The Cryosphere Discuss., 5, 1-39, 2011
www.the-cryosphere-discuss.net/5/1/2011/
doi:10.5194/tcd-5-1-2011
© Author(s) 2011. This work is distributed
under the Creative Commons Attribution 3.0 License.
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This discussion paper has been under review for the journal The Cryosphere (TC). Please refer to the corresponding final paper in TC.
Snow accumulation and compaction derived from GPR data near Ross Island, Antarctica
N. C. Kruetzmann1,2, W. Rack2, A. J. McDonald1, and S. E. George3
1Department of Physics & Astronomy, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand
2Gateway Antarctica, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand
3Antarctic Climate and Ecosystems Cooperative Research Centre, University of Tasmania, Private Bag 80, Hobart, Tasmania 7001, Australia

Abstract. We present a new method of using ground penetrating radar (GPR) for estimating snow accumulation and compaction rates in Antarctica. We process 500 MHz data to produce radargrams with unambiguous reflection horizons that can be observed and tracked in repeat GPR measurements made one year apart. Our processing methodology is a deterministic deconvolution via the Fourier domain using an estimate of the emitted waveform from direct measurement. At two measurement sites near Scott Base, Antarctica, point measurements of average accumulation from snow pits and firn cores are extrapolated to a larger area by identifying a dateable dust layer in the radargrams. Over an 800 m×800 m area on the McMurdo Ice Shelf (77°45´ S, 167°17´ E) the average accumulation is found to be 269 ± 9 kg m−2 a−1. The accumulation over an area of 400 m×400 m in the dry snow zone on Ross Island (77°40´ S, 167°11´ E, 350 m a.s.l.) is found to be higher (404 ± 22 kg m−2 a−1) and shows increased variability related to undulating terrain. Compaction of snow between 2 m and 13 m depth is estimated at both sites by tracking several internal reflection horizons along the radar profiles and calculating the average change in separation of horizon pairs from one year to the next. The derived compaction rates range from 7 cm m−1 at a depth of two metres, down to no measurable compaction at 13 m depth, and are similar to published values from point measurements.

Citation: Kruetzmann, N. C., Rack, W., McDonald, A. J., and George, S. E.: Snow accumulation and compaction derived from GPR data near Ross Island, Antarctica, The Cryosphere Discuss., 5, 1-39, doi:10.5194/tcd-5-1-2011, 2011.
 
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