气候变化领域集成服务门户(CCPortal): Global assessment of how averaging over spatial heterogeneity in precipitation and potential evapotranspiration affects modeled evapotranspiration rates

CCPortal

DOI	10.5194/hess-24-1927-2020
	Global assessment of how averaging over spatial heterogeneity in precipitation and potential evapotranspiration affects modeled evapotranspiration rates
	Rouholahnejad Freund E.; Fan Y.; W. Kirchner J.
发表日期	2020
ISSN	1027-5606
起始页码	1927
结束页码	1938
卷号	24 期号:4
英文摘要	pAccurately estimating large-scale evapotranspiration (ET) rates is essential to understanding and predicting global change. Evapotranspiration models that are applied at a continental scale typically operate on relatively large spatial grids, with the result that the heterogeneity in land surface properties and processes at smaller spatial scales cannot be explicitly represented. Averaging over this spatial heterogeneity may lead to biased estimates of energy and water fluxes. Here we estimate how averaging over spatial heterogeneity in precipitation (span classCombining double low line"inline-formula"iP/i/span) and potential evapotranspiration (PET) may affect grid-cell-averaged evapotranspiration rates, as seen from the atmosphere over heterogeneous landscapes across the globe. Our goal is to identify where, under what conditions, and at what scales this "heterogeneity bias" could be most important but not to quantify its absolute magnitude. We use Budyko curves as simple functions that relate ET to precipitation and potential evapotranspiration. Because the relationships driving ET are nonlinear, averaging over subgrid heterogeneity in span classCombining double low line"inline-formula"iP/i/span and PET will lead to biased estimates of average ET. We examine the global distribution of this bias, its scale dependence, and its sensitivity to variations in span classCombining double low line"inline-formula"iP/i/span vs. PET. Our analysis shows that this heterogeneity bias is more pronounced in mountainous terrain, in landscapes where spatial variations in span classCombining double low line"inline-formula"iP/i/span and PET are inversely correlated, and in regions with temperate climates and dry summers. We also show that this heterogeneity bias increases on average, and expands over larger areas, as the grid cell size increases./p. © 2020 Royal Society of Chemistry. All rights reserved.
语种	英语
scopus关键词	Sensitivity analysis; Evapotranspiration models; Global distribution; Heterogeneous landscapes; Land surface properties; Mountainous terrain; Potential evapotranspiration; Sensitivity to variations; Spatial heterogeneity; Evapotranspiration; global change; global perspective; heterogeneity; land surface; potential evapotranspiration; precipitation (climatology); water flux
来源期刊	Hydrology and Earth System Sciences
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/159437
作者单位	Rouholahnejad Freund, E., Laboratory of Hydrology and Water Management, Ghent University, Ghent, Belgium, Department of Environmental Systems Science, ETH Zurich, Zurich, 8092, Switzerland; Fan, Y., Department of Earth and Planetary Sciences, Rutgers University, New Brunswick, NJ 08854, United States; W. Kirchner, J., Department of Environmental Systems Science, ETH Zurich, Zurich, 8092, Switzerland, Swiss Federal Research Institute WSL, Birmensdorf, 8903, Switzerland, Department of Earth and Planetary Science, University of California, Berkeley, CA 94720, United States
推荐引用方式 GB/T 7714	Rouholahnejad Freund E.,Fan Y.,W. Kirchner J.. Global assessment of how averaging over spatial heterogeneity in precipitation and potential evapotranspiration affects modeled evapotranspiration rates[J],2020,24(4).
APA	Rouholahnejad Freund E.,Fan Y.,&W. Kirchner J..(2020).Global assessment of how averaging over spatial heterogeneity in precipitation and potential evapotranspiration affects modeled evapotranspiration rates.Hydrology and Earth System Sciences,24(4).
MLA	Rouholahnejad Freund E.,et al."Global assessment of how averaging over spatial heterogeneity in precipitation and potential evapotranspiration affects modeled evapotranspiration rates".Hydrology and Earth System Sciences 24.4(2020).