DOI: 10.1111/gcb.13297
论文题名: Phenology and species determine growing-season albedo increase at the altitudinal limit of shrub growth in the sub-Arctic
作者: Williamson S.N. ; Barrio I.C. ; Hik D.S. ; Gamon J.A.
刊名: Global Change Biology
出版年: 2016
卷: 22, 期: 11 起始页码: 3621
结束页码: 3631
语种: 英语
英文关键词: albedo
; alpine tundra
; Betula
; growing season
; phenology
; Salix
Scopus关键词: albedo
; altitude
; growing season
; phenology
; shrub
; tundra
; Arctic
; Betula
; Betula glandulosa
; Salix
; Salix pulchra
; snow
; Arctic
; climate change
; season
; tundra
; Arctic Regions
; Climate Change
; Seasons
; Snow
; Tundra
英文摘要: Arctic warming is resulting in reduced snow cover and increased shrub growth, both of which have been associated with altered land surface–atmospheric feedback processes involving sensible heat flux, ground heat flux and biogeochemical cycling. Using field measurements, we show that two common Arctic shrub species (Betula glandulosa and Salix pulchra), which are largely responsible for shrub encroachment in tundra, differed markedly in albedo and that albedo of both species increased as growing season progressed when measured at their altitudinal limit. A moveable apparatus was used to repeatedly measure albedo at six precise spots during the summer of 2012, and resampled in 2013. Contrary to the generally accepted view of shrub-covered areas having low albedo in tundra, full-canopy prostrate B. glandulosa had almost the highest albedo of all surfaces measured during the peak of the growing season. The higher midsummer albedo is also evident in localized MODIS albedo aggregated from 2000 to 2013, which displays a similar increase in growing-season albedo. Using our field measurements, we show the ensemble summer increase in tundra albedo counteracts the generalized effect of earlier spring snow melt on surface energy balance by approximately 40%. This summer increase in albedo, when viewed in absolute values, is as large as the difference between the forest and tundra transition. These results indicate that near future (<50 years) changes in growing-season albedo related to Arctic vegetation change are unlikely to be particularly large and might constitute a negative feedback to climate warming in certain circumstances. Future efforts to calculate energy budgets and a sensible heating feedback in the Arctic will require more detailed information about the relative abundance of different ground cover types, particularly shrub species and their respective growth forms and phenology. © 2016 John Wiley & Sons Ltd 资助项目: Williamson, S.N.
; Department of Biological Sciences, University of AlbertaCanada
; 电子邮件: snw@ualberta.ca
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/61273
Appears in Collections: 影响、适应和脆弱性
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作者单位: Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada; Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB, Canada; Institute of Life and Environmental Sciences, University of Iceland, Sturlugata 7, Reykjavík, Iceland
Recommended Citation:
Williamson S.N.,Barrio I.C.,Hik D.S.,et al. Phenology and species determine growing-season albedo increase at the altitudinal limit of shrub growth in the sub-Arctic[J]. Global Change Biology,2016-01-01,22(11)