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Recent Variations of UV Irradiance at Seoul 2004~2010

서울의 최근 자외선 복사의 변화 2004~2010

  • Kim, Jhoon (Global Environment Laboratory/Department of Atmospheric Science, Yonsei University) ;
  • Park, Sang Seo (Global Environment Laboratory/Department of Atmospheric Science, Yonsei University) ;
  • Cho, Nayeong (Global Environment Laboratory/Department of Atmospheric Science, Yonsei University) ;
  • Kim, Woogyung (Global Environment Laboratory/Department of Atmospheric Science, Yonsei University) ;
  • Cho, Hi Ku (Global Environment Laboratory/Department of Atmospheric Science, Yonsei University)
  • 김준 (연세대학교 지구환경연구소/대기과학과) ;
  • 박상서 (연세대학교 지구환경연구소/대기과학과) ;
  • 조나영 (연세대학교 지구환경연구소/대기과학과) ;
  • 김우경 (연세대학교 지구환경연구소/대기과학과) ;
  • 조희구 (연세대학교 지구환경연구소/대기과학과)
  • Received : 2011.10.12
  • Accepted : 2011.11.29
  • Published : 2011.12.31

Abstract

The climatology of surface UV radiation for Seoul, presented in Cho et al. (1998; 2001), has been updated using measurement of surface erythemal ultraviolet (EUV) and total ultraviolet (TUV) irradiance (wavelength 286.5~363.0 nm) by a Brewer Spectrophotometer (MK-IV) for the period 2004~2010. The analysis was also carried out together with the broadband total (global) solar irradiance (TR ; 305~2800 nm) and cloud amount to compare with the UV variations, measured by Seoul meteorological station of Korean Meteorological Agency located near the present study site. Under all-sky conditions, the day-to-day variability of EUV exhibits annual mean of 98% in increase and 31% in decrease. It has been also shown that the EUV variability is 17 times as high as the total ozone in positive change, whereas this is 6 times higher in negative change. Thus, the day to day variability is dominantly caused rather by the daily synoptic situations than by the ozone variability. Annual mean value of daily EUV and TUV shows $1.62kJm^{-2}$ and $0.63MJm^{-2}$ respectively, whereas mean value of TR is $12.4MJm^{-2}$ ($143.1Wm^{-2}$). The yearly maximum in noon-time UV Index (UVI) varies between 9 and 11 depending on time of year. The highest UVI shows 11 on 20 July, 2008 during the period 2004~2010, but for the period 1994~2000, the index of 12 was recorded on 13 July, 1994 (Cho et al., 2001). A 40% of daily maximum UVI belongs to "low (UVI < 2)", whereas the UVI less than 5% of the maximum show "very high (8 < UVI < 10)". On average, the maximum UVI exceeded 8 on 9 days per year. The values of Tropospheric Emission Monitoring Internet Service (TEMIS) EUV and UVI under cloud-free conditions are 1.8 times and 1.5 times, respectively, higher than the all-sky measurements by the Brewer. The trend analysis in fractional deviation of monthly UV from the reference value shows a decrease of -0.83% and -0.90% $decade^{-1}$ in the EUV and TUV, respectively, whereas the TR trend is near zero (+0.11% $decade^{-1}$). The trend is statistically significant except for TR trend (p = 0.279). It is possible that the recent UV decrease is mainly associated with increase in total ozone, but the trend in TR can be attributed to the other parameters such as clouds except the ozone. Certainly, the cloud effects suggest that the reason for the differences between UV and TR trends can be explained. In order to estimate cloud effects, the EUV, TUV and TR irradiances have been also evaluated for clear skies (cloud cover < 25%) and cloudy skies (cloud cover ${\geq}$ 75%). Annual mean values show that EUV, TUV and TR are $2.15kJm^{-2}$, $0.83MJm^{-2}$, and $17.9MJm^{-2}$ for clear skies, and $1.24kJm^{-2}$, $0.46MJm^{-2}$, and $7.2MJm^{-2}$ for cloudy skies, respectively. As results, the transmission of radiation through clouds under cloudy-sky conditions is observed to be 58%, 55% and 40% for EUV, TUV and TR, respectively. Consequently, it is clear that the cloud effects on EUV and TUV are 18% and 15%, respectively lower than the effects on TR under cloudy-sky conditions. Clouds under all-sky conditions (average of cloud cover is 5 tenths) reduced the EUV and TUV to about 25% of the clear-sky (cloud cover < 25%) values, whereas for TR, this was 31%. As a result, it is noted that the UV radiation is attenuated less than TR by clouds under all weather conditions.

Keywords

References

  1. 곽민경, 김재환, 2011: 한반도 EUV-B 복사의 특성 분석 및 적정 비타민 D합성을 위한 노출 시간 산출, 대기, 21, 1, 123-130.
  2. 기상청, 2011: 2010 지구대기감시보고서, 기상청, 227p.
  3. 박상서, 김 준, 조나영, 이윤곤, 조희구, 2011: 한반도 상공의 오존층 변화 1985-2009, 대기, 인쇄중.
  4. 박선욱, 2002: 대기광학깊이가 지표자외선 복사에 미치는 효과, 연세대학교 대학원 석사학위 논문, 84p.
  5. 조희구, 권효정, 최치영, 1998: 오존층 감소에 따르는 지표 홍반 자외선 복사의 증가, 한국기상학회지, 34(2), 272-281.
  6. 조희구, 이방용, 이준석, 박선욱, 2001: 한국 전역의 지표 홍반 자외선 복사의 계절기후, 한국기상학회지, 37(5), 525-239.
  7. Allaart, M., van Weele, M., Fortuin, P., and Kelder, H. 2004: An empirical model to predict the UV-index based on solar zenith angles and total ozone. Meteorological Applications, 11: 59-65. doi: 10.1017/S1350482703001130.
  8. Cutchis, P., 1974: Stratospheric Ozone Depletion and Solar Ultraviolet Radiation on Earth, Science, 184, 13-19. https://doi.org/10.1126/science.184.4132.13
  9. Geffen, van J., van der A, R., M. van Weele, M. Allaart, and H. Eskes, 2004: Surface UV radiation monitoring based on GOME and SCIAMACHY, Proceedings on the ENVISAT & ERA Symposium, september, Salzburg, Austria.
  10. Mckenzie, R. C., W. A. Matthews, and P. V. Johnston, 1991: The Relationship between Erythemal UV and Ozone, derived from Spectral irradiance measurements, Geophys. Res. Lett., 18(12), 2269-2272. https://doi.org/10.1029/91GL02786
  11. McKinlay. A. F and B. L. Diffey, 1987: A reference action spectrum for ultraviolet induced erythema in human skin, CIE J., 6, 17-22.
  12. Schafer, J. S., V. K. Saxena, B. N. Wenny, W. Barnard, and J. J. De Luisi: 1996, Observed influence of clouds on ultraviolet-B radiation, Geophys. Res. Lett., 23(19), 2625-2628, doi:10.1029/96GL01984.
  13. SCI-TEC, 1995: Brewer MKIV Spectrophotometer Operator's manual, SCI-TEC Instruments Inc., Canada.
  14. Scotto, J., G. Cotton, F. Urbach, D. Berger, and T. Fears, 1988: Biologically effective ultraviolet radiation: surface measurements in the United States, 1974 to 1985, Science, 239, 762-763. https://doi.org/10.1126/science.3340857
  15. UNEP/WMO, 1989: Scientific assessment of Stratospheric ozone: 1989.
  16. UNEP/WMO, 1994: Scientific assessment of ozone depletion: 1994.
  17. VanHoosier, M. E., 1996: Solar ultraviolet spectral irradiance data with increased wavelength and irradiance accuracy, Proc. SPIE, Vol. 2831, 57, DOI; 10.1117/12.257210.
  18. WMO, 1984: Scientific Plan for the World Climate Research Programme (WCRP). WMO/TD No. 6, Geneva, Switzerland.
  19. WMO, 2006: WMO Greenhouse Gas Bulletin, No. 2. The State of Greenhouse Gases in the Atmosphere Using Global Observations through 2005, World Meteorological Organization, Geneva, Switzerland.
  20. World Health Organization (WHO), 2002: Global Solar UV index : A practical guide report, 26pp, Genova, Switzerland.
  21. World Health Organization (WHO), 1994: Ultra-violet radiation, Environmental Health Criteeria 160, Genova, Switzerland.
  22. Zerefos, C. S., A. F. Bais, and I. C. Ziomas, 1985: Monochromatic UV-magnification factors and total ozone, Atmospheric ozone; Proceedings of the Quadrennial Ozone Symposium, Halkidiki, Greece.
  23. Ziemke, J. R., S. Chandra, J. Herman, and C. Varotsos, 2000: Erythemally weighted UV trends over northern latitudes derived from Nimbus 7 TOMS measurements, J. Geophys. Res., 105(D6), 7373-7382, doi:10.1029/1999JD901131.