|Title||Cryosat-2 delivers monthly and inter-annual surface elevation change for Arctic ice caps|
|Author||Gray, L; Burgess, D; Copland, L; Demuth, M N; Dunse, T; Langley, K; Shuler, T V|
|Source||The Cryosphere vol. 9, 2015 p. 1895-1913, https://doi.org/10.5194/tcd-9-2821-2015|
|Alt Series||Earth Sciences Sector, Contribution Series 20150076|
|Publisher||European Geosciences Union|
|Area||Barnes Ice Cap; Baffin Island; Svalbard; Norway|
|Lat/Long WENS|| -72.0000 -64.0000 68.0000 64.0000|
|Subjects||environmental geology; surficial geology/geomorphology; ice; ice conditions; ice thickness; climate effects; climate, arctic; precipitation; snow; glaciers; glacier surveys; remote sensing; CryoSat-2;
|Illustrations||graphs; tables; location maps; satellite images; histograms; plots|
|Program||Essential Climate Variable Monitoring, Climate Change Geoscience|
|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\'060.36m (2011), 2.55\'060.32m (2012), 1.38\'060.40m (2013) and 1.44\'060.37m (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\'060.20m (winter 2010/11 to winter 2011/12), 1.39\'060.20m (2011/12 to 2012/13) and 0.36\'060.20m (2012/13 to 2013/14); for a total surface elevation
loss of 2.75\'060.20m 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.
|Summary||(Plain Language Summary, not published)|
Analysis of data from the Cryosat radar altimeter reveals significant annual height changes of some large ice caps in the Canadian high Arctic. In this
study, we demonstrate that the frequent coverage by Cryosat allows us to detect interannual changes in ice surface height, and to measure seasonal changes due to summer melting (thinning) and winter accumulation (thickening) over a variety of high
latitude ice caps. The CryoSat radar altimeter is a European Space Agency initiative that will play an integral role in Canada's scaled glacier-climate observing approach, contributing to Climate Change Geoscience Program objectives through provision
of data on glacier mass change as it concerns freshwater flux to oceans.