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Debris thickness of glaciers in the Everest area (Nepal Himalaya) derived from satellite imagery using a nonlinear energy balance model
- Source :
- The Cryosphere, Vol 8, Iss 4, Pp 1317-1329 (2014)
- Publication Year :
- 2014
- Publisher :
- Copernicus Publications, 2014.
-
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 Imja–Lhotse 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.
- Subjects :
- lcsh:GE1-350
geography
geography.geographical_feature_category
lcsh:QE1-996.5
Climate change
Glacier
Debris
lcsh:Geology
Thematic Mapper
Satellite imagery
Satellite
Shortwave radiation
Digital elevation model
Geomorphology
Geology
lcsh:Environmental sciences
Earth-Surface Processes
Water Science and Technology
Subjects
Details
- Language :
- English
- ISSN :
- 19940424 and 19940416
- Volume :
- 8
- Issue :
- 4
- Database :
- OpenAIRE
- Journal :
- The Cryosphere
- Accession number :
- edsair.doi.dedup.....40c11dd88fceecff02b2acc5c52f1cf1