ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-8-3107-2008 Long-term solar UV radiation reconstructed by ANN modelling with emphasis on spatial characteristics of input data Feister U. 1 Junk J. 2 Woldt M. 3 Bais A. 4 Helbig A. 5 Janouch M. 6 Josefsson W. 7 Kazantzidis A. 4 Lindfors A. 8 den Outer P. N. 9 Slaper H. 9 Deutscher Wetterdienst, Richard Aßmann Observatorium Lindenberg, Am Observatorium 12, 15848 Lindenberg, Germany Public Research Centre – Gabriel Lippmann, Department of Environment and Agro-Biotechnologies (EVA), 41, rue du Bril, 4422 Belvaux Grand-Duchy of Luxembourg, Luxembourg Brandenburgische Techn. Univ. Cottbus, Lehrstuhl für Umweltmeteorologie, Burger Chaussee 2, 03044 Cottbus, Germany Aristotle University of Thessaloniki, Laboratory of Atmospheric Physics, 54124, Thessaloniki, Greece Universität Trier, Fachbereich VI, Fach Umweltmeteorologie, 54286 Trier, Germany Solar and Ozone Observatory, Czech Hydrometeorological Inst., Hvezdarna 456, 500 08 Hradec Kralove 8, Czech Republic Swedish Meteorological and Hydrological Institute, 60176, Norrköping, Sweden Finnish Meteorological Institute, P.O. BOX 503 (Erik Palmenin aukio 1), 00101 Helsinki, Finland National Institute for Public Health and the Environment, A. van Leeuwenhoeklaan 9, P.O. Box 1, 3720 BA Bilthoven, The Netherlands 23 06 2008 8 12 3107 3118 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys.net/8/3107/2008/acp-8-3107-2008.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/8/3107/2008/acp-8-3107-2008.pdf

Artificial Neural Networks (ANN) are efficient tools to derive solar UV radiation from measured meteorological parameters such as global radiation, aerosol optical depths and atmospheric column ozone. The ANN model has been tested with different combinations of data from the two sites Potsdam and Lindenberg, and used to reconstruct solar UV radiation at eight European sites by more than 100 years into the past. Special emphasis will be given to the discussion of small-scale characteristics of input data to the ANN model. <br><br> Annual totals of UV radiation derived from reconstructed daily UV values reflect interannual variations and long-term patterns that are compatible with variabilities and changes of measured input data, in particular global dimming by about 1980/1990, subsequent global brightening, volcanic eruption effects such as that of Mt. Pinatubo, and the long-term ozone decline since the 1970s. Patterns of annual erythemal UV radiation are very similar at sites located at latitudes close to each other, but different patterns occur between UV radiation at sites in different latitude regions.

 References Bais, A., Kazantzidis, A., Kazadzis, S., and Kouremeti, N.: Application of a model derived cosine correction method on Brewer spectral measurements. European Geosciences Union, Vienna, 24–29 April 2005, Geophys. Res. Abstr., 7, 07590, 2005. Bais, A. F. and Lubin, D.: Surface Ultraviolet Radiation: Past, Present, and Future, Scientific Assessment of Ozone Depletion: 2006, WMO Global Ozone Research and Monitoring Project, Report No. 50, 7.1–7.54, 2007. Chevallier, F., Chéruy, F., Scott, N. A., and Chédin, A.: A Neural Network Approach for a Fast and Accurate Computation of a Longwave Radiative Budget, J. Appl. Meteorol., 37, 1385–1397, 1998. CIE: A reference action spectrum for ultraviolet induced erythema in human skin, CIE Journal, 6, 17–22, 1987. den Outer, P. N., Slaper, H., Lindfors, A., Kaurola, J., Bais, A., Kazantzidis, A., Feister, U., Junk, J., and Janouch, M.: Best estimate construction for historical UV using models and measurements, Annual SCOUT-O3 meeting, Potsdam, Germany, 21–24 April, 43–20, 2008. Feister, U. and Grewe, R.: Higher UV radiation inferred from low ozone levels at northern mid-latitudes in 1992 and 1993, Global Planet. Change, 11, 25–34, 1995. Feister, U., Grewe, R., and Gericke, K.: A method for correction of cosine errors in measurements of spectral UV irradiance, Sol. Energy, 60(6), 313–332, 1997. Feister, U., Jäkel, E., and Gericke, K.: Parameterization of daily solar global ultraviolet irradiation, Photochem. Photobiol., 76, 281–293, 2002. Feister, U. and Junk, J.: Reconstruction of daily solar UV irradiation by an Artificial Neural Network, SPIE, 6362-94, 63622H, 1–11, 2006. Feister, U., Kaifel, A., Grewe, R.-D., Kaptur, J., Reutter, O., Wohlfart, M., and Gericke, K.: Fast measurements of solar spectral irradiance – first performance results of two novel spectroradiometers, Opt. Eng., 44(4), 041007-1–041007-9, 2005. Josefsson, W.: UV-radiation 1983–2003 measured in Norrköping Sweden, Theor. Appl. Climatol., 83(1–4), 59–76, doi:10.1007/s704-005-0160-1, 2006. Junk, J., Feister, U., and Helbig, A.: Reconstruction of daily solar UV irradiation from 1893 to 2002 in Potsdam, Germany, Int. J. Biometeorol. 51, 505–512, 2007. Kelly, P. M, Jones, P. D., and Pengqun, J.: The spatial response of the climate system to explosive volcanic eruptions, Int. J. Climatol., 16, 537–550, 1996. Koepke, P., Debacker, H., Bais, A., Curylo, A., Eerme, K., Feister, U., Johnsen, B., Junk, J., Krzyscin, J., Lindfors, A., Olseth, J. A., den Outer, P., Pribullova, A., Schmalwieser, A. W., Slaper, H., Staiger, H., Verdebout, J., Vuilleumier, L., and Weihs, P.: Modelling solar UV radiation in the past: comparison of algorithms and input data. Remote Sensing of Clouds and the Atmosphere X1, SPIE, 6362-42, 636215-1–6362-15-11, 2006. Metzdorf, J., Stock, K. D., Sperfeld, P., Sperling, A., Winter, S., and Wittchen, T.: Aspects of quality assurance in monitoring solar UV irradiance, Metrologia, 40, 66–69, 2003. Nagel, D. and Leiterer, U.: Brewer Spektrophotometer MK IV: BMFT-Projekt "Optische Feldmessmethoden" , Abschlussbericht, Deutscher Wetterdienst, Abt. Forschung 22, Offenbach am Main, Germany, 1995. Ohmura, A., and Lang, H.: Secular variation of global radiation in Europe, in: IRS '88: current Problems in Atmospheric Radiation, edited by: Lenoble, J. and Geleyn, J.-F., A. Deepak Publ., Hampton, VA, USA, 298–301, 1989. Oliveira, A. P., Soares, J., Božnar, M. Z., Mlakar, P., and Escobedo, J. F.: An Application of Neural Network Technique to Correct the Dome Temperature Effects on Pyrgeometer Measurements, J. Atmos. Oceanic Technol., 23, 80–89, 2006. Slaper, H., Reinen, A. J. M., Blumthaler, M., Huber, M., and Kuik, F.: Comparing ground-level spectrally resolved solar UV measurements using various instruments: a technique resolving effects of of wavelength shift and slit width, Geophys. Res. Lett. 22, 2721–2724, 1995. Wild, M., Gilgen, H., Roesch, A., Ohmura, A., Long, C. N., Dutton, E. G., Forgan, B., Kallis, A., Russak, V., and Tsvetkov, A.: From dimming to brightening: Decadal changes in solar radiation at Earth's surface, Science, 308, 847–850, 2005.