DOI: 10.1111/gcb.13348
论文题名: Regional atmospheric cooling and wetting effect of permafrost thaw-induced boreal forest loss
作者: Helbig M. ; Wischnewski K. ; Kljun N. ; Chasmer L.E. ; Quinton W.L. ; Detto M. ; Sonnentag O.
刊名: Global Change Biology
出版年: 2016
卷: 22, 期: 12 起始页码: 4048
结束页码: 4066
语种: 英语
英文关键词: boreal forest
; climate change
; eddy covariance
; energy flux
; evapotranspiration
; land cover change
; permafrost
; wetland
Scopus关键词: atmospheric modeling
; boreal forest
; climate change
; cooling
; eddy covariance
; energy flux
; evapotranspiration
; land cover
; permafrost
; regional climate
; thawing
; wetland
; wetting
; North America
; atmosphere
; climate
; cold
; Northwest Territories
; permafrost
; taiga
; Atmosphere
; Climate
; Cold Temperature
; Northwest Territories
; Permafrost
; Taiga
英文摘要: 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. © 2016 John Wiley & Sons Ltd 资助项目: Helbig, M.
; Département de géographie & Centre d’études nordiques, Université de Montréal, 520 Chemin de la Côte Sainte-Catherine, Canada
; 电子邮件: manuel.helbig@umontreal.ca
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/61242
Appears in Collections: 影响、适应和脆弱性
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作者单位: Département de géographie & Centre d’études nordiques, Université de Montréal, 520 Chemin de la Côte Sainte-Catherine, Montréal, QC, Canada; Department of Geography, Swansea University, Swansea, Singleton Park, Swansea, United Kingdom; Department of Geography, University of Lethbridge, 4401 University Drive, Lethbridge, AB, Canada; Cold Regions Research Centre, Wilfrid Laurier University, 75 University Ave. W, Waterloo, ON, Canada; Smithsonian Tropical Research Institute, Luis Clement Ave., Bldg. 401 Tupper, Balboa Ancon, Panama, Panama
Recommended Citation:
Helbig M.,Wischnewski K.,Kljun N.,et al. Regional atmospheric cooling and wetting effect of permafrost thaw-induced boreal forest loss[J]. Global Change Biology,2016-01-01,22(12)