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Changes in palsa distribution in relation to climate change in Laivadalen, northern Sweden, especially 1960–1997
Author(s) -
Zuidhoff Frieda S,
Kolstrup Else
Publication year - 2000
Publication title -
permafrost and periglacial processes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.867
H-Index - 76
eISSN - 1099-1530
pISSN - 1045-6740
DOI - 10.1002/(sici)1099-1530(200001/03)11:1<55::aid-ppp338>3.0.co;2-t
Subject(s) - permafrost , geology , climate change , physical geography , distribution (mathematics) , geomorphology , geography , oceanography , mathematical analysis , mathematics
Changes in the distribution of palsas in Sweden's most southerly major palsa bog are outlined from 1960 to 1997 using aerial photographs taken in 1960 and 1976 as well as a study reported in a publication from 1967 and fieldwork in 1996 and 1997. The geomorphological changes are compared with changes in temperature and precipitation. Between 1960 and 1997, there was a decrease of c . 50% in the area of palsas and no new palsas seem to have developed during the period. Temporary new frost mounds developed during a winter with low snow cover (1995–96) but had disappeared again at the start of the field season of 1997. From open sections in selected palsas, samples were selected at levels of vegetational change indicating stages in palsa development. Radiocarbon dates of 95plusmn;65 a BP and 105plusmn;65 a BP give ages for the start of growth of palsas and a date of 390±70 a BP may represent the last active phase of a previous palsa. The results suggest that some presently existing but decaying palsas started their growth possibly as late as during the last part of the Little Ice Age. It is suggested that the present decay of palsas could be the result of the 1–1.5 °C increase in mean annual temperature in northern Sweden during the last c . 100 years, in particular since the 1930s, probably in combination with increased snowfall since c . 1930. Copyright © 2000 John Wiley & Sons, Ltd.