DOI: 10.1029/2018JD029159
Scopus记录号: 2-s2.0-85052941321
论文题名: Why Do Large-Scale Land Surface Models Produce a Low Ratio of Transpiration to Evapotranspiration?
作者: Chang L.-L. ; Dwivedi R. ; Knowles J.F. ; Fang Y.-H. ; Niu G.-Y. ; Pelletier J.D. ; Rasmussen C. ; Durcik M. ; Barron-Gafford G.A. ; Meixner T.
刊名: Journal of Geophysical Research: Atmospheres
ISSN: 2169897X
出版年: 2018
卷: 123, 期: 17 起始页码: 9109
结束页码: 9130
语种: 英语
英文关键词: complex mountain terrain
; ET partitioning
; land surface models (LSMs)
; lateral surface and subsurface flows
; soil surface evaporation
; three-dimensional process-based ecohydrological model
英文摘要: Most land surface models (LSMs) used in Earth System Models produce a lower ratio of transpiration (T) to evapotranspiration (ET) than field observations, degrading the credibility of Earth System Model-projected ecosystem responses and feedbacks to climate change. To interpret this model deficiency, we conducted a pair of model experiments using a three-dimensional, process-based ecohydrological model in a subhumid, mountainous catchment. One experiment (CTRL) describes lateral water flow, topographic shading, leaf dynamics, and water vapor diffusion in the soil, while the other (LSM like) does not explicitly describe these processes to mimic a conventional LSM using artificially flattened terrain. Averaged over the catchment, CTRL produced a higher T/ET ratio (72%) than LSM like (55%) and agreed better with an independent estimate (79.79 ± 27%) based on rainfall and stream water isotopes. To discern the exact causes, we conducted additional model experiments, each reverting only one process described in CTRL to that of LSM like. These experiments revealed that the enhanced T/ET ratio was mostly caused by lateral water flow and water vapor diffusion within the soil. In particular, terrain-driven lateral water flows spread out soil moisture to a wider range along hillslopes with an optimum subrange from the middle to upper slopes, where evaporation (E) was more suppressed by the drier surface than T due to plant uptake of deep soil water, thereby enhancing T/ET. A more elaborate representation of water vapor diffusion from a dynamically changing evaporating surface to the height of the surface roughness length reduced E and increased the T/ET ratio. ©2018. 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/113206
Appears in Collections: 气候减缓与适应
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作者单位: Department of Hydrology and Atmospheric Sciences, University of Arizona, Tucson, AZ, United States; School of Geography and Development, University of Arizona, Tucson, AZ, United States; Department of Hydrology and Water Resources, Hohai University, Nanjing, China; Biosphere 2, University of Arizona, Tucson, AZ, United States; Department of Geosciences, University of Arizona, Tucson, AZ, United States; Department of Soil, Water, and Environmental Science, University of Arizona, Tucson, AZ, United States
Recommended Citation:
Chang L.-L.,Dwivedi R.,Knowles J.F.,et al. Why Do Large-Scale Land Surface Models Produce a Low Ratio of Transpiration to Evapotranspiration?[J]. Journal of Geophysical Research: Atmospheres,2018-01-01,123(17)