Geophysical mapping of palsa peatland permafrost

• Published in: The Cryosphere
• Main Authors: Sjöberg, Ylva, Marklund, Per, Pettersson, Rickard, Lyon, Steve W.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Stockholms universitet, Institutionen för naturgeografi 2015
• Subjects: permafrost; ground penetrating radar; electrical resistivity tomography; Other Earth and Related Environmental Sciences; Annan geovetenskap och miljövetenskap; Arctic; Northern Sweden; palsa; The Cryosphere
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-115888; https://doi.org/10.5194/tc-9-465-2015

Permafrost peatlands are hydrological and biogeochemicalhotspots in the discontinuous permafrost zone.Non-intrusive geophysical methods offer a possibility tomap current permafrost spatial distributions in these environments.In this study, we estimate the depths to the permafrosttable and base across a peatland in northern Sweden,using ground penetrating radar and electrical resistivitytomography. Seasonal thaw frost tables (at 0.5m depth),taliks (2.1–6.7m deep), and the permafrost base (at 16mdepth) could be detected. Higher occurrences of taliks werediscovered at locations with a lower relative height of permafrostlandforms, which is indicative of lower ground icecontent at these locations. These results highlight the addedvalue of combining geophysical techniques for assessing spatialdistributions of permafrost within the rapidly changingsporadic permafrost zone. For example, based on a back-ofthe-envelope calculation for the site considered here, we estimatedthat the permafrost could thaw completely within thenext 3 centuries. Thus there is a clear need to benchmark currentpermafrost distributions and characteristics, particularlyin under studied regions of the pan-Arctic.