Auxiliary Material for
Changes in the firn stratigraphy and meltwater flow of the accumulation area of the Devon Ice
Cap, Nunavut, Canada, during a period of climate warming.
Gabrielle Gascon (Department of Earth and Atmospheric Sciences, University of Alberta,
Edmonton, Canada)
Martin Sharp (Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton,
Canada)
David Burgess (Geological Survey of Canada, Natural Resources Canada, Ottawa, Canada)
Peter Bezeau (Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton,
Canada)
Andrew B.G. Bush (Department of Earth and Atmospheric Sciences, University of Alberta,
Edmonton, Canada)
Journal of Geophysical Research, Earth Processes, 2013
Introduction
These 5 figures are high resolution versions of Figures 4-8, the radargrams. Description how the
data were collected and processed is provided in the manuscript. Small modifications have been
made to two of the figures to provide additional detail: i) “fs04.jpg” is equivalent to Figure 7 in
the text, but a topographic profile was added to provide additional details on surface topography,
and ii) “fs05.jpg” is equivalent to Figure 8 in the text, but arrows and words have been removed
to display entire profiles.
1. fs01.jpg (Figure 4) High resolution figure of a GPR profile of the surveyed transect from 0 km
(Site 1) to 40 km (Site 3) for spring 2010. Dewow filter, background subtraction, GPS
topography correction and a SEC2 gain were applied to the data. White layers represent ice, and
a purple signature represents firn. The different zones are identified along the profile:
percolation, wet-snow, superimpose ice, and glacier ice. The x-axis unit is distance (in km) from
Site 1, and the surface elevation decreases with increasing horizontal distance. Elevation is in m
a.s.l. Average surface slope of the surveyed transect is 40 km horizontally and 800 m vertically
(2˚). Vertical exaggeration (V.E.) is 500X.
2. fs02.jpg (Figure 5) High resolution figure of a 100-m GPR line across the main transect line,
and firn core stratigraphy at each of the four grid sites showing the GPR characteristics of three
different snow facies in the accumulation area of the Devon Ice Cap in spring 2012: a) HB 4-7;
percolation zone, b)HB 9-1; wet snow zone, c) HB 13-7; SI zone, and d) Site 2; SI zone. Dewow
filter, background subtraction, topography correction and a SEC2 gain were applied to the GPR
data. L2005 indicates the position of the summer 2005 ice layer, and defines the bottom
boundary of the SI region. Vertical exaggeration (V.E.) is 4.1X
3. fs03.jpg (Figure 6) High resolution figure of the Spring 2007-2012 GPR profiles between Site
1 and 2 km above Site 3. Data processed as in Figure 4. 2 km and 6.5 km data gaps in springs
2007 and 2009, respectively, were due to the partial GPR failure. Location of the upperboundary of the wet snow (WS), superimposed ice (SI) and glacier ice (GI) zones are identified.
Vertical exaggeration (V.E.) is 200X.
4. fs04.jpg (Figure 7) High resolution figure of the Spring 2007-2012 GPR profiles between
MB5-8 and MB15-9. Wave-like patterns are associated with rolling topography (and large
vertical exaggeration), where concave regions trap snow. Data processed as in Figure 4, but
enlargement exposes the structure and extent of the ice layer in the wet snow zone in greater
detail. Location of the upper-boundary of the wet snow (WS) and superimposed ice (SI) zones
are identified. Elevation is in m a.s.l. Average surface surface slope is 10 km horizontally and
250 m vertically (2.5˚). Vertical exaggeration (V.E.) is 200X.
5. fs05.jpg (Figure 8) High resolution figure of the subtraction of the GPR profile of subsequent
years to illustrate the evolution of the formation of ice layers in the accumulation area: a) 20092007, b) 2010-2009, c) 2011-2010, and d) 2012-2011. New ice layers are indicated in red. White
regions refer to no change in ice content over the given time period. Vertical exaggeration (V.E.)
is 200X.