New insights into the environmental factors controlling the ground thermal regime across the Northern Hemisphere : a comparison between permafrost and non-permafrost areas

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http://hdl.handle.net/10138/299882

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Karjalainen , O , Luoto , M , Aalto , J & Hjort , J 2019 , ' New insights into the environmental factors controlling the ground thermal regime across the Northern Hemisphere : a comparison between permafrost and non-permafrost areas ' , Cryosphere , vol. 13 , no. 2 , pp. 693-707 . https://doi.org/10.5194/tc-13-693-2019

Julkaisun nimi: New insights into the environmental factors controlling the ground thermal regime across the Northern Hemisphere : a comparison between permafrost and non-permafrost areas
Tekijä: Karjalainen, Olli; Luoto, Miska; Aalto, Juha; Hjort, Jan
Tekijän organisaatio: Helsinki Institute of Sustainability Science (HELSUS)
Department of Geosciences and Geography
BioGeoClimate Modelling Lab
Päiväys: 2019-02-28
Kieli: eng
Sivumäärä: 15
Kuuluu julkaisusarjaan: Cryosphere
ISSN: 1994-0416
DOI-tunniste: https://doi.org/10.5194/tc-13-693-2019
URI: http://hdl.handle.net/10138/299882
Tiivistelmä: The thermal state of permafrost affects Earth surface systems and human activity in the Arctic and has implications for global climate. Improved understanding of the local-scale variability in the global ground thermal regime is required to account for its sensitivity to changing climatic and geoecological conditions. Here, we statistically related observations of mean annual ground temperature (MAGT) and active-layer thickness (ALT) to high-resolution (similar to 1 km(2)) geospatial data of climatic and local environmental conditions across the Northern Hemisphere. The aim was to characterize the relative importance of key environmental factors and the magnitude and shape of their effects on MAGT and ALT. The multivariate models fitted well to both response variables with average R-2 values being similar to 0.94 and 0.78. Corresponding predictive performances in terms of root-mean-square error were similar to 1.31 degrees C and 87 cm. Freezing (FDD) and thawing (TDD) degree days were key factors for MAGT inside and outside the permafrost domain with average effect sizes of 6.7 and 13.6 degrees C, respectively. Soil properties had marginal effects on MAGT (effect size = 0.4-0.7 degrees C). For ALT, rainfall (effect size = 181 cm) and solar radiation (161 cm) were most influential. Analysis of variable importance further underlined the dominance of climate for MAGT and highlighted the role of solar radiation for ALT. Most response shapes for MAGT
Avainsanat: 1172 Environmental sciences
ACTIVE-LAYER THICKNESS
MOUNTAIN PERMAFROST
SNOW COVER
CLIMATE
TEMPERATURES
HEAT
BASIN
STATE
Vertaisarvioitu: Kyllä
Tekijänoikeustiedot: cc_by
Pääsyrajoitteet: openAccess
Rinnakkaistallennettu versio: publishedVersion


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