Volume 1, Issue 3 (December 2016)

Original research papers



Jelena Ajtić, Vladimir Djurdjevic, Darko Sarvan, Erika Brattich, Miguel A. Hernández-Ceballos

Pages: 216-221

DOI: 10.21175/RadJ.2016.03.040

Received: 1 MAR 2016, Received revised: 10 APR 2016, Accepted: 15 APR 2016, Published online: 26 DEC 2016

We present an analysis of the maxima in a large dataset of the beryllium-7 specific activities measured in surface air in Helsinki, Finland, over 25 years (1987-2011), which are stored in the online Radioactivity Environmental Monitoring (REM) database. The maxima are defined as events with the beryllium-7 specific activity above the 95th percentile, which, for the Helsinki data set, equals to 4.82·10-3 Bq·m-3. The beryllium-7 specific activity in Helsinki shows a seasonal pattern with the monthly means above 2.00·10-3 Bq·m-3 during the warm season (April–September), and below 2.00·10-3 Bq·m-3 during the cold season (October–March). The analysis of the extremes shows that 10 % occurred in the cold season, and these “cold extremes” are analysed in more detail. Amongst the cold extremes, three representative “episodes” are identified. The episodes, which occurred in March 1999, February 2003 and February 2005, show extremely high beryllium-7 specific activities measured over several consecutive days. Anomalies of potential vorticity, sea level pressure and surface temperature, as well as precipitation, over Europe and the Atlantic are investigated. A brief analysis of one cold extreme, classified as “burst” since it was an isolated event surrounded by measurements below the 95th percentile, is also presented in an attempt to find common mechanisms that contribute to both cold extreme episodes and bursts. Scandinavia teleconnection index seems to represent a good indicator of potentially preferential atmospheric conditions that could lead to cold extreme episode occurrences in the Scandinavian region.
  1. D. Lal and B. Peters, “Cosmic ray produced radioactivity on the earth,” in Cosmic Rays II, K. Sitte, Ed., Berlin, Heidelberg, Germany: Springer, 1967, pp 551-612
    DOI: 10.1007/978-3-642-46079-1_7
  2. D. M. Koch, D. J. Jacob and W. C. Graustein, “Vertical transport of tropospheric aerosols as indicated by 7Be and 210Pb in a chemical tracer model,” J. Geophys. Res., vol. 101, pp. 18651-18666, 1996.
    DOI: 10.1029/96JD01176
  3. C. Dueñas, M. C. Fernández, J. Carretero, E. Liger and S. Cañete, “Long-term variation of the concentrations of long-lived Rn descendants and cosmogenic 7Be and determination of the MRT of aerosols,” Atmos. Environ., vol. 38, pp. 1291-1301, March 2004.
    DOI: 10.1016/j.atmosenv.2003.11.029
  4. U. Heikkilä, J. Beer and V. Alfimov, “Beryllium-10 and beryllium-7 in precipitation in Dübendorf (440 m) and at Jungfraujoch (3580 m), Switzerland (1998–2005),” J. Geophys. Res., vol. 113, 2008.
    DOI: 10.1029/2007JD009160
  5. E. Gerasopoulos, C. S. Zerefos, C. Papastefanou, P. Zanis and K. O’Brien, “Low-frequency variability of beryllium-7 surface concentrations over the Eastern Mediterranean,” Atmos. Environ., vol. 37, pp. 1745-1756, 2003.
    DOI: 10.1016/S1352-2310(03)00068-2
  6. P. Cristofanelli et al., “A 6-year analysis of stratospheric intrusions and their influence on ozone at Mt. Cimone (2165 m above sea level),” J. Geophys. Res., vol. 111, no. D3, 2006.
    DOI: 10.1029/2005JD006553
  7. P. Zanis et al., “An estimate of the impact of stratosphere-to-troposphere transport (STT) on the lower free tropospheric ozone over the Alps using 10Be and 7Be measurements,” J. Geophys. Res.,vol.108, no. D12, 2003.
    DOI: 10.1029/2002JD002604
  8. M. A. Hernández-Ceballos et al., “A climatology of 7Be in surface air in European Union,” J. Environ. Radioact., vol. 141, pp. 62-70, 2015.
    DOI: 10.1016/j.jenvrad.2014.12.003
  9. J. Ajtić, D. Todorović, J. Nikolić and V. Djurdjević, “A multi-year study of radioactivity in surface air and its relation to climate variables in Belgrade, Serbia,” Nucl. Technol. Radiat., vol. 28, pp. 381-388, 2013.
    DOI: 10.2298/NTRP1304381A
  10. E. Gerasopoulos et al., “A climatology of 7Be at four high-altitude stations at the Alps and the Northern Apennines,” Atmos. Environ., vol. 35, pp. 6347-6360, 2001.
    DOI: 10.1016/S1352-2310(01)00400-9
  11. A. Ioannidou, M. Manolopoulou and C. Papastefanou, “Temporal changes of 7Be and 210Pb concentrations in surface air at temperate latitudes (40 °N),” Appl. Radiat. Isot., vol. 63, pp. 277-284, 2005.
    DOI: 10.1016/j.apradiso.2005.03.010
  12. P. Bonasoni et al., “Stratospheric ozone intrusion episodes recorded at Mt. Cimone during the VOTALP project: case studies,” Atmos. Environ., vol. 34, pp. 1355-1365, 2000.
    DOI: 10.1016/S1352-2310(99)00280-0
  13. P. Zanis et al., “Forecast, observation and modelling of a deep stratospheric intrusion event over Europe,” Atmos. Chem. Phys., vol. 3, pp. 763-777, 2003.
    DOI: 10.5194/acp-3-763-2003
  14. E. F. Danielsen, “Stratospheric-tropospheric exchange based on radioactivity, ozone and potential vorticity”, J. Atmos. Sci., vol. 25, pp. 502-518, 1968.
    DOI: 10.1175/1520-0469(1968)025<0502:STEBOR>2.0.CO;2
  15. P. Cristofanelli et al., “Stratospheric intrusion index (SI2) from baseline measurement data,” Theor. Appl. Climatol., vol. 97, pp. 317-325, 2009.
    DOI: 10.1007/s00704-008-0073-x
  16. A. Ioannidou, A. Vasileiadis and D. Melas, “Time lag between the tropopause height and 7Be activity concentrations on surface air,” J. Environ. Radioact., vol. 129, pp. 80-85, 2014.
    DOI: 10.1016/j.jenvrad.2013.12.013
  17. World Meteorological Organization. (Geneva, 2009). WCDMP-No. 72, Guidelines on Analysis of extremes in a changing climate in support of informed decisions for adaptation Retreived from: http://www.wmo.int/pages/prog/wcp/wcdmp/wcdmp_series/documents/WCDMP_72_TD_1500_en_1.pdf
    Retrieved on: May 5, 2016
  18. M. K. Pham, M. Betti, H. Nies and P. P. Povinec, “Temporal changes of 7Be, 137Cs and 210Pb activity concentrations in surface air at Monaco and their correlation with meteorological parameters,” J. Environ. Radioact., vol. 102, pp. 1045-1054, November 2011.
    DOI: 10.1016/j.jenvrad.2011.06.002
  19. E. Kalnay et al., “The NCEP/NCAR 40-Year Reanalysis Project,” Bull. Am. Meteorol. Soc., vol. 77, pp. 437-471, March 1996.
    DOI: 10.1175/1520-0477(1996)077<0437:TNYRP>2.0.CO;2
  20. M. R. Haylock et al., “A European daily high-resolution gridded dataset of surface temperature and precipitation,” J. Geophys. Res., vol. 113, D20119, 2008.
    DOI: 10.1029/2008JD10201
  21. P. Zanis, E. Schuepbach, H. W. Gäggeler, S. Hübener and L. Tobler, “Factors controlling beryllium-7 at Jungfraujoch in Switzerland,” Tellus B, vol. 51, pp. 789-805, September 1999.
    DOI: 10.1034/j.1600-0889.1999.t01-3-00004.x
  22. A. G. Barnston and R. E. Livezey, “Classification, seasonality and persistence of low-frequency atmospheric circulation patterns,” Mon. Weather Rev., vol. 115, pp. 1083-1126, June 1987.
    DOI: 10.1175/1520-0493(1987)115<1083:CSAPOL>2.0.CO;2
  23. A.-P. Leppänen et al., “Cosmogenic 7Be in air: A complex mixture of production and transport,” J. Atmos. Sol. Terr. Phys., vol. 72, pp. 1036-1043, August 2010.
    DOI: 10.1016/j.jastp.2010.06.006
  24. A.-P. Leppänen, I. G. Usoskin, G. A. Kovaltsov and J. Paatero, “Cosmogenic 7Be and 22Na in Finland: Production, observed periodicities and the connection to climatic phenomena,” J. Atmos. Sol. Terr. Phys., vol. 74, pp. 164-180, January 2012.
    DOI: 10.1016/j.jastp.2011.10.017