scholarly journals Influences of atmospheric conditions and air mass on the ratio of ultraviolet to total solar radiation

1990 ◽  
Author(s):  
C.J. Riordan ◽  
R.L. Hulstrom ◽  
D.R. Myers
2021 ◽  
Vol 2131 (3) ◽  
pp. 032079
Author(s):  
S Golosov ◽  
I Zverev ◽  
A Terzhevik ◽  
N Palshin ◽  
G Zdorovennova ◽  
...  

Abstract Parametrization of the formation of organic matter in ecological models is traditionally carried out by using the dependence of the Michaelis – Menten – Monod type [Monod, 1942], which describes the growth rate of algal biomass depending on the factor limiting their development. One of the biggest drawbacks of these dependences is the presence of empirical parameters in them, which in a complex way depend on environmental factors and are an individual characteristic of various types of algae. These parameters in the models actually become fitting coefficients that provide the best fit between observational data and modeling results, which does not allow for effective diagnostics and forecasting of the state of aquatic ecosystems. In this work, on the basis of dimensional analysis, a parametrization was obtained that describes the photosynthesis of algae depending on the parameters relatively easily measured in natural conditions - total solar radiation, phytoplankton biomass, and water transparency. Parametrization has been verified according to observations on more than 30 different types of lakes located in different regions of the world. The calculated data are in satisfactory agreement with the data of field observations, both qualitatively and quantitatively. Discrepancies in field and calculated data may be due to the fact that the species composition of algae in lakes of different trophic status is not taken into account, which can lead to errors in assessing the efficiency of using solar radiation. Discrepancies may also be related to the total solar radiation, rather than photosynthetic active radiation, which varies in different geographic and atmospheric conditions. The proposed parametrization can be used in the development of mathematical models of lake ecosystems, as well as to determine the trophic status of poorly studied water bodies.


2021 ◽  
Author(s):  
Katarzyna Zielonko-Jung ◽  
Justyna Janiak

AbstractThe present study is aimed at the analysis of possibilities for shading southern frontage of street oriented along the E-W axis by the single row of trees, parallel to the southern elevations. The effectiveness of solar control shading was tested depending on the geometric relationships between trees and buildings. Numerical simulation analyses were conducted in Rhinoceros® program for the street located in humid continental climate in city Płock, Poland (52°32′50 “N 19°42’00 “E), for the day of the highest degree of total solar radiation in the year i.e. June 7th, during hours: 8.00a.m - 5.00 p.m. The analysis has proved that a row of 20–25 year old Sycamore Maple ‘Rotterdam’ in the street 30 m wide and 18 m high (H/W = 0.6), can provide solar protection for the southern frontage, especially when trees are located no more than 4 m away. Location of greenery within the range of 4 to 5 m from the buildings leads to a radical reduction in the possibility of shading the wall surfaces (at 5 m to 0%). Over 90% of the shading area of the ground floor façade walls was found when trees were within the distance 2 and 3 m away from the building.


Solar Energy ◽  
1977 ◽  
Vol 19 (3) ◽  
pp. 307-311 ◽  
Author(s):  
J.A. Sabbagh ◽  
A.A.M. Sayigh ◽  
E.M.A. El-Salam

2015 ◽  
Vol 19 (suppl. 2) ◽  
pp. 427-435 ◽  
Author(s):  
Jelena Lukovic ◽  
Branislav Bajat ◽  
Milan Kilibarda ◽  
Dejan Filipovic

Solar radiation is a key driving force for many natural processes. At the Earth?s surface solar radiation is the result of complex interactions between the atmosphere and Earth?s surface. Our study highlights the development and evaluation of a data base of potential solar radiation that is based on a digital elevation model (DEM) with a resolution of 90 m over Serbia. The main aim of this paper is to map solar radiation in Serbia using DEM. This is so far the finest resolution being applied and presented using DEM. The final results of the potential direct, diffuse and total solar radiation as well as duration of insolation databases of Serbia are portrayed as thematic maps that can be communicated and shared easily through the cartographic web map-based service.


Ekosistemy ◽  
2021 ◽  
pp. 5-15
Author(s):  
R. V. Gorbunov ◽  
T. Yu. Gorbunova ◽  
V. A. Tabunshchik ◽  
A. V., Drygval

The research team calculated the values of the radiation balance elements of the plain Crimea ecosystems on the bases of open databases of climate data and GIS-modeling and, moreover, analyzed their spatial and temporal differentiation. It is revealed that the spatial distribution of the radiation balance is characterized by an increase in values from the center to the coast of the peninsular. It correlates with the spatial differentiation of both total solar radiation and all other elements of the short-wave part of the radiation balance. There is a significant excess of radiation balance values of the plateau landscape level ecosystems over values of the hydromorphic landscape level ecosystems. This difference is determined by the location of selected key areas on the western coast of the Crimean Peninsula, which is characterized by the maximum values of total solar radiation supply. The elements of the long-wave part of the radiation balance change in the opposite direction, compared with the short-wave part of the radiation balance, which is associated with an increase of air temperature and climate continentality in the direction from the coast to the center of the peninsula. Two periods were identified in the interannual dynamics corresponding to the change of the circulatory periods of the Northern Hemisphere. In general, the considered ecosystems are characterized by trends of increasing radiation balance values in conditions of growth of all its elements. Such growth is provided by significant increase of values during the second period compared with the negative trends of radiation balance values for a number of ecosystems in the first one.


2021 ◽  
pp. 34-38
Author(s):  
A. V. Kurepin ◽  
A. F. Pershin ◽  
V. N. Shevkunov

Relevance. Among the main factors that determine the productivity of vegetable yields in protected ground, the main one is light. For the formation of 1 kg/m2 of cucumber fruits with a length of 18-22 cm, on average about 3500-4000 J/cm2 of solar radiation is required. In the winter-spring cycle, in the absence of artificial lighting in greenhouses, there is an unevenness of scattered solar radiation and a general shortage of incoming light energy. At the same time, the amount of total solar radiation required for the formation of a 1 kg of fruit ("lighting price") is not the same for different hybrids. To increase the profitability of production in the winter-spring turnover in greenhouses that are not equipped with artificial lighting, it is necessary to choose hybrids with the lowest "lighting price" of the crop, that is, hybrids that use less light energy to form a 1 kg of fruit.The purpose of the study: evaluation of F1 hybrids of cucumber on the basis of resistance to lack of lighting by comparing their "lighting price" of the crop: how much energy is spent on the formation of 1 kg of marketable products.Methods. The research was carried out at the variety testing site in the Crimean breeding Center of the Scientific Research Institute of Vegetable Crop Selection "Gavrish", in the conditions of winter-spring turnover, in greenhouses not equipped with artificial lighting. We tested seven medium-fruited (18-22 cm) spined-fruited cucumber hybrids recommended for growing in winter-spring turnover.Results. The analysis of the data on the input of solar radiation and the formation of a standard yield showed that there is a direct relationship between the amount of incoming light and the level of productivity. The period of conversion of the received solar energy into the fruit harvest varied during the growing season from 14 to 8 days, depending on the degree of plant development. The "lighting price" of the crop was not the same for different hybrids: the hybrids tested in the experiment spent an average of 2900 J/cm2 per 1 kg of product, which is 18% more efficient than for standard greenhouse cucumbers. 


Author(s):  
Kacem Gairaa ◽  
Abdallah Khellaf ◽  
Farouk Chellali ◽  
Said Benkaciali ◽  
Yahia Bakelli ◽  
...  

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