Greenland ice sheet rainfall, heat and albedo feedback impacts from the mid-August 2021 atmospheric river

Jason E. Box, Adrien Wehrlé, Dirk van As, Robert S. Fausto, Kristian K. Kjeldsen, Amrin Dachauer, Andreas P. Ahlstrøm, Ghislain Picard

Research output: Contribution to journalArticleResearchpeer-review

19 Citations (Scopus)


Rainfall at the Greenland ice sheet Summit 14 August 2021, was delivered by an atmospheric river (AR). Extreme surface ablation expanded the all-Greenland bare ice area to near-record-high with snowline climbing up to 788 ± 90 m. Ice sheet wet snow extent reached 46%, a record high for the 15–31 August AMSR data since 2003. Heat-driven firn deflation averaged 0.14 ± 0.05 m at four accumulation area automatic weather stations (AWSs). Energy budget calculations from AWS data indicate that surface heating from rainfall is much smaller than from either the sensible, latent, net-longwave or solar energy fluxes. Sensitivity tests show that without the heat-driven snow-darkening, melt at 1,840 m would have totaled 28% less. Similarly, at 1,270 m elevation, without the bare ice exposure, melting would have been 51% less. Proglacial river discharge was the highest on record since 2006 for late August and confirms the melt-sustaining effect of the albedo feedback.

Original languageEnglish
Article numbere2021GL097356
Number of pages11
JournalGeophysical Research Letters
Issue number11
Publication statusPublished - 16 Jun 2022


  • albedo feedback
  • atmospheric river
  • Greenland ice sheet
  • heatwave
  • rain on snow
  • runoff

Programme Area

  • Programme Area 5: Nature and Climate


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