Retrievals of Arctic sea-ice volume and its trend significantly affected by interannual snow variability

• Published in: Geophysical Research Letters
• Main Authors: Bunzel, F., Notz, D., Pedersen, L.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2018
• Subjects: Arctic; Sea ice
• Online Access: http://hdl.handle.net/21.11116/0000-0002-8060-0; http://hdl.handle.net/21.11116/0000-0002-9E76-8

We estimate the uncertainty of satellite-retrieved Arctic sea-ice thickness, sea-ice volume, and their trends stemming from the lack of reliable snow-thickness observations. To do so, we simulate a Cryosat2-type ice-thickness retrieval in an ocean-model simulation forced by atmospheric reanalysis, pretending that only freeboard is known as model output. We then convert freeboard to sea-ice thickness using different snow climatologies and compare the resulting sea-ice thickness retrievals to each other and to the real sea-ice thickness of the reanalysis-forced simulation. We find that different snow climatologies cause significant differences in the obtained ice thickness and ice volume. In addition, we show that Arctic ice-volume trends derived from ice-thickness retrievals using any snow-depth climatology are highly unreliable because the estimated trend in ice volume can strongly be influenced by the neglected interannual variability in snow volume. ©2018. American Geophysical Union. All Rights Reserved.