Inversion for the density-depth profile of polar firn using a stepped-frequency radar

Arthern, Robert J.; Corr, Hugh F.J.; Gillet-Chaulet, Fabien; Hawley, Robert L.; Morris, Elizabeth M.

Inversion for the density-depth profile of polar firn using a stepped-frequency radar

Arthern, Robert J. ORCID: https://orcid.org/0000-0002-3762-8219; Corr, Hugh F.J.; Gillet-Chaulet, Fabien; Hawley, Robert L.; Morris, Elizabeth M.. 2013 Inversion for the density-depth profile of polar firn using a stepped-frequency radar. Journal of Geophysical Research: Earth Surface, 118 (3). 1257-1263. 10.1002/jgrf.20089

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Abstract/Summary

Translating satellite measurements of ice sheet volume change into sea level contribution requires knowledge of the profile of density as a function of depth within the ice sheet, and how this profile changes over time. This paper describes an interferometric method of inverting ground-penetrating radar returns for the profile of firn density as a function of depth. The method is an interferometric implementation of the common-midpoint approach, performed using a stepped-frequency, phase-sensitive ground-penetrating radar. By recording the phase difference of returns with a range of antenna separations, the different path lengths through the firn allow recovery of a smoothed representation of the density profile. This density model is characterised by three parameters: surface density and two decay lengths for porosity, each operating over a different density range. Our results suggest that the stepped-frequency radar used here can accurately recover differences in two-way travel time and produce useful estimates of the density profile. In a test of the method performed at Summit station in Greenland, the recovered density-depth profile agreed with indepenent density measurements from an ice core and a neutron probe to within 6% root-mean-square error.

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1002/jgrf.20089

Programmes:

BAS Programmes > Polar Science for Planet Earth (2009 - ) > Ice Sheets

ISSN:

2169-9011

Additional Keywords:

Common-Midpoint; Phase-Sensitive; Firn; Depth-Density; Density-Depth

Date made live:

31 Aug 2012 09:22 +0 (UTC)