Regional atmospheric cooling and wetting effect of permafrost thaw‐induced boreal forest loss
Abstract In the sporadic permafrost zone of North America, thaw‐induced boreal forest loss is leading to permafrost‐free wetland expansion. These land cover changes alter landscape‐scale surface properties with potentially large, however, still unknown impacts on regional climates. In this study, we...
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crwiley:10.1111/gcb.13348 2024-09-15T18:26:40+00:00 Regional atmospheric cooling and wetting effect of permafrost thaw‐induced boreal forest loss Helbig, Manuel Wischnewski, Karoline Kljun, Natascha Chasmer, Laura E. Quinton, William L. Detto, Matteo Sonnentag, Oliver Fonds de Recherche du Québec - Nature et Technologies German Academic Exchange Service New Delhi Canada Research Chairs Canada Foundation for Innovation Natural Sciences and Engineering Research Council of Canada 2016 http://dx.doi.org/10.1111/gcb.13348 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fgcb.13348 https://onlinelibrary.wiley.com/doi/pdf/10.1111/gcb.13348 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Global Change Biology volume 22, issue 12, page 4048-4066 ISSN 1354-1013 1365-2486 journal-article 2016 crwiley https://doi.org/10.1111/gcb.13348 2024-08-30T04:12:16Z Abstract In the sporadic permafrost zone of North America, thaw‐induced boreal forest loss is leading to permafrost‐free wetland expansion. These land cover changes alter landscape‐scale surface properties with potentially large, however, still unknown impacts on regional climates. In this study, we combine nested eddy covariance flux tower measurements with satellite remote sensing to characterize the impacts of boreal forest loss on albedo, eco‐physiological and aerodynamic surface properties, and turbulent energy fluxes of a lowland boreal forest region in the Northwest Territories, Canada. Planetary boundary layer modelling is used to estimate the potential forest loss impact on regional air temperature and atmospheric moisture. We show that thaw‐induced conversion of forests to wetlands increases albedo: and bulk surface conductance for water vapour and decreases aerodynamic surface temperature. At the same time, heat transfer efficiency is reduced. These shifts in land surface properties increase latent at the expense of sensible heat fluxes, thus, drastically reducing Bowen ratios. Due to the lower albedo of forests and their masking effect of highly reflective snow, available energy is lower in wetlands, especially in late winter. Modelling results demonstrate that a conversion of a present‐day boreal forest–wetland to a hypothetical homogeneous wetland landscape could induce a near‐surface cooling effect on regional air temperatures of up to 3–4 °C in late winter and 1–2 °C in summer. An atmospheric wetting effect in summer is indicated by a maximum increase in water vapour mixing ratios of 2 mmol mol −1 . At the same time, maximum boundary layer heights are reduced by about a third of the original height. In fall, simulated air temperature and atmospheric moisture between the two scenarios do not differ. Therefore, permafrost thaw‐induced boreal forest loss may modify regional precipitation patterns and slow down regional warming trends. Article in Journal/Newspaper Northwest Territories permafrost Wiley Online Library Global Change Biology 22 12 4048 4066 |
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Wiley Online Library |
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English |
description |
Abstract In the sporadic permafrost zone of North America, thaw‐induced boreal forest loss is leading to permafrost‐free wetland expansion. These land cover changes alter landscape‐scale surface properties with potentially large, however, still unknown impacts on regional climates. In this study, we combine nested eddy covariance flux tower measurements with satellite remote sensing to characterize the impacts of boreal forest loss on albedo, eco‐physiological and aerodynamic surface properties, and turbulent energy fluxes of a lowland boreal forest region in the Northwest Territories, Canada. Planetary boundary layer modelling is used to estimate the potential forest loss impact on regional air temperature and atmospheric moisture. We show that thaw‐induced conversion of forests to wetlands increases albedo: and bulk surface conductance for water vapour and decreases aerodynamic surface temperature. At the same time, heat transfer efficiency is reduced. These shifts in land surface properties increase latent at the expense of sensible heat fluxes, thus, drastically reducing Bowen ratios. Due to the lower albedo of forests and their masking effect of highly reflective snow, available energy is lower in wetlands, especially in late winter. Modelling results demonstrate that a conversion of a present‐day boreal forest–wetland to a hypothetical homogeneous wetland landscape could induce a near‐surface cooling effect on regional air temperatures of up to 3–4 °C in late winter and 1–2 °C in summer. An atmospheric wetting effect in summer is indicated by a maximum increase in water vapour mixing ratios of 2 mmol mol −1 . At the same time, maximum boundary layer heights are reduced by about a third of the original height. In fall, simulated air temperature and atmospheric moisture between the two scenarios do not differ. Therefore, permafrost thaw‐induced boreal forest loss may modify regional precipitation patterns and slow down regional warming trends. |
author2 |
Fonds de Recherche du Québec - Nature et Technologies German Academic Exchange Service New Delhi Canada Research Chairs Canada Foundation for Innovation Natural Sciences and Engineering Research Council of Canada |
format |
Article in Journal/Newspaper |
author |
Helbig, Manuel Wischnewski, Karoline Kljun, Natascha Chasmer, Laura E. Quinton, William L. Detto, Matteo Sonnentag, Oliver |
spellingShingle |
Helbig, Manuel Wischnewski, Karoline Kljun, Natascha Chasmer, Laura E. Quinton, William L. Detto, Matteo Sonnentag, Oliver Regional atmospheric cooling and wetting effect of permafrost thaw‐induced boreal forest loss |
author_facet |
Helbig, Manuel Wischnewski, Karoline Kljun, Natascha Chasmer, Laura E. Quinton, William L. Detto, Matteo Sonnentag, Oliver |
author_sort |
Helbig, Manuel |
title |
Regional atmospheric cooling and wetting effect of permafrost thaw‐induced boreal forest loss |
title_short |
Regional atmospheric cooling and wetting effect of permafrost thaw‐induced boreal forest loss |
title_full |
Regional atmospheric cooling and wetting effect of permafrost thaw‐induced boreal forest loss |
title_fullStr |
Regional atmospheric cooling and wetting effect of permafrost thaw‐induced boreal forest loss |
title_full_unstemmed |
Regional atmospheric cooling and wetting effect of permafrost thaw‐induced boreal forest loss |
title_sort |
regional atmospheric cooling and wetting effect of permafrost thaw‐induced boreal forest loss |
publisher |
Wiley |
publishDate |
2016 |
url |
http://dx.doi.org/10.1111/gcb.13348 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fgcb.13348 https://onlinelibrary.wiley.com/doi/pdf/10.1111/gcb.13348 |
genre |
Northwest Territories permafrost |
genre_facet |
Northwest Territories permafrost |
op_source |
Global Change Biology volume 22, issue 12, page 4048-4066 ISSN 1354-1013 1365-2486 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1111/gcb.13348 |
container_title |
Global Change Biology |
container_volume |
22 |
container_issue |
12 |
container_start_page |
4048 |
op_container_end_page |
4066 |
_version_ |
1810467182190002176 |