Mean Daily Solar Radiation Research Articles

Estimation of Solar Radiation on a PV Panel Surface with an Optimal Tilt Angle Using Electric Charged Particles Optimization

Solar energy is a promising renewable energy source that can fulfill the world’s current and future energy needs. The angle at which a photovoltaic (PV) panel faces the horizon determines the incidence of solar radiation. The incident solar radiation on PV panels could be optimized by adjusting their tilt angles and increasing the power output of the PV array. In this study, solar energy model-based research was conducted in the Saudi Arabian cities of Dhahran and Makkah. This study investigated the performance of a 1 kW monocrystalline silicon PV array in these cities. Analyzing the optimal tilt angle for efficiency and performance improvement of the PV panel is challenging. The optimal tilt angle is determined by combining the data of the Sun’s diffuse, direct radiation and the global horizontal Sun radiation. This research examined the four empirical models by applying the electric charged particle optimization (ECPO) algorithm to estimate the solar radiation on sloped surfaces. The model’s results were compared to the global horizontal solar radiation based on the daily mean solar radiation value in these cities. The Hay–Davies–Klucher–Reindel model presented the maximum amount of tilted surface solar radiation in the year and at different periods. In contrast, the Badescu model exhibited the weakest results of all the isotropic and anisotropic models. Finally, using the ECPO algorithm, all models indicated that tilted surfaces (IT) received more solar radiation than horizontal surfaces (Ig).

A novel combined multi-task learning and Gaussian process regression model for the prediction of multi-timescale and multi-component of solar radiation

A novel combined multi-task learning and Gaussian process regression (MTGPR) model is proposed to predict the multi-time scale (daily and monthly mean daily) and multi-component (global and diffuse) solar radiation simultaneously. Compared to conventional Gaussian process regression (GPR) which can only be used for specific solar radiation component prediction on a specific timescale, the MTGPR can utilize the correlated information between different tasks to improve the model generalization and accuracy. Meteorological data from ten stations in China were used to train and validate the GPR and MTGPR models for daily global, monthly mean daily global, daily diffuse and monthly mean daily diffuse solar radiation prediction. The results showed that the GPR and MTGPR models are highly accurate in estimating daily and monthly mean daily solar radiation with coefficient of determination (R2), root mean square error (RMSE), relative root mean square error (rRMSE) and mean bias error (MBE) of GPR in ranges of 0.4623–0.9892, 0.5542–4.1591 MJm−2d−1, 4.70–39.75% and −1.1750–1.5347 MJm−2d−1, respectively. Because the MTGPR learned the intercorrelated information between different tasks, compared to GPR models, the MTGPR models performed better. For daily prediction, the average R2, RMSE and rRMSE of the MTGPR improved by 0.19–0.48%, 0.57–0.65% and 0.51–0.52%, respectively. In terms of monthly mean daily prediction, the corresponding values of MTGPR improved by 2.62–2.65%, 5.50–12.07% and 5.21–12.08%, respectively. This paper provides a compact guide for the simultaneous prediction of combined parameters.

A weather‐adaptive topdressing method to enhance rice yield in southwestern Japan

AbstractRice (Oryza sativa L.) plants grown in southwestern Japan are subjected to large variations in air temperature and solar radiation during the rainy season which can affect their growth. Therefore, in this study, a novel nitrogen (N) application method for topdressing was proposed to increase grain yield under different weather conditions. Field experiments were conducted to determine the grain yield response to the soil and plant analyzer development (SPAD) readings and normalized difference vegetation index (NDVI) during the early reproductive stage in 2018 and 2019. As the rainy season ended in early July in 2018 but continued until late July in 2019, the daily mean solar radiation during the vegetative and early reproductive stages was 26% lower in 2019 than in 2018. Grain yield was 10% lower in 2019 than in 2018, mainly due to the lower number of spikelets. During the early reproductive stage, the SPAD readings and NDVI were higher in 2019 than in 2018, suggesting that the biomass and N concentration in 2019 were lower and higher than those in 2018, respectively. Statistical modeling examination of grain yield response to growth‐related factors revealed that the N application rate during the reproductive stage and SPAD readings were significant predictors in 2018, whereas the N application rate and NDVI were significant predictors in 2019. Our findings suggest that SPAD readings and NDVI are key factors for determining N application rate during the reproductive stage under higher and lower solar radiation conditions during the vegetative and reproductive stages, respectively.

The effects of sowing date on cottonseed properties at different fruiting-branch positions

A two-year field experiment was conducted to illustrate the effects of sowing date on cottonseed properties at different fruiting-branch positions (FBPs). Two cotton cultivars (Kemian 1 and Sumian 15) were sowed on 25 April, 25 May, and 10 June in 2010 and 2011, respectively. The boll maturation period increased with the delaying of sowing date. Normal sowing treatment (25 April) had higher seed weight, embryo weight, embryo oil content and protein content than late sowing treatments (25 May and 10 June). The flowering date, seed weight, embryo weight, embryo oil and protein contents, and the dynamic changes of embryo oil and protein contents were altered by different FBPs. A significant interaction of sowing date×FBP was observed on embryo weight, embryo oil content, embryo protein content and the dynamic changes of embryo oil and protein contents, but was not observed on seed weight. Seed weight, embryo weight, embryo oil and protein content had significant positive correlations with the mean daily temperature (MDT), mean daily maximum temperature (MDTmax), mean daily minimum temperature (MDTmin), and mean daily solar radiation (MDSR), indicating that temperature and light resources were the main reasons for different sowing dates affecting the cottonseed properties at different FBPs. Moreover, the difference in MDT was the main difference in climatic factors among different sowing dates.

Analyses of Transpiration and Growth of Paprika (Capsicum annuum L.) as Affected by Moisture Content of Growing Medium in Rockwool Culture

Since the moisture content (MC) of growing medium closely related with the crop transpiration, the MC should be included to the environmental factors to be considered for irrigation control in soilless culture. The objective of this study was to analyze the transpiration of paprika plants using daily mean solar radiation (RAD) and vapor pressure deficit (VPD) as well as the growth of the plants at different MCs of rockwool growing media. The starting points of irrigation were controlled by a moisture sensor with minimum set points of 40%, 50%, and 60% of MCs. The canopy transpirations were measured for 80 to 120 days after transplanting and analyzed. The transpirations were well regressed with a combination of both RAD and VPD rather than daily mean RAD only under the controlled MCs. The transpiration at 60% MC was higher than those at 50% and 40% MCs. Leaf area, leaf fresh and dry weights at 60% MC were higher than those at 50% and 40% MCs while the number of leaves had no significant difference among the MCs. There were no significant differences in number of fruits and fruit size among all the MCs, while fruit weight was significantly lower at 40% MC than other treatments. Fresh and dry fruit yields were the highest at 60% MC. Therefore it was concluded that the transpiration was affected by the MC of rockwool growing medium and the minimum set point of 50-60% MC of rockwool growing medium gave better effects on the growth of the paprika plants.

Predicting solar radiation fluxes for solar energy system applications

The mean daily global solar radiation flux is influenced by astronomical, climatological, geographical, geometrical, meteorological, and physical parameters. This paper deals with the study of the effects of influencing parameters on the mean daily global solar radiation flux, and also with the computation of the solar radiation flux at the surface of the earth in locations without solar radiation measurements. The reference–real data were borrowed from the Iranian Meteorological Organization. The analysis of data showed that the mean daily solar radiation flux on a horizontal surface is related to parameters such as: mean daily extraterrestrial solar radiation, average daily ratio of sunshine duration, mean daily relative humidity, mean daily maximum air temperature, mean daily maximum dew point temperature, mean daily atmospheric pressure, and sine of the solar declination angle. Multiple regression and correlation analysis were applied to predict the mean daily global solar radiation flux on a horizontal surface. The models were validated when compared with the reference–measured data of global solar radiation flux. The results showed that the models estimate the global solar radiation flux within a narrow relative error band. The values of mean bias errors and root mean square errors were within acceptable margins. The predicted values of global solar radiation flux by this approach can be used for the design and performance estimation in solar applications. The model can be used in areas where meteorological stations do not exist and information on solar radiation flux cannot be obtained experimentally.

지형조건에 따른 제주도의 일사량 분포 추정

The solar radiation is the primary energy source that drives many of the earth`s physical and biological processes and climate change. Understanding its importance to the solar radiation observation is a key to understanding a broad range of natural processes, agricultural, energy and human activities. The purpose of this study is to estimate solar radiation using sunshine duration, and to estimate distribution of solar radiation using a topography factor considering surface slope and aspect in complex terrain. The result of regression analysis between ratio of solar radiation and sunshine duration from 2001 to 2010 shows high value of 0.878. Regression analyses indicated that topographic attributes including elevation, slope and aspect had significant effects on solar radiation. The variation of topographic factor with aspect and slope for the summer and winter are considered. The highest month of daily mean solar radiation at Jeju island appears in April of 20.61 , and the lowest month appears in December of 6.90 . These results provided useful quantitative information about the influence of topography on solar radiation in the island region.

Simulation and Comparison on Photoelectric Conversion Efficiency for Auto Tracking Solar System and Fixed Solar System

Assuming the clearness and cloudless weather in Beijing area, the received solar radiation power is simulated according to three different auto-tracking solar systems and fixed solar system by Matlab. The tracking intervals of three different auto-tracking solar systems are separately 60mins, 30mins and 10mins. The daily mean solar radiation, the monthly mean solar radiation and the yearly mean solar radiation are simulated for three auto-tracking solar systems and fixed solar system. The simulation results can be used as the auto-tracking solar system design reference for engineers, and helpful for solar system optimizing.

Impact of aerosol direct radiative forcing on the radiative budget, surface heat fluxes, and atmospheric dynamics during the heat wave of summer 2003 over western Europe: A modeling study

[1] In this work, an off-line coupling between the chemistry-transport model CHIMERE (associated with an aerosol optical module) and the meteorological model Weather Research and Forecasting (WRF) is used to study (1) the direct radiative forcing of pollution aerosols during the heat wave of summer 2003 over western Europe and (2) the possible feedbacks of this direct radiative forcing on the surface-atmosphere system. Simulations performed for the period 7–15 August 2003 reveal a significant decrease of daily mean solar radiation reaching the surface (ΔFBOA = −(10–30) W/m2) because of back scattering at the top of the atmosphere (ΔFTOA = −(1–12) W/m2) and also absorption of solar radiation by polluted particles (ΔFatm = + (5–23) W/m2). During daytime, the aerosol surface dimming induces a mean reduction of both sensible (16 W/m2) and latent (21 W/m2) heat fluxes emitted by the terrestrial surface, resulting in a radiative cooling of the air near the surface (up to 2.9 K/d at noon). Simultaneously, the absorption of solar energy by aerosols causes an atmospheric radiative heating within the planetary boundary layer reaching 1.20 K/d at noon. As a consequence, the direct radiative effect of aerosols is shown to reduce both the planetary boundary layer height (up to 30%) and the horizontal wind speed (up to 6%); that may have contributed to favor the particulate pollution during the heat wave of summer 2003.

AN 'ALTERNATIVE' MODEL TO ESTIMATE SOLAR RADIATION

Solar radiation is extremely useful in modelling many agricultural applications, but ishardly used due to the difficulty in obtaining data, and the time consuming process inestimating it by the Angstrom (1924) formula which uses world geographical relationships.To estimate solar radiation at the Coconut Research Institute, Lunuwila (7° 20' N; 71° 5 3 'E; 30.5 m ) an alternative model was developed from measured sunshine hours data only.The model had good fit (R2 = 0.90, P < 0.001) and was found to have agreement with theestimates obtained from the Angstrom model. The alternative model is more flexible anduseful in estimating crop evapotranspiration, and for crop-weather modelling. The mean dailysolar radiation at Lunuwila was estimated to be 18.3 MJ m"2d "' and .the total annual solarradiation receipts is 6680 MJ m'2 (66.8 TJ ha-1). The monthly solar radiation was highestin March (21.7 MJ m'2 d ' ) and the estimated 75% probability value was 22.5. June had thelowest (16.1 MJ m"2 d'1) value and the estimated 75% probability value was 17.8.

Diurnal Coupling in the Tropical Oceans of CCSM3

Abstract New features that may affect the behavior of the upper ocean in the Community Climate System Model version 3 (CCSM3) are described. In particular, the addition of an idealized diurnal cycle of solar forcing where the daily mean solar radiation received in each daily coupling interval is distributed over 12 daylight hours is evaluated. The motivation for this simple diurnal cycle is to improve the behavior of the upper ocean, relative to the constant forcing over each day of previous CCSM versions. Both 1- and 3-h coupling intervals are also considered as possible alternatives that explicitly resolve the diurnal cycle of solar forcing. The most prominent and robust effects of all these diurnal cycles are found in the tropical oceans, especially in the Pacific. Here, the mean equatorial sea surface temperature (SST) is warmed by as much as 1°C, in better agreement with observations, and the mean boundary layer depth is reduced. Simple rectification of the diurnal cycle explains about half of the shallowing, but less than 0.1°C of the warming. The atmospheric response to prescribed warm SST anomalies of about 1°C displays a very different heat flux signature. The implication, yet to be verified, is that large-scale air–sea coupling is a prime mechanism for amplifying the rectified, daily averaged SST signals seen by the atmosphere. Although the use of upper-layer temperature for SST in CCSM3 underestimates the diurnal cycle of SST, many of the essential characteristics of diurnal cycling within the equatorial ocean are reproduced, including boundary layer depth, currents, and the parameterized vertical heat and momentum fluxes associated with deep-cycle turbulence. The conclusion is that the implementation of an idealized diurnal cycle of solar forcing may make more frequent ocean coupling and its computational complications unnecessary as improvements to the air–sea coupling in CCSM3 continue. A caveat here is that more frequent ocean coupling tends to reduce the long-term cooling trends typical of CCSM3 by heating already too warm ocean depths, but longer integrations are needed to determine robust features. A clear result is that the absence of diurnal solar forcing of the ocean has several undesirable consequences in CCSM3, including too large ENSO variability, much too cold Pacific equatorial SST, and no deep-cycle turbulence.

コムギ４品種の登熟性に関する気象反応

This paper describes effects of varied meteorological conditions on the grain filling periods, stabilities of yield and quality of winter wheat cultivars with different maturity characteristics (cv. Ayahikari, Norin61, Bandowase, Tsurupikari). In the field experiments, the meteorological treatments were made during the first heading time on 17 April 2001 and the middle heading time on 24 April 2000. Air temperature, global solar radiation and soil moisture were controlled using a rain shelter, cheesecloth and irrigation system. The growth speed and growth period of wheat grains varied among four winter wheat cultivars, depending on meteorological conditions. The growth speed increased within 18.4℃ of mean air temperature over the 30 days after the anthesis. On the other hand, it was found that the growth speed of wheat grains and the maximum number of wheat grains (Ymax) decreased greatly with the 44.4% interception of global solar radiation. Logistic functions were fitted to the relationship between the relative thousand-kernel-weight (Y/Ymax) and the total integrated temperature (ΣTa) after heading for all treatment conditions.The maximum weight of grains (Ymax) achieved at the harvest time varied somewhat clearly among four winter wheat cultivars and meteorological conditions. Multiple regression analysis showed that the grain yield (Ymax) of four wheat cultivars correlated positively with daily mean solar radiation. It was also found that the cultivar Ayahikari had a highly significant negative correlation between its grain weight and soil moisture. Namely, the grain weight of high soil moisture plot with pF=1.5 was lower by about 9% than that of a control plot with pF=3.5. On the other hand, the grain yield of cultivar Norin61 responded inversely to a wet environment, indicating that its grain weight was higher for high soil moisture and high wet-bulb temperature than for a dry environment. The grain yield of early varieties of Bandowase and Tsurupikari increased with the increasing temperature difference (Td—Tw). Ash and protein contents of wheat grains in the restricted global solar radiation plot and higher temperature plot were higher than those for the control plot, independently of the four winter wheat cultivars.

Observational Study on the Downward Solar Radiation at the Sea Surface in the Western Pacific

In situ observation of downward solar radiation in the Western Pacific were carried out with voluntary merchant ships for five years from autumn 1990 through autumn 1995. Daily means of the short wave radiation were computed from the observed solar radiation. Then, the effects of shadows of the ship's superstructures on the observed radiation were corrected if needed. A 5-year average of short wave radiation along the main sea-lanes in the Western Pacific was calculated based on the observed daily mean solar radiation. Maximum values of 270–280 Wm−2 are found around 15°–20°N in May and June, while those of 290 Wm−2 are observed south of 18°S in November and December along the lanes. Small annual variations are found in the equatorial region. Annual mean values at the equator are about 230 Wm−2 between New Guinea and Indonesia, and 200 Wm−2 east of New Guinea. The 5-year average of short wave radiation was compared with the climatologies given in previous studies. We have concluded that some of results of previous studies are significantly underestimated.

Seasonal changes in growth and yield of sugarcane plants in southwestern islands of Japan. II. Changes in growth of internodes.

The internode of each stalk in three varieties, NCo 310, F 161 and Yomitanzan rapidly elongated and thickened within 10 days after the time of unfolding of the leaf attached at each node and attained the maximum size within 20 days after the time. Dry matter weight and Brix of the internode in NCo 310 and F 161 continuously increased within 100 days after the time of unfolding of the leaf, while the dry weight in Yomitanzan reached the maximum within 70 days afrer the time. The moisture content of the internode gradually decreased with time. The length and diameter of internodes in the main stalk of F 161 planted every month from June, 1980 to May, 1981 showed the pronounced variation. The length of all upper internodes from 11th node order was significantly correlated with mean daily air temperature, mean daily solar radiation and precipitation during the growing period of each internode. Partial correlations between the length of internodes from 11th to 40th node order and precipitation and between the length of upper internodes from 11th and mean daily solar radiation were positive, but those between the length of internodes from 11th to 40th and the mean daily temperature were negative. The each diameter of internodes from 11th to 30th node order was negatively correlated with the mean daily air temperature and precipitation, but the each diameter of upper node order from 31th was positively correlated with the three climatic factors. Partial correlations of the diameter with mean daily air temperature were highly negative, but those of the diameter with mean daily solar radiation and precipitation were positive.

A design procedure for an air-type solar heating system for greenhouses

System performance, crop yield and cost are the major criteria for design optimization of a greenhouse solar heating system. While experimental study and evaluation of each plausible design are cost-prohibitive, resorting to detailed computer simulations would enable the prediction of system performance at specified locations. This paper discusses the development of a design procedure for greenhouse space heating. A simulation model that describes the greenhouse thermal environment and thermal storage, is verified by short-term actual data. Monthly average meteorological data were then used as inputs to the computer program for predicting long-term system performance, as indicated by the fraction of annual heating load supplied by solar energy. Results from simulation runs suggested that monthly solar heating fraction may be correlated with a dimensionless variable that involved mean daily solar radiation on an outside horizontal surface, total capture factor of the greenhouse cover, and night-time heat load. Such correlation was presented as a preliminary guidline for designers. Crop yield and economic analyses have to be carried out before selecting an optimum design for a particular location.

Aspect influences on pasture microclimate at Coopers Creek, North Canterbury

Abstract Rainfall, soil moisture, and soil and air temperatures were measured over five years on north and south aspects (about 25°slope) of a grazed pasture and on the exposed intervening ridge crest at Coopers Creek, North Canterbury (43° 15‘S) at about 380 m a.s.l. Solar radiation and wind were measured only on the ridge, and radiation received on north and south slopes was derived from ridge measurements. Potential evapotranspiration on all aspects was calculated from solar radiation and air temperature according to the Priestley and Taylor formula. Daily mean solar radiation on the ridge averaged 332 langleys per day with a maximum of 591 langleys per day in December and a minimum of 118 langleys per day in June. Over a year the north aspect received 80% more radiation than the south. North-west winds prevailed; windrun at 2.1 m above ground was usually over 200 km.d–1and occasionally was over 2000 km.d–1. Total potential evapotranspiration on the ridge averaged 1093 mm.a–1 with a maximum of 5...

Seasonal Variation of Net Assimilation Rate (NAR) of rice plants

For the purpose of obtaining some data serving as the basic ones for analyzing the relationship of rice growing seasons or areas to rice yields, authors tested the seasonal changes in NAR of rice plants, i. e., the seasonal changes in NAR in response to those in solar radiation and air temperature. For this test, Fujiminori Variety's young seedlings (at the fourth-leaf fully developed stage) grown in soil cultures were used as samples. The test results might be summarized as follows: 1. It was noted that NAR at the daily mean air temperature of 15°to 21°C changed favorably in proportion to the increases both in solar radiation and air temperature, but at the temperature of 21°to 30°C, NAR changed in response only to the increase in solar radiation, irrespective of air temperature. 2. Based upon the test results showing the above-mentioned seasonal changes in NAR as well as upon the daily mean solar radiation and air temperature at Zentsuji (in Shikoku), authors could observe the probable seasonal changes in NAR as described below in the months from late April to late October. 3. It was estimated that NAR took a rapid upward trend in the month from late April to late May, but in June it showed a rather retarding trend. After the opening of July, however, NAR continued to take the upward trend again, thus reaching the peak in late July and then it dropped with rapidity.