DOI: 10.5194/hess-18-1137-2014
Scopus记录号: 2-s2.0-84897085504
论文题名: Generalized combination equations for canopy evaporation under dry and wet conditions
作者: Lhomme J ; P ; , Montes C
刊名: Hydrology and Earth System Sciences
ISSN: 10275606
出版年: 2014
卷: 18, 期: 3 起始页码: 1137
结束页码: 1149
语种: 英语
Scopus关键词: Grading
; Available energy
; Canopy evaporations
; Dry and wet conditions
; Exchange surfaces
; One-dimensional model
; Penman-Monteith models
; Vapour pressure deficits
; Vegetation-atmosphere interactions
; Evaporation
; atmosphere-biosphere interaction
; boundary layer
; canopy
; evaporation
; leaf area
; numerical model
; one-dimensional modeling
; Penman-Monteith equation
; seasonality
; soil surface
; vapor pressure
; vegetation cover
英文摘要: The formulation of canopy evaporation is investigated on the basis of the combination equation derived from the Penman equation. All the elementary resistances (surface and boundary layer) within the canopy are taken into account, and the exchange surfaces are assumed to be subject to the same vapour pressure deficit at canopy source height. This development leads to generalized combination equations: one for completely dry canopies and the other for partially wet canopies. These equations are rather complex because they involve the partitioning of available energy within the canopy and between the wet and dry surfaces. By making some assumptions and approximations, they can provide simpler equations similar to the common Penman-Monteith model. One of the basic assumptions of this down-grading process is to consider that the available energy intercepted by the different elements making up the canopy is uniformly distributed and proportional to their respective area. Despite the somewhat unrealistic character of this hypothesis, it allows one to retrieve the simple formulations commonly and successfully used up to now. Numerical simulations are carried out by means of a simple one-dimensional model of the vegetation-atmosphere interaction with two different leaf area profiles. In dry conditions and when the soil surface is moist (low surface resistance), there is a large discrepancy between the generalized formulation and its simpler Penman-Monteith form, but much less when the soil surface is dry. In partially wet conditions, the Penman-Monteith-type equation substantially underestimates the generalized formulation when leaves are evenly distributed, but provides better estimates when leaves are concentrated in the upper half of the canopy. © 2014 Author(s). Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/78292
Appears in Collections: 气候变化事实与影响
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作者单位: IRD, UMR, LISAH, 2 Place Viala, 34060 Montpellier, France
Recommended Citation:
Lhomme J,P,, Montes C. Generalized combination equations for canopy evaporation under dry and wet conditions[J]. Hydrology and Earth System Sciences,2014-01-01,18(3)