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

2011 ◽  
Vol 71 (1) ◽  
pp. 122-131 ◽  
Author(s):  
Ricardo Oyarzún ◽  
Claudio Stöckle ◽  
Joan Wu ◽  
Matthew Whiting
Keyword(s):  
Solar Radiation ◽  
Global Solar Radiation ◽  
Photosynthetic Active Radiation ◽  
Active Radiation ◽  
Field Assessment ◽  
The Relationship

scholarly journals The seasonal variability of the amount of global solar radiation reaching the ground in urban and rural areas on the example of Warsaw and Belsk

2016 ◽  
Vol 20 (4) ◽  
pp. 29-37
Author(s):  
Kinga Nelken ◽  
Kamil Leziak
Keyword(s):  
Solar Radiation ◽  
Urban Area ◽  
Rural Area ◽  
Rural Areas ◽  
Meteorological Data ◽  
Global Solar Radiation ◽  
Urban Station ◽  
Reverse Relationship ◽  
Urban And Rural Areas ◽  
The Relationship

AbstractThe aim of this paper is to determine the contemporary differences in the inflow of global solar radiation in Warsaw (urban station) and Belsk (rural station). The meteorological data used comprised daily sums of global solar radiation (in MJ•m−2) and the duration of sunshine (in hours) for the period 2008 2014. On clear days in spring and summer, the rural area receives more solar radiation in comparison to the urban area, whereas in autumn a reverse relationship occurs. On cloudy days in all seasons, the rural area receives more solar radiation than the urban area, and the relationship is the strongest in winter. Differences between urban and rural areas on cloudy days are smaller than those observed on clear days.

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.

ESTIMATION OF NET AND SOLAR RADIATION

1971 ◽  
Vol 51 (1) ◽  
pp. 35-39 ◽  
Author(s):  
I. S. SELIRIO ◽  
D. M. BROWN ◽  
K. M. KING
Keyword(s):  
Regression Analysis ◽  
Solar Radiation ◽  
Global Solar Radiation ◽  
Daily Basis ◽  
Net Radiation ◽  
Climatological Station ◽  
The Relationship ◽  
Good Agreement

Relationships between net radiation (QN) and global solar radiation (QS) and between the ratios of QS and solar radiation at the top of the atmosphere (QS/QA) and duration of bright sunshine and daylength (n/N) were determined by regression analysis at Guelph, Ontario, Canada. The data used were recorded at the Guelph O.A.C. climatological station from March, 1964 to February, 1969. Results showed that during the spring, summer, and autumn seasons, QS alone can be used to estimate QN satisfactorily. Daily values of QN are about 50% of QS. The relationship derived for estimating QS from duration of bright sunshine (n) showed good agreement with findings of previous workers. QS varies between 20 and 80% of QA for overcast to cloudless days. The relationships derived in this study can be used to estimate net and solar radiation on a daily basis when these measurements are unavailable.

scholarly journals Relationship between photosynthetically active radiation with global solar radiation using empirical model over selected climatic zones in Nigeria

2017 ◽  
Vol 6 (1) ◽  
pp. 1
Author(s):  
Nwokolo Samuel Chukwujindu ◽  
Ogbulezie Julie C. ◽  
John-Jaja Sylvia Alwell
Keyword(s):  
Solar Radiation ◽  
Empirical Model ◽  
Photosynthetically Active Radiation ◽  
Global Solar Radiation ◽  
Hadley Cell ◽  
Circulation System ◽  
Climatic Zones ◽  
Active Radiation ◽  
North East ◽  
Port Harcourt

In this study, relationship between photosynthetically active radiation (PAR) and global solar radiation (H) over selected climatic zones in Nigeria using 22-years data (July 1983 – June 2005) was analysed. Empirical model was employed as the baseline for theoretical formulation and estimation of the ratio of PAR/H over climatic zones in Nigeria. From the estimated values, the seasonal PAR/H ranged from 1.946-2.005, 1.909-1.955, 1.968-2.039, 1.987-2.060, 1.961-2.041, 1.928-1.984 and 1.946-2.005 in rainy season, and the high values were due to low influence from clearness index, harmattan dust and pyrogenic aerosols from regional biomass burning compared with 1.906-1.923, 1.905-1.917, 1.927-1.952, 1.950-1.999, 1.971-1.985 and 1.889-1.923 recorded in dry season as a result of combined high influence from cloudiness, pyogenic aerosols and harmattan dust with annual mean values of 1.943, 1.921, 1.975, 2.007, 1.986 and 1.936 for Ilorin, Sokoto, Abeokuta, Port Harcourt, Enugu and Gusau respectively. The annual ratio of PAR/H revealed that there is an evidence increase of the values from North-East (Gusau) to South-South (Port Harcourt). These variations were mainly due to trends in cloudiness and associated atmospheric moisture with the movement of the Hadley cell circulation system along the equatorial line. From the analysed results, the model was found suitable and meteorologically reliable to estimate PAR/H accurately from commonly available H data when compared with results within and beyond tropical locations in Nigeria.

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