Thermal state and active layer thickness in Collado Irizar, Deception Island, Antarctica: 2009-2013 period

GOYANES G.; VIEIRA, G.; CASELLI, A.

La Serena

Congreso; VII Congreso Latinoamericano de Ciencia Antártica; 2013

Centro de Estudios Avanzados en Zonas Áridas e Instituto Antártico Chileno

The Antarctic Peninsula is one of the regions in the World with a stronger climate warming trend, with an increase of ca. +2.5ºC in the mean annual air temperatures (MAAT) since 1950. While glaciers and ice-shelves are being monitored to evaluate the effects of climate change, permafrost, an important component of the Antarctic cryosphere has been largely neglected and only recently started to be monitored systematically (Vieira et al. 2010a, Bockheim et al. 2013). Permafrost is present beneath virtually all ice-free terrain, except at the lowest elevations of the maritime Antarctic and sub-Antarctic islands (Ramos et al. 2012). In addition, permafrost occurrence has been confirmed in the South Shetlands through both periglacial landform analysis, exposures, geophysics and boreholes. Climate at the South Shetland is cold-oceanic at sea level, with frequent summer rainfalls and a moderate annual temperature range. Mean annual air temperatures are close to -2 ºC at sea level and average relative humidity is very high (80-90%, Ramos et al. 2012). Deception Island (62º57?S; 60º38?W) is the south-westernmost island of the Bransfield Strait. The island represents the top of a complex volcanic structure characterized by a horseshoe-like shape with an opening in the south-east sector (Neptune Bellows) and a flooded caldera (Port Foster). The volcanic activity on the island developed in the last 0.2 Ma and the latest eruptions occurred in 1967, 1969 and 1970. The island has a distinct annual cycle of ground freezing (from autumn to mid-spring) and thawing (austral summer) (Ramos et al. 2012). The aim of this work is showing the first results about the thermal regime and the active layer thickness (ALT) evolution from the summer of 2008-2009 to the summer of 2012-2013 at Irizar CALM-S site in Deception Island. This site is part of The Global Terrestrial Network for Permafrost (GTN-P) and of the Circumpolar Active Layer Monitoring (CALM), initiated by the International Permafrost Association (IPA) to organize and manage a global network of permafrost observatories for detecting, monitoring and predicting climate change, and to monitor changes in active layer thickness and temperature.