North Atlantic Oscillation Projection on Romanian Climate Fluctuations in the Cold Season

  • Roxana Bojariu
  • Daniela-Mihaela Paliu
Chapter

Abstract

The North Atlantic Oscillation (NAO) is one of the most important modes of large scale variability in the Northern Hemisphere. In this study a more detailed regional projection of NAO related climate fluctuations over the Romanian territory is investigated. Monthly air surface temperature and precipitation anomalies from 62 Romanian stations and NCEP reanalysis data have been analysed to identify the local response to the NAO influences for the periods 1961–1990, and 1961–1999, respectively. The winter responses to the large scale circulation over the Romanian regions configure patterns of positive (negative) thermal anomalies, and negative (positive) precipitation anomalies associated with a high (low) NAO index. The winter NAO related signal is stronger in the extra-Carpathian regions, due to the orographic effects imposed on the atmospheric flow by the Carpathian mountains. NAO related behaviour is revealed by a lagged correlation between temperature anomalies in January and the following November and between temperature anomalies in November and the following January over the Romanian regions. Furthermore, a source of NAO related predictability has been identified over Central and Eastern European regions. November thermal anomalies over these regions are negatively correlated with the NAO index and could be used to predict the onset of the NAO phase in the following winter.

Keywords

Europe Assimilation Cyclone Romania Eurasia 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Barston, A. and R.E. Livezey, 1987: Classification, seasonality and persistence of low frequency atmospheric circulation patterns. Mon. Wea. Rev. 115, 1083–1126.CrossRefGoogle Scholar
  2. Bretherton, C. S., C. Smith and J. M. Wallace, 1992: An intercomparison methods for finding coupled patterns in climate data. J. Climate 5, 541–560.CrossRefGoogle Scholar
  3. Bojariu, R. and G. Reverdin, 2001: Large scale variability modes of freshwater flux and precipitation over the Atlantic. Accepted in Climate Dynamics. Google Scholar
  4. Cayan, D.R., 1992: Latent and sensible heat flux anomalies over the northern oceans: the connection to monthly atmospheric circulation. J.Climate 5, 354–369.CrossRefGoogle Scholar
  5. Hurrell, J.W. 1995: Decadal trends in the North Atlantic Oscillation: regional temperature and precipitation. Science 269, 676–679.CrossRefGoogle Scholar
  6. Hurrell, J.W., 1996: Influence of variations in extratropical wintertime teleconnections on Northern Hemisphere temperature. Geophys. Res. Lett. 23, 665–668.CrossRefGoogle Scholar
  7. Kalnay, E., M. Kanamitsu, R. Kistler, W. Collins, D. Deaven, L. Gandin, M. Iredell, S. Saha, G. White, J. Woollen, Y. Zhu, A. Leetmaa, R. Reynolds M. Chelliah, W. Ebisuzaki, W. Higgins, J. Janowiak, K. C. Mo, C. Ropelewski, J. Wang, Roy Jenne, Dennis Joseph, 1996. The NCEP/NCAR 40-Year Reanalysis Project. Bulletin of the American Meteorological Society, March 1996.Google Scholar
  8. Kharin, V. 1994. The relationship between sea surface temperature anomalies and atmospheric circulation in general circulation model experiments. Max-Planck-Institute fur Meteorologie, Hamburg, Report No.136.Google Scholar
  9. Ion-Bordei, N., 1988: Meteoclimatic phenomena induced by the Carpathian configuration in the Romanian Plain. Ed. Academiei, 174 pp. (in Romanian).Google Scholar
  10. Kalnay, E., M. Kanamitsu, R. Kistler, W. Collins, D. Deaven, L. Gandin, M. Iredell, S. Saha, G. White, J. Wollen, Y. Zhu, A. Letmaa, R. Reynolds, M. Chelliah, W. Ebisuzaki, W. Higgins, J. Janowiak, K.C. Moo, C. Ropelewski, J. Wang, Roy Jenne, Dennis Joseph, 1996: The NCEP/NCAR 40-Year Reanalysis Project. Bulletin of the American Meteorological Society, March 1996.Google Scholar
  11. Plaut, G., and R. Vautard, 1994: Spells of low-frequency oscillations and weather regimes in the Northern Hemisphere. J. Atmos. Sci. 51, 210–236.CrossRefGoogle Scholar
  12. Preisendorfer, R.W., 1988: Principal component analysis in Meteorology and Oceanography. Elsevier. 425 pp.Google Scholar
  13. Rogers, J.C., 1990: Patterns of low frequency monthly sea level pressure variability (1899–1986) and associated wave cyclone frequencies. J. Climate 3, 1364–1379.CrossRefGoogle Scholar
  14. Stephenson, D., V. Pavan, R. Bojariu, 2000: Is the North Atlantic Oscillation a random walk? International Journal of Climatology 20, 1–18.CrossRefGoogle Scholar
  15. Thompson, D. W. J and J. M. Wallace, 1998: The Arctic Oscillation signature in the wintertime geopotential height and temperature fields. Geophys. Res. Lett. 25, 1297–1300.CrossRefGoogle Scholar
  16. Thompson, D. W. J and J. M. Wallace, 2000: Annular modes in the extratropical circulation. Part I: Month to month variability. J. Climate 13, 1000–1016.CrossRefGoogle Scholar
  17. Van Loon, H. and J.C. Rogers, 1978: The see-saw in winter temperatures between Greenland and Northern Europe. Part I: General Description. Mon. Wea. Rev. 106, 293–310.Google Scholar
  18. Von Storch, H., 1995. Spatial patterns: EOFs and CCA. In: Analysis of climate variability: applications of statistical techniques (Von Storch, H. and Navarra A., Eds). Springer, 227–258.Google Scholar
  19. Zorita, E., V. Kharin and H. von Storch, 1992: The Atmospheric Circulation and Sea Surface Temperature in the North Atlantic Area in Winter: Their Interaction and Relevance for Iberian Precipitation. J. Climate 5, 1097–1108.CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2001

Authors and Affiliations

  • Roxana Bojariu
    • 1
  • Daniela-Mihaela Paliu
    • 1
  1. 1.National Institute of Meteorology and HydrologyBucharestRomania

Personalised recommendations