Comparing the frost environment of three disparate locations: Western Dronning Maud Land of Antarctica, sub-Antarctic Marion Island and the High Drakensberg of South Africa

Abstract

Frost processes occur across climatic zones and warming temperatures affect regions where climatic thresholds are narrow. This paper explores the annual, seasonal and diurnal frost environments of three locations: western Dronning Maud Land (WDML) of Antarctica, sub-Antarctic Marion Island, and the High Drakensberg of the Eastern Cape of South Africa. WDML is characterised by continuous permafrost and a paucity of diurnal thawing and a shallow active layer. Permafrost is absent on both sub-Antarctic Marion Island and in continental South Africa. Marion Island is, however, characterised by a dynamic diurnal frost environment, with shallow and high-frequency cycles. The High Drakensberg of the Eastern Cape of South Africa exhibit seasonal freezing at higher altitudes with frozen ground occurring for periods of up two months at ~ 3000 m.a.s.l. Global warming scenarios (1°C, 2°C and 5°C increases) and how these affect freezing cycles are explored, as are environmental and locational forcings on freezing cycles observed. The results from WDML contribute towards scientific output and research of ANTPAS (Antarctic Permafrost and Soils) and the Global Terrestrial Network for Permafrost (GTN-P). Higher altitudes show an increase in frost cycles; vegetation cover dampens such cycles. Furthermore, snow cover reduces diurnal frost in WDML, whereas it increases the depth of freezing on Marion Island. Finally, diurnal frost cycles are highly sensitive to temperature changes and associated thresholds and that such cycles can be used as indicators for warming conditions.