Greenland 2012 melt event effects on CryoSat-2 radar altimetry

CryoSat-2 data are used to study elevation changes over an area in the interior part of the Greenland Ice Sheet during the extreme melt event in July 2012. The penetration of the radar signal into dry snow depends heavily on the snow stratigraphy, and the rapid formation of refrozen ice layers can b...

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Bibliographic Details
Published in:Geophysical Research Letters
Main Authors: Nilsson, Johan, Vallelonga, Paul Travis, Simonsen, Sebastian Bjerregaard, Sørensen, Louise Sandberg, Forsberg, René, Dahl-Jensen, Dorthe, Hirabayashi, Motohiro, Goto-Azuma, Kumiko, Hvidberg, Christine S., Kjær, Helle A., Satow, Kazuhide
Format: Article in Journal/Newspaper
Language:English
Published: 2015
Subjects:
Greenland
Ice Sheet
North Greenland
Online Access:https://orbit.dtu.dk/en/publications/ae2aad7a-9e10-4693-9652-ee19b1c1762c
https://doi.org/10.1002/2015GL063296
Description
Summary:CryoSat-2 data are used to study elevation changes over an area in the interior part of the Greenland Ice Sheet during the extreme melt event in July 2012. The penetration of the radar signal into dry snow depends heavily on the snow stratigraphy, and the rapid formation of refrozen ice layers can bias the surface elevations obtained from radar altimetry. We investigate the change in CryoSat-2 waveforms and elevation estimates over the melt event and interpret the findings by comparing in situ surface and snow pit observations from the North Greenland Eemian Ice Drilling Project camp. The investigation shows a major transition of scattering properties around the area, and an apparent elevation increase of 56±26 cm is observed in reprocessed CryoSat-2 data. We suggest that this jump in elevation can be explained by the formation of a refrozen melt layer that raised the reflective surface, introducing a positive elevation bias.

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