Impact of Cloud Cover on Global UV Irradiance over Baghdad, Iraq

Kais J. AL-Jumaily, Natiq A. Zaki, Ali M. AL-Salihi
2014 IOSR Journal of Applied Physics  
Six months of continuous of hourly records of Ultraviolet irradiance recorded at Baghdad, (33.34 o N, 44.45 o E, 34 m a.m.s.l.), Iraq, were combined with concurrent synoptic cloud observations to investigate the relative influence of clouds on UV irradiance. The ratio of UV irradiance to the total solar irradiance increases with cloud cover, especially for cloud cover greater than 4 octas, In order to determine the effect of cloud on UV irradiance, a cloud modification factor was considered, it
more » ... is defined as the ratio between the UV measurements and the corresponding clear sky UV irradiance that would be expected for the same time period and atmospheric conditions. It was shown that the effect of cloud with 4 octas increases demonstrating the spectral dependence of the cloud radiative extinction, while the impact of cloud cover less than 4 octas is relatively constant and ranged between (3.6 -4.3%).
doi:10.9790/4861-06116369 fatcat:z7ktir7rzjfy5hensctbccp5o4