Remote Sens. 2012, 4(9), 2554-2575; doi:10.3390/rs4092554
Estimation of Supraglacial Dust and Debris Geochemical Composition via Satellite Reflectance and Emissivity
1
Cryospheric Sciences Laboratory, NASA Goddard Space Flight Center, Code 615, Greenbelt, MD 20771, USA
2
Department of Geosciences, University of Oslo, 0316 Oslo, Norway
*
Author to whom correspondence should be addressed.
Received: 1 June 2012 / Revised: 31 August 2012 / Accepted: 3 September 2012 / Published: 7 September 2012
Abstract
We demonstrate spectral estimation of supraglacial dust, debris, ash and tephra geochemical composition from glaciers and ice fields in Iceland, Nepal, New Zealand and Switzerland. Surface glacier material was collected and analyzed via X-ray fluorescence spectroscopy (XRF) and X-ray diffraction (XRD) for geochemical composition and mineralogy. In situ data was used as ground truth for comparison with satellite derived geochemical results. Supraglacial debris spectral response patterns and emissivity-derived silica weight percent are presented. Qualitative spectral response patterns agreed well with XRF elemental abundances. Quantitative emissivity estimates of supraglacial SiO2 in continental areas were 67% (Switzerland) and 68% (Nepal), while volcanic supraglacial SiO2 averages were 58% (Iceland) and 56% (New Zealand), yielding general agreement. Ablation season supraglacial temperature variation due to differing dust and debris type and coverage was also investigated, with surface debris temperatures ranging from 5.9 to 26.6 °C in the study regions. Applications of the supraglacial geochemical reflective and emissive characterization methods include glacier areal extent mapping, debris source identification, glacier kinematics and glacier energy balance considerations. View Full-TextKeywords:
glaciology; remote sensing; supraglacial dust; tephra; reflectance; ASTER; MODIS; Hyperion
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Casey, K.; Kääb, A. Estimation of Supraglacial Dust and Debris Geochemical Composition via Satellite Reflectance and Emissivity. Remote Sens. 2012, 4, 2554-2575.
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