Partitioning of evapotranspiration and its controls in four grassland ecosystems: Application of a two-source model

NWIPB OpenIR

	Partitioning of evapotranspiration and its controls in four grassland ecosystems: Application of a two-source model
	Hu Zhongmin 1,3; Yu Guirui 1; Zhou Yanlian 2; Sun Xiaomin 1; Li Yingnian 4; Shi Peili 1; Wang Yanfen 3; Song Xia 5; Zheng Zemei 1,3; Zhang Li 1; Li Shenggong 1
	2009-09-01
发表期刊	AGRICULTURAL AND FOREST METEOROLOGY
ISSN	0168-1923
卷号	149 期号:9 页码:1410-1420
文章类型	Article
摘要	Quantifying the partitioning of evapotranspiration (ET) and its controls are particularly important for accurate prediction of the climatic response of ecosystem carbon, water, and energy budgets. in this study, we employed the Shuttleworth-Wallace model to partition ET into soil water evaporation (E) and vegetation transpiration (7) at four grassland ecosystems in China. Two to three years (2003-2005) of continuous measurements of ET with the eddy covariance technique were used to test the long-term performance of the model. Monte Carlo simulations were performed to estimate the key parameters in the model and to evaluate the accuracy in model partitioning (i.e. E/ET). Results indicated that the simulated ET at the four ecosystems was in good agreement with the measurements at both the diurnal and seasonal timescales, but the model tended to underestimate ET by 3-11% on rainy days. probably due to the lack of model representation of rainfall interception. In general, E accounted for a large proportion of ET at these grasslands. The monthly E/ET ranged from 12% to 56% in the peak growing seasons and the annual E/ET ranged from 51% to 67% across the four ecosystems. Canopy stomatal conductance controlled E/ET at the diurnal timescale, and the variations and magnitude of leaf area index (LAI) explained most of the seasonal, annual, and site-to-site variations in E/ET. A simple linear relationship between growing season LAI and E/ET explained ca. 80% of the variation observed at the four sites for the 10 modeled site-years. Our work indicated that the daily E/ET decreased to a minimum value of ca. 10% for values of LAI greater than 3 m(2) m(-2) at the ecosystem with a dense canopy. The sensitivities of E/ET to changes in LAI increased with the decline in water and vegetation conditions at both the seasonal and the annual time scales, i.e., the variations in LAI could cause stronger effects on E/ET in the sparse-canopy ecosystems than in the dense-canopy ecosystems. It implies that the hydrological processes and vegetation productivity for ecosystems in and environments might be more vulnerable to projected climate change than those in humid environments. (C) 2009 Elsevier B.V. All rights reserved.; Quantifying the partitioning of evapotranspiration (ET) and its controls are particularly important for accurate prediction of the climatic response of ecosystem carbon, water, and energy budgets. in this study, we employed the Shuttleworth-Wallace model to partition ET into soil water evaporation (E) and vegetation transpiration (7) at four grassland ecosystems in China. Two to three years (2003-2005) of continuous measurements of ET with the eddy covariance technique were used to test the long-term performance of the model. Monte Carlo simulations were performed to estimate the key parameters in the model and to evaluate the accuracy in model partitioning (i.e. E/ET). Results indicated that the simulated ET at the four ecosystems was in good agreement with the measurements at both the diurnal and seasonal timescales, but the model tended to underestimate ET by 3-11% on rainy days. probably due to the lack of model representation of rainfall interception. In general, E accounted for a large proportion of ET at these grasslands. The monthly E/ET ranged from 12% to 56% in the peak growing seasons and the annual E/ET ranged from 51% to 67% across the four ecosystems. Canopy stomatal conductance controlled E/ET at the diurnal timescale, and the variations and magnitude of leaf area index (LAI) explained most of the seasonal, annual, and site-to-site variations in E/ET. A simple linear relationship between growing season LAI and E/ET explained ca. 80% of the variation observed at the four sites for the 10 modeled site-years. Our work indicated that the daily E/ET decreased to a minimum value of ca. 10% for values of LAI greater than 3 m(2) m(-2) at the ecosystem with a dense canopy. The sensitivities of E/ET to changes in LAI increased with the decline in water and vegetation conditions at both the seasonal and the annual time scales, i.e., the variations in LAI could cause stronger effects on E/ET in the sparse-canopy ecosystems than in the dense-canopy ecosystems. It implies that the hydrological processes and vegetation productivity for ecosystems in and environments might be more vulnerable to projected climate change than those in humid environments. (C) 2009 Elsevier B.V. All rights reserved.
关键词	Canopy Stomatal Conductance Evapotranspiration Leaf Area Index Shuttleworth-wallace Soil Water Evaporation
WOS标题词	Science & Technology ; Life Sciences & Biomedicine ; Physical Sciences
关键词[WOS]	WATER-USE EFFICIENCY ; SHUTTLEWORTH-WALLACE ; CARBON-DIOXIDE ; CHIHUAHUAN DESERT ; ENERGY-BALANCE ; EVAPORATION ; CANOPY ; SOIL ; TRANSPIRATION ; VEGETATION
收录类别	SCI
语种	英语
WOS研究方向	Agriculture ; Forestry ; Meteorology & Atmospheric Sciences
WOS类目	Agronomy ; Forestry ; Meteorology & Atmospheric Sciences
WOS记录号	WOS:000267626300004
引用统计	被引频次：214[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://210.75.249.4/handle/363003/1832
专题	中国科学院西北高原生物研究所
作者单位	1.Chinese Acad Sci, Inst Geog Sci & Nat Resources Res, Synth Res Ctr,Chinese Ecosyst Res Network, Key Lab Ecosyst Network Observat & Modeling, Beijing 100101, Peoples R China 2.Nanjing Univ, Sch Geog & Oceanog Sci, Nanjing 210093, Peoples R China 3.Chinese Acad Sci, Grad Univ, Beijing 100049, Peoples R China 4.Chinese Acad Sci, NW Inst Plateau Biol, Xining 810001, Peoples R China 5.Auburn Univ, Sch Forestry & Wildlife Sci, Ecosyst Dynam & Global Ecol Lab, Auburn, AL 36849 USA
推荐引用方式 GB/T 7714	Hu Zhongmin,Yu Guirui,Zhou Yanlian,et al. Partitioning of evapotranspiration and its controls in four grassland ecosystems: Application of a two-source model[J]. AGRICULTURAL AND FOREST METEOROLOGY,2009,149(9):1410-1420.
APA	Hu Zhongmin.,Yu Guirui.,Zhou Yanlian.,Sun Xiaomin.,Li Yingnian.,...&Li Shenggong.(2009).Partitioning of evapotranspiration and its controls in four grassland ecosystems: Application of a two-source model.AGRICULTURAL AND FOREST METEOROLOGY,149(9),1410-1420.
MLA	Hu Zhongmin,et al."Partitioning of evapotranspiration and its controls in four grassland ecosystems: Application of a two-source model".AGRICULTURAL AND FOREST METEOROLOGY 149.9(2009):1410-1420.