气候变化领域集成服务门户(CCPortal): Effects of Gentle Topography on Forest-Atmosphere Gas Exchanges and Implications for Eddy-Covariance Measurements

CCPortal

DOI	10.1029/2020JD032581
	Effects of Gentle Topography on Forest-Atmosphere Gas Exchanges and Implications for Eddy-Covariance Measurements
	Chen B.; Chamecki M.; Katul G.G.
发表日期	2020
ISSN	2169897X
卷号	125 期号:11
英文摘要	The interpretation of tower-based eddy-covariance (EC) turbulent flux measurements above forests hinges on three key assumptions: (1) steadiness in the flow statistics, (2) planar homogeneity of scalar sources or sinks, and (3) planar homogeneity in the flow statistics. Large eddy simulations (LESs) were used to control the first two so as to explore the break-down of the third for idealized and real gentle topography such as those encountered in Amazonia. The LES runs were conducted using uniformly distributed sources inside homogeneous forests covering complex terrain to link the spatial patterns of scalar turbulent fluxes to topographic features. Results showed strong modulation of the fluxes by flow features induced by topography, including large area with negative fluxes compensating “chimney” regions with fluxes almost an order of magnitude larger than the landscape flux. Significant spatial heterogeneity persisted up to at least two canopy heights, where most eddy-covariance measurements are performed above tall forests. A heterogeneity index was introduced to characterize and contrast different scenarios, and a topography categorization was shown to have predictive capabilities in identifying regions of negative and enhanced fluxes. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	Eddy covariance; Forest canopy; Gas transport; Lagrangian tracking model; Large eddy simulation; Topography
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/185983
作者单位	Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, CA, United States; Nicholas School of the Environment, Duke University, Durham, NC, United States; Department of Civil and Environmental Engineering, Duke University, Durham, NC, United States
推荐引用方式 GB/T 7714	Chen B.,Chamecki M.,Katul G.G.. Effects of Gentle Topography on Forest-Atmosphere Gas Exchanges and Implications for Eddy-Covariance Measurements[J],2020,125(11).
APA	Chen B.,Chamecki M.,&Katul G.G..(2020).Effects of Gentle Topography on Forest-Atmosphere Gas Exchanges and Implications for Eddy-Covariance Measurements.Journal of Geophysical Research: Atmospheres,125(11).
MLA	Chen B.,et al."Effects of Gentle Topography on Forest-Atmosphere Gas Exchanges and Implications for Eddy-Covariance Measurements".Journal of Geophysical Research: Atmospheres 125.11(2020).