Measuring glacier surface roughness using plot-scale, close-range digital photogrammetry

Irvine-Fynn, Tristram, Sanz-Ablanedo, Enoc, Rutter, Nick, Smith, Mark and Chandler, Jim (2014) Measuring glacier surface roughness using plot-scale, close-range digital photogrammetry. Journal of Glaciology, 60 (223). pp. 957-969. ISSN 0022-1430

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Abstract

Glacier roughness at sub-metre scales is an important control on the ice surface energy balance and has implications for scattering energy measured by remote-sensing instruments. Ice surface roughness is dynamic as a consequence of spatial and temporal variation in ablation. To date, studies relying on singular and/or spatially discrete two-dimensional profiles to describe ice surface roughness have failed to resolve common patterns or causes of variation in glacier surface morphology. Here we demonstrate the potential of close-range digital photogrammetry as a rapid and cost-effective method to retrieve three-dimensional data detailing plot-scale supraglacial topography. The photogrammetric approach here employed a calibrated, consumer-grade 5 Mpix digital camera repeatedly imaging a plotscale (≤25m2) ice surface area on Midtre Lovénbreen, Svalbard. From stereo-pair images, digital surface models (DSMs) with sub-centimetre horizontal resolution and 3mm vertical precision were achieved at plot scales ≤4m2. Extraction of roughness metrics including estimates of aerodynamic roughness length (z0) was readily achievable, and temporal variations in the glacier surface topography were captured. Close-range photogrammetry, with appropriate camera calibration and image acquisition geometry, is shown to be a robust method to record sub-centimetre variations in ablating ice topography. While the DSM plot area may be limited through use of stereo-pair images and issues of obliquity, emerging photogrammetric packages are likely to overcome such limitations.

Item Type:	Article
Uncontrolled Keywords:	applied glaciology, energy balance, glaciological instruments and methods, snow/ice surface processes, surface melt
Subjects:	F800 Physical and Terrestrial Geographical and Environmental Sciences
Department:	Faculties > Engineering and Environment > Geography and Environmental Sciences
Depositing User:	Nick Rutter
Date Deposited:	02 Oct 2014 15:28
Last Modified:	13 Oct 2019 00:21
URI:	http://nrl.northumbria.ac.uk/id/eprint/17686

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