In Field Assessment on the Relationship between Photosynthetic Active Radiation (PAR) and Global Solar Radiation Transmittance through Discontinuous Canopies

In many crop models, the process of radiation transmittance through the canopy is normally described as an exponential attenuation process (Beer’s Law equation), which is assumed to be valid for canopies covering the ground with a random spatial distribution of leaves. However, for discont...

Descripción completa

Guardado en:

Detalles Bibliográficos
Autores principales:	Oyarzún,Ricardo, Stöckle,Claudio, Wu,Joan, Whiting,Matthew
Lenguaje:	English
Publicado:	Instituto de Investigaciones Agropecuarias, INIA 2011
Materias:	radiation interception extinction coefficient crop simulation model
Acceso en línea:	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392011000100015
Etiquetas:	Agregar Etiqueta Sin Etiquetas, Sea el primero en etiquetar este registro!

id	oai:scielo:S0718-58392011000100015
record_format	dspace
spelling	oai:scielo:S0718-583920110001000152018-10-01In Field Assessment on the Relationship between Photosynthetic Active Radiation (PAR) and Global Solar Radiation Transmittance through Discontinuous CanopiesOyarzún,RicardoStöckle,ClaudioWu,JoanWhiting,Matthew radiation interception extinction coefficient crop simulation model In many crop models, the process of radiation transmittance through the canopy is normally described as an exponential attenuation process (Beer’s Law equation), which is assumed to be valid for canopies covering the ground with a random spatial distribution of leaves. However, for discontinuous canopies, where a distinctive row pattern of plant exists, there is a more complex situation because of the presence of gaps between individual plants. This must be accounted for when characterizing radiation relationships for these kinds of systems, in particular when short time-scales are of interest. Photosynthetically active radiation (PAR) transmittance (τPAR) is more commonly studied and reported than global solar radiation (Sg) transmittance (τSg). However, both PAR and Sg are important in radiative transfer sub-models used in plant growth simulation. In this work simultaneous measurements of τSg and τPAR under discontinuous canopies were performed, and the hourly changes in radiation transmittance for PAR and global solar radiation were characterized. Two methods were assessed to transform between τSg and τPAR. The two methods yielded similar results for low values of transmittance, but disagreement occurred for higher values of transmittance. The method based on a fixed value for the ratio of extinction coefficients for PAR and Sg outperformed the method based on a linear relationship between τPAR and τSg with average relative errors (RE) of 7.97% vs. 13.29% and 2.84% vs. 7.77% for hourly and daily time-scale, respectively.info:eu-repo/semantics/openAccessInstituto de Investigaciones Agropecuarias, INIAChilean journal of agricultural research v.71 n.1 20112011-03-01text/htmlhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392011000100015en10.4067/S0718-58392011000100015
institution	Scielo Chile
collection	Scielo Chile
language	English
topic	radiation interception extinction coefficient crop simulation model
spellingShingle	radiation interception extinction coefficient crop simulation model Oyarzún,Ricardo Stöckle,Claudio Wu,Joan Whiting,Matthew In Field Assessment on the Relationship between Photosynthetic Active Radiation (PAR) and Global Solar Radiation Transmittance through Discontinuous Canopies
description	In many crop models, the process of radiation transmittance through the canopy is normally described as an exponential attenuation process (Beer’s Law equation), which is assumed to be valid for canopies covering the ground with a random spatial distribution of leaves. However, for discontinuous canopies, where a distinctive row pattern of plant exists, there is a more complex situation because of the presence of gaps between individual plants. This must be accounted for when characterizing radiation relationships for these kinds of systems, in particular when short time-scales are of interest. Photosynthetically active radiation (PAR) transmittance (τPAR) is more commonly studied and reported than global solar radiation (Sg) transmittance (τSg). However, both PAR and Sg are important in radiative transfer sub-models used in plant growth simulation. In this work simultaneous measurements of τSg and τPAR under discontinuous canopies were performed, and the hourly changes in radiation transmittance for PAR and global solar radiation were characterized. Two methods were assessed to transform between τSg and τPAR. The two methods yielded similar results for low values of transmittance, but disagreement occurred for higher values of transmittance. The method based on a fixed value for the ratio of extinction coefficients for PAR and Sg outperformed the method based on a linear relationship between τPAR and τSg with average relative errors (RE) of 7.97% vs. 13.29% and 2.84% vs. 7.77% for hourly and daily time-scale, respectively.
author	Oyarzún,Ricardo Stöckle,Claudio Wu,Joan Whiting,Matthew
author_facet	Oyarzún,Ricardo Stöckle,Claudio Wu,Joan Whiting,Matthew
author_sort	Oyarzún,Ricardo
title	In Field Assessment on the Relationship between Photosynthetic Active Radiation (PAR) and Global Solar Radiation Transmittance through Discontinuous Canopies
title_short	In Field Assessment on the Relationship between Photosynthetic Active Radiation (PAR) and Global Solar Radiation Transmittance through Discontinuous Canopies
title_full	In Field Assessment on the Relationship between Photosynthetic Active Radiation (PAR) and Global Solar Radiation Transmittance through Discontinuous Canopies
title_fullStr	In Field Assessment on the Relationship between Photosynthetic Active Radiation (PAR) and Global Solar Radiation Transmittance through Discontinuous Canopies
title_full_unstemmed	In Field Assessment on the Relationship between Photosynthetic Active Radiation (PAR) and Global Solar Radiation Transmittance through Discontinuous Canopies
title_sort	in field assessment on the relationship between photosynthetic active radiation (par) and global solar radiation transmittance through discontinuous canopies
publisher	Instituto de Investigaciones Agropecuarias, INIA
publishDate	2011
url	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392011000100015
work_keys_str_mv	AT oyarzunricardo infieldassessmentontherelationshipbetweenphotosyntheticactiveradiationparandglobalsolarradiationtransmittancethroughdiscontinuouscanopies AT stockleclaudio infieldassessmentontherelationshipbetweenphotosyntheticactiveradiationparandglobalsolarradiationtransmittancethroughdiscontinuouscanopies AT wujoan infieldassessmentontherelationshipbetweenphotosyntheticactiveradiationparandglobalsolarradiationtransmittancethroughdiscontinuouscanopies AT whitingmatthew infieldassessmentontherelationshipbetweenphotosyntheticactiveradiationparandglobalsolarradiationtransmittancethroughdiscontinuouscanopies
_version_	1714205293084147712

In Field Assessment on the Relationship between Photosynthetic Active Radiation (PAR) and Global Solar Radiation Transmittance through Discontinuous Canopies

Ejemplares similares