DOI: 10.5194/hess-21-1875-2017
Scopus记录号: 2-s2.0-85016816123
论文题名: Cosmic-ray neutron transport at a forest field site: The sensitivity to various environmental conditions with focus on biomass and canopy interception
作者: Andreasen M ; , Jensen K ; H ; , Desilets D ; , Zreda M ; , Bogena H ; R ; , Looms M ; C
刊名: Hydrology and Earth System Sciences
ISSN: 10275606
出版年: 2017
卷: 21, 期: 4 起始页码: 1875
结束页码: 1894
语种: 英语
Scopus关键词: Biomass
; Cosmology
; Forestry
; Moisture
; Neutron flux
; Neutrons
; Sensitivity analysis
; Soil moisture
; Soils
; Transport properties
; Upper atmosphere
; Canopy interception
; Cosmic ray neutron
; Dry bulk densities
; Environmental conditions
; Epithermal neutron
; Neutron intensities
; Neutron transport
; Soil moisture estimation
; Cosmic rays
; biomass
; bulk density
; cosmic ray
; environmental conditions
; environmental effect
; estimation method
; forest canopy
; forest soil
; fundamental particle
; hydrogen
; interception
; measurement method
; sensitivity analysis
; soil moisture
; transport process
; Denmark
英文摘要: Cosmic-ray neutron intensity is inversely correlated to all hydrogen present in the upper decimeters of the subsurface and the first few hectometers of the atmosphere above the ground surface. This correlation forms the base of the cosmic-ray neutron soil moisture estimation method. The method is, however, complicated by the fact that several hydrogen pools other than soil moisture affect the neutron intensity. In order to improve the cosmic-ray neutron soil moisture estimation method and explore the potential for additional applications, knowledge about the environmental effect on cosmic-ray neutron intensity is essential (e.g., the effect of vegetation, litter layer and soil type). In this study the environmental effect is examined by performing a sensitivity analysis using neutron transport modeling. We use a neutron transport model with various representations of the forest and different parameters describing the subsurface to match measured height profiles and time series of thermal and epithermal neutron intensities at a field site in Denmark. Overall, modeled thermal and epithermal neutron intensities are in satisfactory agreement with measurements; however, the choice of forest canopy conceptualization is found to be significant. Modeling results show that the effect of canopy interception, soil chemistry and dry bulk density of litter and mineral soil on neutron intensity is small. On the other hand, the neutron intensity decreases significantly with added litter-layer thickness, especially for epithermal neutron energies. Forest biomass also has a significant influence on the neutron intensity height profiles at the examined field site, altering both the shape of the profiles and the ground-level thermal-to-epithermal neutron ratio. This ratio increases with increasing amounts of biomass, and was confirmed by measurements from three sites representing agricultural, heathland and forest land cover. A much smaller effect of canopy interception on the ground-level thermal-to-epithermal neutron ratio was modeled. Overall, the results suggest a potential to use ground-level thermal-to-epithermal neutron ratios to discriminate the effect of different hydrogen contributions on the neutron signal. © 2017 The Author(s). Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/79206
Appears in Collections: 气候变化事实与影响
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作者单位: Department of Geosciences and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark; Hydroinnova LLC, Albuquerque, United States; Department of Hydrology and Water Resources, University of Arizona, United States; Agrosphere IBG-3, Forschungszentrum Jülich GmbH, Jülich, Germany
Recommended Citation:
Andreasen M,, Jensen K,H,et al. Cosmic-ray neutron transport at a forest field site: The sensitivity to various environmental conditions with focus on biomass and canopy interception[J]. Hydrology and Earth System Sciences,2017-01-01,21(4)