Inversion for the density-depth profile of polar firn using a stepped-frequency radar
Article first published online: 19 JUL 2013
©2013. The Authors.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Journal of Geophysical Research: Earth Surface
Volume 118, Issue 3, pages 1257–1263, September 2013
How to Cite
2013), Inversion for the density-depth profile of polar firn using a stepped-frequency radar, J. Geophys. Res. Earth Surf., 118, 1257–1263, doi:10.1002/jgrf.20089., , , , and (
- Issue published online: 15 OCT 2013
- Article first published online: 19 JUL 2013
- Accepted manuscript online: 17 JUN 2013 07:01AM EST
- Manuscript Accepted: 2 JUN 2013
- Manuscript Revised: 30 MAY 2013
- Manuscript Received: 25 JUN 2012
- NERC. Grant Number: NE/F00446X/1
 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 characterized 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 traveltime 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 independent density measurements from an ice core and a neutron probe to within 6% root-mean-square error.