scholarly journals Relationship between photosynthetically active radiation and global radiation in Petrolina and Brasília, Brazil

2021 ◽  
Vol 25 (9) ◽  
pp. 612-619
Author(s):  
Lady L. M. Custódio ◽  
Bernardo B. da Silva ◽  
Carlos A. C. dos Santos
Keyword(s):  
Photosynthetically Active Radiation ◽  
Mean Absolute Error ◽  
Global Radiation ◽  
Absolute Error ◽  
Global Solar Radiation ◽  
Clearness Index ◽  
Active Radiation ◽  
Mean Relative Error ◽  
Instantaneous Values ◽  
The Relationship

ABSTRACT Photosynthetically active radiation (PAR) comprises the spectral range of global solar radiation (Rs) that is highly related to vegetation productivity. The study aimed to evaluate the relationship between PAR and Rs in Petrolina, PE, and Brasília, DF, Brazil, with data measured in 2011 and 2013 at two stations of the Sistema Nacional de Organização de Dados Ambientais located in Petrolina, PE and Brasília, DF, Brazil, and the obtained models were evaluated using the measurements of 2014. It was verified that the PAR, in instantaneous values (μmol m-2 s-1), can be estimated at 2.31 times the Rs (W m-2) measured in Petrolina, while for daily values of PAR (MJ m-2) is equal to 50% of Rs (MJ m-2). In Brasília, PAR (μmol m-2 s-1) is 2.05 times the Rs (W m-2) and, in daily values, equal to 44% of Rs (MJ m-2). The variability of the PAR/Rs ratio followed the local variations of clearness index (Kt) and Rs. The models presented an adequate performance based on statistical indices mean absolute error, mean relative error, and root mean square error and can be used to estimate PAR.

scholarly journals Emerald zoyzia grass development regarding photosynthetically active radiation in different slopes

2012 ◽  
Vol 32 (3) ◽  
pp. 501-509 ◽  
Author(s):  
Ruchele M. Coan ◽  
José E. P. Turco ◽  
Kathia F. L. Pivetta ◽  
Madson N. da Costa ◽  
Caroline de M. D'A. Mateus
Keyword(s):  
Photosynthetically Active Radiation ◽  
Dry Matter ◽  
Global Radiation ◽  
Global Solar Radiation ◽  
State University ◽  
Active Radiation ◽  
Agricultural Engineering ◽  
Paulo State ◽  
Tukey Test ◽  
Engineering Department

With this study, the objective was to estimate the photosynthetically active radiation (PAR) and to correlate it with the dry matter (MMSPA) of the emerald zoysia (Zoysia japonica Steud.) on surfaces with different expositions and slopes. The research was conducted at the Experimental Watershed of the Agricultural Engineering Department, School of Agriculture and Veterinary Sciences of São Paulo State University (FCAV/UNESP), Brazil, where the surfaces (H, 10 N, 30 N, 50 N, 10 S, 30 S, 50 S, 10 L, 30 L, 50 L, 10 O, 30 O and 50 O) were used. To obtain the global solar radiation, it was installed an automated weather station where the PAR (dependent variable) was obtained by the equation y = a + bx, and the global radiation was independent. To compare means of MMSPA, it was used the Tukey test at 5% probability, and to assess the relation PAR/MMSPA, the simple linear correlation coefficient. The result showed that the accumulation of these effects in the PAR increases with North exposure and decreases with the South, and exposure to 50N is most suitable for slopes, not having correlation between the PAR and the MMSPA for the surfaces evaluated for the study period.

scholarly journals Influência entre relação de radiação fotossinteticamente ativa e radiação global na produtividade primária bruta para Santa Rita do Passa Quatro - SP

2018 ◽  
Vol 40 ◽  
pp. 52
Author(s):  
Celina Cândida Ferreira Rodrigues ◽  
Maria Do Rosário Alves Patriota ◽  
Bernardo Barbosa da Silva ◽  
André Bezerra Oliveira
Keyword(s):  
Data Analysis ◽  
Primary Production ◽  
Linear Equation ◽  
Photosynthetically Active Radiation ◽  
Gross Primary Production ◽  
Global Radiation ◽  
Active Radiation ◽  
The Relationship

This work aims to establish a relationship between the photosynthetically active radiation (PAR) and the global radiation (Rg) for Santa Rita do Passa Quatro (SP), during the period from February 2005 to February 2006 and evaluate its impact on gross primary production (GPP). Data of Rg (Wm-2) and PAR (μmols s-1m-2) were obtained from the mirometeorological tower located in Gleba Cerrado Giant Foot. Data analysis allowed the establishment of a linear equation to express the relationship between PAR (MJ m-2) and Rg (MJ m-2) as: PAR = 0.3787 Rg or PAR = 1.742 Rg, for PAR (μmols s-1m-2) and Rg (MJ m-2). This relationship is indicated for the GPP determination when there is no PAR measurements.

scholarly journals MODELOS DE ESTIMATIVA DA RADIAÇÃO FOTOSSINTETICAMENTE ATIVA GLOBAL E DIFUSA EM FUNÇÃO DA RADIAÇÃO DE ONDAS CURTAS E DO ÍNDICE DE CLARIDADE (Kt)

Irriga ◽  
2002 ◽  
Vol 7 (2) ◽  
pp. 123-129
Author(s):  
Eduardo Nardini Gomes ◽  
João Francisco Escobedo
Keyword(s):  
Solar Radiation ◽  
Photosynthetically Active Radiation ◽  
Model Development ◽  
Diffuse Radiation ◽  
Global Solar Radiation ◽  
Clearness Index ◽  
Active Radiation ◽  
Diffuse Solar Radiation ◽  
Proposed Model ◽  
Index 2

MODELOS DE ESTIMATIVA DA RADIAÇÃO FOTOSSINTETICAMENTE ATIVA GLOBAL E DIFUSA EM FUNÇÃO DA RADIAÇÃO DE ONDAS CURTAS E DO ÍNDICE DE CLARIDADE (Kt)   Eduardo Nardini GomesJoão Francisco EscobedoDepartamento de Recursos Naturais, Faculdade de Ciências Agronômicas, Universidade Estadual Paulista, CP 237, CEP 18603-970, Botucatu – SP, Fone: (0xx14) 6802-7162   1 RESUMO  O presente trabalho apresenta equações de estimativa da radiação fotossinteticamente ativa global () e difusa () em função das respectivas radiações global () e difusa () do espectro solar total, bem como a estimativa da fração PAR difusa da PAR global () em função do índice de transmissividade atmosférica ().A base de dados foi adquirida no período de 01/06/1999 a 31/09/2000 na Estação de Radiometria Solar da FCA-UNESP, Botucatu. Foram utilizados dados adicionais, diferentes dos utilizados na geração dos modelos, de forma a possibilitar uma validação adequada dos modelos propostos.   UNITERMOS: radiação fotossinteticamente ativa global e difusa, transmissividade atmosférica, modelos de estimativa da radiação solar.   GOMES, E.N., ESCOBEDO, J.F  MODELS FOR GLOBAL AND DIFFUSE PHOTOSYNTHETICALLY ACTIVE RADIATION IN RELATION TO GLOBAL, DIFFUSE RADIATION  AND CLEARNESS INDEX.   2 SUMMARY  This work describes typical correlations between global solar radiation () and its global PAR component (), diffuse solar radiation () and its diffuse PAR component (), clearness index () and the diffuse PAR fraction of global PAR (). Database was recorded from June 1st 1999 to September 31st 2000 at the  Solar Radiometric Station, Botucatu, SP. Additional data which are not part of the model development were used to validate each  proposed model.  KEYWORDS: global and diffuse photosynthetically active radiation, clearness index, estimating models.

The transmission of global and photosynthetically active radiation within a dwarf apple orchard

1975 ◽  
Vol 53 (14) ◽  
pp. 1428-1441 ◽  
Author(s):  
P. W. Suckling ◽  
J. A. Davies ◽  
J. T. A. Proctor
Keyword(s):  
Satisfactory Agreement ◽  
Photosynthetically Active Radiation ◽  
Cloud Cover ◽  
Global Radiation ◽  
Daily Basis ◽  
Apple Orchard ◽  
Active Radiation

Measurements of incoming global radiation, K↓, beneath a dwarf apple orchard canopy were made with a traversing sensor and a randomly located set of 10 stationary sensors. The location of the latter was changed once during the period of the experiment. On a daily basis, satisfactory agreement between the two sets of measurements was attained only for the second network location.Above-canopy and track measurements were used to calculate diurnal and daily values of canopy transmissivity, absorptivity, and reflectivity. Average values for the whole period were 0.53, 0.28, and 0.19. Analogous coefficients were obtained for photosynthetically active radiation (PAR). Extracanopy values of PAR were evaluated from PAR = 0.49 K↓ on 'bright' days (days with cloud cover less than [Formula: see text]) and PAR = 0.5 K↓ for cloudy days. These relationships were obtained by regression from sample measurements of PAR and K↓. Average PAR transmissivity, absorptivity, and reflectivity were evaluated as 0.42, 0.51, and 0.07.

scholarly journals Global radiation, photosynthetically active radiation, and the diffuse component dataset of China, 1981–2010

2018 ◽  
Vol 10 (3) ◽  
pp. 1217-1226 ◽  
Author(s):  
Xiaoli Ren ◽  
Honglin He ◽  
Li Zhang ◽  
Guirui Yu
Keyword(s):  
Solar Radiation ◽  
Photosynthetically Active Radiation ◽  
Global Radiation ◽  
Terrestrial Ecosystem ◽  
Diffuse Radiation ◽  
Research Network ◽  
Diffuse Component ◽  
Ecosystem Productivity ◽  
Ecosystem Models ◽  
Active Radiation

Abstract. Solar radiation, especially photosynthetically active radiation (PAR), is the main energy source of plant photosynthesis, and the diffuse component can enhance canopy light use efficiency, thus increasing ecosystem productivity. In order to predict the terrestrial ecosystem productivity precisely, we not only need global radiation and PAR as driving variables, but also need to treat diffuse radiation and diffuse PAR explicitly in ecosystem models. Therefore, we generated a series of radiation datasets, including global radiation, diffuse radiation, PAR, and diffuse PAR of China from 1981 to 2010, based on the observations of the China Meteorology Administration (CMA) and the Chinese Ecosystem Research Network (CERN). The dataset should be useful for the analysis of the spatiotemporal variations of solar radiation in China and the impact of diffuse radiation on terrestrial ecosystem productivity based on ecosystem models. The dataset is freely available from Zenodo on the following website: https://zenodo.org/record/1198894#.Wx6–C_MwWo (https://doi.org/10.11922/sciencedb.555, Ren et al., 2018).

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