ACP Atmospheric Chemistry and Physics ACP Atmos. Chem. Phys. 1680-7324 Copernicus Publications Göttingen, Germany 10.5194/acp-13-7183-2013 Simulations of the transport and deposition of <sup>137</sup>Cs over Europe after the Chernobyl Nuclear Power Plant accident: influence of varying emission-altitude and model horizontal and vertical resolution Evangeliou N. https://orcid.org/0000-0001-7196-1018 1 Balkanski Y. https://orcid.org/0000-0001-8241-2858 1 Cozic A. 1 Møller A. P. 2 Laboratoire des Sciences du Climat et de l'Environnement (LSCE), CEA-UVSQ-CNRS UMR8212, Institut Pierre et Simon Laplace, L'Orme des Merisiers, 91191 Gif sur Yvette Cedex, France Laboratoire d'Ecologie, Systématique et Evolution, CNRS UMR8079, Université Paris-Sud, Bâtiment 362, 91405 Orsay Cedex, France 29 07 2013 13 14 7183 7198 Copyright: © 2013 N. Evangeliou et al. 2013 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://acp.copernicus.org/articles/13/7183/2013/acp-13-7183-2013.html The full text article is available as a PDF file from https://acp.copernicus.org/articles/13/7183/2013/acp-13-7183-2013.pdf

The coupled model LMDZORINCA has been used to simulate the transport, wet and dry deposition of the radioactive tracer <sup>137</sup>Cs after accidental releases. For that reason, two horizontal resolutions were deployed and used in the model, a regular grid of 2.5° × 1.27°, and the same grid stretched over Europe to reach a resolution of 0.66° × 0.51°. The vertical dimension is represented with two different resolutions, 19 and 39 levels respectively, extending up to the mesopause. Four different simulations are presented in this work; the first uses the regular grid over 19 vertical levels assuming that the emissions took place at the surface (RG19L(S)), the second also uses the regular grid over 19 vertical levels but realistic source injection heights (RG19L); in the third resolution the grid is regular and the vertical resolution 39 levels (RG39L) and finally, it is extended to the stretched grid with 19 vertical levels (Z19L). The model is validated with the Chernobyl accident which occurred in Ukraine (ex-USSR) on 26 May 1986 using the emission inventory from Brandt et al. (2002). This accident has been widely studied since 1986, and a large database has been created containing measurements of atmospheric activity concentration and total cumulative deposition for <sup>137</sup>Cs from most of the European countries. <br><br> According to the results, the performance of the model to predict the transport and deposition of the radioactive tracer was efficient and accurate presenting low biases in activity concentrations and deposition inventories, despite the large uncertainties on the intensity of the source released. The best agreement with observations was obtained using the highest horizontal resolution of the model (Z19L run). The model managed to predict the radioactive contamination in most of the European regions (similar to De Cort et al., 1998), and also the arrival times of the radioactive fallout. As regards to the vertical resolution, the largest biases were obtained for the 39 layers run due to the increase of the levels in conjunction with the uncertainty of the source term. Moreover, the ecological half-life of <sup>137</sup>Cs in the atmosphere after the accident ranged between 6 and 9 days, which is in good accordance to what previously reported and in the same range with the recent accident in Japan. The high response of LMDZORINCA model for <sup>137</sup>Cs reinforces the importance of atmospheric modelling in emergency cases to gather information for protecting the population from the adverse effects of radiation.

 References Albergel, A., Martin, D., Strauss, B., and Gros, J.-M.: The Chernobyl accident: Modelling of dispersion over Europe of the radioactive plume and comparison with air activity measurements, Atmos. Environ., 22, 2431–2444, 1988. ApSimon, H. M., Goddard, A. J. H., and Wrigley, J.: Long-range atmospheric dispersion of radioisotopses. The MESOS model, Atmos. Environ., 19, 113–125, 1985. ApSimon, H. M., Wilson, J. J. N., and Scott, P. A.: Assessment of the Chernobyl release in the immediate aftermath of the accident, Nucl. Energy, 26, 295–301, 1987. Balkanski, Y. J., Jacob, D. J. Arimoto, R., and Kritz, M. A.: Distribution of <sup>222</sup>Rn over the North Pacific: Implications for continental influences, J. Atmos. Chem., 14, 353–371, 1992. Ballestra, S. B., Holm, E., Walton, A., and Whitehead, N. E.: Fallout deposition at Monaco following the Chernobyl accident, J. Environ. Radioactiv., 5, 391–400, 1987. Bonelli, P., Calori, G., and Finzi, G.: A fast long-range transport model for operational use in episode simulation. Application to the Chernobyl accident, Atmos. Environ., 26, 2523–2535, 1992. Brandt, J., Christensen, J. H., and Frohn, L. M.: Modelling transport and deposition of caesium and iodine from the Chernobyl accident using the DREAM model, Atmos. Chem. Phys., 2, 397–417, <a href="http://dx.doi.org/10.5194/acp-2-397-2002">https://doi.org/10.5194/acp-2-397-2002</a>, 2002. Cambray, R. S., Cawse, P. A., Garland, J. A., Gibson, J. A. B., Johnson, P., Lewis, G. N. J., Newton, D., Salmon, L., and Wade, B. O.: Observations on radioactivity from the Chernobyl accident, Nucl. Energy, 26, 77–101, 1987. Carbol, P., Solatie, D., Erdmann, N., Nylen, T., and Betti, M.: Deposition and distribution of Chernobyl fallout fission products and actinides in a Russian soil profile, J. Environ. Radioactiv., 68, 27–46, 2003. Choi, S. C.: Test of equality of dependent correlations, Biometrika, 64, 645–647, 1977. Christensen, D.: Fast algorithms for the calculation of Kendall's τ, Computation. Stat., 20, 51–62, 2005. De Cort, M., Dubois, G., Fridman, Sh. D., Germenchuk, M. G., Izrael, Yu. A., Janssens, A., Jones, A. R., Kelly, G. N., Kvasnikova, E. V., Matveenko, I. I., Nazarov, I. M., Pokumeiko, Yu. M., Sitak, V. A., Stukin, E. D., Tabachny, L. Ya., Tsaturov, Yu. S., and Avdyushin, S. I.: Atlas of caesium deposition on Europe after the Chernobyl accident, Luxembourg, Office for Official Publications of the European Communities 1998, ISBN 92-828-3140-X, Catalogue number CG-NA-16-733-29-C. EUR 16733, 1–63, 1998. Desiato, F.: A long-range dispersion model evaluation study with Chernobyl data, Atmos. Environ., 26, 2805–2820, 1992 Devell, L., Guntay, S., and Powers, D. A.: The Chernobyl reactor accident source term. Development of a consensus view, NEA/CSNI/R(95)24, OECD Nuclear Energy Agency, Paris, 1996. ECMWF: ERA-40, forty-year European re-analysis of the global atmosphere, available at: <a href="http://www.ecmwf.int/products/data/archive/descriptions/e4">http://www.ecmwf.int/products/data/archive/descriptions/e4</a>, 2002. Elliassen, A.: The OCDE study of long range transport or air pollutants: long-range transport modelling, Atmos. Environ., 12, 479–487, 1978. Elliassen, A. and Saltbones, J.: Modelling of long-range transport of sulphur over Europe: a two-year model run and some model experiments, Atmos. Environ., 17, 1457–1473, 1983. Hass, H., Memmesheimer, M., Geiss, H., Jakobs, H. J., Laube, M., and Ebel, A.: Simulation of the Chernobyl radioactive cloud over Europe using EURAD model, Atmos. Environ., 24, 673–692, 1990. Hatano, Y., Hatano, N., Amano, H., Ueno, T., Sukhoruchkin, A. K., and Kazakov, S. V.: Aerosol migration near Chernobyl: long-term data and modelling, Atmos. Environ., 32, 2587–2594, 1998. Hourdin, F. and Issartel, J. P.: Sub-surface nuclear tests monitoring through the CTBT xenon network, Geophys. Res. Lett., 27, 2245–2248, 2000. Huneeus, N., Schulz, M., Balkanski, Y., Griesfeller, J., Prospero, J., Kinne, S., Bauer, S., Boucher, O., Chin, M., Dentener, F., Diehl, T., Easter, R., Fillmore, D., Ghan, S., Ginoux, P., Grini, A., Horowitz, L., Koch, D., Krol, M. C., Landing, W., Liu, X., Mahowald, N., Miller, R., Morcrette, J.-J., Myhre, G., Penner, J., Perlwitz, J., Stier, P., Takemura, T., and Zender, C. S.: Global dust model intercomparison in AeroCom phase I, Atmos. Chem. Phys., 11, 7781–7816, <a href="http://dx.doi.org/10.5194/acp-11-7781-2011">https://doi.org/10.5194/acp-11-7781-2011</a>, 2011. International Atomic Energy Agency (IAEA): Regulations for the Safe Transport of Radioactive Material, IAEA Safety Requirements, no. TS-R-1, Vienna, 2005. International Atomic Energy Agency (IAEA): Environmental consequences of the Chernobyl accident and their remediation: Twenty years of experience. Report of the Chernobyl Forum Expert Group "Environment", Radiological Assessment Reports Series, Vienna, 2006. International Atomic Energy Agency (IAEA): Regulations for the Safe Transport of Radioactive Material, IAEA Safety Requirements, no. TS-R-1, Vienna, 2009. Ishikawa, H.: Evaluation of the effect of horizontal diffusion on the long-range atmospheric transport simulation with Chernobyl data, J. Appl. Meteorol., 34, 1653–1665, 1995. Jacob, D. J., Prather, M. J., Wofsy, S. C., and Mcelroy M. B.: Atmospheric distribution of 85Kr simulated with a general circulation modelJGR, J. Geophys. Res., 92, 6614–6626, 1987. Jacob, D. J., Prather, M. J., Rasch, P. J., Shia, R. L., Balkanski, Y. J., Beagley, S. R., Bergmann, D. J., Blackshear, W. T., Brown, M., Chiba, M., Chipperfield, M. P., De Grandpré, J., Dignon, J.E., Feichter, J., Genthon, C., Grose, W. L., Kasibhatla, P. S., Köhler, I., Kritz, M. A., Law, K., Penner, J. E., Ramonet, M., Reeves, C. E., Rotman, D. A., Stockwell, D. Z., Van Velthoven, P. F. J., Verver, G., Wild, O., Yang, H., and Zimmermann, P.: Evaluation and intercomparison of global atmospheric transport models using <sup>222</sup>Rn and other short-lived tracers, J. Geophys. Res., 102, 5953–5970, 1997. Klug, W., Graziani, G., Grippa, G., Pierce, D., and Tassone, C.: Evaluation of long range atmospheric transport models using environmental radioactivity data from the Chernobyl accident, The ATMES Report, Elsevier Applied Science, London and New York, 366 pp., 1992. Koch, D., Schulz, M., Kinne, S., McNaughton, C., Spackman, J. R., Balkanski, Y., Bauer, S., Berntsen, T., Bond, T. C., Boucher, O., Chin, M., Clarke, A., De Luca, N., Dentener, F., Diehl, T., Dubovik, O., Easter, R., Fahey, D. W., Feichter, J., Fillmore, D., Freitag, S., Ghan, S., Ginoux, P., Gong, S., Horowitz, L., Iversen, T., Kirkevåg, A., Klimont, Z., Kondo, Y., Krol, M., Liu, X., Miller, R., Montanaro, V., Moteki, N., Myhre, G., Penner, J. E., Perlwitz, J., Pitari, G., Reddy, S., Sahu, L., Sakamoto, H., Schuster, G., Schwarz, J. P., Seland, Ø., Stier, P., Takegawa, N., Takemura, T., Textor, C., van Aardenne, J. A., and Zhao, Y.: Evaluation of black carbon estimations in global aerosol models, Atmos. Chem. Phys., 9, 9001–9026, <a href="http://dx.doi.org/10.5194/acp-9-9001-2009">https://doi.org/10.5194/acp-9-9001-2009</a>, 2009. Kornberg, H. A.: The use of element-pairs in radiation hazard assessment, Health Phys., 6, 46–62, 1961. Kristiansen, N. I., Stohl, A., and Wotawa, G.: Atmospheric removal times of the aerosol-bound radionuclides <sup>137</sup>Cs and <sup>131</sup>I measured after the Fukushima Dai-ichi nuclear accident – a constraint for air quality and climate models, Atmos. Chem. Phys., 12, 10759–10769, <a href="http://dx.doi.org/10.5194/acp-12-10759-2012">https://doi.org/10.5194/acp-12-10759-2012</a>, 2012. Kritidis, P.: Radioactive contamination of the environment, in: Ourselves and Radioactivity, University of Crete Publications, edited by: Verganelakis, A., Kritidis, P., Economou, L., Papazoglou, I., Papanikolaou, E., Sideris, L., and Simopoulos, T., Heraklion, Greece, 235–270, 1989 (in Greek). Kritidis, P. and Florou, H.: Environmental study of radioactive caesium in Greek lake fish after the Chernobyl accident, J. Environ. Radioactiv., 28, 285–293, 1995. Kritidis, P., Florou, H., and Papanicolaou, E.: Delayed and late impact of the Chernobyl accident on the Greek environment, Radiat. Prot. Dosim., 30, 187–190, 1990. Lange, R., Dickerson, M. H., and Gudiksen, P. H.: Dose estimates from the Chernobyl accident, Nucl. Technol., 82, 311–323, 1988. Lee, D.S., Nemitz, E., Fowler, D., and Kingdon, R.D.: Modelling atmospheric mercury transport and deposition across Europe and the UK, Atmos. Environ., 35, 5455–5466, 2001. Lelieveld, J., Kunkel, D., and Lawrence, M. G.: Global risk of radioactive fallout after major nuclear reactor accidents, Atmos. Chem. Phys., 12, 4245–4258, <a href="http://dx.doi.org/10.5194/acp-12-4245-2012">https://doi.org/10.5194/acp-12-4245-2012</a>, 2012. Mattsson, S. and Vesanen, R.: Patterns of Chernobyl fallout in relation to local weather conditions, Environ. Int., 14, 177–180, 1988. Morino, Y., Ohara, T., and Nishizawa, M.: Atmospheric behavior, deposition, and budget of radioactive materials from the Fukushima Daiichi nuclear power plant in March 2011, Geophys. Res. Lett., 38, L00G11, <a href="http://dx.doi.org/10.1029/2011GL048689">https://doi.org/10.1029/2011GL048689</a>, 2011 Olivié, D. J. L., Cariolle, D., Teyssèdre, H., Salas, D., Voldoire, A., Clark, H., Saint-Martin, D., Michou, M., Karcher, F., Balkanski, Y., Gauss, M., Dessens, O., Koffi, B., and Sausen, R.: Modelling the climate impact of road transport, maritime shipping and aviation over the period 1860–2100 with an AOGCM, Atmos. Chem. Phys., 12, 1449–1480, <a href="http://dx.doi.org/10.5194/acp-12-1449-2012">https://doi.org/10.5194/acp-12-1449-2012</a>, 2012. Peplow, M.: Counting the dead (special report about the death toll of the Chernobyl accident), Nature, 440, 982–983, 2006. Piedelievre, J. P., Musson-Genon, L., and Bompay, F.: MEDIA – An Eulerian model for atmospheric dispersion: First validation on the Chernobyl release, J. Appl. Meteorol., 29, 1205–1220, 1990. Potiriadis, C., Kolovou, M., Clouvas, A., and Xanthos, S.: Environmental radioactivity measurements in Greece following the Fukushima Daichi nuclear accident, Radiat. Prot. Dosim., 150, 441–447, 2011. Prather, M., McElroy, M., Wofsy, S., Russell, G., and Rind, D.: Chemistry of the global troposphere: Fluorocarbons as tracers of air motion, J. Geophys. Res., 92, 6579–6613, 1987. Quélo, D., Krysta, M., Bocquet, M., Isnard, O., Minier, Y., and Sportisse, B.: Validation of the Polyphemus platform on the ETEX, Chernobyl and Algeciras cases, Atmos. Environ., 41, 5300–5315, 2007. Ritchie, J. C. and McHenry, J. R.: Application of radioactive fallout cesium-137 for measuring soil erosion and sediment accumulation rates and patterns: A review, J. Environ. Qual., 19, 215–233, 1990. Salvadori, G., Ratti, S. P., and Belli, G.: Modelling the Chernobyl radioactive fallout (II): A multifractal approach in some European countries, Chemosphere, 33, 2359–2371, 1996. Sportisse, B.: A review of parameterizations for modelling dry deposition and scavenging of radionuclides, Atmos. Environ., 41, 2683–2698, 2007. Stier, P., Feichter, J., Kinne, S., Kloster, S., Vignati, E., Wilson, J., Ganzeveld, L., Tegen, I., Werner, M., Balkanski, Y., Schulz, M., Boucher, O., Minikin, A., and Petzold, A.: The aerosol-climate model ECHAM5-HAM, Atmos. Chem. Phys., 5, 1125–1156, <a href="http://dx.doi.org/10.5194/acp-5-1125-2005">https://doi.org/10.5194/acp-5-1125-2005</a>, 2005. Stohl, A., Seibert, P., Wotawa, G., Arnold, D., Burkhart, J. F., Eckhardt, S., Tapia, C., Vargas, A., and Yasunari, T. J.: Xenon-133 and caesium-137 releases into the atmosphere from the Fukushima Dai-ichi nuclear power plant: determination of the source term, atmospheric dispersion, and deposition, Atmos. Chem. Phys., 12, 2313–2343, <a href="http://dx.doi.org/10.5194/acp-12-2313-2012">https://doi.org/10.5194/acp-12-2313-2012</a>, 2012. Szopa, S., Balkanski, Y., Cozic, A., Deandreis, C., Dufresne, J.-L., Hauglustaine, D., Lathiere, J., Schulz, M., Vuolo, R., Yan, N., Marchand, M., Bekki, S., Cugnet, D., Idelkadi, A., Denvil, S., Foujols, M.-A., Caubel, A., and Fortems-Cheiney, A.: Aerosol and Ozone changes as forcing for Climate Evolution between 1850 and 2100, Clim. Dynam., in press, <a href="http://dx.doi.org/10.1007/s00382-012-1408-y">https://doi.org/10.1007/s00382-012-1408-y</a>, 2012. Waight, P., Métivier, H., Jacob, P., Souchkevitch, G., Viktorsson, C., Bennett, B., Hance, R., Kumazawa, S., Kusumi, S., Bouville, A., Sinnaeve, J., Ilari, O., and Lazo, E.: Chernobyl Ten Years On. Radiological and Health Impact. An Assessment by the NEA Committee on 10 Radiation Protection and Public Health, November 1995, OECD Nuclear Agency, <a href="http://www.nea.fr/">http://www.nea.fr/</a>, 74 pp., 1995. Woodhead, D. S.: Levels of radioactivity in the marine environment and the dose commitment to the marine organisms, I.A.E.A. – S.M. 158/31, Vienna, 1973. Yoschenko, V. I., Kashparov, V. A., Protsak, V. P., Lundin, S. M., Levchuk, S. E., Kadygrib, A. M., Zvarich, S. I., Khomutinin, Yu. V., Maloshtan, I.M., Lanshin, V. P., Kovtun, M. V., and Tschiersch, J.: Resuspension and redistribution of radionuclides during grassland and forest fires in the Chernobyl exclusion zone: part I. Fire experiments, J. Environ. Radioactiv., 86, 143–163, 2006.