DOI: 10.1002/2017JG003988
Scopus记录号: 2-s2.0-85041211958
论文题名: Impact of Canopy Decoupling and Subcanopy Advection on the Annual Carbon Balance of a Boreal Scots Pine Forest as Derived From Eddy Covariance
作者: Jocher G. ; Marshall J. ; Nilsson M.B. ; Linder S. ; De Simon G. ; Hörnlund T. ; Lundmark T. ; Näsholm T. ; Ottosson Löfvenius M. ; Tarvainen L. ; Wallin G. ; Peichl M.
刊名: Journal of Geophysical Research: Biogeosciences
ISSN: 21698953
出版年: 2018
卷: 123, 期: 2 起始页码: 303
结束页码: 325
语种: 英语
英文关键词: ecosystem respiration (Reco)
; flux partitioning
; gap filling
; gross primary production (GPP)
; net ecosystem CO2 exchange (NEE)
; Pinus sylvestris
Scopus关键词: advection
; carbon balance
; carbon dioxide
; coniferous forest
; eddy covariance
; forest canopy
; net ecosystem exchange
; radiation budget
; respiration
; stand structure
; wind velocity
; Sweden
; Pinus sylvestris
英文摘要: Apparent net uptake of carbon dioxide (CO2) during wintertime by an ∼ 90 year old Scots pine stand in northern Sweden led us to conduct canopy decoupling and subcanopy advection investigations over an entire year. Eddy covariance (EC) measurements ran simultaneously above and within the forest canopy for that purpose. We used the correlation of above- and below-canopy standard deviation of vertical wind speed (σw) as decoupling indicator. We identified 0.33 m s−1 and 0.06 m s−1 as site-specific σw thresholds for above- and below-canopy coupling during nighttime (global radiation <20 W m−2) and 0.23 m s−1 and 0.06 m s−1 as daytime (global radiation >20 W m−2) σw thresholds. Decoupling occurred in 53% of the annual nighttime and 14% of the annual daytime. The annual net ecosystem exchange (NEE), gross ecosystem exchange (GEE), and ecosystem respiration (Reco) derived via two-level filtered EC data were −357 g C m−2, −1,138 g C m−2, and 781 g C m−2, respectively. In comparison, both single-level friction velocity (u*) and quality filtering resulted in ~ 22% higher NEE, mainly caused by ~ 16% lower Reco. GEE remained similar among filtering regimes. Accounting for changes of CO2 storage across the canopy in the single-level filtered data could only marginally decrease these discrepancies. Consequently, advection appears to be responsible for the major part of this divergence. We conclude that the two-level filter is necessary to adequately address decoupling and subcanopy advection at our site, and we recommend this filter for all forested EC sites. ©2017. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/114508
Appears in Collections: 气候减缓与适应
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作者单位: Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden; Southern Swedish Forest Research Centre, SLU, Alnarp, Sweden; Vindeln Experimental Forests, SLU, Vindeln, Sweden; Department of Biological and Environmental Science, University of Gothenburg, Gothenburg, Sweden
Recommended Citation:
Jocher G.,Marshall J.,Nilsson M.B.,et al. Impact of Canopy Decoupling and Subcanopy Advection on the Annual Carbon Balance of a Boreal Scots Pine Forest as Derived From Eddy Covariance[J]. Journal of Geophysical Research: Biogeosciences,2018-01-01,123(2)