气候变化领域集成服务门户(CCPortal): Groundwater Regulates Interannual Variations in Evapotranspiration in a Riparian Semiarid Ecosystem

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DOI	10.1029/2020JD033078
	Groundwater Regulates Interannual Variations in Evapotranspiration in a Riparian Semiarid Ecosystem
	Missik J.E.C.; Liu H.; Gao Z.; Huang M.; Chen X.; Arntzen E.; Mcfarland D.P.; Verbeke B.
发表日期	2021
ISSN	2169897X
卷号	126 期号:7
英文摘要	Drylands are an important component of Earth's carbon, water, and energy budgets. Changes in hydroclimatic conditions can significantly alter land surface fluxes in these ecosystems. In regions with groundwater-river water exchange, land surface fluxes are strongly modulated by groundwater table fluctuations in response to river stage variations; however, interactions between fluxes and groundwater remain poorly understood in drylands. Here, we use eddy covariance data collected in paired upland and riparian semiarid ecosystems (AmeriFlux sites US-Hn1 and US-Hn2) during 4 years with contrasting river flow conditions to examine interactions among river stage, water table dynamics, meteorological drivers, and ecosystem fluxes. Elevated groundwater availability resulting from groundwater-surface water exchange at the riparian site enhanced the latent heat flux (LE, the energy form of evapotranspiration), which was sustained longer in the growing season. Interannual variation of dry season LE was small at the upland site, while at the riparian site contrasting river flow conditions resulted in large interannual variability in LE, with June LE of high-flow years being 2.3 times that of low-flow years. The 4-year mean summer LE at the riparian site was 2.1 times larger than that at the upland site. Carbon uptake (NEP) and LE were well correlated at the upland site at the monthly and annual timescales, but at the riparian site enhanced LE due to shallow water table depth did not correspond to enhanced NEP. Our results demonstrate that enhanced groundwater availability modulated by river stage is a critical driver of land surface fluxes in semiarid riparian ecosystems. © 2021. American Geophysical Union. All Rights Reserved.
英文关键词	eddy covariance; groundwater; semiarid ecosystems; sensible and latent heat fluxes; surface energy budget
语种	英语
来源期刊	Journal of Geophysical Research: Atmospheres
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/185324
作者单位	Laboratory for Atmospheric Research, Department of Civil and Environmental Engineering, Washington State University, Pullman, WA, United States; Pacific Northwest National Laboratory, Richland, WA, United States; Now at Office of Science and Technology Integration, National Weather Service, National Oceanic and Atmospheric Administration, Washington, DC, United States
推荐引用方式 GB/T 7714	Missik J.E.C.,Liu H.,Gao Z.,et al. Groundwater Regulates Interannual Variations in Evapotranspiration in a Riparian Semiarid Ecosystem[J],2021,126(7).
APA	Missik J.E.C..,Liu H..,Gao Z..,Huang M..,Chen X..,...&Verbeke B..(2021).Groundwater Regulates Interannual Variations in Evapotranspiration in a Riparian Semiarid Ecosystem.Journal of Geophysical Research: Atmospheres,126(7).
MLA	Missik J.E.C.,et al."Groundwater Regulates Interannual Variations in Evapotranspiration in a Riparian Semiarid Ecosystem".Journal of Geophysical Research: Atmospheres 126.7(2021).