Some measurements of the extinction coefficients of solar radiation in Lagos

1980 ◽  
Vol 118 (2) ◽  
pp. 775-782 ◽  
Author(s):  
C. O. Oluwafemi
Keyword(s):  
Solar Radiation ◽  
Extinction Coefficients

scholarly journals Modeling Approach for Determining Equivalent Optical Constants of Plastic Shading Nets under Solar Radiation Conditions

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
A. M. Abdel-Ghany ◽  
I. M. Al-Helal
Keyword(s):  
Solar Radiation ◽  
Optical Constants ◽  
Present Model ◽  
Incident Angle ◽  
Radiative Properties ◽  
Beam Radiation ◽  
Extinction Coefficients ◽  
Average Value ◽  
Texture Structure ◽  
Radiation Conditions

The radiative properties of several plastic shading nets were measured under natural solar radiation conditions. We found that the plastic nets behave as homogeneous translucent materials (e.g., plastic film, plastic sheets, and glass). Based on this behavior, we suggest that it is possible to treat plastic nets as translucent materials and to characterize them with equivalent optical constants (i.e., equivalent refractive indexes,neq, and equivalent extinction coefficients,σeq). Here a physical model to determineneqandσeqof plastic nets was described in analogy to homogeneous translucent materials. We examined three groups of nets based on their color (black, black-green, and beige). Each group consisted of nets with four or five different porosities. Nets of each group had almost the same texture structure. For each group, we derived an equation forneqas a function of the net porosity and determined an average value forσeq. Once values ofneqandσeqwere determined, the solar radiative properties of a net could then be calculated fromneqandσeqfor any incident angle of solar beam radiation without the need of measurements. The present model was validated by comparing the calculated with the measured radiative properties of three nets at different incident angle of solar beam radiation. The calculated radiative properties reasonably agreed with measured values.

scholarly journals Parameterization of Solar Radiation Absorption by Snow–ice Cover in the Thermodynamic Sea Ice Model of the Sea of Azov

2021 ◽  
Vol 28 (5) ◽  
Author(s):  
D. D. Zavyalov ◽  
T. A. Solomakha ◽  
◽  
Keyword(s):  
Solar Radiation ◽  
Sea Ice ◽  
Ice Cover ◽  
Wave Radiation ◽  
Thermophysical Characteristics ◽  
Extinction Coefficients ◽  
Seasonal Evolution ◽  
Cover Thickness ◽  
Taganrog Bay ◽  
Snow And Ice

Purpose. The work is aimed at assessing the influence of choice of the parameterization scheme of the snow and ice radiation features upon reproduction of seasonal evolution of the snow–ice cover thickness and temperature distribution in it in the Taganrog Bay top part. Methods and Results. Thermal seasonal dynamics of the snow–ice cover thickness in the northeastern part of the Taganrog Bay was studied using a non-stationary thermodynamic model of sea ice. The model reproduces formation of ice and accumulation of snow on its surface, spatial-temporal change in their thermophysical characteristics, melting of the snow–ice cover, vertical distribution of temperature, and solar radiation absorbed in its thickness at a preset timed data on the meteorological parameters. In the numerical solution of the heat conductivity equation for snow and ice including a radiation source, a computational grid permitting to maintain spatial resolution of the temperature profiles in the snow–ice cover during its melting and growth was applied. Two variants of parameterization of solar radiation transfer in the sea ice were considered. The first version assumed exponential decay of radiation with the constant transmittance and extinction coefficients. In the second one, a two-layer scheme of the solar radiation penetration into ice was used; it simulated the near-surface transition layer. Attenuation of intensity of solar radiation in the snow thickness was described by the Bouguer–Lambert law with the extinction coefficient both as independent of the snow thermophysical characteristics and as represented by the function of its density. The numerical experiments with the purpose to reproduce seasonal evolution of the snow–ice cover thickness and its vertical temperature profile in the Taganrog Bay top part were performed for the winter season, 2016/17. Comparative analysis of the simulation results and the sea ice thickness values taken from the ESIMO ice maps made it possible to choose a combination of the model parameters that provides the best correspondence between the calculated and actual values. Conclusions. It is shown that in reproducing the seasonal changes in the ice cover thickness in the Taganrog Bay top part in winter, 2016/17, the choice of the transmittance and extinction coefficients for white ice represented by the cloudiness functions, on the one hand, and the thickness of the layer with the most intense absorption of short-wave radiation ~ 4 cm, on the other, turned out to be the most justified.

Report Details Solar Radiation Alert and Recommendations

Space Weather ◽  
2006 ◽  
Vol 4 (6) ◽  
pp. n/a-n/a ◽  
Author(s):  
Tracy Staedter
Keyword(s):  
Solar Radiation

Production of methymercury by solar radiation

2003 ◽  
Vol 107 ◽  
pp. 743-747
Author(s):  
D. R.S. Lean ◽  
SD. Siciliano
Keyword(s):  
Solar Radiation

Influence of trees on the energy consumption of a social housing in mid-western Brazil

2019 ◽  
pp. 53-65
Author(s):  
Renata Domingos ◽  
Emeli Guarda ◽  
Elaise Gabriel ◽  
João Sanches
Keyword(s):  
Energy Consumption ◽  
Solar Radiation ◽  
Thermal Comfort ◽  
Air Conditioning ◽  
Computational Simulation ◽  
Building Energy ◽  
General Idea ◽  
Heat Island ◽  
Study Region ◽  
Ample Evidence

In the last decades, many studies have shown ample evidence that the existence of trees and vegetation around buildings can contribute to reduce the demand for energy by cooling and heating. The use of green areas in the urban environment as an effective strategy in reducing the cooling load of buildings has attracted much attention, though there is a lack of quantitative actions to apply the general idea to a specific building or location. Due to the large-scale construction of high buildings, large amounts of solar radiation are reflected and stored in the canyons of the streets. This causes higher air temperature and surface temperature in city areas compared to the rural environment and, consequently, deteriorates the urban heat island effect. The constant high temperatures lead to more air conditioning demand time, which results in a significant increase in building energy consumption. In general, the shade of the trees reduces the building energy demand for air conditioning, reducing solar radiation on the walls and roofs. The increase of urban green spaces has been extensively accepted as effective in mitigating the effects of heat island and reducing energy use in buildings. However, by influencing temperatures, especially extreme, it is likely that trees also affect human health, an important economic variable of interest. Since human behavior has a major influence on maintaining environmental quality, today's urban problems such as air and water pollution, floods, excessive noise, cause serious damage to the physical and mental health of the population. By minimizing these problems, vegetation (especially trees) is generally known to provide a range of ecosystem services such as rainwater reduction, air pollution mitigation, noise reduction, etc. This study focuses on the functions of temperature regulation, improvement of external thermal comfort and cooling energy reduction, so it aims to evaluate the influence of trees on the energy consumption of a house in the mid-western Brazil, located at latitude 15 ° S, in the center of South America. The methodology adopted was computer simulation, analyzing two scenarios that deal with issues such as the influence of vegetation and tree shade on the energy consumption of a building. In this way, the methodological procedures were divided into three stages: climatic contextualization of the study region; definition of a basic dwelling, of the thermophysical properties; computational simulation for quantification of energy consumption for the four facade orientations. The results show that the façades orientated to north, east and south, without the insertion of arboreal shading, obtained higher values of annual energy consumption. With the adoption of shading, the facades obtained a consumption reduction of around 7,4%. It is concluded that shading vegetation can bring significant climatic contribution to the interior of built environments and, consequently, reduction in energy consumption, promoting improvements in the thermal comfort conditions of users.

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