Estimation of ozone content employing ground- based UV measurements over Baghdad City, Iraq

In terms of surface temperature control, ozone is a greenhouse gas that has a significant influence on weather and climate system regulation. O3 absorbs the visible and ultraviolet region of the spectrum solar radiation, leading to a variation in the electronic energy of the molecule. The more powerful absorption occurs in UV rays, with lower absorption in the visible region. O3 may absorb the infrared (IR rays) of the earth's atmospheric system. The methods used in the present study were based on ground-based UV measurements over Baghdad City- Iraq, where the considered UV radiation values were measured every 10 minutes during the period from October 2014 to December 2015. The sun radiation was measured by a station located at Mustansiriyah University in Iraq (33º08’44” N; 44º05’53” E; altitude 34 m). The results showed a positive direct relationship between the ultraviolet B (UV-B) and Global Solar Radiation (G) for hourly values in Baghdad, with a correlation coefficient of R = 0.885, and the UV levels rise with an increase in G. As a result, an empirical relationship association between them were established. In all areas of correlation relationship, the Determination Coefficient (R2) of the two variables was greater than 0.98. With a good agreement between calculated values of hourly UV (UVe), and corresponding measured values (UVm), correlation coefficient R = 0.94. Calculated linear regression accounted for 90 % of the variance. So, the results of the UV-G relationship may be used to estimate UV-B values for measurements taken over a period of time at the Mustansiriyah site, for values that are difficult to measure, or for any place in Baghdad or the central area of Iraq, or sites with comparable climates.