Ice-shelf microtopography observed using satellite thermal imagery

Anderson, P.S.. 2005 Ice-shelf microtopography observed using satellite thermal imagery. Journal of Glaciology, 51 (175). 528-538. 10.3189/172756505781829025

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Abstract/Summary

Small anomalies in ice-shelf surface temperature correlate with measured microtopography. Clear-sky thermal infrared (TIR) images of the Brunt Ice Shelf, Antarctica, frequently show persistent patterns of anomalous snow surface temperatures. The anomalous signatures appear as stripes orientated along the ice flowline and are of the order of 5 K in magnitude. The positional persistence of the stripes suggests a topographic mechanism for their formation. In order to test this hypothesis, the TIR stripes are compared to a digital terrain model (DTM) derived from a kinematic global positioning system survey of the ice shelf. Ridges and valleys are seen in the DTM; the ridges correspond to the warmer TIR stripes, the valleys to the colder areas. In order to investigate the mechanism that couples elevation with thermal signature, two comparable but contrasting sets of clear-sky infrared images are presented, along with surface meteorological data. The first shows strong TIR stripes, whilst the second, despite similar snow- and air-temperature profiles, shows a weaker signature and smaller sensible-heat flux, H. Two possible mechanisms are presented which explain the TIR signature: surface elevation mapping onto the vertical air-temperature profile or, alternatively, enhanced surface sensible-heat flux on elevated areas. At present, there is insufficient information to resolve this uncertainty.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.3189/172756505781829025
Programmes:	BAS Programmes > Antarctic Science in the Global Context (2000-2005) > Antarctic Climate Processes
ISSN:	0022-1430
Additional Keywords:	remote sensing
NORA Subject Terms:	Glaciology
Date made live:	13 Dec 2007 13:37 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/1614

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