DOI: 10.5194/hess-21-533-2017
Scopus记录号: 2-s2.0-85011030497
论文题名: Response of water vapour D-excess to land-atmosphere interactions in a semi-arid environment
作者: Parkes S ; D ; , McCabe M ; F ; , Griffiths A ; D ; , Wang L ; , Chambers S ; , Ershadi A ; , Williams A ; G ; , Strauss J ; , Element A
刊名: Hydrology and Earth System Sciences
ISSN: 10275606
出版年: 2017
卷: 21, 期: 1 起始页码: 533
结束页码: 548
语种: 英语
Scopus关键词: Evaporation
; Moisture
; Recycling
; Soil moisture
; Soils
; Water vapor
; Hydrological process
; Land atmosphere interaction
; Moisture sources
; Semi-arid environments
; Spatial and temporal variability
; Stable isotopic compositions
; Strong correlation
; Traditional measurement techniques
; Water recycling
; air-soil interaction
; evapotranspiration
; inversion layer
; isotopic composition
; moisture content
; relative humidity
; soil moisture
; soil water
; spatial variation
; temporal variation
; water vapor
英文摘要: The stable isotopic composition of water vapour provides information about moisture sources and processes difficult to obtain with traditional measurement techniques. Recently, it has been proposed that the D-excess of water vapour (dv =δ2H-8× δ18O) can provide a diagnostic tracer of continental moisture recycling. However, D-excess exhibits a diurnal cycle that has been observed across a variety of ecosystems and may be influenced by a range of processes beyond regional-scale moisture recycling, including local evaporation (ET) fluxes. There is a lack of measurements of D-excess in evaporation (ET) fluxes, which has made it difficult to assess how ET fluxes modify the Dexcess in water vapour (dv). With this in mind, we employed a chamber-based approach to directly measure D-excess in ET (dET) fluxes. We show that ET fluxes imposed a negative forcing on the ambient vapour and could not explain the higher daytime dv values. The low dET observed here was sourced from a soil water pool that had undergone an extended drying period, leading to low D-excess in the soil moisture pool. A strong correlation between daytime dv and locally measured relative humidity was consistent with an oceanic moisture source, suggesting that remote hydrological processes were the major contributor to daytime dv variability. During the early evening, ET fluxes into a shallow nocturnal inversion layer caused a lowering of dv values near the surface. In addition, transient mixing of vapour with a higher D-excess from above the nocturnal inversion modified these values, causing large variability during the night. These results indicate dET can generally be expected to show large spatial and temporal variability and to depend on the soil moisture state. For long periods between rain events, common in semi-arid environments, ET would be expected to impose negative forcing on the surface dv. Spatial and temporal variability of D-excess in ET fluxes therefore needs to be considered when using dv to study moisture recycling and during extended dry periods with weak moisture recycling may act as a tracer of the relative humidity at the oceanic moisture source. © Author(s) 2017. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/79279
Appears in Collections: 气候变化事实与影响
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作者单位: Water Desalination and Reuse Centre, King Abdullah University of Science and Technology (KAUST), Jeddah, Saudi Arabia; Department of Civil and Environmental Engineering, University of New South Wales, Sydney, Australia; Australian Nuclear Science and Technology Organization, Sydney, NSW, Australia; Department of Earth Sciences, Indiana University, Purdue University Indianapolis (IUPUI), Indianapolis, IN, United States
Recommended Citation:
Parkes S,D,, McCabe M,et al. Response of water vapour D-excess to land-atmosphere interactions in a semi-arid environment[J]. Hydrology and Earth System Sciences,2017-01-01,21(1)