Impact of UV-A radiation on erythemal UV and UV-index estimation over Korea

Because total UV(TUV) in the UV-A region is 100 times higher than in the UV-B region,UV-A is a considerable component when calculating erythemal UV(EUV) and UV-index.The ratio of EUV to TUV in the UV-A value [EUV(A)/TUV(A)]is investigated to convert the EUV(A) from TUV(A) for broadband observation. The representative value of EUV(A)/TUV(A),from the simulation study,is 6.9 × 10-4,changing from 6.1 × 10-4to 7.0 × 10-4as aerosol optical depth,total ozone and solar zenith angle change. By adopting the observational data of EUV(B) and TUV(A) from UV-biometer measurements at Yonsei University [(37.57?N,126.95?E),84 m above sea level],the EUV irradiance increases to 15% of EUV(B) due to the consideration of EUV(A) from the data of TUV(A) observation. Compared to the total EUV observed from the Brewer spectrophotometer at the same site,the EUV(B) from the UV-biometer observes only 95% of total EUV,and its underestimation is caused by neglecting the effect of UV-A. However,the sum of EUV(B) and EUV(A) [EUV(A+B)] from two UV-biometers is 10% larger than the EUV from the Brewer spectrophotometer because of the spectral overlap effect in the range 320–340nm. The correction factor for the overlap effect adjusts 8% of total EUV.     

Solar UV-A and UV-B radiation fluxes at two Alpine stations at different altitudes

Summary Daily totals of UV-A and UV-B radiation fluxes and global radiation were measured since 1981 at Jungfraujoch (3576 m) a.s.l.) and in Innsbruck (577 m a.s.l.) in their seasonal course. The altitude effect of annual totals yields 19%/1000 m (UV-B), 11%/1000 m (UV-A) and 9%/1000 m (global radiation) with reference to Innsbruck station. The ratio of the daily totals of UV-B/global radiation shows a significant seasonal course with the maximum in summer, whereas the ratio of the daily totals of UV-A/global radiation shows no significant seasonal variation. The biological effective doses of erythema reaction, delayed tanning and immediate tanning by UV-A and UV-B radiant exposure are reported in the seasonal course at Jungfraujoch and in Innsbruck.Dedicated to O. Univ.-Prof. Dr. F. Steinhauser.With 6 Figures     

长春地区紫外光谱（UV-A，UV-B）辐射观测和初步分析

利用我们研制的太阳—大气紫外光谱辐射计，从1992年5月在长春开始试验了野外观测，监视到达地表的太阳直射和大气散射紫外光谱辐射，主要给出长春地区地面紫外辐射，特别是紫外（UV）B段（280～320 nm）光谱辐射的一些基本特点和初步统计特征。由于地表UV-B辐射对生态系统和人类健康有危害作用，其强度随着臭氧减少而增加。该项观测分析将有助于监测和研究臭氧层变薄的实际效应。