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In the present work, the variations in Total Electron Content (TEC) induced by changes in the ionizing radiation of the Sun, which are related to the rotation period (about 27 days), were investigated. This study was based on a 30-year period. The relative deviations in the TEC and F10.7 values were used in the data analysis. The use of this modification aimed to eliminate the stationary diurnal, seasonal, and solar course of the TEC over the course of the long-term variations in solar activity, preserving the variations within a time scale of 27 days and less. As a result, the values of the linear regression coefficient between the relative deviations in the two considered quantities from the median (quiet conditions) for one rotation period were obtained. Depending on the general level of solar activity, the season, and the latitude, this coefficient varied between 40% and 60%. The analysis showed that the minimum values were observed during high solar activity. The latitudinal distribution demonstrated an increase in the area of the Equatorial Ionization Anomaly (EIA) under the influence of the so-called "fountain effect". As a result, there was a seasonal variation and an increase in the winter months at mid and high latitudes and a decrease in the months of the minimum zenith angle of the Sun at low latitudes. A well-pronounced asymmetry in the equinox months was also obtained. The obtained results are the novelty of this study and can be used to improve empirical models for short-term TEC forecasting. [ABSTRACT FROM AUTHOR]

Accurate and reliable measurements of the total solar radiation flux make it possible to evaluate the efficiency of using stand-alone photovaltaic systems in various meteorological conditions. These measurements allow more accurately predict in time the energy production volume, accumulator and capacitive storage devices parameters and the payback period. Research purpose was to study the possibility of creating a photoelectric sensor and a method of uninterrupted measurement based on this sensor which allows to measure total solar radiation flux including its direct, diffused and reflected components simultaneously. The photovaltaic sensor with bifacial photosensitivity was manufactured and applied, which is low-inertia comparing to traditional thermoelectric pyranometers, and its spectral sensitivity is quite close to the same parameter of photovoltaic power supply system. It creates the possibility to estimate the insolation level capable to be completely converted into electrical energy without an ineffective heat-generating long-wavelength part of the solar spectrum. A laboratory measuring stand was made to test the sensor's operability. Modeling and experiments’ the sensor parameters were carried out and confirmed its operability. The bifacial photosensitivity sensor allows to control simultaneously direct, diffused and reflected from the earth's surface components of solar radiation, what gives more complete information about the energy potential of the photovoltaic power supply system location.

In the present work, the variations in Total Electron Content (TEC) induced by changes in the ionizing radiation of the Sun, which are related to the rotation period (about 27 days), were investigated. This study was based on a 30-year period. The relative deviations in the TEC and F10.7 values were used in the data analysis. The use of this modification aimed to eliminate the stationary diurnal, seasonal, and solar course of the TEC over the course of the long-term variations in solar activity, preserving the variations within a time scale of 27 days and less. As a result, the values of the linear regression coefficient between the relative deviations in the two considered quantities from the median (quiet conditions) for one rotation period were obtained. Depending on the general level of solar activity, the season, and the latitude, this coefficient varied between 40% and 60%. The analysis showed that the minimum values were observed during high solar activity. The latitudinal distribution demonstrated an increase in the area of the Equatorial Ionization Anomaly (EIA) under the influence of the so-called “fountain effect”. As a result, there was a seasonal variation and an increase in the winter months at mid and high latitudes and a decrease in the months of the minimum zenith angle of the Sun at low latitudes. A well-pronounced asymmetry in the equinox months was also obtained. The obtained results are the novelty of this study and can be used to improve empirical models for short-term TEC forecasting.

A precise knowledge of solar radiation flux distribution in each particular geographical location is key to the promotion of solar energy technology. The amount of solar radiation flux can be estimated using experimental data and modeling parameters as well. This research work is based on the use of the RadEst 3.0 ver software to estimate daily solar radiation flux at high altitude mountain area using meteorological parameters such as precipitation, maximum and minimum temperature, and solar radiation of Simikot, Nepal (Lat. 29.967 °N, Lon. 81.833 °E and Alt. 2990.0 m). The radiation is estimated using four different models: Bristow and Campbell, Campbell and Donatelli, Donatelli and Bellocchi, Donatelli-Campbell-Bristow-Bellocchi as the product of the estimated transmissivity of radiation for each model and radiation outside the earth's atmosphere and compared with measured solar radiation. The model parameters are fitted in two years (2012 and 2015) ground measured data by using iterative procedures. The performance of the models was evaluated using statistical tools such as root mean square error, mean bias error, mean percentage error, co-efficient of residual mass, and coefficient of determination. The graphics and statistical evaluation suggested that among the four models, the Donatelli-Campbell-Bristow-Bellocchi model is better than others for Simikot. The value of statistical tools for this last model are 3.012 MJ/m2/day, −0.029 MJ/m2/day, 2.402%, 0.002 MJ/m2/day and 0.595 respectively. The finding empirical coefficients of different models can be utilized to estimate of solar radiation flux at similar geographical locations in Nepal. [ABSTRACT FROM AUTHOR]

The renewable sources of energy are of utmost importance in context of the increasing energy demands. The sun energy available in abundance can be utilized effectively subjected to the availability of data on solar radiation flux, which remains the major concern. Solar radiation measurements are not economically feasible, requires maintenance and thus estimation of solar radiation flux data for utilization of solar irradiance plays vital role. For designing of any solar power systems, global solar radiation flux values are vital variables as solar energy generation depends on amount of solar radiation flux. Solar radiation flux is estimated to evaluate the workability of solar energy at Amravati, Maharashtra, India (20.9374 oN, 77.7796 oE). Solar radiation flux calculation is carried out for one year using MATLAB.

By its physical nature, the interannual variability of the solar radiation arriving at the Earth is a duplex with varying ratios of the amplitudes of the components depending on the time resolution. The analysis shows that the amplitude of the long-term variability of the radiation intensity is approximately 95% determined by the variations related to changes in the solar activity. At an annual resolution, the component determined by the solar activity is predominant in amplitude (approximately 80%). At a monthly resolution, the leading component of the duplex is the variation caused by the celestial-mechanical processes (approximately 55%). Thus, the interannual variations determined by the celestial-mechanical processes dominate in the interannual variability of incoming solar radiation within seasonal changes. The results point toward the necessity for a differentiated approach to the use of the values of the interannual solar radiation variability of different physical nature in the climatic models since their weight ratios depend on the time resolution. [ABSTRACT FROM AUTHOR]

Severe air pollution in the northern India coupled with the formation of secondary pollutants results in severe fog conditions during the winter. Black carbon (BC) and particulate matter (PM 2.5 ) play a vital role within the planetary boundary layer (PBL) to degrade atmospheric visibility. These species were continuously monitored during the winter of 2014 in the National Capital Region (NCR) of Delhi. The average BC concentration was 8.0 ± 3.1 μg/m 3 with the January mean (11.1 ± 5.4 μg/m 3 ) approximately two times higher than February (5.9 ± 2.1 μg/m 3 ). The average PM 2.5 concentration was 137 ± 67 μg/m 3 with monthly area-average maximum and minima in December and February, respectively. Higher concentrations of BC at 10:00 local standard time LST (8.5 μg/m 3 ) and 22:00 LST (9.7 μg/m 3 ) were consistently observed and assigned to morning and evening rush-hour traffic across Delhi. Daily average solar fluxes, varied between 17.9 and 220.7 W/m 2 and had a negative correlation (r = − 0.5) with BC during fog episodes. Ventilation coefficient (VC) reduced from ‘no fog’ to fog phase over Palam Airport (PLM) (0.49) times and Hindon Airport (HND) (0.28) times and from fog to prolonged fog (> 14 h) phase over PLM (0.35) times and HND (0.41) times, respectively, indicating high pollution over the NCR of Delhi. Ground measurements showed that daily mean aerosol optical depth at 500 nm (AOD 500 ) varied between 0.32 and 1.18 with mean AOD 500 nm being highest during the prolonged fog (> 14 h) episodes (0.98 ± 0.08) consistent with variations in PM 2.5 and BC. Angstrom exponent ( α ) and Angstrom turbidity coefficient ( β ) were found to be > 1 and 0.2, respectively, during fog showing the dominance of fine mode particles in the atmosphere. [ABSTRACT FROM AUTHOR]