Preprints
https://doi.org/10.5194/egusphere-2023-2385
https://doi.org/10.5194/egusphere-2023-2385
02 Nov 2023
 | 02 Nov 2023

Mapping the vertical heterogeneity of Greenland’s firn from 2011–2019 using airborne radar and laser altimetry

Anja Rutishauser, Kirk Michael Scanlan, Baptiste Vandecrux, Nanna B. Karlsson, Nicolas Jullien, Andreas Peter Ahlstrøm, Robert S. Fausto, and Penelope How

Abstract. The firn layer on the Greenland Ice Sheet (GrIS) plays a crucial role in buffering surface meltwater runoff, which is constrained by the available firn pore space and impermeable ice layers that limit deeper meltwater percolation. Understanding these firn properties is essential for predicting current and future meltwater runoff and its contribution to global sea-level rise. While very high-frequency (VHF) radars have been extensively used for surveying the GrIS, their lower bandwidth restricts direct firn stratigraphy extraction. In this study, we use concurrent VHF airborne radar and laser altimetry data collected as part of Operation Ice Bridge (OIB) over the period 2011–2019 to investigate vertical offsets in the radar surface reflection (dz). Our results, corroborated by modelling and firn core analyses, show that a dz larger than 1 m is strongly related to the vertical heterogeneity of a firn profile, and effectively delineates between vertically homogeneous and vertically heterogeneous firn profiles. Temporal variations in dz align with climatic events and reveal an expansion of heterogeneous firn between 2011–2013 covering an area of ~338,450 km2, followed by firn replenishment over the years 2014–2019 spanning an area of ~664,734 km2. Our approach reveals the firn evolution of key regions on the Greenland Ice Sheet, providing valuable insights for detecting potential alterations in meltwater runoff patterns.

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this preprint. The responsibility to include appropriate place names lies with the authors.
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Journal article(s) based on this preprint

17 May 2024
Mapping the vertical heterogeneity of Greenland's firn from 2011–2019 using airborne radar and laser altimetry
Anja Rutishauser, Kirk M. Scanlan, Baptiste Vandecrux, Nanna B. Karlsson, Nicolas Jullien, Andreas P. Ahlstrøm, Robert S. Fausto, and Penelope How
The Cryosphere, 18, 2455–2472, https://doi.org/10.5194/tc-18-2455-2024,https://doi.org/10.5194/tc-18-2455-2024, 2024
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The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.

Short summary
The Greenland Ice sheet interior is covered by a layer of firn, which is important for surface...
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