Journal cover Journal topic
The Cryosphere An interactive open-access journal of the European Geosciences Union
The Cryosphere, 9, 1895-1913, 2015
https://doi.org/10.5194/tc-9-1895-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
25 Sep 2015
CryoSat-2 delivers monthly and inter-annual surface elevation change for Arctic ice caps
L. Gray1, D. Burgess2, L. Copland1, M. N. Demuth2, T. Dunse3, K. Langley3, and T. V. Schuler3 1Department of Geography, University of Ottawa, Ottawa, K1N 6N5, Canada
2Natural Resources Canada, Ottawa, Canada
3Department of Geosciences, University of Oslo, Oslo, Norway
Abstract. We show that the CryoSat-2 radar altimeter can provide useful estimates of surface elevation change on a variety of Arctic ice caps, on both monthly and yearly timescales. Changing conditions, however, can lead to a varying bias between the elevation estimated from the radar altimeter and the physical surface due to changes in the ratio of subsurface to surface backscatter. Under melting conditions the radar returns are predominantly from the surface so that if surface melt is extensive across the ice cap estimates of summer elevation loss can be made with the frequent coverage provided by CryoSat-2. For example, the average summer elevation decreases on the Barnes Ice Cap, Baffin Island, Canada were 2.05 ± 0.36 m (2011), 2.55 ± 0.32 m (2012), 1.38 ± 0.40 m (2013) and 1.44 ± 0.37 m (2014), losses which were not balanced by the winter snow accumulation. As winter-to-winter conditions were similar, the net elevation losses were 1.0 ± 0.20 m (winter 2010/11 to winter 2011/12), 1.39 ± 0.20 m (2011/12 to 2012/13) and 0.36 ± 0.20 m (2012/13 to 2013/14); for a total surface elevation loss of 2.75 ± 0.20 m over this 3-year period. In contrast, the uncertainty in height change from Devon Ice Cap, Canada, and Austfonna, Svalbard, can be up to twice as large because of the presence of firn and the possibility of a varying bias between the true surface and the detected elevation due to changing year-to-year conditions. Nevertheless, the surface elevation change estimates from CryoSat for both ice caps are consistent with field and meteorological measurements.

Citation: Gray, L., Burgess, D., Copland, L., Demuth, M. N., Dunse, T., Langley, K., and Schuler, T. V.: CryoSat-2 delivers monthly and inter-annual surface elevation change for Arctic ice caps, The Cryosphere, 9, 1895-1913, https://doi.org/10.5194/tc-9-1895-2015, 2015.
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Short summary
We show that the Cryosat (CS) radar altimeter can measure elevation change on a variety of Arctic ice caps. With the frequent coverage of Cryosat it is even possible to track summer surface height loss due to extensive melt; no other satellite altimeter has been able to do this. However, we also show that under cold conditions there is a bias between the surface and Cryosat detected elevation which varies with the conditions of the upper snow and firn layers.
We show that the Cryosat (CS) radar altimeter can measure elevation change on a variety of...
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