Abstract:
This study investigates the extent of solar ultraviolet radiation (UVR), wavelength ranges
from 280nm-315nm which is called UV-B, distribution in Bahir Dar and Ras Dashan.On the
other hand, when materials exposed to the solar ultraviolet ray, materials tend to change their
colour (fade), exposed to weathering; where all this result in degrading and shortened service life
of materials.Besides, the UV-B has effect on semiconductor materials in relation to charge
transport and photoelectric effect. Furthermore, the UV-B has penetrative effect on our body,
which can result in skin cancer, sunburn, cataract and skin aging. In this study, satellite based
data (from NASA) was used to study solar UV-B radiation in daily, monthly and annually in
selected two places. The study period ranges from beginning of January 1st 2010 until the end of
December 2020. The results indicate that UV-B, in both place, are periodical – season and month
dependent within each year. The highest and lowest UV-B radiations at Ras Dashen were
recorded in spring (mainly April) and winter (mainly December), respectively. On the other
hand, the highest and lowest UV-B radiations at Bahir Dar were recorded in spring (mainly
April) and summer (July) respectively. Using mean equation formula, maximum average in
Bahir Dar was 0.468W/m2 whilst in Ras Dashen found to be 0.445 W/m2
. Furthermore, on
average at different months/ seasons, the UV-B radiation was higher in Bahir Dar than in Ras
Dashen.