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 Radiation balance of coffee hedgerows

2008 ◽  
Vol 12 (3) ◽  
pp. 274-281 ◽  
Author(s):  
Luiz R. Angelocci ◽  
Fábio R. Marin ◽  
Felipe G. Pilau ◽  
Evandro Z. Righi ◽  
José L. Favarin
Keyword(s):  
Solar Radiation ◽  
Cover Crops ◽  
Ground Cover ◽  
Global Solar Radiation ◽  
Important Variable ◽  
Field Conditions ◽  
Radiation Balance ◽  
Net Radiation ◽  
Energy Exchanges ◽  
Good Agreement

The radiation balance of hedgerows is an important variable in studies of mass and energy exchanges between parcial ground cover crops and the atmosphere. This paper describes a device with eight net radiometers encompassing the plants of a hedgerow. The radiometers were moved along a length of hedgerow, in a continuous and reversible movement. The canopy net radiation in this length (Rnc) was found by integration of the measurements over the notional cylinder formed. The device showed good performance and provided reliable measurements of Rnc of coffee hedgerows, showing itselfto be an useful technique of measurement in field conditions. Good correlations between Rnc and global solar radiation, turfgrass and coffee crop net radiation were found in 15-min, daytime and 24-hr periods, allowing the possibility of estimating Rnc from these simple measurements. Beer’s law was also used to have an independent estimation of Rnc. A good agreement was found between values of Rnc estimated by this law of attenuation and those integrated by the device in periods of 15 min, with overestimation of 10%, whereas for values integrated over daytime periods the agreement was not satisfactory.

Solar Radiation Over the Caribbean Island of Puerto Rico

Solar Energy ◽  
2004 ◽  
Author(s):  
Ramiro L. Rivera ◽  
Karim Altaii
Keyword(s):  
Puerto Rico ◽  
Solar Radiation ◽  
Global Radiation ◽  
Global Solar Radiation ◽  
Time Frame ◽  
Daily Basis ◽  
Caribbean Island ◽  
Monthly Average ◽  
Energy Conversion System ◽  
The Caribbean

Solar radiation was measured and recorded on a 5-minute, hourly and daily basis at a number of sites on the Caribbean island of Puerto Rico (located from 18° to 18° 30’N latitude and from 65° 30’ to 67° 15’W longitude) over a 24 calendar month time frame. The global solar radiation was measured at four sites (namely: Aguadilla, Ponce, Gurabo, and San Juan). The global solar radiation data was measured by an Eppley Precision Spectral Pyranometer (model PSP) mounted on a horizontal surface. This pyranometer is sensitive to solar radiation in the range of 0.285 ≤ λ ≤ 2.8 μm wavelengths. Statistical analysis such as the daily average, monthly average hourly, monthly average daily, and annual average daily global radiation are presented in this paper. Despite its small size, a 13 percent variation in the global solar radiation has been observed within the island. Reasonable solar radiation values, for solar energy conversion system installation, seem to exist at and possibly around Aguadilla.

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 Estimation methods of reference evapotranspiration (ETo) for Uberlândia -MG

2015 ◽  
Vol 35 (1) ◽  
pp. 27-38 ◽  
Author(s):  
ZILDA C. DE LACERDA ◽  
JOSÉ E. P. TURCO
Keyword(s):  
Solar Radiation ◽  
Reference Evapotranspiration ◽  
Global Solar Radiation ◽  
Daily Basis ◽  
Meteorological Station ◽  
Estimation Methods ◽  
Food And Agriculture ◽  
Food And Agriculture Organization ◽  
Daily Data ◽  
Analysis Of Results

One approach to verify the adequacy of estimation methods of reference evapotranspiration is the comparison with the Penman-Monteith method, recommended by the United Nations of Food and Agriculture Organization - FAO, as the standard method for estimating ET0. This study aimed to compare methods for estimating ET0, Makkink (MK), Hargreaves (HG) and Solar Radiation (RS), with Penman-Monteith (PM). For this purpose, we used daily data of global solar radiation, air temperature, relative humidity and wind speed for the year 2010, obtained through the automatic meteorological station, with latitude 18° 91' 66" S, longitude 48° 25' 05" W and altitude of 869m, at the National Institute of Meteorology situated in the Campus of Federal University of Uberlandia - MG, Brazil. Analysis of results for the period were carried out in daily basis, using regression analysis and considering the linear model y = ax, where the dependent variable was the method of Penman-Monteith and the independent, the estimation of ET0 by evaluated methods. Methodology was used to check the influence of standard deviation of daily ET0 in comparison of methods. The evaluation indicated that methods of Solar Radiation and Penman-Monteith cannot be compared, yet the method of Hargreaves indicates the most efficient adjustment to estimate ETo.

scholarly journals Analysis and correlation of ultraviolet solar radiation from routine meteorological measurements over Egypt

MAUSAM ◽  
2021 ◽  
Vol 51 (3) ◽  
pp. 275-280
Author(s):  
A. I. SALEM
Keyword(s):  
Regression Analysis ◽  
Solar Radiation ◽  
Arabian Peninsula ◽  
Global Radiation ◽  
Global Solar Radiation ◽  
Correlation Equations ◽  
Monthly Average ◽  
Solar Radiation Incident ◽  
Radiation Measurements ◽  
Ultraviolet Solar Radiation

For three years (1990-92) measurements of the monthly average daily global, G, and ultraviolet, UV, solar radiation incident on a horizontal surface at Cairo (30°15'N, 31°17'E) and Aswan (23°58'N, 32°47'E) are presented. processed and analysed. It was found that the computed monthly average daily values for the obtained solar radiation components, G and UV, were (18.1 MJ/m2, 0.55 MJ/m2, for Cairo and (22.1 MJ/m2, 0.71 MJ/m2, for Aswan. The effect of atmospheric dust on the measured solar radiation components is also investigated and discussed. The ratio of the ultraviolet to global radiation (UV/G) are calculated and compared with other sites in the Arabian Peninsula. A regression analysis has been done to find a correlation between G and UV at the selected sites during the three year period and the recommended correlation equations have also been stated.   Since the meteorological measurements of UV solar radiation are not available over Egypt. except at Cairo (Lower Egypt) and Aswan (Upper Egypt) stations, our correlation equations can be used to calculate this component from the available global solar radiation measurements at any site in the two zones of Upper and Lower Egypt.

Estimation of net radiation for a coniferous forest, and the effects of logging on net radiation and the reflection coefficient

1978 ◽  
Vol 8 (4) ◽  
pp. 450-455 ◽  
Author(s):  
J. H. McCaughey
Keyword(s):  
Reflection Coefficient ◽  
Solar Radiation ◽  
Coniferous Forest ◽  
Field Studies ◽  
Global Solar Radiation ◽  
Balsam Fir ◽  
Net Radiation ◽  
Linear Regression Equation ◽  
Simple Linear Regression ◽  
Clear Cut

The results of field studies on the radiation climate at Montmorency, Quebec, are presented. These studies were conducted in the summers of 1975 and 1976, and two sites were used. The first site, used in both years, was forested with 50- to 60-year-old balsam fir (Abiesbalsamea L. Mill.). The second site, originally forested with balsam fir, was clear-cut in the fall of 1975. The daily mean reflection coefficient for solar radiation of the forest is 7% (sample of 264 hourly values). In contrast, the clear-cut site has a daily mean reflection coefficient of 18% (sample of 171 hourly values). There is no evidence of a systematic variation of hourly reflection coefficients with solar zenith angle for either site. The effect of logging on net radiation is characterized by a sample of 21 days in 1976 when hourly values of net radiation were available for both sites. Typically, during the night, the magnitude of net radiation on the forested site is less than that on the clear-cut site, and during the day, the net radiation on the clear-cut site is less than that on the forested site. In terms of daily totals, the effect of logging is to reduce net radiation by 10%.A simple linear regression equation for the calculation of net radiation for the forested site is presented. Global solar radiation (hourly values) is used as the predictor. The parameters of the model are similar to other equations for similar surfaces.

Preliminary Investigation of The Attenuation of Solar Radation in The Atmosphere Over Makurdi, Nigeria

2014 ◽  
Vol 4 (1) ◽  
pp. 392-396
Author(s):  
Bernadette Chidomnso Isikwue ◽  
Ada Amedu Aiji ◽  
Mathias Idugba Echi
Keyword(s):  
Solar Radiation ◽  
Air Force ◽  
Preliminary Investigation ◽  
Global Solar Radiation ◽  
Clearness Index ◽  
Geographic Latitude ◽  
A Value ◽  
Pattern Of Variation ◽  
Air Force Base ◽  
Good Agreement

The attenuation of solar radiation in the atmosphere over Makurdi (Latitude 7o 7’ N and longitude 8o 6’ E) was investigated by measurements of direct solar radiation (I) carried out using a digital sun photometer that measured in Wm- 2. The measurements were made at 9:00hrs, 12:00 hrs and 15: 00hrs daily for six months. Global solar radiation, (IG) was calculated for the six months using Gun Bellani measurements from Air Force Base, Makurdi. The diffuse component of solar radiation (ID) was evaluated and the extraterrestrial solar radiation (Io) was obtained by calculation using the equation of Duffie and Beckman (1983) and Liou (1980). The variation of attenuation with clearness index Ki was found. The attenuation in the atmosphere over Makurdi was found to be highest in the month of August with a value of 0.975 and lowest in December with a value of 0.427. There was good agreement in the pattern of variation of attenuation in Makurdi when compared with that of Ilorin that lies in the same geographic latitude.

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