Scalar turbulent behavior in the roughness sublayer of an Amazonian forest.

Detalhes bibliográficos
Autor(a) principal: ZAHN, E.
Data de Publicação: 2016
Outros Autores: DIAS, N. L., ARAUJO, A., SÁ, L. D. A., SÖRGEL, M., TREBS, I., WOLFF, S., MANZI, A.
Tipo de documento: Artigo
Idioma: eng
Título da fonte: Repositório Institucional da EMBRAPA (Repository Open Access to Scientific Information from EMBRAPA - Alice)
Texto Completo: http://www.alice.cnptia.embrapa.br/alice/handle/doc/1053165
Resumo: An important current problem in micrometeorology is the characterization of turbulence in the roughness sublayer (RSL), where most of the measurements above tall forests are made. There, scalar turbulent fluctuations display significant departures from the predictions of Monin?Obukhov similarity theory (MOST). In this work, we analyze turbulence data of virtual temperature, carbon dioxide, and water vapor in the RSL above an Amazonian forest (with a canopy height of 40&#8239;m), measured at 39.4 and 81.6&#8239;m above the ground under unstable conditions. We found that dimensionless statistics related to the rate of dissipation of turbulence kinetic energy (TKE) and the scalar variance display significant departures from MOST as expected, whereas the vertical velocity variance follows MOST much more closely. Much better agreement between the dimensionless statistics with the Obukhov similarity variable, however, was found for the subset of measurements made at a low zenith angle Z, in the range 0°&#8239;&#8201;<&#8201;&#8239;|Z|&#8239;&#8201;<&#8201;&#8239;20°. We conjecture that this improvement is due to the relationship between sunlight incidence and the ?activation?deactivation? of scalar sinks and sources vertically distributed in the forest. Finally, we evaluated the relaxation coefficient of relaxed eddy accumulation: it is also affected by zenith angle, with considerable improvement in the range 0°&#8239;&#8201;<&#8201;&#8239;|Z|&#8239;&#8201;<&#8201;&#8239;20°, and its values fall within the range reported in the literature for the unstable surface layer. In general, our results indicate the possibility of better stability-derived flux estimates for low zenith angle ranges.
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spelling Scalar turbulent behavior in the roughness sublayer of an Amazonian forest.ClimatologiaFloresta TropicalAn important current problem in micrometeorology is the characterization of turbulence in the roughness sublayer (RSL), where most of the measurements above tall forests are made. There, scalar turbulent fluctuations display significant departures from the predictions of Monin?Obukhov similarity theory (MOST). In this work, we analyze turbulence data of virtual temperature, carbon dioxide, and water vapor in the RSL above an Amazonian forest (with a canopy height of 40&#8239;m), measured at 39.4 and 81.6&#8239;m above the ground under unstable conditions. We found that dimensionless statistics related to the rate of dissipation of turbulence kinetic energy (TKE) and the scalar variance display significant departures from MOST as expected, whereas the vertical velocity variance follows MOST much more closely. Much better agreement between the dimensionless statistics with the Obukhov similarity variable, however, was found for the subset of measurements made at a low zenith angle Z, in the range 0°&#8239;&#8201;<&#8201;&#8239;|Z|&#8239;&#8201;<&#8201;&#8239;20°. We conjecture that this improvement is due to the relationship between sunlight incidence and the ?activation?deactivation? of scalar sinks and sources vertically distributed in the forest. Finally, we evaluated the relaxation coefficient of relaxed eddy accumulation: it is also affected by zenith angle, with considerable improvement in the range 0°&#8239;&#8201;<&#8201;&#8239;|Z|&#8239;&#8201;<&#8201;&#8239;20°, and its values fall within the range reported in the literature for the unstable surface layer. In general, our results indicate the possibility of better stability-derived flux estimates for low zenith angle ranges.Einara Zahn, Graduate Program in Environmental Engineering (PPGEA), UFPR; Nelson L. Dias, UFPR; ALESSANDRO CARIOCA DE ARAUJO, CPATU; Leonardo D. A. Sá, INPE; Matthias Sörgel, Max Planck Institute for Chemistry; Ivonne Trebs, Environmental Research and Innovation (ERIN); Stefan Wolff, Max Planck Institute for Chemistry; Antônio Manzi, INPE.ZAHN, E.DIAS, N. L.ARAUJO, A.SÁ, L. D. A.SÖRGEL, M.TREBS, I.WOLFF, S.MANZI, A.2016-09-20T11:11:11Z2016-09-20T11:11:11Z2016-09-2020162017-03-02T11:11:11Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleAtmospheric Chemistry and Physics, v. 16, p. 11349-11366, 2016.http://www.alice.cnptia.embrapa.br/alice/handle/doc/105316510.5194/acp-16-11349-2016enginfo:eu-repo/semantics/openAccessreponame:Repositório Institucional da EMBRAPA (Repository Open Access to Scientific Information from EMBRAPA - Alice)instname:Empresa Brasileira de Pesquisa Agropecuária (Embrapa)instacron:EMBRAPA2017-08-16T03:44:52Zoai:www.alice.cnptia.embrapa.br:doc/1053165Repositório InstitucionalPUBhttps://www.alice.cnptia.embrapa.br/oai/requestopendoar:21542017-08-16T03:44:52falseRepositório InstitucionalPUBhttps://www.alice.cnptia.embrapa.br/oai/requestcg-riaa@embrapa.bropendoar:21542017-08-16T03:44:52Repositório Institucional da EMBRAPA (Repository Open Access to Scientific Information from EMBRAPA - Alice) - Empresa Brasileira de Pesquisa Agropecuária (Embrapa)false
dc.title.none.fl_str_mv Scalar turbulent behavior in the roughness sublayer of an Amazonian forest.
title Scalar turbulent behavior in the roughness sublayer of an Amazonian forest.
spellingShingle Scalar turbulent behavior in the roughness sublayer of an Amazonian forest.
ZAHN, E.
Climatologia
Floresta Tropical
title_short Scalar turbulent behavior in the roughness sublayer of an Amazonian forest.
title_full Scalar turbulent behavior in the roughness sublayer of an Amazonian forest.
title_fullStr Scalar turbulent behavior in the roughness sublayer of an Amazonian forest.
title_full_unstemmed Scalar turbulent behavior in the roughness sublayer of an Amazonian forest.
title_sort Scalar turbulent behavior in the roughness sublayer of an Amazonian forest.
author ZAHN, E.
author_facet ZAHN, E.
DIAS, N. L.
ARAUJO, A.
SÁ, L. D. A.
SÖRGEL, M.
TREBS, I.
WOLFF, S.
MANZI, A.
author_role author
author2 DIAS, N. L.
ARAUJO, A.
SÁ, L. D. A.
SÖRGEL, M.
TREBS, I.
WOLFF, S.
MANZI, A.
author2_role author
author
author
author
author
author
author
dc.contributor.none.fl_str_mv Einara Zahn, Graduate Program in Environmental Engineering (PPGEA), UFPR; Nelson L. Dias, UFPR; ALESSANDRO CARIOCA DE ARAUJO, CPATU; Leonardo D. A. Sá, INPE; Matthias Sörgel, Max Planck Institute for Chemistry; Ivonne Trebs, Environmental Research and Innovation (ERIN); Stefan Wolff, Max Planck Institute for Chemistry; Antônio Manzi, INPE.
dc.contributor.author.fl_str_mv ZAHN, E.
DIAS, N. L.
ARAUJO, A.
SÁ, L. D. A.
SÖRGEL, M.
TREBS, I.
WOLFF, S.
MANZI, A.
dc.subject.por.fl_str_mv Climatologia
Floresta Tropical
topic Climatologia
Floresta Tropical
description An important current problem in micrometeorology is the characterization of turbulence in the roughness sublayer (RSL), where most of the measurements above tall forests are made. There, scalar turbulent fluctuations display significant departures from the predictions of Monin?Obukhov similarity theory (MOST). In this work, we analyze turbulence data of virtual temperature, carbon dioxide, and water vapor in the RSL above an Amazonian forest (with a canopy height of 40&#8239;m), measured at 39.4 and 81.6&#8239;m above the ground under unstable conditions. We found that dimensionless statistics related to the rate of dissipation of turbulence kinetic energy (TKE) and the scalar variance display significant departures from MOST as expected, whereas the vertical velocity variance follows MOST much more closely. Much better agreement between the dimensionless statistics with the Obukhov similarity variable, however, was found for the subset of measurements made at a low zenith angle Z, in the range 0°&#8239;&#8201;<&#8201;&#8239;|Z|&#8239;&#8201;<&#8201;&#8239;20°. We conjecture that this improvement is due to the relationship between sunlight incidence and the ?activation?deactivation? of scalar sinks and sources vertically distributed in the forest. Finally, we evaluated the relaxation coefficient of relaxed eddy accumulation: it is also affected by zenith angle, with considerable improvement in the range 0°&#8239;&#8201;<&#8201;&#8239;|Z|&#8239;&#8201;<&#8201;&#8239;20°, and its values fall within the range reported in the literature for the unstable surface layer. In general, our results indicate the possibility of better stability-derived flux estimates for low zenith angle ranges.
publishDate 2016
dc.date.none.fl_str_mv 2016-09-20T11:11:11Z
2016-09-20T11:11:11Z
2016-09-20
2016
2017-03-02T11:11:11Z
dc.type.driver.fl_str_mv info:eu-repo/semantics/publishedVersion
info:eu-repo/semantics/article
format article
status_str publishedVersion
dc.identifier.uri.fl_str_mv Atmospheric Chemistry and Physics, v. 16, p. 11349-11366, 2016.
http://www.alice.cnptia.embrapa.br/alice/handle/doc/1053165
10.5194/acp-16-11349-2016
identifier_str_mv Atmospheric Chemistry and Physics, v. 16, p. 11349-11366, 2016.
10.5194/acp-16-11349-2016
url http://www.alice.cnptia.embrapa.br/alice/handle/doc/1053165
dc.language.iso.fl_str_mv eng
language eng
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
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dc.source.none.fl_str_mv reponame:Repositório Institucional da EMBRAPA (Repository Open Access to Scientific Information from EMBRAPA - Alice)
instname:Empresa Brasileira de Pesquisa Agropecuária (Embrapa)
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instname_str Empresa Brasileira de Pesquisa Agropecuária (Embrapa)
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institution EMBRAPA
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collection Repositório Institucional da EMBRAPA (Repository Open Access to Scientific Information from EMBRAPA - Alice)
repository.name.fl_str_mv Repositório Institucional da EMBRAPA (Repository Open Access to Scientific Information from EMBRAPA - Alice) - Empresa Brasileira de Pesquisa Agropecuária (Embrapa)
repository.mail.fl_str_mv cg-riaa@embrapa.br
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