred from tributary to trunk glaciers are unique to each case, but the surging ice melted rapidly in about 2 to 4 years for some cases such as Little Skamri and Drenmang. The tributary ice modified all studied trunk glacier dynamics, morphology, distribution of debris and hypsography. The ice transferred from tributaries such as Little Skamri and Drenmang blocked the flow of trunk Nobande Sobonde Glacier from 2004 to 2006. Such ice transfer by surge tributaries to the main trunk glacier is referred here as surge-modified ice. It introduces indirect and post-surge effects and complicates or delay in tracking glacier responses to climate change. Also, mass balance in surge-type and surge-modified glaciers differ from systematic direct responses to climate in non-surge-type glaciers. Therefore, more research and monitoring are required to address the distinct responses of such glaciers and individual tributaries to better understand the heterogeneity of surging glaciers in Karakoram. � 2022 Elsevier B.V.Item The retreat of mountain glaciers since the little ice age: A spatially explicit database(MDPI, 2021-10-11T00:00:00) Marta, Silvio; Azzoni, Roberto Sergio; Fugazza, Davide; Tielidze, Levan; Chand, Pritam; Sieron, Katrin; Almond, Peter; Ambrosini, Roberto; Anthelme, Fabien; Alviz Gazit�a, Pablo; Bhambri, Rakesh; Bonin, Aur�lie; Caccianiga, Marco; Cauvy-Frauni�, Sophie; Lievano, Jorge Luis Ceballos; Clague, John; Rapre, Justiniano Alejo Cochach�n; Dangles, Olivier; Deline, Philip; Eger, Andre; Encarnaci�n, Rolando Cruz; Erokhin, Sergey; Franzetti, Andrea; Gielly, Ludovic; Gili, Fabrizio; Gobbi, Mauro; Guerrieri, Alessia; H�gvar, Sigmund; Khedim, Norine; Kinyanjui, Rahab; Messager, Erwan; Morales-Mart�nez, Marco Aurelio; Peyre, Gwendolyn; Pittino, Francesca; Poulenard, Jerome; Seppi, Roberto; Sharma, Milap Chand; Urseitova, Nurai; Weissling, Blake; Yang, Yan; Zaginaev, Vitalii; Zimmer, Ana�s; Diolaiuti, Guglielmina Adele; Rabatel, Antoine; Ficetola, Gentile FrancescoMost of the world�s mountain glaciers have been retreating for more than a century in response to climate change. Glacier retreat is evident on all continents, and the rate of retreat has accelerated during recent decades. Accurate, spatially explicit information on the position of glacier margins over time is useful for analyzing patterns of glacier retreat and measuring reductions in glacier surface area. This information is also essential for evaluating how mountain ecosystems are evolving due to climate warming and the attendant glacier retreat. Here, we present a non-comprehensive spatially explicit dataset showing multiple positions of glacier fronts since the Little Ice Age (LIA) maxima, including many data from the pre-satellite era. The dataset is based on multiple historical archival records including topographical maps; repeated photographs, paintings, and aerial or satellite images with a supplement of geochronology; and own field data. We provide ESRI shapefiles showing 728 past positions of 94 glacier fronts from all continents, except Antarctica, covering the period between the Little Ice Age maxima and the present. On average, the time series span the past 190 years. From 2 to 46 past positions per glacier are depicted (on average: 7.8). � 2021 by the authors. Licensee MDPI, Basel, Switzerland.