Atmospheric Chemistry and Physics www.atmos-chem-phys.net 1680-7316 1680-7324 8 18 2008 10.5194/acp-8-5683-2008 http://www.atmos-chem-phys.net/8/5683/2008/ http://www.atmos-chem-phys.net/8/5683/2008/acp-8-5683-2008.html http://www.atmos-chem-phys.net/8/5683/2008/acp-8-5683-2008.pdf 5683 5697 2008-09-29 Effects of urban pollution on UV spectral irradiances R. L. McKenzie r.mckenzie@niwa.co.nz C. Weinreis P. V. Johnston B. Liley H. Shiona M. Kotkamp D. Smale N. Takegawa Y. Kondo National Institute of Water and Atmospheric Research (NIWA), Lauder, PB 50061 Omakau, Central Otago, New Zealand Institute of Meteorology and Climatology, Leibniz University of Hannover, Hannover, Germany Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8904, Japan Spectral measurements of UV irradiances at Tokyo are compared with corresponding measurements at a pristine site (Lauder New Zealand) to identify the causes of the reductions in urban UV irradiances, and to quantify their effects. Tropospheric extinctions in Tokyo were found to be up to ~40% greater than at Lauder. Most of these differences can be explained by differences in cloud and aerosols, but ozone differences are also important in the summer. Examining spectral signatures of tropospheric transmission of both sites shows that reductions due to mean NO₂ and SO₂ amounts are generally small. However, at times the amount of NO₂ can be 10 times higher than the mean amount, and on these days it can decrease the UVA irradiance up to 40%. If SO₂ shows comparable day to day variability, it would contribute to significant reductions in UVB irradiances. The results indicate that at Tokyo, interactions between the larger burden of tropospheric ozone and aerosols also have a significant effect. These results have important implications for our ability to accurately retrieve surface UV irradiances at polluted sites from satellites that use backscattered UV. Supplementary data characterising these boundary layer effects are probably needed. Badosa, J., McKenzie, R. L., Kotkamp, M., Calb\'σ, J., GonzΓ‘lez, J. A., Johnston, P. V., O'Neill, M., and Anderson, D. J.: Towards closure between measured and modelled UV under clear skies at four diverse sites, Atmos. Chem. Phys., 7, 2817–2837, 2007. Bais, A., Kazantzidis, A., Kazadzis, S., Balis, D. S., Zerefos, C. S., and Meleti, C.: Deriving an effective aerosol single scattering albedo from spectral surface UV irradiance measurements, Atmos. Environ., 39, 1093–1102, 2005. Bais, A. F., Zerefos, C. S., Meleti, C., Ziomas, I. C., and Tourpali, K.: Spectral measurements of solar UVB radiation and its relations to total ozone, SO₂, and clouds, J. Geophys. Res., 98, 5199–5204, 1993. Bodeker, G. E. and McKenzie, R. L.: An algorithm for inferring surface UV irradiance including cloud effects, J. Appl. Meteorol., 35, 1860–1877, 1996. Bodeker, G. E., Scott, J. C., Kreher, K., and McKenzie, R. L.: Global ozone trends in potential vorticity coordinates using TOMS and GOME intercompared against the Dobson network: 1978–1998, J. Geophys. Res., 106, 23 029–23 042, 2001. Bruhl, C. and Crutzen, P. J.: On the disproportionate role of tropospheric ozone as a filter against solar UV-B radiation, Geophys. Res. Lett., 16, 703–706, 1989. Chin, M., Chu, A., Levy, R., Remer, L., Kaufman, Y., Holben, B., Eck, T., Ginoux, P., and Gao, Q.: Aerosol distribution in the Northern Hemisphere during ACE-Asia: Results from global model, satellite observations, and Sun photometer measurements, J. Geophys. Res, 109, D23S90, doi:10.1029/2004JD004829, 2004. Chubarova, N.: UV variability in Moscow according to long-term UV measurements and reconstruction model, Atmos. Chem. Phys., 8, 3025–3031, 2008. Hassler, B., Bodeker, G. E., and Dameris, M.: Technical Note: A new global database of trace gases and aerosols from multiple sources of high vertical resolution measurements, Atmos. Chem. Phys., 8, 5403–5421, 2008. Hofmann, D., Bonasoni, P., De~Maziere, M., Evangelisti, F., Giovanelli, G., Goldman, A., Goutail, F., Harder, J., Jakoubek, R., Johnston, P., Kerr, J., Matthews, W. A., McElroy, T., McKenzie, R., Mount, G., Platt, U., Pommereau, J. P., Sarkissian, A., Simon, P., Solomon, S., Stutz, J., Thomas, A., Van~Roosendael, M., and Wu, E.: Intercomparison of UV/visible spectrometers for measurements of stratospheric NO₂ for the Network for the Detection of Stratospheric Change, J. Geophys. Res., 100, 16 765–16 791, 1995. HΓΆnninger, G., von~Friedeburg, C., and Platt, U.: Multi axis differential optical absorption spectroscopy (MAX-DOAS), Atmos. Chem. Phys., 4, 231–254, 2004. Jacobson, M. Z.: Isolating the causes and effects of large ultraviolet reductions in Los Angeles, J. Aerosol Sci., 29, S655–S656, 1998. Johnston, P. V. and McKenzie, R. L.: Long-path absorption measurements of tropospheric NO₂ in rural New Zealand, Geophys. Res. Lett., 11, 69–72, 1984. Johnston, P. V. and McKenzie, R. L.: NO₂ observations at 45° S during the decreasing phase of solar cycle~21, from 1980 to 1987, J. Geophys. Res., 94, 3473–3486, 1989. Kazantzidis, A., Bais, A. F., Balis, D. S., Kosmidis, E., and Zerefos, C. S.: Sensitivity of solar UV radiation to ozone and temperature profiles at Thessaloniki (40.5° N, 23° E), Greece, J. Atmos. Solar-Terr. Phys., 67, 1321–1330, 2005. Kerr, J. and Davis, J.: New methodology applied to deriving total ozone and other atmospheric variables from global irradiance spectra, Geophys. Res.-Atmos., 112, D21301, doi:10.1029/2007JD008708, 2007. Krotkov, N. A., McClure, B., Dickerson, R. R., Carn, S. A., Li, C., Bhartia, P. K., Yang, K., Krueger, A. J., Li, Z., Levelt, P. F., Chen, H., Wang, P., and Lu, D.: Validation of SO₂ retrievals from the Ozone Monitoring Instrument over NE China, J. Geophys. Res., 113, D16S40 doi:10.1029/2007JD008818, 2008. Liley, J. B.: Global dimming, clouds and aerosols, in: UV Radiation and its Effects: an update, Royal Society of New Zealand, Wellington, New Zealand, Misc. Series, 68, 14–15, 2006. Madronich, S. and Flocke, S.: Theoretical estimation of biologically effective UV radiation at the earth's surface, in: Solar Ultraviolet Radiation. NATO, Series I: Advanced Study Institute, edited by: Zerefos, C. S. and Bais, A. F., Springer, Berlin, 23–48, 1995. Mayer, B. and Seckmeyer, G.: Retrieving ozone colums from spectral direct and global UV irradiance measurements, in: Proceedings of the XVIII Quadrennial Ozone Symposium, edited by: Bojkov, R. D. and Visconti, G., Parco Scientifico e Technologico d'Abruzzio, L'Aquila, Italy, 935–938, 1998. McKenzie, R., Smale, D., Bodeker, G., and Claude, H.: Ozone profile differences between Europe and New Zealand: Effects on surface UV irradiance and its estimation from satellite sensors, J. Geophys. Res., 108, 4179, doi:10.1029/2002JD002770, 2003. McKenzie, R., Smale, D., and Kotkamp, M.: Relationship between UVB and erythemally weighted radiation, Photochem. Photobiol. Sci., 3, 252–256, 2004. McKenzie, R. L., Kotkamp, M., and Ireland, W.: Upwelling UV spectral irradiances and surface albedo measurements at Lauder, New Zealand, Geophys. Res. Lett., 23, 1757–1760, 1996. McKenzie, R. L., Johnston, P. V., and Seckmeyer, G.: UV spectro-radiometry in the network for the detection of stratospheric change (NDSC), in: Solar Ultraviolet Radiation. Modelling, Measurements and Effects, edited by: Zerefos, C. S. and Bais, A. F., Springer-Verlag, Berlin, 279–287, 1997. McKenzie, R. L., Paulin, K. J., and Madronich, S.: Effects of snow cover on UV radiation and surface albedo: a case study, J. Geophys. Res., 103, 28 785–28 792, 1998. McKenzie, R. L., Bodeker, G. E., Scott, G., and Slusser, J.: Geographical differences in erythemally-weighted UV measured at mid-latitude USDA sites, Photochem. Photobiol. Sci., 5, 343–352, 2006. Oltmans, S. J., Johnson, B. J., Harris, J. M., Thompson, A. M., Liu, H. Y., Chan, C. Y., Vomel, H., Fujimoto, T., Brackett, V. G., Chang, W. L., Chen, J.-P., Kim, J. H., Chan, L. Y. and Chang, H.-W.: Tropospheric ozone over the North Pacific from ozonesonde observations, J. Geophys. Res., 109, D21301, doi:10.1029/2003JD003466, 2004. Petters, J. L., Saxena, V. K., Slusser, J. R., Wenny, B. N., and Madronich, S.: Aerosol single scattering albedo retrieved from measurements of surface UV irradiance and a radiative transfer model, J. Geophys. Res., 108, 4288, doi:10.1029/2002JD002360, 2003. Pfister, G., McKenzie, R. L., Liley, J. B., Thomas, A., Forgan, B. W., and Long, C. N.: Cloud coverage based on all-sky imaging and its impact on surface solar irradiance, J. Appl. Meteorol., 42, 1421–1434, 2003. Seckmeyer, G. and McKenzie, R. L.: Increased ultraviolet radiation in New Zealand (45° S) relative to Germany (48° N), Nature, 359, 135–137, 1992. Shirai, T., Yokouchi, Y., Blake, D., Kita, K., Izumi, K., Koike, M., Komazaki, Y., Miyazaki, Y., Fukuda, M., and Kondo, Y.: Seasonal variations of atmospheric C-2-C-7 nonmethane hydrocarbons in Tokyo, J. Geophys. Res., 112, 24 305–24 305, 2007. Tanskanen, A., MÀÀttΓ€, A., Krotkov, N., Kaurola, J., Koskela, T., Karpetchko, A., Fioletov, V., and Bernhard, G., Validation of the OMI surface UV data, in: AGU Fall Meeting, American Geophysical Union, 2005. Wang, Y., Xin, J., Li, Z., Wang, S., Wang, P., Hao, W. M., Nordgren, B. L., Chen, H., Wang, L., and Sun, Y.: Seasonal variations in aerosol optical properties over China, Atmos. Chem. Phys. Discuss., 8, 8431–8453, 2008. Wuttke, S., Bernhard, G., Ehramjian, J. C., McKenzie, R., Johnston, P., O'Neill, M., and Seckmeyer, G.: New spectrometers complying with the NDSC standards, J. Ocean. Atmos. Technol., 23, 241–251, 2006.