Physical conditions of fast glacier flow: 3. Seasonally-evolving ice deformation on Store Glacier, West Greenland ...

• Main Authors: Young, Tun Jan, Christoffersen, Poul, Doyle, Samuel, Nicholls, Keith, Stewart, Craig, Hubbard, Bryn, Hubbard, Alun, Lok, Lai Bun, Bennan, Paul, Luckman, Adrian, Bougamont, Marion
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley-Blackwell 2019
• Subjects: Glacier; Greenland; Ice Sheet; Radar; Strain; glacier
• Online Access: https://dx.doi.org/10.17863/cam.36083; https://www.repository.cam.ac.uk/handle/1810/288820

Temporal variations in ice sheet flow directly impact the internal structure within ice sheets through englacial deformation. Large-scale changes in the vertical stratigraphy within ice sheets have been previously conducted on centennial to millennial timescales; however, intra-annual changes in the morphology of internal layers have yet to be explored. Over a period of two years, we use autonomous phase-sensitive radio-echo sounding (ApRES) to track the daily displacement of internal layers on Store Glacier, West Greenland to millimeter accuracy. At a site located ~30 km from the calving terminus, where the ice is ~600m thick and flows at ~700m/yr, we measure distinct seasonal variations in vertical velocities and vertical strain rates over a two-year period. Prior to the melt season (March–June), we observe increasingly non-linear englacial deformation with negative vertical strain rates (i.e. strain thinning) in the upper half of the ice column of ~0.03 a-1, whereas the ice below thickens under vertical ...