气候变化领域集成服务门户(CCPortal): Drought effects on evapotranspiration and energy exchange over a rain-fed maize cropland in the Chinese Loess Plateau

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DOI	10.1016/j.agwat.2024.108711
	Drought effects on evapotranspiration and energy exchange over a rain-fed maize cropland in the Chinese Loess Plateau
	Zheng, Han; Sun, Yuchen; Bao, Han; Niu, Panpan; Jin, Zhao; Niu, Zhongen
发表日期	2024
ISSN	0378-3774
EISSN	1873-2283
起始页码	293
卷号	293
英文摘要	Characterizing dynamics of evapotranspiration (ET) and energy exchange is of particular importance for the water resource use and management in the water -limited agricultural areas under global climate change. Based on eddy covariance method, this study analyzed the seasonal and interannual variations of ET and energy fluxes over a rain -fed spring maize cropland in the Chinese Loess Plateau during 2 years which presented contrasting precipitation (P) totals and patterns in 2019 (drought year) and 2020 (normal year). Results showed obvious intra- and inter -annual variabilities of ET and energy fluxes related with crop phenology and water availability. Annual ET were 339.3 and 386.5 mm yr-1 in 2019 and 2020, respectively, with separate annual ET/P ratios of 0.84 and 0.70. Annual ET was dominated by ET during growing season (May -September), with close proportions of 75.8% and 72.9% for the two years. The partitioning of net radiation (Rn) was dominated by latent heat flux (LE) during growing season, but was primarily driven by sensible heat flux (H) during non -growing season. Annual ratios of LE/Rn and H/Rn were comparable in the drought year (0.46 -0.47), while LE/Rn (0.52) dominated over H/Rn (0.46) in the normal year. Similar seasonal courses were observed in surface conductance (gs), decoupling factor (omega), and Priestley -Taylor coefficient (alpha), consistently peaking during the rapid growth period of maize (July -August). The low annual means of omega (0.20 -0.25) and alpha (0.44 -0.45) implied the strongly aerodynamical coupling and biophysical control on ET for the study area. Moreover, daily alpha in this study increased significantly with increasing gs until a threshold around 10 mm s- 1. Structural equation modelling revealed that the environmental constraints on ET were mainly affected by Rn , soil water content and vapor pressure deficit (VPD) in the drought year, and prone to be dominated by Rn , leaf area index (LAI) and VPD in the normal year. These results indicated that drought may increase the sensitivity of maize ET to water supply condition, and decrease the sensitivity to changes in available energy, aerodynamic condition and vegetation coverage. This study will provide insights into the effects of drought on energy partitioning and the environmental and biophysical controls on ET in the region.
英文关键词	Drought; Evapotranspiration; Energy partitioning; Eddy covariance; Maize; Surface conductance
语种	英语
WOS研究方向	Agriculture ; Water Resources
WOS类目	Agronomy ; Water Resources
WOS记录号	WOS:001175559900001
来源期刊	AGRICULTURAL WATER MANAGEMENT
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/305834
作者单位	Chang'an University; Chang'an University; Chinese Academy of Sciences; Institute of Earth Environment, CAS; Xi'an Jiaotong University; Beijing Normal University; Ludong University
推荐引用方式 GB/T 7714	Zheng, Han,Sun, Yuchen,Bao, Han,et al. Drought effects on evapotranspiration and energy exchange over a rain-fed maize cropland in the Chinese Loess Plateau[J],2024,293.
APA	Zheng, Han,Sun, Yuchen,Bao, Han,Niu, Panpan,Jin, Zhao,&Niu, Zhongen.(2024).Drought effects on evapotranspiration and energy exchange over a rain-fed maize cropland in the Chinese Loess Plateau.AGRICULTURAL WATER MANAGEMENT,293.
MLA	Zheng, Han,et al."Drought effects on evapotranspiration and energy exchange over a rain-fed maize cropland in the Chinese Loess Plateau".AGRICULTURAL WATER MANAGEMENT 293(2024).