Vol. 15, issue 11, article # 3
pdf Shalin A. Yu. Specific features of the UV radiation spectrum at the ground level in Irkutsk. // Atmospheric and oceanic optics. 2002. V. 15. No. 11. P. 874-877.Copy the reference to clipboard
Abstract:
The peculiarities of the solar UV radiation spectrum at the ground level are investigated. The degree of influence of the variation of atmospheric parameters, such as the total ozone content (TOC), atmospheric pressure, and aerosol, on the variability of the ground-level UV radiation in the region of 300 to 350 nm has been studied in Irkutsk. The most significant of them were determined in separate bands of the selected range on different time scales. Functions of spectral responses of direct midday UVR to variations of the atmospheric parameters by 1% about their mean values for Irkutsk were constructed. These functions can be used to assess the influence of actual changes under atmospheric conditions. It is pointed out that the aerosol and cloud state are the factors that determine the overall UVR level. The effect of pressure fluctuations on UVR variability is insignificant; however, under conditions of optical stability of the atmosphere, which can persist for several days, the influence of pressure variations on UVR can become predominant. TOC and the Sun's zenith angle govern the spectral composition. It was found that at the wavelengths longer than 320 nm the spectral structure of the UVR variation coefficient coincides with the system of Huggins bands in the ozone absorption spectrum, and for the wavelengths shorter than 320 nm, it coincides with the typical spectral patterns of the extra-terrestrial solar UV spectrum. It was ascertained that small-scale structure of the ground-level spectrum is determined by the structure of the extra-terrestrial solar UV spectrum, while the overall spectral variation is determined mainly by the large-scale spectral behavior of the ozone absorption coefficient.