Pan-Antarctic map of near-surface permafrost temperatures at 1 km&amp;lt;sup&amp;gt;2&amp;lt;/sup&amp;gt; scale

Andrey Abramov,Megan Ruby Balks,Miguel Ramos,Gonçalo Vieira,Annett Bartsch,Jaroslav Obu,Filip Hrbáček,Andreas Kääb,Sebastian Westermann

doi:10.5194/tc-14-497-2020

Abstract

Abstract. 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.

Highlights

Permafrost in the Antarctic is present beneath all ice-free terrain, except for the lowest elevations of the maritime Antarctic and sub-Antarctic islands (Vieira et al, 2010)
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
Near-surface permafrost temperatures in the Antarctic were most commonly modelled as being between −23 and −18 ◦C for mountainous areas rising above the Antarctic Ice Sheet

Summary

Introduction

Permafrost in the Antarctic is present beneath all ice-free terrain, except for the lowest elevations of the maritime Antarctic and sub-Antarctic islands (Vieira et al, 2010). Despite the relatively small area, in comparison to glaciated areas, permafrost is one of the major factors controlling terrestrial ecosystem dynamics in the Antarctic (Bockheim et al, 2008). Compared with the Northern Hemisphere, where the first permafrost investigations date back to the 19th century (Shiklomanov, 2005; Humlum et al, 2003), the ground temperatures in the Antarctic have been systematically stud-. J. Obu et al.: Pan-Antarctic map of near-surface permafrost temperatures at 1 km scale ied only during the last 2 decades. The first Antarctic permafrost borehole network was implemented in 1999 in Victoria Land (Transantarctic Mountains) and was extended during the International Polar Year 2007–2009 to cover all eight major ice-free regions (Vieira et al, 2010)

Methods

Results

Discussion

Conclusion