Pan-Antarctic map of near-surface permafrost temperatures at 1 km2 scale

• Published in: The Cryosphere
• Main Authors: J. Obu, S. Westermann, G. Vieira, A. Abramov, M. R. Balks, A. Bartsch, F. Hrbáček, A. Kääb, M. Ramos
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2020
• Subjects: geo; envir; Antarctic; Markham; Mount Markham; Queen Elizabeth Range; The Antarctic; Transantarctic Mountains; Antarc*; Ice; Ice Sheet; permafrost; The Cryosphere
• Online Access: https://doi.org/10.5194/tc-14-497-2020; https://www.the-cryosphere.net/14/497/2020/tc-14-497-2020.pdf; https://doaj.org/article/cac86d94f32c45888670b926495dda43

Permafrost is present within almost all of the Antarctic's ice-free areas, but little is known about spatial variations in permafrost temperatures except for a few areas with established ground temperature measurements. We modelled a temperature at the top of the permafrost (TTOP) for all the ice-free areas of the Antarctic mainland and Antarctic islands at 1 km2 resolution during 2000–2017. The model was driven by remotely sensed land surface temperatures and downscaled ERA-Interim climate reanalysis data, and subgrid permafrost variability was simulated by variable snow cover. The results were validated against in situ-measured ground temperatures from 40 permafrost boreholes, and the resulting root-mean-square error was 1.9 ∘C. The lowest near-surface permafrost temperature of −36 ∘C was modelled at Mount Markham in the Queen Elizabeth Range in the Transantarctic Mountains. This is the lowest permafrost temperature on Earth, according to global-scale modelling results. The temperatures were most commonly modelled between −23 and −18 ∘C for mountainous areas rising above the Antarctic Ice Sheet and between −14 and −8 ∘C for coastal areas. The model performance was good where snow conditions were modelled realistically, but errors of up to 4 ∘C occurred at sites with strong wind-driven redistribution of snow.