SOLAR RADIATION INCIDENCE UNDER DIFFERENT SHADING SCREENS IN TROPICAL CLIMATE: DIURNAL EVOLUTION AND ESTIMATES

Autor: Borella, Daniela Roberta, Nogueira , Herculis, Aloisio Moratelli , Francielli, Kraeski, Aline, Souza, Adilson Pacheco de
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: Nativa; v. 9 n. 5 (2021); 612-627
Nativa; Vol. 9 No. 5 (2021); 612-627
Nativa (Sinop)
Universidade Federal de Mato Grosso (UFMT)
instacron:UFMT
ISSN: 2318-7670
Popis: The objective of this work was to describe the diurnal and seasonal evolution of incidence of global irradiance (IG), photosynthetically active irradiance (IPAR), and luminance in aboveground forest nurseries under different shading screens. Radiometric fractions were evaluated and statistical equations were obtained based on the external incidence. Instantaneous measurements of IG, IPAR, and luminance in the exterior and interior of nurseries (East-West direction), solstices (22/12/2018 and 22/06/2019) and equinoxes (21/03/2019 and 21/09/2019), and local zenithal culminations (18/02/2019 and 20/10/2019) were evaluated between 7:00 and 17:00 h. Estimates were evaluated and the data were grouped into two databases composed of 70% and 30%, respectively, to generate and validate regressions for each variable. The statistical performance of regressions was evaluated using the following statistical indicators: coefficient of determination (R2), mean square error (MSE), root mean square error (RMSE), and Willmott index (d). IG, IPAR, and luminance presented similar dynamics of diurnal and seasonal evolution under the shading screens for external conditions, and the transmissivity was affected by the environmental conditions (water seasonality and solar declination) and intrinsic characteristics of the shading screens (porosity and color). The transmission and absorption of IG, IPAR, and luminance were affected by color and porosity of the shading screens, whereas the reflection was affected only by the color. The agreement indexes (d) were higher than 0.9975 and 0.9973 for black screen and photoselective screen, respectively, and were considered as good, indicating that the equations generated good estimates of IG, IPAR, and luminance for application in different regions. The choice of shading screens for crops are dependent on spectral composition requirements and IPAR transmissivity of each species.
Radiação solar incidente sob diferentes telas de sombreamentos em clima tropical: evolução diurna e estimativas RESUMO: O uso de telas foto-seletivas melhora a produtividade e qualidade das plantas, e é necessário compreender a dinâmica da transmissividade da radiação solar sob esses microambientes para subsidiar projetos de produção agrícolas e florestais. Nesse sentido, o objetivo foi descrever a evolução diurna e sazonal das irradiâncias global (IG), fotossintéticamente ativa (IPAR) e luminância incidentes em viveiros florestais suspensos sob diferentes telas de sombreamento. Além disso foram avaliadas as frações radiométricas e obtidas equações estatísticas de estimativas baseadas na incidência externa. As medidas instantâneas de IG, IPAR e luminância ocorreram no exterior e interior dos viveiros (alinhados no sentido Leste-Oeste), nos solstícios (22/12/2018 e 22/06/2019), equinócios (21/03/2019 e 21/09/2019) e nas culminações zenitais locais (18/02/2019 e 20/10/2019), entre às 7h00min e 17h00min. Para avaliação das estimativas, os dados foram agrupados em duas bases, compostas por 70 e 30% para geração e validação das regressões, para cada variável, respectivamente. Para avaliação do desempenho estatístico das regressões foram empregados os indicativos estatísticos: coeficiente de determinação (R2), erro absoluto médio (MBE), raiz quadrada do erro quadrático médio (RMSE) e índice de Willmott (d). IG, IPAR e luminância apresentaram dinâmicas semelhantes na evolução diurna e sazonal sob as telas de sombreamento em relação as condições externas, sendo a transmissividade influenciados por condições ambientais (sazonalidade hídrica e declinação solar) e intrínsecas a tela (porosidade e cor). A transmissão e absorção de IG, IPAR e luminância foram afetadas pela cor e porosidade líquida, enquanto que a reflexão apenas pela cor. Os valores do índice de Willmott foram superiores a 0,9975 e 0,9973 para as telas pretas e foto-seletivas, respectivamente, sendo considerado como ótimos, indicando que as equações ajustadas permitem boas estimativas de IG, IPAR e luminância para aplicação em diferentes regiões. A escolha da tela de sombreamento para o cultivo de plantas fica dependente das necessidades de composição espectral e transmissividade da IPAR de cada espécie. Palavras-chave: propriedades radiométricas de telas foto-seletivas; radiação fotossinteticamente ativa; irradiâncias; luminância; indicadores estatísticos. ABSTRACT: The use of photoselective screens improves plant productivity and quality, and it is necessary to understand the dynamics of solar radiation transmissivity under these microenvironments to subsidize agricultural and forestry production projects. Therefore, the objective of this work was to describe the diurnal and seasonal evolution of incidence of global irradiance (IG), photosynthetically active irradiance (IPAR), and luminance in aboveground forest nurseries under different shading screens. Radiometric fractions were evaluated and statistical equations were obtained based on the external incidence. Instantaneous measurements of IG, IPAR, and luminance in the exterior and interior of nurseries (East-West direction), solstices (12/22/2018 and 06/20/2019) and equinoxes (03/21/2019 and 09/21/2019), and local zenithal culminations (02/18/2019 and 10/20/2019) were evaluated between 7h00min and 17h00min. Estimates were evaluated and the data were grouped into two databases composed of 70% and 30%, respectively, to generate and validate regressions for each variable. The statistical performance of regressions was evaluated using the following statistical indicators: coefficient of determination (R2), mean square error (MSE), root mean square error (RMSE), and Willmott index (d). IG, IPAR, and luminance presented similar dynamics of diurnal and seasonal evolution under the shading screens for external conditions, and the transmissivity was affected by the environmental conditions (water seasonality and solar declination) and intrinsic characteristics of the shading screens (porosity and color). The transmission and absorption of IG, IPAR, and luminance were affected by color and porosity of the shading screens, whereas the reflection was affected only by the color. The values of Willmott index were higher than 0.9975 and 0.9973 for black screen and photoselective screen, respectively, and were considered as good, indicating that the equations generated good estimates of IG, IPAR, and luminance for application in different regions. The choice of shading screens for crops are dependent on spectral composition requirements and IPAR transmissivity of each species. Keywords: radiometric properties of photoselective screens; photosynthetically active radiation; irradiance; luminance; statistical indicators.
Databáze: OpenAIRE
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