Global radiation within subarctic open forest canopies

1994 ◽  
Vol 24 (5) ◽  
pp. 1062-1066 ◽  
Author(s):  
Peter M. Lafleur ◽  
Blair K. Mantha
Keyword(s):  
Solar Radiation ◽  
Global Radiation ◽  
Tree Height ◽  
Global Solar Radiation ◽  
Canopy Closure ◽  
Predictive Equations ◽  
Forest Canopies ◽  
Open Forest ◽  
Linear Relationships ◽  
The Mean

Measurements of global solar radiation were made at six sites with varying architecture within a subarctic open forest near Churchill, Manitoba. Below-canopy radiation was determined from a network of nine sensors and the mean was compared with global radiation above the canopy. The ratio of below- to above-canopy radiation, R, ranged from 0.52 to 0.7 for the six sites. This range falls within the range of observations from other subarctic sites. At all sites, R was smaller for clear than for overcast skies; however, the differences were not statistically significant. The data from this study were combined with data from the literature in order to develop predictive equations for solar radiation at the floor of subarctic forests, based on easily derived forest parameters. Linear relationships were found between R and canopy closure (r2 = 0.76) and between R and tree height (r2 = 0.88).

scholarly journals Forecasting of Solar Radiation using an Empirical Model

2019 ◽  
Vol 01 (02) ◽  
pp. 212-219 ◽  
Author(s):  
Djelloul BENATIALLAH ◽  
Kada BOUCHOUICHA ◽  
Ali BENATIALLAH ◽  
Abdelkader HARROUZ ◽  
Bahous Nasri ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Global Radiation ◽  
Global Solar Radiation ◽  
Climatic Conditions ◽  
Mean Bias Error ◽  
Percentage Error ◽  
Bias Error ◽  
Energy Needs ◽  
Natural Energy ◽  
The Mean

Global demand for energy is increasing rapidly and natural energy resources such as oil, gas and uranium are declining due to the widespread diffusion and development of the industry in recent years. To cover energy needs, research is being conducted on renewable energy. One of the renewable energies that can meet the world's demand so far is solar energy, which is free and inexhaustible in most parts of the world, and it has become an economic source. In this article we will make a forecast of the empirical Campbell model which will allow us to estimate the daily global irradiation on a horizontal plane and to compare it with the results measured at the Adrar site. The results show that the mean absolute percentage error (MAPE) less than 7%, the mean bias error does not exceed 3% in absolute value, relative RMSE does not exceed 7% and the correlation coefficient greater than 0.99 for the annual global radiation. It was concluded that this model could be used to predict the global solar radiation for Adrar site and for other sites with similar climatic conditions.

scholarly journals Comparative Study of Ground Measured, Satellite-Derived, and Estimated Global Solar Radiation Data in Nigeria

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Boluwaji M. Olomiyesan ◽  
Onyedi D. Oyedum
Keyword(s):  
Solar Radiation ◽  
Comparative Study ◽  
Global Radiation ◽  
Statistical Error ◽  
Global Solar Radiation ◽  
Coefficient Of Determination ◽  
Mean Bias Error ◽  
Percentage Error ◽  
Radiation Data ◽  
Proposed Model

In this study, the performance of three global solar radiation models and the accuracy of global solar radiation data derived from three sources were compared. Twenty-two years (1984–2005) of surface meteorological data consisting of monthly mean daily sunshine duration, minimum and maximum temperatures, and global solar radiation collected from the Nigerian Meteorological (NIMET) Agency, Oshodi, Lagos, and the National Aeronautics Space Agency (NASA) for three locations in North-Western region of Nigeria were used. A new model incorporating Garcia model into Angstrom-Prescott model was proposed for estimating global radiation in Nigeria. The performances of the models used were determined by using mean bias error (MBE), mean percentage error (MPE), root mean square error (RMSE), and coefficient of determination (R2). Based on the statistical error indices, the proposed model was found to have the best accuracy with the least RMSE values (0.376 for Sokoto, 0.463 for Kaduna, and 0.449 for Kano) and highest coefficient of determination, R2 values of 0.922, 0.938, and 0.961 for Sokoto, Kano, and Kaduna, respectively. Also, the comparative study result indicates that the estimated global radiation from the proposed model has a better error range and fits the ground measured data better than the satellite-derived data.

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 Development of a Daily Databank of Solar Radiation Components for Moroccan Territory

2019 ◽  
Vol 2019 ◽  
pp. 1-20 ◽  
Author(s):  
Mohammed Benchrifa ◽  
Hajar Essalhi ◽  
Rachid Tadili ◽  
Mohammed N. Bargach ◽  
Abdellah Mechaqrane
Keyword(s):  
Solar Radiation ◽  
Global Radiation ◽  
Global Solar Radiation ◽  
The Other ◽  
Correlation Equations ◽  
Spectral Radiation ◽  
Solar Systems ◽  
Statistical Indicators ◽  
Radiation Measurements ◽  
Estimation Models

The main objective of this work is to create a daily updated database that includes all components of solar radiation, either energetic or spectral radiation. This will lead us to quantify the Moroccan solar potential and to determine the dimensions of all types of solar thermal and photovoltaic systems. Consequently, the obtained database will be the fundamental support for engineers, designers, and all organizations interested in developing solar systems, in different regions throughout Morocco. It will also be a basic tool for researchers in modelling and simulating the new solar systems. Firstly, we used one year’s worth of measurements of the different components of the solar radiation, provided by the National Meteorological Department, to establish the extrapolation equations between the global radiation at the reference site and the global radiation of twenty-eight other sites. As well as with the same measurements, we developed the correlation equations between the global solar radiation and the other solar radiation components. Secondly, from ten years of Fez station’s daily global radiation measurements and through the extrapolation equations, we were able to estimate the global radiation of all Moroccan cities. Then, by using the obtained global radiation data and the correlation equations, we predicted the other components of solar radiation. Subsequently, with a new measurement campaign carried out on several sites, we validated the estimation models by using the usual statistical indicators. In addition, we compared our results with those obtained by other estimation models. The resulting differences for each solar component display the advantage of our model with errors under 6%. To facilitate the use of our results, we compiled them into maps representing the spread of solar radiation across Morocco.

scholarly journals Yield and crown structure characteristics in a black locust (Robinia pseudoacacia L.) stand: A case study – Short Communication

2018 ◽  
Vol 64 (No. 2) ◽  
pp. 96-100 ◽  
Author(s):  
Rédei Károly ◽  
Bakti Beatrix ◽  
Kiss Tamás ◽  
Takács Marianna ◽  
Keserű Zsolt
Keyword(s):  
Black Locust ◽  
Robinia Pseudoacacia ◽  
Tree Height ◽  
Class Iii ◽  
Timber Volume ◽  
Crown Diameter ◽  
Crown Length ◽  
Linear Relationships ◽  
The Mean ◽  
Robinia Pseudoacacia L

The paper provides the results of a detailed analysis of timber volume and the most important crown variables of black locust (Robinia pseudoacacia Linnaeus) based on an experimental plot in southern Hungary. At the age of 20 years the crop trees belonged to different height classes. If the volume of the mean tree from height class I is considered as 100%, the volume of the mean tree of class II is 44.0%, and the mean tree of class III is only 30.3%. In case of timber volume per 1 m<sup>2</sup> crown surface, the values are 72.9 and 61.7%. The DBH of trees showed a positive linear correlation with crown diameter (r = 0.942). Additionally, there were also positive linear relationships between crown diameter and volume (r = 0.901), between crown length and volume (r = 0.721) as well as tree height and crown length (r = 0.661). The variation of crown indices is height even within the same stand and indicates the importance of following a selective thinning operation method.

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 Time Series and Empirical Orthogonal Transformation Using Meteorological Parameters across the Climatic Zones in Nigeria

2019 ◽  
pp. 257-272
Author(s):  
D. O. Akpootu ◽  
B. I. Tijjani ◽  
U. M. Gana
Keyword(s):  
Time Series ◽  
Relative Humidity ◽  
Solar Radiation ◽  
Meteorological Parameters ◽  
Orthogonal Transformation ◽  
Global Solar Radiation ◽  
Climatic Zones ◽  
Sunshine Hours ◽  
Dry Seasons ◽  
The Mean

Time series and empirical orthogonal transformation analysis was carried out for four (4) selected tropical sites, which are situated across the four different climatic zones, viz. Sahelian, Midland, Guinea savannah and Coastal region in Nigeria using measured monthly average daily global solar radiation, maximum and minimum temperatures, sunshine hours, rainfall, wind speed, cloud cover and relative humidity meteorological data during the period of thirty one years (1980-2010). Seasonal Auto Regressive Integrated Moving Average (ARIMA) models were developed along with their respective statistical indicators of coefficient of determination (R2), Root Mean Square Error (RMSE), Mean Absolute Percentage Error (MAPE) and Mean Absolute Error (MAE). The results indicated that the models were found suitable for one step ahead global solar radiation forecast for the studied locations. Furthermore, the results of the time series analysis revealed that the model type for all the meteorological parameters show a combination of simple seasonal with one or more of either ARIMA, winter’s additive and winter’s multiplicative with the level been more significant as compared to the trend and seasonal variations for the exponential smoothing model parameters in all the locations. The results of the correlation matrix revealed that the global solar radiation is more correlated to the mean temperature except for Akure where it is more correlated to the sunshine hours; the mean temperature is more correlated to the global solar radiation; the rainfall is more correlated to the relative humidity and the relative humidity is more correlated to the rainfall in all the locations. The results of the component matrix revealed that three seasons are identified in Nguru located in the Sahelian region namely, the rainy, the cool dry (harmattan) and the hot dry seasons while in Zaria, Makurdi and Akure located in the Midland, Guinea savannah and Coastal zones two distinct seasons are identified namely, the rainy and dry seasons.

scholarly journals General Formula for Estimation of Monthly Mean Global Solar Radiation in Different Climates on the South and North Coasts of Iran

2007 ◽  
Vol 2007 ◽  
pp. 1-7 ◽  
Author(s):  
Ali A. Sabziparvar
Keyword(s):  
Relative Humidity ◽  
Solar Radiation ◽  
General Formula ◽  
Sunshine Duration ◽  
Global Radiation ◽  
Global Solar Radiation ◽  
Maximum Temperature ◽  
The South ◽  
Coastal Regions ◽  
Different Climates

Using sunshine duration, cloud cover, relative humidity, average of maximum temperature, and ground albedo as the input of several radiation models, the monthly average daily solar radiation on horizontal surface in various coastal cities of the South (25.23∘N) and the North (38.42∘N) of Iran are estimated. Several radiation models are tested and further are revised by taking into consideration the effects of relative humidity, ground albedo, and Sun-Earth distance. Model validation is performed by using up to 13 years (1988–2000) of daily solar observations. Errors are calculated using MBE, MABE, MPE, and RMSE statistical criteria (see nomenclature) and further a general formula which estimates the global radiation in different climates of coastal regions is suggested. The proposed method shows a good agreement (less than7%deviation) with the long-term pyranometric data. In comparison with other works done so far, the suggested method performs a higher degree of accuracy for those of two regions. The model results can be extended to other locations in coastal regions where solar data are not available.

scholarly journals The potential of global solar radiation in the Silesia region as a renewable source of energy

2016 ◽  
Vol 4 (4) ◽  
pp. 32-40 ◽  
Author(s):  
Katarzyna Waniek
Keyword(s):  
Solar Radiation ◽  
Solar Energy ◽  
Global Radiation ◽  
Three Dimensional ◽  
Global Solar Radiation ◽  
Economic Transformation ◽  
Coal Industry ◽  
Terrain Model ◽  
Digital Elevation ◽  
Research Period

AbstractHistorically, Silesia has been at the centre of the Polish coal industry for many years and thus has experienced poorer air quality compared to other voivodeships. However, in recent years strong economic transformation in the area has led to a considerable reduction in coal production. This study aimed to assess the variability of global solar radiation at selected stations within the Silesian voivodeship, in order to re-evaluate the resources of renewable solar energy during the period 1994–2013. The theoretical potential of solar radiation was calculated based on a three-dimensional terrain model. The data on global solar radiation from 13 stations within the Silesia region, covering the period 1994–2013, were obtained from the Regional Inspectorate of Environmental Protection in Katowice. The most favourable conditions for the use of solar energy were found at the cities Sosnowiec and Cieszyn. The largest increase in global radiation over the research period was observed in Zabrze. The average annual global radiation ranged between 600–1300 kWh·m−2. Digital Elevation Models (DEM) for selected districts of the Silesia region were used to calculate the theoretical potential of global solar radiation. The highest theoretical potential of global radiation was found in the district of Cieszyn, located at the highest altitude.

scholarly journals Estimation of Global Solar Radiation in Mubi, Nigeria

2021 ◽  
Vol 2 (3) ◽  
Author(s):  
Ogbaka D.T ◽  
Bassi H ◽  
Lami D.S ◽  
Tahir M.A
Keyword(s):  
Solar Radiation ◽  
Global Radiation ◽  
Energy System ◽  
Global Solar Radiation ◽  
Solar Irradiation ◽  
Ann Model ◽  
Acceptable Error ◽  
Solar Radiation Intensity ◽  
Artificial Neural ◽  
Artificial Neural Network Ann

Application of solar energy system requires having knowledge about solar irradiation potential in different locations. This study therefore used artificial neural networks for predicting solar global radiation by using metrological data. There is no report about prediction of solar radiation potential for Mubi by using Artificial Neural Network (ANN) method. It is very encouraging to observe a very fine agreement between the measured and estimated values shown in study. The ANN Model is considered the best relation for estimating the global solar radiation intensity for Mubi region with an acceptable error. The MSE, RMSE, MBE, MABE and MAPE values are 0.930, 0.964, 0.3358 MJm−2day−1, 0.8175 MJm−2day−1 and 19.30%, respectively. The ANN models appear auspicious for estimating the Global Solar Radiation in the locations where there are no solar radiation measurement stations.

Sign in / Sign up

Export Citation Format

Share Document