Performance of Incoming Solar Radiation Components in Partial Annular Solar Eclipse on June 21^st, 2020 in Helwan, Egypt

Observing and studying the solar radiation during solar eclipses is important in knowing the changes that occur to the environmental elements during this event. The main objective of this paper is the performance of the incoming variation of solar radiation components, global, direct and diffuse and their fractions during the partial annular solar eclipse on June 21st, 2020 in Helwan, Egypt (Lat. 29.866°N and Long. 31.20°E) has been made. A pyrheliometer for measuring the direct solar radiation, in three different bands;direct yellow (Y), direct red (R), direct infrared (IR), and also the total direct band (I);A pyranometers for measuring the different components of global solar radiation (G), global ultraviolet (GUV), global infrared (GIR) and a meteorological station to measure the different meteorological parameters. The duration of the solar eclipse was 01 h:59 m, and the maximum magnitude of the eclipse in this region was 0.449. The depression is clear at the solar radiation of all components due to the annular solar eclipse, while the depressions of the diffuse and global infrared solar radiation are lower. In all direct radiation compounds (I, Y, R and IR) are greatly affected by the eclipse. The diffuse fraction Kd is higher in the early time, before the partial eclipse, but during the partial annular eclipse time Kd values are suffers variation and through the day, where the values of Kd lies between Kt and KUV. The values of direct infrared solar radiation are dominant before and after the partial annular solar eclipse. The intensity of color bands (W∙m−2∙nm−1) are DIB3 > DIB2 > DIB4, and DIB1 is opposite direction with DIB3 and DIB2, the highest intensity is direct red and the lowest intensity is the direct infrared. The highest values of extinction coefficient in (GIR) solar radiation and the lowest values occur in (GUV) solar radiation, while the values of (G) solar radiation occur between them. In general trend, the values of extinction coefficient during the partial eclipse are increasing, while the minimum values of extinction coefficient occur at noon time due to the air mass is less value in the noon.

A Study of Linke Turbidity Factor over Qena / Egypt

Data on instantaneous atmospheric Linke turbidity factor TL (m) are reported for clear days at Qena/Egypt in the period from June 1992 to May 1993.TL(m) is determined using the values of irradiance of direct solar radiation (I),which are calculated from global (G) and diffuse (D) - solar radiation measurements.Monthly and seasonally variations of both diurnal and daily average values of TL (m) increases steadily in the direction of sunset in the months from June to December 1992 as well as Summer and Autumn seasons,while it falls generally in this direction for the months from January to March and Winter season.In April and May,TL (m) fluctuates obviously through the day hours,it is also shown that the average values of TL(m) are particularly large during Summer months compared to other months of the year.This behavior of TL(m) is discussed in view of the variations of some weather elements,which affect the content of water vapor and dust particle in the atmosphere of the study region.It seems t be of similar trends to that of other locations inside and outside Egypt.The virtual variation of TL(m) is eliminated by reducing its value to relative optical air mass m=2,according to Kasten formula.The resulting TL (2) is more representative for the content of dust particles and water vapor in the atmosphere.