Greenland bare-ice albedo from PROMICE automatic weather station measurements and Sentinel-3 satellite observations

• Published in: GEUS Bulletin
• Main Authors: Adrien Wehrlé, Jason E. Box, Masashi Niwano, Alexandre M. Anesio, Robert S. Fausto
• Format: Article in Journal/Newspaper
• Language: English
• Published: Geological Survey of Denmark and Greenland 2021
• Subjects: greenland ice sheet; albedo; ice ablation; promice; sentinel-3; Geology; QE1-996.5; Geophysics. Cosmic physics; QC801-809; Greenland; Ice Sheet
• Online Access: https://doi.org/10.34194/geusb.v47.5284; https://doaj.org/article/2294f1775fee486e88121ef69546937f

The Programme for Monitoring of the Greenland Ice Sheet (PROMICE) provides surface meteorological and glaciological measurements from widespread on-ice automatic weather stations since mid-2007. In this study, we use 105 PROMICE ice-ablation time series to identify the timing of seasonal bare-ice onset preceded by snow cover conditions. From this collection, we find a bare-ice albedo at ice-ablation onset (here called bare-ice-onset albedo) of 0.565 ± 0.109 that has no apparent spatial dependence among 20 sites across Greenland. We then apply this snow-to-ice albedo transition value to measure the variations in daily Greenland bare-ice area in Sentinel-3 optical satellite imagery covering the extremely low and high respective melt years of 2018 and 2019. Daily Greenland bare-ice area peaked at 153 489 km² in 2019, 1.9 times larger than in 2018 (80 220 km²), equating to 9.0% (in 2019) and 4.7% (in 2018) of the ice sheet area.