Amount Of Global Solar Radiation Research Articles

Influence of Air Mass Advection on the Amount of Global Solar Radiation Reaching the Earth’s Surface in Poland, Based on the Analysis of Backward Trajectories (1986–2015)

The paper aims to analyse the relationship between the amount of global solar radiation (GSR) reaching the Earth’s surface in Poland and the direction of air mass advection, using 72-h backward trajectories (1986–2015). The study determined average daily sums of GSR related to groups of trajectories with certain similarities in shape. It was found that the average daily sums of GSR during air mass inflow from all the directions (clusters) identified were significantly different from the average daily sum in the multi-year period. A significant increase in the amount of GSR over Poland is accompanied by air mass inflow from the north and east. The frequency of these advection directions is 27% of all days. The western directions of advection prompt different GSR sums: from slightly increased during advection from the north-west, to significantly decreased during advection from the west (from the central and western part of the North Atlantic). Special attention was given to days with extremely large (above the 0.95 percentile) and with the largest (above the 0.99 percentile) GSR sums. These are prompted by two main types of synoptic conditions: the Azores High ridge covering Central and Southern Europe; and the high-pressure areas which appear in Northern and Central Europe.

Optimal Parameters for Spatial Distribution Modeling of Global Horizontal Solar Radiation in Iraq

Solar radiation plays an essential role in all interior physical processes and the radiative budget of the earth-atmosphere system. However, information about the spatial distribution of global solar radiation or its components is limited and exclusive at some scientific centers that specialized in solar radiation physics. Based on daily data of global solar radiation from (1984) to (2004) available at (16) locations in Iraq retrieved from NASA e-archive, this study aims to determine the optimal parameters of the experimental model to estimate the amount of global solar radiation on a horizontal surface as a function of latitude only. The results showed that the suggested model which is mathematically expressed by the sum of sine of latitude is highly appropriate for estimation of global solar radiation in clear sky conditions after adjusting the parameters according to geographical location. Through comparison between modeled output and an independent measured, globally used, and satellite available data and based on overall results besides some validity metrics: MBE, RMSE, pRMSD, NSE, R2, and r; It can be concluded the proposed model is achievable with high accurate practically performance to calculate and estimate the horizontal global solar radiation (GH) in Iraq region.

Design and economic analysis of off-grid solar PV system in Jos-Nigeria

Around the globe, renewable energy sources and their associated technologies are critical to power generation. The solar photovoltaic (PV) system is one of the renewable energy systems supporting electricity consumption in the residential domain. Despite the potential of solar PV as well as an appreciable amount of global solar radiation in the region, no previous study has examined the viability of the PV system for off-grid electricity production in Jos, Nigeria. This paper focuses on examining the feasibility of deploying an off-grid PV system to drive the electricity consumption of a residential building in Jos, Nigeria (9.9ON, 8.9OE, 1204.87 m). The paper adopts a mathematical modelling method for designing and analyzing the entire PV systems to drive the power consumption of the households. By applying mathematical modelling approach, the results demonstrate that 10 MLE275HD2 PV modules each of 275 Wp and five batteries of 100 Ah can satisfy the annual electricity consumption of approximately 3132 kWh. Further, an economic analysis carried out by using the life-cycle cost (LCC) analysis depicts that the LCC, the annualized life-cycle cost (ALCC) and cost of electricity (COE) to be US$ 10,110.85, US$ 593.75 and US$ 0.18/kWh respectively. The results of this modelling demonstrate both the technical and economic viability of the off-grid PV system for power generation, and can serve as a model to the successful development of the system for real application. Further, the model can encourage the stakeholders in the renewable sector to provide the support mechanisms towards the adoption of the PV system in the residential buildings.

Multistep-Ahead Solar Radiation Forecasting Scheme Based on the Light Gradient Boosting Machine: A Case Study of Jeju Island

Smart islands have focused on renewable energy sources, such as solar and wind, to achieve energy self-sufficiency. Because solar photovoltaic (PV) power has the advantage of less noise and easier installation than wind power, it is more flexible in selecting a location for installation. A PV power system can be operated more efficiently by predicting the amount of global solar radiation for solar power generation. Thus far, most studies have addressed day-ahead probabilistic forecasting to predict global solar radiation. However, day-ahead probabilistic forecasting has limitations in responding quickly to sudden changes in the external environment. Although multistep-ahead (MSA) forecasting can be used for this purpose, traditional machine learning models are unsuitable because of the substantial training time. In this paper, we propose an accurate MSA global solar radiation forecasting model based on the light gradient boosting machine (LightGBM), which can handle the training-time problem and provide higher prediction performance compared to other boosting methods. To demonstrate the validity of the proposed model, we conducted a global solar radiation prediction for two regions on Jeju Island, the largest island in South Korea. The experiment results demonstrated that the proposed model can achieve better predictive performance than the tree-based ensemble and deep learning methods.

Influence of air pressure patterns over Europe on solar radiation variability over Poland (1986–2015)

AbstractThe key factor that affects the inflow of radiant energy to the Earth's surface is the circulation of the atmosphere (caused by uneven distribution of air pressure on the globe) and the related changes in the amount of aerosols and cloudiness. This paper identified the areas in the Euro‐Atlantic region where the air pressure change had a significant impact on global solar radiation (GSR) changes over Poland, during the period 1986–2015. In general, growing GSR sums over Poland are to some extent related to the positive phase of the NAO (simultaneous pressure growth in the area of the Azores High and the pressure decrease in the area of the Icelandic Low). Correlation coefficient between the NAO index and GSR over Poland equals 0.18 (statistically significant at α = 0.05). In turn, in summer and autumn the pressure growth in southern Scandinavia results in a significant increase in the amount of GSR over Poland. Days with extremely large GSR sums (above the 95th percentile) are also prompted by the Azores High ridge which covers Central and Southern Europe, and by air mass inflow from the Atlantic.

A mathematical model of global solar radiation to select the optimal shape and orientation of the greenhouses in southern China

In this study, we calculated the amount of global solar radiation captured by the greenhouses at different latitudes. The energy can be used to heat the greenhouses in winter, hence reducing the consumption of fossil energy for greenhouse heating. A script developed in Matlab was used to calculate the captured amount of global solar radiation from 1 November to 1 March of the next year for all the selected greenhouse shapes. The mathematical model of the greenhouse global solar radiation is applicable not only to different regions of the world but also to other types of buildings. This analysis compared six typical greenhouse shapes commonly found in southern China (even span, uneven span, ellipse, arch, sawtooth, and vinery) to select the most suitable type for maximum solar radiation capture. The latitudes ranged from 20° N to 30.6° N. In addition, we considered the orientation of the greenhouse and calculated the cost savings per square meter regarding greenhouse heating in winter. The results showed that sawtooth captured the highest amount of global solar radiation in winter at all latitudes. E-W orientation greenhouses captured the maximum amount of global solar radiation in winter at all latitudes.

Spatiotemporal variability and trends in global solar radiation over Poland based on satellite‐derived data (1986–2015)

AbstractIncoming solar radiation is the most important factor shaping climate system on Earth and the main element of the surface heat balance. The main aim of this study was to investigate the changes in the amount of global solar radiation reaching the Earth's surface in Poland during the 30‐year period 1986–2015. Trends in changes and fluctuations in the size of global solar radiation over Poland were determined. The solar radiation was described based on satellite products originating from the Surface Incoming Shortwave Radiation product from the Surface Solar Radiation Data Set – Heliosat, Edition 2 (SARAH‐2). The average annual sum of global solar radiation over Poland amounted to 3,902 MJ·m−2. The average annual radiation sums were the smallest in northern Poland and mountain basins, while they were the largest in southern Poland. The average annual radiation sum over Poland increased by 7.16 MJ·m−2·year−1 on average. The areas with the largest increase in the amount of solar radiation had the smallest average radiation sums during the multi‐year period (Pomerania, Northern Poland), and those where the increase in radiation was moderate had the highest average radiation sums (Central and Southern Poland). This shows that the spatial differentiation of the amount of solar radiation over Poland was gradually decreasing during this period. A several‐year cycle (of 12–13 years) of annual fluctuations in global solar radiation sums was observed using wavelet analysis. The cycle was visible between the early 1990s and 2005. It resulted from the medium‐term cyclical component (an 11.3‐year cycle which was the strongest until 2010) that occurred in summer. In the long term, the occurrence of cycles in the time series of solar radiation may result from cyclical or quasi‐cyclical changes in aerosol concentration, but this requires a separate study and further in‐depth research based on much longer data series.

Measurement of global and direct normal solar energy radiation in Seri Iskandar and comparison with other cities of Malaysia

Potential solar data are an essential tool for successful solar design and application. However, because of the limited availability of solar radiation stations, spatial resolution is affected whenever an attempt to construct a solar radiation map is made. In this paper, actual solar data were acquired in Universiti Teknologi PETRONAS (UTP), Seri Iskandar, Malaysia (4°24′latitude, 100°58′E longitude, 24 m altitude). The measurements of global solar radiation and direct normal radiation were gathered and analyzed for the whole of 2018. In addition to solar data collection, real-time solar radiation, high accuracy, and related meteorological data were also obtained. With 1-min recorded average values the everyday and monthly solar radiation averages were determined. A record of 1068.10 W/m2 as maximum daily global solar radiation and 915 W/m2 for direct normal radiation was observed on 9 September 2018. Discussions on daily and monthly average clearness index differences are also elaborated in this paper. The acquired data were compared with corresponding data obtained from other selected Malaysian cities and the widely useable data resource, the NASA solar energy model and surface meteorology. Investigation of the data indicated that Seri Iskandar obtains an ample amount of global solar radiation, indicating the strong potential for the use of solar energy.

Comparative Study on Mass loss by the Sun and Energy Available for Utilization between two Tropical Stations in Nigeria

The electromagnetic radiation emitted from the Sun is called solar radiation. Almost all life on Earth evolved with the Sun as a major influence. The rising and setting Sun defined the daily cycle we still respond to biologically. This study investigates theyearly, monthly and daily variation of mass loss by the Sun for two locations; Gusau and Calabar situated across the Sahelianand Coastal climatic zones of Nigeria using daily, monthly and yearly global solar radiation meteorological data obtained fromthe National Aeronautics and Space Administration (NASA) during the period of twenty two years (July 1983 – June 2005). Theenergy available for utilization based on the mass loss by the Sun for the two locations was also investigated. The fluctuations inthe results revealed that the mass loss by the Sun varies significantly from year to year, month to month and from day to day; thus, indicating that it is site dependent and strongly depends on the global solar radiation and solar activities in each of the locations. The highest yearly, monthly and daily mass losses by the Sun for Gusau are 6.3155 1017 kg y -1 in 1985, 5.5691 1016 kg m -1 in April and 2.3482 1015 kg d -1 on April 21, 1985 respectively and the lowest yearly, monthly and daily mass losses by the Sun are 5.6423 1017 kg y -1 in 1999, 4.2740 1016 kg m -1 in December and 1.3031 1015 kg d -1 on December 25, 1999 respectively. The highest yearly, monthly and daily mass losses by the Sun for Calabar are 4.6558 1017 kg y -1 in 1984, 4.6451 1016kg m -1 in February and 2.0252 1015 kg d -1 on February16, 1984 respectively and the lowest yearly, monthly and daily mass losses by the Sun are3.6806 1017 kg y-1 in 1983, 2.5346 1016 kg m-1 in August and 1.9546 1014 kg d-1 on August7, 1983 respectively. The results indicated that the solar energy available for utilization for Gusau are greater than that of Calabar and this is a reflection of the abundant amount of global solar radiation received on a horizontal surface for Gusau as compared to Calabar.

Uwarunkowania cyrkulacyjne ilości całkowitego promieniowania słonecznego docierającego do powierzchni ziemi w Polsce w latach 1986–2015 = Atmospheric circulation determinants of the amount of global solar radiation reaching the land surface in Poland in the years 1986–2015

Solar radiation is a key element of the Earth’s climate system and one of the most important variables in the energy balance of the active surface. The inflow of radiant energy to the Earth’s surface depends on the movement (circulation) of the atmosphere and on the associated changes in the amount of aerosols contained in the atmosphere as well as on cloudiness changes (which reduce the inflow of radiation to the Earth’s surface through reflection, dispersion and absorption processes). In that context, the work detailed in this paper had as its main aim a determination of the influence of atmospheric circulation on the amount of global solar radiation reaching the land surface in Poland. The research was based on source material from 1986–2015, originating from meteorological reanalyses and satellite products. Global solar radiation was analysed based on data from CM SAF satellite products, while atmospheric circulation types were designated with the use of modified version of the Lityński’s classification. Mean daily sums of radiation during individual circulation types, during A, 0, C macrotypes and on days with advection from particular directions were presented. Also the spatial distribution of radiation over the area of Poland during individual circulation types was shown. In the analyses special attention was paid to days with extremely large sums of solar radiation (above the 0.95 percentile). The largest daily sums of solar radiation are connected with anticyclonic circulation types, and the smallest ones – with cyclonic types. The largest mean daily sum of solar radiation occurs during south-western anticyclonic circulation, which is related to the significantly expanded Azores High. The smallest daily sums of solar radiation occur during cyclonic types, with advection of air masses from the north and east – in spring during NWC type, in autumn during EC type, in summer and winter during NEC type. The spatial distribution of solar radiation daily sums over the territory of Poland also depends on the circulation type. For most of the year, the circulation types with the northern and eastern components (N-NE-E) are associated with the reduction of the amount of solar radiation from north to south, while the inflow of air masses from the S-SW-W directions favours the reduction of radiation from south to north. Extremely large sums of solar radiation occur most probably during anticyclonic types with advection of air masses from SW, S and SE, and during the advectionless circulation 0A (conditional probability 0.13, 0.13, 0.11 and 0.10 respectively). The paper also demonstrates that the circulation type (i.e. prevailing pressure system) has a greater influence on daily sums of global solar radiation over Poland than the direction of air masses advection. The research results show that atmospheric circulation plays a significant role in determining the amount of solar radiation reaching the land surface in Poland.

Quantifying the global solar radiation received in Pietermaritzburg, KwaZulu-Natal to motivate the consumption of solar technologies

Abstract In South Africa, power outages and scheduled load shedding are common practices in a bid to safeguard power resources. With the increase in cost of conventional energy sources, and the depletion of fossil fuels, attempts to use renewable resources to their full potential are underway. South Africa and in particular Pietermaritzburg receives sunshine throughout the year, making it suitable for harnessing solar power. In this work we estimate the amount of Global Solar Radiation (GSR) received in Pietermaritzburg which is the capital of the KwaZulu-Natal province. An air temperature model (Hargreaves-Samani) is used to approximate the GSR received in Bisley in comparison to measured data obtained from the ARC, for a period of one calendar year (July 2014 – June 2015). We proceed to apply the Angstrom-Prescott model to evaluate the competence of the initial prediction method. The primary aim of this study is to validate the efficiency and accuracy of the above-mentioned forecasting models, for areas within close proximity. Our results compare fairly well with the observed data provided by the ARC. Both models prove to sufficiently estimate the amount of GSR incident in Bisley. The deviations from the actual measured values suggest that a model which incorporates both variables may improve the accuracy of GSR estimations. The use of comprehensive prediction and forecasting models will allow for optimal placement of solar technologies for the harnessing of GSR within Pietermaritzburg. Though Pietermaritzburg may not be suitable for large scale solar power plants, the employment of solar panels in both industrial and residential areas will contribute greatly to a decrease in demand of grid electricity.

English

In this study, working parameters of the system consisting of air heaters and dryer with solar energy of 0.20 m2 with a space of 0.72 m2 and 10 pieces in the cabin were investigated experimentally. Average atmospheric air temperature and relative humidity values during the dry daylight hours were measured at 49°C and 35%, respectively. As a result of the examination of the test results, the atmospheric air temperature of 56°C was reached in the dryer depending on the solar radiation and environmental conditions. In addition, the accuracy of solar radiation data in the design of solar energy systems was extremely important. Six different models and MBE, RMSE and t-stat comparison methods were used to calculate the amount of global solar radiation on the horizontal surface. The best results were given by Model-3 with values of MBE=0.130 and RMSE=1.401, while the best result from t-statistics was with t-ist=0.282 with Model-5. When the equations are evaluated statistically, it has been shown that the solar-powered family type shelf dryer and tomato drying conditions can be used for Aksaray province. Key words: Solar energy, shelf dryer, tomato, solar radiation, relative humidity.

Wildfires as a major challenge for natural regeneration in Atlantic Forest

The natural regeneration management is a good strategy of ecological restoration of the Atlantic Forest, one of the most devastated biomes on the planet. However, the frequent occurrence of wildfires is one of the challenges to the success of this method. The objective of this study was to evaluate the effects of wildfires on forest dynamics in Atlantic Forest. The studied area was explored during the coffee cycle when plantations replaced primary forests. We used remote sensing data to analyze the forest dynamics over a period of 50 years (1966–2016). We used the INPE burn database to find the occurrence of hot spots from 1998 to 2016. During this period, we selected the years most affected by the fires for the identification of fire scars using the Normalized Burn Ratio spectral index. From this set of information, we used the methodology of weights of evidence to relate forest dynamics and wildfire events with biophysical and anthropic variables. The results showed that in 1966 the forest area accounted for 8.01% of the land cover, and in 2016 this number rose to 18.55% due to the spontaneous natural regeneration process. The regenerating areas were mainly related to the proximity of the remaining fragments and the portions of the landscape receiving the least amount of global solar radiation. The proximity to urban areas, roads and highways, damaged regeneration and favored both deforestation and wildfire events. Fire scars preferentially occur where there is greater sun exposure. It is possible to observe a negative correlation between the natural regeneration process and the fire scars. We concluded that fire severity is one of the factors that shape the landscape of the region while slowing the regeneration process in preferential areas.

Solar water heaters as a pre-heating system for industrial processes

Although solar heating for hot-water production is a mature technology, the general public’s knowledge is mostly confined to domestic uses such as cleaning and washing. In the industrial sector, there is a demand for thermal energy of lower than 250 °C, but to develop applications for industrial heat processes, real energy savings are one of the key issues determining customers’ choice of energy. However, the solar gain from solar water heaters based on the lab tests may be misleading, so field measurements are important to evaluate a system’s financial viability. This study presents 1 year of field measurements for solar water heaters installed as the pre-heating system in a poultry slaughterhouse. The system efficiency is compared with that installed in a dormitory, where the hot-water consumption pattern is similar to that in the domestic sector. These results demonstrate that the amount of global solar radiation and hot-water consumption patterns have a significant effect on the system’s efficiency. A simple cost-to-benefit analysis is also presented based on this real application for solar water heaters.

Three Years of Observations on Global Solar Radiation at Mădârjac Weather Station (270 m) - Central Moldavian Plateau

Abstract This study is based on 3 years of hourly observations of global solar radiation (2014-2016), at a new weather station installed in the region of Central Moldavian Plateau, at Mădârjac (47.05°N, 27.25°E, 270 m). The main characteristics of annual, monthly and daily regime of global radiation were emphasized using for comparison similar data from Iașioficial weather station. Smaller annual amount of global solar radiation than those observed in previous studies were observed, reaching 4734 MJ/m2 in Iași and 4454 MJ/m2 in Mădârjac. An altidudinal gradient of global solar radiation close to 140 MJ/m2 was identified for the hilly region of Moldova. Despite the overall higher values in Iași, 30% of days indicates higher values of this parameter at Mădârjac weather station. These results can be used for the evaluation of the photo-voltaic potential in the region, but also to understand the altitudinal differences of solar radiation in the hilly region in Moldavia, since the only long-range actinometric stations from this part of Romania, Iași and Galați, are located at low altitudes.

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

Abstract The 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.

POTENTIAL AREAS FOR THE FORMATION OF ECOLOGICAL CORRIDORS BETWEEN REMNANTS OF ATLANTIC FOREST

ABSTRACT In Brazil, the remaining areas of Atlantic Forest are intensely fragmented. The connection of forest fragments through ecological corridors is an important step in biodiversity conservation. Certain areas are more resilient, and in those areas, natural forest regeneration, for example, can be encouraged. The aim of this study was to identify areas of greater resilience in order to support the connection of Atlantic Forest fragments with ecological corridors. Forest fragments in the municipality of Paraíba do Sul, in the state of Rio de Janeiro, were mapped using the supervised maximum likelihood classification of an Operational Land Imager (OLI)/Landsat-8 sensor image. Next, we analyzed the influence of terrain attributes (aspect, incident solar radiation, slope, and curvature profile) on natural regeneration. The areas with the greatest potential to achieve natural regeneration and to form ecological corridors were indicated through fuzzy membership functions. Within Paraíba do Sul, 31% of the territory is covered by vegetation in different stages of regeneration. Recordings were made of 1,251 forest fragments in a middle or advanced stage of regeneration. These fragments are usually situated in the southeast, south, and southwest aspects, in areas that receive the least amount of global solar radiation (Wh·m-2) per year, and on slopes with an angle of inclination greater than 20%. The adjustment of fuzzy functions identified 17,327.5 ha with a tendency to recover, and which are therefore strategic areas in the development of ecological corridors.

Effect of Climate Change on Fagaceae Airborne Pollen in Japan as Allergic Causative Agent Associated with Food Allergy

Rational: It is no exaggeration to say that Japanese allergic people has increased according to the increase of Japanese Cedar (JC) pollinosis since the first case report, 1964. In Japan allergenic conifer airborne pollen counts have been increasing with a concomitant change in the start of pollination as a result of climate change during about 30 years. We also investigated as if Fagaceae pollen counts have been affected on climate change. In Japan patients with Fagaceae pollinosis is not so clear although this vegetation distributed almost all of Japan Island. Fagaceae pollen antigen has cross-reactivity to Betula (birch) pollen antigen observed in north part of Japan. Especially in Hokkaido district, a lot of patients with birch pollen have rhinoconjunctivitis and pollen related food allergy, oral allergy syndrome (OAS). In order to analyze and ameliorate the suffering of those with pollinosis, we have estimated the correlation between the Fagaceae pollen counts and meteorological conditions affecting those counts and we will inform the tendency of the pollen disperse for prevent and treatment against Fagaceae pollinosis. Method: There are institutions in fifteen locations monitoring airborne pollen by Durham sampler in Japan between the latitude of 30 to 40 degrees north. At each institute daily airborne pollen samples were collected including holidays and sent to our hospital. We counted pollen grains per cm2 through 100 to 400-power microscopes, classifying and summarizing them. From 1986 to 2014 we have referred to the change in monthly mean temperature, humidity, total monthly sunshine duration and amount of global solar radiation at the close to 9 of the pollen monitoring locations by the Meteorological Agency open data. Result: Fagaceae pollen counts have not shown annual fluctuation compared to conifer but have increased gradually. Only total monthly sunshine duration before the pollination in March has a weak significant correlation with Fagaceae pollen counts (r=0.4~0.53, p<0.05) only in some cities. The start of pollination season has been earlier except north of Japan and correlated with March/April mean temperature significantly with the prolongation of pollination season. Conclusion: Fagaceae pollen counts in Japan have been increasing and in the south of Japan Island the pollination season has prolonged during about 30 years climate change. In near future patients with Fagaceae pollinosis will increase in the southern part of Japan and birch/alder pollinosis with oral allergy syndrome will exacerbate during Fagaceae pollination season. We will inform Fagaceae pollen allergen is important for Japanese allergic people from aerobiology site.

New horizontal global solar radiation estimation models for Turkey based on robust coplot supported genetic programming technique

Renewable energy sources have been attracting more and more attention of researchers due to the diminishing and harmful nature of fossil energy sources. Because of the importance of solar energy as a renewable energy source, an accurate determination of significant covariates and their relationships with the amount of global solar radiation reaching the Earth is a critical research problem. There are numerous meteorological and terrestrial covariates that can be used in the analysis of horizontal global solar radiation. Some of these covariates are highly correlated with each other. It is possible to find a large variety of linear or non-linear models to explain the amount of horizontal global solar radiation. However, models that explain the amount of global solar radiation with the smallest set of covariates should be obtained. In this study, use of the robust coplot technique to reduce the number of covariates before going forward with advanced modelling techniques is considered. After reducing the dimensionality of model space, yearly and monthly mean daily horizontal global solar radiation estimation models for Turkey are built by using the genetic programming technique. It is observed that application of robust coplot analysis is helpful for building precise models that explain the amount of global solar radiation with the minimum number of covariates without suffering from outlier observations and the multicollinearity problem. Consequently, over a dataset of Turkey, precise yearly and monthly mean daily global solar radiation estimation models are introduced using the model spaces obtained by robust coplot technique and inferences on the sensitivity of the amount of global solar radiation to covariates and the magnitude and direction of effect of covariates on the global solar radiation are drawn.

Effects of air pollution for estimating global solar radiation in India

Solar energy is the primary resource for all biological, chemical and physical processes. The amount of global solar radiation is an important parameter for solar energy applications. It is common to estimate a monthly average of daily global solar radiation using different regression models. These models in turn exploit the correlation between solar radiation and various atmospheric factors. These factors are commonly derived from meteorological, geographical and climatological data that are readily available for majority of weather stations across the world. In this paper, a novel regression model that can predict location-independent daily global solar radiation is presented. The proposed exponential quadratic model captures the correlation between measured global solar radiation values, sunshine hour and Air Pollution Index for Indian cities. In addition to this, an extended study of several other regression models (e.g. linear, quadratic, exp.-linear and exp.-quadratic) is also presented. This analysis with real data from Indian cities suggests that air pollution is a more significant factor than location when predicting solar radiation. Finally, the model parameters (regression coefficients) for each model are listed out. Additionally, the generalised model equation for the best performing model is also presented.