Helheim Glacier ice velocity variability responds to runoff and terminus position change at different timescales

Lizz Ultee; Denis Felikson; Brent Minchew; Leigh A Stearns; Bryan Riel

doi:10.1038/s41467-022-33292-y

Helheim Glacier ice velocity variability responds to runoff and terminus position change at different timescales

Nat Commun. 2022 Oct 12;13(1):6022. doi: 10.1038/s41467-022-33292-y.

Authors

Lizz Ultee^{1

2

3}, Denis Felikson^{4

5}, Brent Minchew⁶, Leigh A Stearns⁷, Bryan Riel^{6

8}

Affiliations

¹ Dept. of Earth & Climate Sciences, Middlebury College, Middlebury, VT, USA. eultee@middlebury.edu.
² School of Earth & Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA. eultee@middlebury.edu.
³ Dept. of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA. eultee@middlebury.edu.
⁴ Cryospheric Sciences Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, USA.
⁵ Goddard Earth Sciences Technology and Research II, Morgan State University, Baltimore, MD, USA.
⁶ Dept. of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA.
⁷ Department of Geology, University of Kansas, Lawrence, KS, USA.
⁸ School of Earth Sciences, Zhejiang University, 310027, Hangzhou, China.

Abstract

The Greenland Ice Sheet discharges ice to the ocean through hundreds of outlet glaciers. Recent acceleration of Greenland outlet glaciers has been linked to both oceanic and atmospheric drivers. Here, we leverage temporally dense observations, regional climate model output, and newly developed time series analysis tools to assess the most important forcings causing ice flow variability at one of the largest Greenland outlet glaciers, Helheim Glacier, from 2009 to 2017. We find that ice speed correlates most strongly with catchment-integrated runoff at seasonal to interannual scales, while multi-annual flow variability correlates most strongly with multi-annual terminus variability. The disparate time scales and the influence of subglacial topography on Helheim Glacier's dynamics highlight different regimes that can inform modeling and forecasting of its future. Notably, our results suggest that the recent terminus history observed at Helheim is a response to, rather than the cause of, upstream changes.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Greenland
Ice Cover*
Oceans and Seas