POL: P & P Abstract VOL 67:PG 657

Comparison of Models Used for UV Index Calculations

Peter Koepke*1, Alkiviadis Bais2, Dimitrios Balis2, Michael Buchwitz3, Hugo De Backer4, Xavier de Cabo5, Pierre Eckert6, Paul Eriksen7, Didier Gillotay8, Anu Heikkilä9, Tapani Koskela9, Bozena Lapeta10, Zenobia Litynska10, Jeronimo Lorente5, Bernhard Mayer11, Anne Renaud12, Ansgar Ruggaber1, Günther Schauberger13, Gunther Seckmeyer11, Peter Seifert1, Alois Schmalwieser13, Harry Schwander1, Karel Vanicek14 and Mark Weber3

1Meteorologisches Institut at Ludwig-Maximilians-Universität, Munich, Germany
2Laboratory of Atmospheric Physics at Aristotle University of Thessaloniki, Greece
3Institute of Environmental Physics at Universität Bremen, Germany
4Royal Meteorological Institute, Brussels, Belgium
5Department of Astronomy and Meteorology, University of Barcelona, Spain
6Centre Meteorologique, Geneva, Switzerland
7Danish Meteorological Institute, Copenhagen, Denmark
8Belgian Institute for Space Aeronomy, Brussels, Belgium
9Finnish Meteorological Institute, Helsinki, Finland
10Institute of Meteorology and Water Management, Legionowo, Poland
11Fraunhofer Institute (IFU), Garmisch-Partenkirchen, Germany
12Institute for Atmospheric Science ETH, Zürich, Switzerland
13Institute of Medical Physics and Biostatistics, University of Veterinary Medicine, Vienna, Austria
14SOO CHMI, Hradec Kralove, Czech Republik

*To whom correspondence should be addressed at: Meteorol. Inst., Theresienstr. 37, D-80333 Muenchen, Germany. Fax: ++49 89 23944381; e-mail: peter.koepke@lrz.uni-muenchen.de


Eighteen radiative transfer models in use for calculation of UV index are compared with respect to their results for more than 100 cloud-free atmospheres, which describe present, possible future and extreme conditions. The comparison includes six multiple-scattering spectral models, eight fast spectral models and four empirical models. Averages of the results of the six participating multiple-scattering spectral models are taken as a basis for assessment. The agreement among the multiple-scattering models is within +/-0.5 UV index values for more than 80% of chosen atmospheric parameters. The fast spectral models have very different agreement, between +/-1 and up to 12 UV index values. The results of the empirical models agree reasonably well with the reference models but only for the atmospheres for which they have been developed. The data to describe the atmospheric conditions, which are used for the comparison, together with the individual results of all participating models and model descriptions are available on the Internet: http://www.meteo.physik.uni-muenchen.de/strahlung/cost/.

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