DOI: 10.1016/j.agrformet.2020.107936
论文题名: Precipitation extremes influence patterns and partitioning of evapotranspiration and transpiration in a deciduous boreal larch forest
作者: Liu J. ; Cheng F. ; Munger W. ; Jiang P. ; Whitby T.G. ; Chen S. ; Ji W. ; Man X.
刊名: Agricultural and Forest Meteorology
ISSN: 1681923
出版年: 2020
卷: 287 语种: 英语
英文关键词: Boreal forests
; Climate anomaly
; Ecosystem stability
; Phenology
; Precipitation extreme
Scopus关键词: boreal forest
; deciduous forest
; ecosystem function
; eddy covariance
; evapotranspiration
; hydrological change
; MODIS
; permafrost
; phenology
; precipitation (climatology)
; pressure gradient
; vapor pressure
; water availability
; China
; Siberia
; Coniferophyta
; Larix
英文摘要: High latitude boreal forests are experiencing dramatic changes in climate and hydrology. It is not clear how boreal forests will adapt to hydrological change or how stable they will be to extreme climate fluctuations and shifts in ecosystem water availability (EWA; residuals between precipitation and evapotranspiration). Although there have been numerous studies in North American and European boreal forests, the Siberian boreal region is underrepresented. Moreover, Siberia is dominated by deciduous conifers (larch) that may have different response to shifting hydrology than boreal evergreens do. We observed evapotranspiration (ET) by eddy covariance technique and transpiration (T) by sap-flow probes on a subsample of trees within the flux-tower footprint through two growing seasons in a larch forest in northernmost China. Ecosystems at the margins of their zone could be amongst the first to experience significant shifts in structure and function. At this site there have already been signs of permafrost degradation and more frequent temperature and precipitation anomalies. The canopy-dominant larch accounted for half the total T fluxes. The remaining 50% was distributed evenly among intermediate and suppressed trees. T is the dominant subcomponent in ET, where overall T/ET varies of 66%–84% depending on precipitation patterns. In dormant and early growing seasons, T still constitutes a majority of ET even though the canopy foliage is not fully developed because cold soil creates a negative soil to air vapor pressure gradient that impedes evaporation. However, in the peak growing season, excess precipitation reduces T while providing sufficient wetness for surface evaporation. ET from standard data product based on MODIS satellite reflectance underestimates tower ET by 17%–29%. Solar-induced chlorophyll fluorescence measured by satellite is well correlated with tower ET (r2 = 0.69–0.73) and could provide a better basis for regional ET extrapolations. A global comparison of data for 2000–2018 period reveals that boreal forests not only have the smallest annual MODIS ET but also the least EWA compared to temperate and tropical forests. Also, even though boreal deciduous and evergreens have comparable annual ET, their T/ET and EWA are distinct. This work highlights how short-term precipitation extremes may shift ecosystem function and structure by changing EWA through exported runoff. Sites along boreal ecotones are critical to observe for signs of shifts in their structure, function, and response to climate anomalies. © 2020 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/158088
Appears in Collections: 气候变化与战略
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作者单位: Arts and Science, New York University Shanghai, 1555 Century Avenue, Shanghai, 200122, China; School of Engineering and Applied Sciences, Harvard University, 29 Oxford Street, Cambridge, 02138, United States; School of Life Sciences, Fudan University, 2005 Songhu Road, Shanghai, 200438, China; Department of Earth and Planetary Sciences, Harvard University, 20 Oxford Street, Cambridge, 02138, United States; College of Urban and Environmental Sciences, Peking University, 5 Yiheyuan Road, Beijing, 100871, China; School of Physics, Peking University, 5 Yiheyuan Road, Beijing, 100871, China; School of Forestry, Northeastern Forestry University, 26 Hexing Road, Harbin, 150040, China
Recommended Citation:
Liu J.,Cheng F.,Munger W.,et al. Precipitation extremes influence patterns and partitioning of evapotranspiration and transpiration in a deciduous boreal larch forest[J]. Agricultural and Forest Meteorology,2020-01-01,287