A1 Refereed original research article in a scientific journal
Aeolian blowout dynamics in subarctic Lapland based on decadal levelling investigations
Authors: Kayhko Jukka
Publisher: WILEY-BLACKWELL
Publication year: 2007
Journal:Geografiska Annaler: Series A, Physical Geography
Journal name in sourceGEOGRAFISKA ANNALER SERIES A-PHYSICAL GEOGRAPHY
Journal acronym: GEOGR ANN A
Volume: 89A
Issue: 1
First page : 65
Last page: 81
Number of pages: 17
ISSN: 0435-3676
DOI: https://doi.org/DOI: 10.1111/j.1468-0459.2007.00308.x
Web address : http://onlinelibrary.wiley.com/doi/10.1111/j.1468-0459.2007.00308.x/pdf
Aeolian processes in the subarctic ecocline were investigated by measuring present-day erosion and deposition rates over a decade in blowouts scoured into stabilized Early to Mid-Holocene dunes. Four localities from different vegetation zones in Finnish Lapland were surveyed using precision levelling (infrared tachymeter) along eight transects at 1-m intervals. During an 11-year observation period, a total of 1439 observation points were monitored in three measurement campaigns, in 1993, 1994 and 2004. Together with dating results reported elsewhere, the results demonstrate the relative quiescence of these subarctic blowouts compared to many coastal dunes. On average, the deflation rate of the studied basins was 8.8 mm a(-1), which corresponds well with the age and depth of the blowouts. Net deposition had taken place at 30% of the observation points, and one of the eight studied transects showed net deposition as the transect average. Symmetrical, smooth basins showed more consistent changes than basins with a complex form, indicating that internal factors are important in blowout formation under the Lapland climatic range. The deepest part of a blowout was generally found in the upwind end. The erosion/deposition patterns of the transects over a one-year monitoring period were interpreted with Fourier analysis revealing along-transect cyclicity, possibly reflecting the movement of small migrating bedforms in the blowouts. Generally, deflation rates at the latitudinal pine forest line were smaller than at those well outside the pine forest suggesting that the coniferous forest at the subarctic ecocline affects the intensity of present-day aeolian activity in Fennoscandia.
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