Climatic influences on active layer depth between 2000 and 2018 in the McMurdo Dry Valleys, Ross Sea Region, Antarctica

• Published in: Geoderma Regional Vol. 29; p. e00497
• Main Authors: Carshalton, A.G., Balks, M.R., O'Neill, T.A., Bryan, K.R., Seybold, C.A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.06.2022
• Subjects: Active layer; Amundsen Sea Low; Antarctica; Climatic drivers; Cryosols; ENSO; Gelisols; McMurdo Dry Valleys; Permafrost temperature; Southern Annular Mode; McMurdo Dry Valleys; ENSO; Climatic drivers; Permafrost temperature; Southern Annular Mode; Active layer; Cryosols; Antarctica; Amundsen Sea Low; Gelisols
• ISSN: 2352-0094; 2352-0094
• DOI: 10.1016/j.geodrs.2022.e00497

The maximum seasonal depth of thaw (the active layer depth) in permafrost soils is influenced by a range of soil and atmospheric variables. The active layer depth and the temperature at the top of the permafrost have potential to provide a clear signal of a changing climate, damping out noise more effectively than atmospheric variables. A monitoring network of nine soil climate stations was established in the McMurdo Dry Valleys between 1999 and 2012. Each station monitors soil temperature to a depth of up to 1.2 m, along with a range of atmospheric variables including air temperature, solar radiation, and wind speed. Over the period of record included in this study (2000–2018): the mean active layer depth ranged from 7.6 cm at Mt. Fleming to >90 cm at Granite Harbour; the mean annual shallow (15 cm) soil temperature ranged from −24 °C at Mt. Fleming to −14 °C at Granite Harbour; and the mean summer air temperature ranged from −11 °C at Mt. Fleming to −1 °C at Granite Harbour. There was marked between-year variation but no significant trends of increase or decrease in active layer depth, or temperature at the top of the permafrost, between 2000 and 2018. Wavelet analysis showed that both global and regional climate systems correlated with de-seasonalised temperature at the top of the permafrost. The Southern Annular Mode had relationships at both annual and biannual timescales (p < 0.05); the Southern Oscillation Index had a relationship at a 2–3 year timescale (p < 0.05); and the Amundsen Sea Low had an annual signal and some between season signals (p < 0.05). The data set is too short to draw conclusions on potential longer-term changes in the soil climate. Nevertheless, the database provides a baseline against which future change can be assessed and will increase in value the longer it is maintained. •Soil climate has been monitored in the McMurdo Region, Antarctica for up to 18 years between 2000 and 2018.•Active layer Depth in the Ross Sea Region, Antarctica showed no trends of warming or cooling between 2000 and 2018.•Annual and summer air and top of the permafrost temperatures showed no trends of warming or cooling between 2000 and 2018.•There was a correlation between continental climate systems SAM and SOI and deseasonalised permafrost.•There was a correlation between the Amundsen Sea Low and deseasonalised permafrost data.