Digital terrain modelling using Corona and ALOS PRISM data to investigate the distal part of Imja Glacier, Khumbu Himal, Nepal

Lamsal, Damodar; Sawagaki, Takanobu; Watanabe, Teiji

doi:10.1007/s11629-011-2064-0

Cited by 59 publications

(66 citation statements)

References 23 publications

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“…6 by assuming that the lake surface has not changed since 2002. This assumption is reasonable as various studies have shown that the level of the lake has not changed significantly since 2002 (Sakai et al, 2007;Lamsal et al, 2011;Fujita et al, 2009).…”

Section: Bathymetric Surveymentioning

confidence: 80%

“…A number of authors have discussed the details of Imja Tsho's development (Quincey et al, 2007;Bajracharya et al, 2007;Yamada, 1998;Watanabe et al, 2009;Ives et al, 2010;Lamsal et al, 2011). Imja Tsho is bounded to the east by the Imja-Lhotse Shar glacier, to the north and south by lateral moraines, and to the west by the moraine of the former glacier terminus.…”

Section: Introductionmentioning

confidence: 99%

“…The former glacier tongue still contains ice, as clearly evidenced by outcrops of bare ice, ponds formed by meltwater from ice in the moraine, and traces of old ponds (Yamada and Sharma, 1993). The incision of the outlet channel complex has lowered the lake level by some 37 m over the last 4 decades Lamsal et al, 2011). The outlet flow from the lake forms the river Imja Khola, which is a tributary of the Dudh Koshi river.…”

Section: Introductionmentioning

confidence: 99%

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Changes in Imja Tsho in the Mount Everest region of Nepal

et al. 2014

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Abstract. Imja Tsho, located in the Sagarmatha (Everest) National Park of Nepal, is one of the most studied and rapidly growing lakes in the Himalayan range. Compared with previous studies, the results of our sonar bathymetric survey conducted in September of 2012 suggest that its maximum depth has increased from 90.5 to 116.3 ± 5.2 m since 2002, and that its estimated volume has grown from 35.8 ± 0.7 to 61.7 ± 3.7 million m 3 . Most of the expansion of the lake in recent years has taken place in the glacier terminus-lake interface on the eastern end of the lake, with the glacier receding at about 52 m yr −1 and the lake expanding in area by 0.04 km 2 yr −1 . A ground penetrating radar survey of the Imja-Lhotse Shar glacier just behind the glacier terminus shows that the ice is over 200 m thick in the center of the glacier. The volume of water that could be released from the lake in the event of a breach in the damming moraine on the western end of the lake has increased to 34.1 ± 1.08 million m 3 from the 21 million m 3 estimated in 2002.

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Section: Bathymetric Surveymentioning

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Changes in Imja Tsho in the Mount Everest region of Nepal

et al. 2014

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“…The high-resolution DEM used in this study was generated by Lamsal et al (2011) from Advanced Land Observing Satellite (ALOS) Pranchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) images. The generated DEM has a horizontal resolution of 5 m and relative error of ± 4 m. In order to coregister the DEM with the panchromatic band from the Landsat7 imagery, a shaded version of the DEM was generated using the Hillshade tool in ArcGIS 10.3.…”

Section: Remotely Sensed Datamentioning

confidence: 99%

Debris thickness of glaciers in the Everest area (Nepal Himalaya) derived from satellite imagery using a nonlinear energy balance model

2014

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Abstract. Debris thickness is an important characteristic of debris-covered glaciers in the Everest region of the Himalayas. The debris thickness controls the melt rates of the glaciers, which has large implications for hydrologic models, the glaciers' response to climate change, and the development of glacial lakes. Despite its importance, there is little knowledge of how the debris thickness varies over these glaciers. This paper uses an energy balance model in conjunction with Landsat7 Enhanced Thematic Mapper Plus (ETM+) satellite imagery to derive thermal resistances, which are the debris thickness divided by the thermal conductivity. Model results are reported in terms of debris thickness using an effective thermal conductivity derived from field data. The developed model accounts for the nonlinear temperature gradient in the debris cover to derive reasonable debris thicknesses. Fieldwork performed on ImjaLhotse Shar Glacier in September 2013 was used to compare to the modeled debris thicknesses. Results indicate that accounting for the nonlinear temperature gradient is crucial. Furthermore, correcting the incoming shortwave radiation term for the effects of topography and resampling to the resolution of the thermal band's pixel is imperative to deriving reasonable debris thicknesses. Since the topographic correction is important, the model will improve with the quality of the digital elevation model (DEM). The main limitation of this work is the poor resolution (60 m) of the satellite's thermal band. The derived debris thicknesses are reasonable at this resolution, but trends related to slope and aspect are unable to be modeled on a finer scale. Nonetheless, the study finds this model derives reasonable debris thicknesses on this scale and was applied to other debris-covered glaciers in the Everest region.

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“…Methods for quantifying glacial lake bathymetry include the interpolation of spot depths calculated from manual 'plumb line' surveys (Yamada and Sharma, 1993;Fujita et al, 2009) or GPS-integrated SONAR (Lamsal et al, 2011;Sawagaki et al, 2012). Such methods are appropriate for the survey of extant glacial lakes, but quantification of the bathymetry of drained lakes necessitated an alternative approach.…”

Section: Moraine-dammed Lake Reconstructionmentioning

confidence: 99%

Reconstructing historic Glacial Lake Outburst Floods through numerical modelling and geomorphological assessment: Extreme events in the Himalaya

Westoby

Glasser

Hambrey

et al. 2014

Earth Surf Processes Landf

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Recession of high-mountain glaciers in response to climatic change frequently results in the development of morainedammed glacial lakes. Moraine dam failure is often accompanied by the release of large volumes of water and sediment, termed a Glacial Lake Outburst Flood (GLOF). Chukhung Glacier is a small (~3 km 2 ) receding valley glacier in Mt. Everest (Sagarmatha) National Park, Nepal. Unlike many Himalayan glaciers, which possess a thick mantle of supraglacial debris, its surface is relatively clean. The glacier terminus has receded 1.3 km from its maximum Holocene position, and in doing so provided the space for an icecontact moraine-dammed lake to develop. The lake had a maximum volume of 5.5 × 10 5 m 3 and drained as a result of breaching of the terminal moraine. An estimated 1.3 × 10 5 m 3 of material was removed from the terminal moraine during breach development. Numerical dam-breach modelling, implemented within a Generalised Likelihood Uncertainty Estimation (GLUE) framework, was used to investigate a range of moraine-dam failure scenarios. Reconstructed outflow peak discharges, including failure via overtopping and piping mechanisms, are in the range 146-2200 m 3 s -1 . Results from two-dimensional hydrodynamic GLOF modelling indicate that maximum local flow depths may have exceeded 9 m, with maximum flow velocities exceeding 20 m s -1 within 700 m of the breach. The floodwaters mobilised a significant amount of material, sourced mostly from the expanding breach, forming a 300 m long and 100 m wide debris fan originating at the breach exit. moraine-dam. These results also suggest that inundation of the entire floodplain may have been achieved within ten minutes of initial breach development, suggesting that debris fan development was rapid. We discuss the key glaciological and geomorphological factors that have determined the evolution of a hazardous moraine-dammed lake complex and the subsequent generation of a GLOF and its geomorphological impact.

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Digital terrain modelling using Corona and ALOS PRISM data to investigate the distal part of Imja Glacier, Khumbu Himal, Nepal

Cited by 59 publications

References 23 publications

Changes in Imja Tsho in the Mount Everest region of Nepal

Changes in Imja Tsho in the Mount Everest region of Nepal

Debris thickness of glaciers in the Everest area (Nepal Himalaya) derived from satellite imagery using a nonlinear energy balance model

Reconstructing historic Glacial Lake Outburst Floods through numerical modelling and geomorphological assessment: Extreme events in the Himalaya

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