The patterns and implications of diurnal variations in the d-excess of plant water, shallow soil water and air moisture (EI)

CORC > 寒区旱区环境与工程研究所 > 中科院寒区旱区环境与工程研究所（未分类） > 期刊论文

	The patterns and implications of diurnal variations in the d-excess of plant water, shallow soil water and air moisture (EI)
	Zhao L. ; Wang L. ; Liu X. ; Xiao H. ; Ruan Y. ; Zhou M.
刊名	Hydrology and Earth System Sciences
	2014
卷号	18 期号:10 页码:4129-4151
英文摘要	Deuterium excess (d-excess) of air moisture is traditionally considered a conservative tracer of oceanic evaporation conditions. Recent studies challenge this view and emphasize the importance of vegetation activity in controlling the dynamics of air moisture d-excess. However, direct field observations supporting the role of vegetation in d-excess variations are not well documented. In this study, we quantified the d-excess of air moisture, shallow soil water (5 and 10 cm) and plant water (leaf, root and xylem) of multiple dominant species at hourly intervals during three extensive field campaigns at two climatically different locations within the Heihe River basin, northwestern China. The ecosystems at the two locations range from forest to desert. The results showed that with the increase in temperature (T) and the decrease in relative humidity (RH), the D-18O regression lines of leaf water, xylem water and shallow soil water deviated gradually from their corresponding local meteoric water line. There were significant differences in d-excess values between different water pools at all the study sites. The most positive d-excess values were found in air moisture (9.3) and the most negative d-excess values were found in leaf water (85.6). The d-excess values of air moisture (dmoisture) and leaf water (dleaf) during the sunny days, and shallow soil water (dsoil) during the first sunny day after a rain event, showed strong diurnal patterns. There were significantly positive relationships between dleaf and RH and negative relationships between dmoisture and RH. The correlations of dleaf and dmoisture with T were opposite to their relationships with RH. In addition, we found opposite diurnal variations for dleaf and dmoisture during the sunny days, and for dsoil and dmoisture during the first sunny day after the rain event. The steady-state Craig-Gordon model captured the diurnal variations in dleaf, with small discrepancies in the magnitude. Overall, this study provides a comprehensive and high-resolution data set of d-excess of air moisture, leaf, root, xylem and soil water. Our results provide direct evidence that dmoisture of the surface air at continental locations can be significantly altered by local processes, especially plant transpiration during sunny days. The influence of shallow soil water on dmoisture is generally much smaller compared with that of plant transpiration, but the influence could be large on a sunny day right after rainfall events. 2014 Author(s).
收录类别	EI
公开日期	2015-12-24
内容类型	期刊论文
源URL	[http://ir.casnw.net/handle/362004/25184]
专题	寒区旱区环境与工程研究所_中科院寒区旱区环境与工程研究所（未分类）_期刊论文
推荐引用方式 GB/T 7714	Zhao L.,Wang L.,Liu X.,et al. The patterns and implications of diurnal variations in the d-excess of plant water, shallow soil water and air moisture (EI)[J]. Hydrology and Earth System Sciences,2014,18(10):4129-4151.
APA	Zhao L.,Wang L.,Liu X.,Xiao H.,Ruan Y.,&Zhou M..(2014).The patterns and implications of diurnal variations in the d-excess of plant water, shallow soil water and air moisture (EI).Hydrology and Earth System Sciences,18(10),4129-4151.
MLA	Zhao L.,et al."The patterns and implications of diurnal variations in the d-excess of plant water, shallow soil water and air moisture (EI)".Hydrology and Earth System Sciences 18.10(2014):4129-4151.