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Incorporating the effect of heterogeneous surface heating into a semi-empirical model of the surface energy balance closure

It was discovered several decades ago that eddy covariance measurements systematically underestimate sensible and latent heat fluxes, creating an imbalance in the surface energy budget. Since then, many studies have addressed this problem and proposed a variety of solutions to the problem, including...

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Autores principales: Wanner, Luise, Calaf, Marc, Mauder, Matthias
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9159583/
https://www.ncbi.nlm.nih.gov/pubmed/35648756
http://dx.doi.org/10.1371/journal.pone.0268097
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author Wanner, Luise
Calaf, Marc
Mauder, Matthias
author_facet Wanner, Luise
Calaf, Marc
Mauder, Matthias
author_sort Wanner, Luise
collection PubMed
description It was discovered several decades ago that eddy covariance measurements systematically underestimate sensible and latent heat fluxes, creating an imbalance in the surface energy budget. Since then, many studies have addressed this problem and proposed a variety of solutions to the problem, including improvements to instruments and correction methods applied during data postprocessing. However, none of these measures have led to the complete closure of the energy balance gap. The leading hypothesis is that not only surface-attached turbulent eddies but also sub-mesoscale atmospheric circulations contribute to the transport of energy in the atmospheric boundary layer, and the contribution from organized motions has been grossly neglected. The problem arises because the transport of energy through these secondary circulations cannot be captured by the standard eddy covariance method given the relatively short averaging periods of time (~30 minutes) used to compute statistics. There are various approaches to adjust the measured heat fluxes by attributing the missing energy to the sensible and latent heat flux in different proportions. However, few correction methods are based on the processes causing the energy balance gap. Several studies have shown that the magnitude of the energy balance gap depends on the atmospheric stability and the heterogeneity scale of the landscape around the measurement site. Based on this, the energy balance gap within the surface layer has already been modelled as a function of a nonlocal atmospheric stability parameter by performing a large-eddy simulation study with idealized homogeneous surfaces. We have further developed this approach by including thermal surface heterogeneity in addition to atmospheric stability in the parameterization. Specifically, we incorporated a thermal heterogeneity parameter that was shown to relate to the magnitude of the energy balance gap. For this purpose, we use a Large-Eddy Simulation dataset of 28 simulations with seven different atmospheric conditions and three heterogeneous surfaces with different heterogeneity scales as well as one homogeneous surface. The newly developed model captures very well the variability in the magnitude of the energy balance gap under different conditions. The model covers a wide range of both atmospheric stabilities and landscape heterogeneity scales and is well suited for application to eddy covariance measurements since all necessary information can be modelled or obtained from a few additional measurements.
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spelling pubmed-91595832022-06-02 Incorporating the effect of heterogeneous surface heating into a semi-empirical model of the surface energy balance closure Wanner, Luise Calaf, Marc Mauder, Matthias PLoS One Research Article It was discovered several decades ago that eddy covariance measurements systematically underestimate sensible and latent heat fluxes, creating an imbalance in the surface energy budget. Since then, many studies have addressed this problem and proposed a variety of solutions to the problem, including improvements to instruments and correction methods applied during data postprocessing. However, none of these measures have led to the complete closure of the energy balance gap. The leading hypothesis is that not only surface-attached turbulent eddies but also sub-mesoscale atmospheric circulations contribute to the transport of energy in the atmospheric boundary layer, and the contribution from organized motions has been grossly neglected. The problem arises because the transport of energy through these secondary circulations cannot be captured by the standard eddy covariance method given the relatively short averaging periods of time (~30 minutes) used to compute statistics. There are various approaches to adjust the measured heat fluxes by attributing the missing energy to the sensible and latent heat flux in different proportions. However, few correction methods are based on the processes causing the energy balance gap. Several studies have shown that the magnitude of the energy balance gap depends on the atmospheric stability and the heterogeneity scale of the landscape around the measurement site. Based on this, the energy balance gap within the surface layer has already been modelled as a function of a nonlocal atmospheric stability parameter by performing a large-eddy simulation study with idealized homogeneous surfaces. We have further developed this approach by including thermal surface heterogeneity in addition to atmospheric stability in the parameterization. Specifically, we incorporated a thermal heterogeneity parameter that was shown to relate to the magnitude of the energy balance gap. For this purpose, we use a Large-Eddy Simulation dataset of 28 simulations with seven different atmospheric conditions and three heterogeneous surfaces with different heterogeneity scales as well as one homogeneous surface. The newly developed model captures very well the variability in the magnitude of the energy balance gap under different conditions. The model covers a wide range of both atmospheric stabilities and landscape heterogeneity scales and is well suited for application to eddy covariance measurements since all necessary information can be modelled or obtained from a few additional measurements. Public Library of Science 2022-06-01 /pmc/articles/PMC9159583/ /pubmed/35648756 http://dx.doi.org/10.1371/journal.pone.0268097 Text en © 2022 Wanner et al https://creativecommons.org/licenses/by/4.0/This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Wanner, Luise
Calaf, Marc
Mauder, Matthias
Incorporating the effect of heterogeneous surface heating into a semi-empirical model of the surface energy balance closure
title Incorporating the effect of heterogeneous surface heating into a semi-empirical model of the surface energy balance closure
title_full Incorporating the effect of heterogeneous surface heating into a semi-empirical model of the surface energy balance closure
title_fullStr Incorporating the effect of heterogeneous surface heating into a semi-empirical model of the surface energy balance closure
title_full_unstemmed Incorporating the effect of heterogeneous surface heating into a semi-empirical model of the surface energy balance closure
title_short Incorporating the effect of heterogeneous surface heating into a semi-empirical model of the surface energy balance closure
title_sort incorporating the effect of heterogeneous surface heating into a semi-empirical model of the surface energy balance closure
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9159583/
https://www.ncbi.nlm.nih.gov/pubmed/35648756
http://dx.doi.org/10.1371/journal.pone.0268097
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