文章基本信息

标题：Non-closure of the surface energy balance explained by phase difference between vertical velocity and scalars of large atmospheric eddies
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作者：Zhongming Gao ; Heping Liu ; Gabriel G Katul 等
期刊名称：Environmental Research Letters
印刷版ISSN：1748-9326
电子版ISSN：1748-9326
出版年度：2017
卷号：12
期号：3
页码：034025
DOI：10.1088/1748-9326/aa625b
语种：English
出版社：IOP Publishing Ltd
摘要：It is now accepted that large-scale turbulent eddies impact the widely reported non-closure of the surface energy balance when latent and sensible heat fluxes are measured using the eddy covariance method in the atmospheric surface layer (ASL). However, a mechanistic link between large eddies and non-closure of the surface energy balance remains a subject of inquiry. Here, measured 10 Hz time series of vertical velocity, air temperature, and water vapor density collected in the ASL are analyzed for conditions where entrainment and/or horizontal advection separately predominate. The series are decomposed into small- and large- eddies based on a frequency cutoff and their contributions to turbulent fluxes are analyzed. Phase difference between vertical velocity and water vapor density associated with large eddies reduces latent heat fluxes, especially in conditions where advection prevails. Enlarged phase difference of large eddies linked to entrainment or advection occurrence leads to increased residuals of the surface energy balance.