Improved Accuracy Models For Hourly Diffuse Solar Radiation

2005 ◽  
Vol 128 (1) ◽  
pp. 104-117 ◽  
Author(s):  
T. Muneer ◽  
S. Munawwar
Keyword(s):  
Solar Radiation ◽  
Regression Models ◽  
Global Radiation ◽  
Diffuse Radiation ◽  
Evaluation Procedure ◽  
Accuracy Score ◽  
Error Statistics ◽  
Diffuse Solar Radiation ◽  
Energy Applications ◽  
Extensive Evaluation

Solar energy applications require readily available, site-oriented, and long-term solar data. However, the frequent unavailability of diffuse irradiation, in contrast to its need, has led to the evolution of various regression models to predict it from the more commonly available data. Estimating the diffuse component from global radiation is one such technique. The present work focuses on improvement in the accuracy of the models for predicting horizontal diffuse irradiation using hourly solar radiation database from nine sites across the globe. The influence of sunshine fraction, cloud cover, and air mass on estimation of diffuse radiation is investigated. Inclusion of these along with hourly clearness index, leads to the development of a series of models for each site. Estimated values of hourly diffuse radiation are compared with measured values in terms of error statistics and indicators like, R2, mean bias deviation, root mean square deviation, skewness, and kurtosis. A new method called “the accuracy score system” is devised to assess the effect on accuracy with subsequent addition of each parameter and increase in complexity of equation. After an extensive evaluation procedure, extricate but adequate models are recommended as optimum for each of the nine sites. These models were found to be site dependent but the model types were fairly consistent for neighboring stations or locations with similar climates. Also, this study reveals a significant improvement from the conventional k-kt regression models to the presently proposed models.

scholarly journals Monthly average daily diffuse solar radiation in Poland within the period 2005–2015

2018 ◽  
Vol 23 ◽  
pp. 00020
Author(s):  
Małgorzata Kleniewska ◽  
Dorota Mitrowska ◽  
Bogdan H. Chojnicki
Keyword(s):  
Solar Radiation ◽  
Linear Relationship ◽  
Global Radiation ◽  
Diffuse Radiation ◽  
Diffuse Fraction ◽  
Diffuse Solar Radiation ◽  
Monthly Average

In this paper an 11-year series of daily values of diffuse solar radiation registered at 8 actinometric stations in Poland was used to describe the characteristics of diffuse radiation and diffuse fraction of global radiation for the area of Poland. Based on the monthly average daily diffuse, global and extraterrestrial solar radiation a linear relationship between these elements was determined. The obtained equation enables the calculation of the monthly average daily diffuse solar radiation for Poland and the application of its values to further climatology studies.

Diffuse Sky Measurements and Determination of Corrected Shadow Band Multiplication Factors

1983 ◽  
Vol 105 (3) ◽  
pp. 305-310 ◽  
Author(s):  
W. D. Turner ◽  
A. M. Mujahid
Keyword(s):  
Solar Radiation ◽  
Correction Factor ◽  
Global Radiation ◽  
Diffuse Radiation ◽  
Monitoring Station ◽  
Radiation Measurement ◽  
Correction Factors ◽  
Diffuse Solar Radiation ◽  
Variable Factor

A meteorological monitoring station was operated at Blytheville, Arkansas, from April 1978 to April 1980. Direct normal, global, and diffuse sky radiation were monitored. From these data, models have been developed for the prediction of solar radiation, and discussions of several diffuse solar radiation models are included herein. Comparisons are made with these current diffuse models, and the correlation is quite good. In addition, instantaneous shadow band correction factors are presented which will allow a more accurate correction to be applied to the measured diffuse sky reading. The instantaneous correction factors are keyed to the global radiation measurement. Instead of applying a fixed correction factor to the diffuse measurement, regardless of sky condition, a variable factor can be applied. This will solve some of the current errors observed in diffuse measurements, because the current factors overpredict the diffuse radiation on cloudy days and underpredict the diffuse on clear days.

scholarly journals Diffuse solar radiation and associated meteorological parameters in India

1996 ◽  
Vol 14 (10) ◽  
pp. 1051-1059 ◽  
Author(s):  
A. B. Bhattacharya ◽  
S. K. Kar ◽  
R. Bhattacharya
Keyword(s):  
Solar Radiation ◽  
Meteorological Parameters ◽  
Global Radiation ◽  
Low Frequency ◽  
Diffuse Radiation ◽  
Global Solar Radiation ◽  
Surface Radiation ◽  
Diffuse Solar Radiation ◽  
Sunshine Hours ◽  
The Tropics

Abstract. Solar diffuse radiation data including global radiation, shortwave and longwave balances, net radiation and sunshine hours have been extensively analyzed to study the variation of diffuse radiation with turbidity and cloud discharges appearing in the form of atmospherics over the tropics. Results of surface radiation measurements at Calcutta, Poona, Delhi and Madras are presented together with some meteorological parameters. The monthly values of diffuse radiation and the monthly ratios of diffuse to global solar radiation have been examined, with a special emphasis in relation to the noise level of atmospherics at Calcutta in the very low frequency band. The results exhibit some definite seasonal changes which appear to be in close agreement with one another.

scholarly journals The diffuse component of the global solar radiation at Qena / Egypt

MAUSAM ◽  
2021 ◽  
Vol 49 (4) ◽  
pp. 469-474
Author(s):  
Dr. SAYED. M. EL. SHAZLY
Keyword(s):  
Solar Radiation ◽  
Regression Models ◽  
Radiation Effect ◽  
Statistical Evaluation ◽  
Diffuse Radiation ◽  
Global Solar Radiation ◽  
Climatic Conditions ◽  
Diffuse Component ◽  
Diffuse Solar Radiation ◽  
Basic Procedure

Diffuse solar radiation on horizontal surfaces is estimated at Qena / Egypt. The basic procedure is to develop relationships of the widespread use Liu & Jordan types between the daily global horizontal radiation (G) and its diffuse component (D) using measured values of these two quantities. An error analysis has been done for the results of diffuse radiation calculated using the regression models obtained in this paper and those estimated from other known ones of the Liu & Jordan type, According to statistical evaluation of the various relationships, it is seen that our models provide the best estimation of the diffuse radiation, Effect of climatic conditions was considered in the discussion.

Developing and Evaluation of Various Correlations for Diffuse Solar Radiation for Urla (Izmir, Turkey)

2012 ◽  
Vol 135 (2) ◽  
Author(s):  
Orhan Ekren
Keyword(s):  
Solar Radiation ◽  
Solar Energy ◽  
Tracking System ◽  
Diffuse Radiation ◽  
Energy System ◽  
Solar Irradiation ◽  
Total Solar Radiation ◽  
Total Radiation ◽  
Diffuse Solar Radiation ◽  
Tilted Surface

Characteristics of site-specific solar irradiation is required to optimize a solar energy system. If no tracking system is used, the amount of electricity or heat produced by solar energy depends on the total solar radiation on a tilted surface. Although pyranometer measures direct plus diffuse solar radiation on a horizontal surface, there are many locations where diffuse radiation is not measured. Also, diffuse radiation is necessary to determine the total radiation on a tilted surface. Therefore, in this study, new correlations for diffuse solar radiation is proposed as a function of atmospheric parameters for Urla (Izmir, Turkey). After applying the statistical procedure on the measured data, seven new correlations are proposed for the ratio of hourly average diffuse and total radiation. Also, the ratio of monthly average daily diffuse and total radiation for this region is proposed.

scholarly journals Coupling Diffuse Sky Radiation and Surface Albedo

2005 ◽  
Vol 62 (7) ◽  
pp. 2580-2591 ◽  
Author(s):  
Bernard Pinty ◽  
Alessio Lattanzio ◽  
John V. Martonchik ◽  
Michel M. Verstraete ◽  
Nadine Gobron ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Land Surface ◽  
Surface Albedo ◽  
Climate Models ◽  
Diffuse Radiation ◽  
Atmospheric Model ◽  
Time Of Day ◽  
Mathematical Form ◽  
Diffuse Solar Radiation ◽  
Atmospheric Scattering

Abstract New satellite instruments have been delivering a wealth of information regarding land surface albedo. This basic quantity describes what fraction of solar radiation is reflected from the earth’s surface. However, its concept and measurements have some ambiguity resulting from its dependence on the incidence angles of both the direct and diffuse solar radiation. At any time of day, a surface receives direct radiation in the direction of the sun, and diffuse radiation from the various other directions in which it may have been scattered by air molecules, aerosols, and cloud droplets. This contribution proposes a complete description of the distribution of incident radiation with angles, and the implications in terms of surface albedo are given in a mathematical form, which is suitable for climate models that require evaluating surface albedo many times. The different definitions of observed albedos are explained in terms of the coupling between surface and atmospheric scattering properties. The analytical development in this paper relates the various quantities that are retrieved from orbiting platforms to what is needed by an atmospheric model. It provides a physically simple and practical approach to evaluation of land surface albedo values at any condition of sun illumination irrespective of the current range of surface anisotropic conditions and atmospheric aerosol load. The numerical differences between the various definitions of albedo for a set of typical atmospheric and surface scattering conditions are illustrated through numerical computation.

Study of the Intensity of Global Solar Radiation Incident in Suan Sunandha Rajabhat University

2013 ◽  
Vol 770 ◽  
pp. 229-232
Author(s):  
A. Sansomboon ◽  
N. Luewarasirikul ◽  
A. Ittipongse ◽  
W. Phae-Ngam ◽  
S. Pattarapanitchai
Keyword(s):  
Solar Radiation ◽  
Solar Energy ◽  
Alternative Energy ◽  
Global Radiation ◽  
Global Solar Radiation ◽  
Digital Data ◽  
Data Logger ◽  
Language Version ◽  
Energy Applications ◽  
Yearly Average

Solar radiation is one of mains alternative energy, widely used in present day. Measure solar radiation accurately is an essential for planning in application of used. Universities are the places that have used significant of energy all year long. Therefore, long-term measured solar radiation data is important, for understand in both quantity and variation in time period, for application of the alternative energy in future. The main objective of this research is to investigate solar energy potentials of Suan Sunandha Rajabhat University, Bongkok, Thailand (Latitude 13.46°N, Longitude 100.31°E). A station for solar radiation was installed at Suan Sunandha Rajabhat University. The main equipment is composed of two parts: 1) a pyranometer from Kipp & Zonen Ltd., model CMP11, and 2) a digital data logger from Measurement Systems Ltd. model DX2000. The pyranometer is permanently installed on the top of a building. The data logger is keeping clean and safe inside the building. To analyze the values of the global solar radiations, the computer source code is written in Interactive Data Language version 6.1 (IDL6.1). The results show the variation of the average hourly global irradiance is about 800-900 W/m2 at 12:00 UTC. The maximum monthly average daily global radiation is 21.5 MJ/m2-day in April. The yearly average daily radiation at Suan Sunandha Rajabhat University is found to be 16.55 MJ/m2-day. The information from the monthly and yearly global radiation has relatively high solar energy potentials. Finally, the solar radiation database was also developed for use in solar energy applications in Suan Sunandha Rajabhat University and neighbor areas.

scholarly journals Surface global and diffuse solar radiation over China acquired from geostationary Multi-functional Transport Satellite data

2019 ◽  
Author(s):  
Hou Jiang ◽  
Ning Lu ◽  
Jun Qin ◽  
Ling Yao
Keyword(s):  
Solar Radiation ◽  
Satellite Data ◽  
Power Plants ◽  
Numerical Models ◽  
Regional Climate ◽  
Diffuse Radiation ◽  
Terrestrial Ecosystems ◽  
Global Solar Radiation ◽  
Surface Solar Radiation ◽  
Diffuse Solar Radiation

Abstract. Surface solar radiation drives the water cycle and energy exchange on the earth's surface, being an indispensable parameter for many numerical models to estimate soil moisture, evapotranspiration and plant photosynthesis, and its diffuse component can promote carbon uptake in ecosystems as a result of improvements of plant productivity by enhancing canopy light use efficiency. To reproduce the spatial distribution and spatiotemporal variations of solar radiation over China, we generate the high-accuracy radiation datasets, including global solar radiation (GSR) and the diffuse radiation (DIF) with spatial resolution of 1/20 degree, based on the observations from the China Meteorology Administration (CMA) and Multi-functional Transport Satellite (MTSAT) satellite data, after tackling the integration of spatial pattern and the simulation of complex radiation transfer that the existing algorithms puzzle about by means of the combination of convolutional neural network (CNN) and multi-layer perceptron (MLP). All data cover a period from 2007 to 2018 in hourly, daily total and monthly total scales. The validation in 2008 shows that the root mean square error (RMSE) between our datasets and in-situ measurements approximates 73.79 W/m2 (0.27 MJ/m2) and 58.22 W/m2 (0.21 MJ/m2) for GSR and DIF, respectively. Besides, the spatially continuous hourly estimates properly reflect the regional differences and restore the diurnal cycles of solar radiation in fine scales. Such accurate knowledge is useful for the prediction of agricultural yield, carbon dynamics of terrestrial ecosystems, research on regional climate changes, and site selection of solar power plants etc. The datasets are freely available from Pangaea at https://doi.org/10.1594/PANGAEA.904136 (Jiang and Lu, 2019).

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