PREDICTING SOLAR RADIATION FOR TROPICAL ISLANDS FROM RAINFALL DATA

There are many correlations developed to predict incident solar radiation at a given location developed based on geographical and meteorological parameters. However, all correlations depend on accurate measurement and availability of weather data such as sunshine duration, cloud cover, relative humidity, maximum and minimum temperatures etc, which essentially is a costly exercise in terms of equipment and labour. Sri Lanka being a tropical island of latitudinal change of only 30 along the length of the country, the meteorological factors govern the amount of incident radiation. Considering the cloud formation and wind patterns over Sri Lanka as well as the seasonal rainfall patterns, it can be observed that the mean number of rainy days can be used to predict the monthly average daily global radiation which can be used for calculations in solar related activities conveniently.

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Global radiation within subarctic open forest canopies

Canadian Journal of Forest Research ◽

10.1139/x94-139 ◽

1994 ◽

Vol 24 (5) ◽

pp. 1062-1066 ◽

Cited By ~ 4

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).

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

International Journal of Environment and Climate Change ◽

10.9734/ijecc/2019/v9i530113 ◽

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.

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A Comparative Study of Some Regression Models to Estimate the Global Solar Radiation on a Horizontal Surface from Sunshine Duration and Meteorological Parameters for Ghardaïa Site, Algeria

ISRN Renewable Energy ◽

10.1155/2013/754956 ◽

2013 ◽

Vol 2013 ◽

pp. 1-11 ◽

Cited By ~ 8

Author(s):

Kacem Gairaa ◽

Yahia Bakelli

Keyword(s):

Solar Radiation ◽

Horizontal Plane ◽

Regression Models ◽

Meteorological Parameters ◽

Sunshine Duration ◽

Global Solar Radiation ◽

Mean Bias Error ◽

Percentage Error ◽

Bias Error ◽

Quadratic Models

A comparison between some regression correlations for predicting the global solar radiation received on a horizontal plane has been processed. Seven models for estimating the global solar radiation from sunshine duration and two meteorological parameters (air temperature and relative humidity) are presented. The root mean square error (RMSE), mean bias error (MBE), correlation coefficient (CC), and percentage error () have been also computed to test the accuracy of the proposed models. Comparisons between the measured and the calculated values have been made. The results obtained show that the linear and quadratic models are the most suitable for estimating the global solar radiation from sunshine duration, and for the models based on meteorological parameters, Abdalla and Ojosu's models give the best performance with a CC of 0.898 and 0.892, respectively.

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

International Journal of Photoenergy ◽

10.1155/2007/94786 ◽

2007 ◽

Vol 2007 ◽

pp. 1-7 ◽

Cited By ~ 16

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.

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1961–1990 monthly high-resolution solar radiation climatologies for Italy

Advances in Science and Research ◽

10.5194/asr-8-19-2012 ◽

2012 ◽

Vol 8 (1) ◽

pp. 19-25 ◽

Cited By ~ 4

Author(s):

J. Spinoni ◽

M. Brunetti ◽

M. Maugeri ◽

C. Simolo

Keyword(s):

High Resolution ◽

Solar Radiation ◽

Normal Values ◽

Sunshine Duration ◽

Global Radiation ◽

Data Set ◽

Sparse Network ◽

Duration Data ◽

Atmospheric Turbidity ◽

Preliminary Version

Abstract. We present a methodology for estimating solar radiation climatologies from a sparse network of global radiation and/or sunshine duration records: it allows to obtain high-resolution grids of monthly normal values for global radiation (and for the direct and diffuse components), atmospheric turbidity, and surface absorbed radiation. We discuss the application of the methodology to a preliminary version of an Italian global radiation and sunshine duration data set, which completion is still in progress and present the resulting 1961–1990 monthly radiation climatologies.

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PROCESSING SUNSHINE DURATION MEASUREMENTS FOR THE ASSESSMENT OF SOLAR RADIATION IN CLIMATIC REGIONS OF THE CENTRAL AFRICAN REPUBLIC

Journal of Solar Energy Engineering ◽

10.1115/1.4053483 ◽

2022 ◽

pp. 1-27

Author(s):

Venant Sorel Chara-Dackou ◽

Donatien Njomo ◽

Mahamat Hassane Babikir ◽

mbouombouo ngapouth ibrahim ◽

Gboulie Pofoura Aicha sidica ◽

...

Keyword(s):

Solar Radiation ◽

Large Scale ◽

Central African Republic ◽

Polynomial Regression ◽

Least Squares Method ◽

Sunshine Duration ◽

Global Radiation ◽

Diffuse Radiation ◽

Ordinary Least Squares ◽

Climatic Regions

Abstract The objectives of this work carried out in the Central African Republic are to propose new correlations between the components of solar radiation and the sunshine duration on a horizontal surface on the ground, and then to make an evaluation of the solar potential in the cities of Bambari, Birao and Bangui. Polynomial regression models were used and their parameters were estimated by the ordinary least squares method. A statistical evaluation allowed us to compare the performance of the models. The best correlations are then used to estimate the global and diffuse radiation. In the city of Birao, the estimated global radiation is around 6 kWh/m2.j and the diffuse radiation around 2 kWh/m2.j ; in Bambari the global radiation is around 5.4 kWh/m2.j and the diffuse around 2.3 kWh/m2.j ; in Bangui the global radiation is around 5 kWh/m2.j and the diffuse radiation around 2.3 kWh/m2.j. The potential solar in all these regions is very favorable for small and large-scale solar photovoltaic applications.

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Estimation of daily diffuse solar radiation from clearness index, sunshine duration and meteorological parameters for different climatic conditions

Sustainable Energy Technologies and Assessments ◽

10.1016/j.seta.2021.101544 ◽

2021 ◽

Vol 47 ◽

pp. 101544

Author(s):

Zia ul Rehman Tahir ◽

Saiqa Hafeez ◽

Muhammad Asim ◽

Muhammad Amjad ◽

Muhammad Farooq ◽

...

Keyword(s):

Solar Radiation ◽

Meteorological Parameters ◽

Sunshine Duration ◽

Climatic Conditions ◽

Clearness Index ◽

Diffuse Solar Radiation

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Comparison of Solar Radiation and Myopia Occurrence in South Korean Children

Journal of Ophthalmology ◽

10.1155/2019/7643850 ◽

2019 ◽

Vol 2019 ◽

pp. 1-6

Author(s):

Hun Gu Choo ◽

Sang Hoon Rah ◽

Soo Han Kim

Keyword(s):

Solar Radiation ◽

Sunshine Duration ◽

Population Based ◽

Spherical Equivalent ◽

Regression Analyses ◽

Cross Sectional ◽

Korean Children ◽

Entire Cohort ◽

South Korean ◽

The Mean

Purpose. To investigate the association between regional solar radiation and myopia occurrence in South Korean children. Materials and Methods. A population-based cross-sectional study using data of 1218 children aged 7–9 years from the Korea National Health and Nutritional Examination Survey was conducted from January 1, 2008, to December 31, 2012. Myopia prevalence and the mean spherical equivalent were estimated; myopia was defined as spherical equivalent refraction <−1.5 D. Data regarding solar radiation and sunshine duration were collected from 21 national monitoring stations in South Korea. Multiple logistic regression analyses and multiple linear regression analyses were used to evaluate the associations. However, the most important covariate, the time spent outdoors, was not measured and could not be used. Results. In the entire cohort of 1218 participants, solar radiation and sunshine duration were significantly associated with the mean spherical equivalent (P=0.001 and P=0.014, B = 0.088 and B = 0.069, respectively) and solar radiation was significantly associated with myopia prevalence (P=0.008). And, a negative but not statistically significant association between sunshine duration and myopia prevalence was observed (P=0.064, respectively). Conclusions. Solar radiation and sunshine duration are associated with the mean spherical equivalent and myopia prevalence in South Korean children.

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Potential for year-round forage production in Puerto Rico and St. Croix

The Journal of Agriculture of the University of Puerto Rico ◽

10.46429/jaupr.v89i3-4.1035 ◽

1969 ◽

Vol 89 (3-4) ◽

pp. 133-148

Author(s):

Thomas R. Sinclair ◽

Yoana C. Newman ◽

María de L. Lugo ◽

Elide Valencia ◽

Ann R. Blount

Keyword(s):

Puerto Rico ◽

Solar Radiation ◽

Plant Growth ◽

Forage Yield ◽

Weather Data ◽

Rooting Depth ◽

Tropical Islands ◽

Forage Production ◽

Large Yield ◽

Low Levels

Forage production can vary substantially during the annual cycle in the tropical islands of Puerto Rico and St. Croix. Cool temperatures, low levels of solar radiation, and low rainfall in December and January have been hypothesized to cause decrease in forage growth. A forage growth model was used to simulate yield in different environments in order to examine these hypotheses quantitatively. Weather data were obtained over a period of three to six years from three locations in Puerto Rico and one location in St. Croix. Minimum temperatures were always near or above 20° C and, consequently, did not appear to cause serious losses in forage production. The forage model predicted a decrease in forage production during the winter months due to decreased levels of solar radiation; however, yields were estimated to be approximately 70 to 80% of summer yields. Whereas shallow rooting depth of 45 cm could cause decreased yields in some situations, inadequate rainfall could not explain large yield decreases in winter months. This research indicates that a factor in addition to the ones tested contributes to the loss in winter forage yield. It is speculated that short day lengths directly influence the regulation of plant growth such that forage yield is decreased in winter months.

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