Climate Dynamics

, Volume 23, Issue 1, pp 17–28 | Cite as

Climate impact of the European winter blocking episodes from the NCEP/NCAR Reanalyses

  • R. M. Trigo
  • I. F. Trigo
  • C. C. DaCamara
  • T. J. Osborn


A comprehensive multivariable characterisation of the climatic impacts of winter blocking and strong zonal-flow (non-blocking) episodes over the Euro-Atlantic sector is presented here, using a 40-year (1958–97) consistent dataset from NCEP/NCAR. Anomaly fields of surface or low troposphere climate variables are then interpreted based on large-scale physical mechanisms, namely, the anomalous mean flow (characterised by the 500 hPa geopotential height and the surface wind) and the anomalous eddy activity (characterised by the surface vorticity and cyclonic activity). It is shown that the lower troposphere (850 hPa) temperature patterns are mainly controlled by the advection of heat by the anomalous mean flow. However, at the surface level, the anomaly patterns obtained for maximum and minimum temperatures present important asymmetries, associated with a different control mechanism, namely the modulation of shortwave and longwave radiation by cloud cover variations. It is shown that blocking and non-blocking episodes are typically associated with important meridional shifts in the location of maximum activity of transient eddies. The influence of persistent anomaly events in precipitable water is strongly related to the corresponding anomaly fields of lower troposphere temperature. The precipitation rate, however, appears to be essentially controlled by the surface vorticity field and preferred locations of associated cyclones.


Cyclone Precipitable Water Vorticity Field Anomaly Field Transient Eddy 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



The Reanalyses data have been produced by the NCEP and NCAR DSS. The window (30°N–80°N, 60°E–70°W) has been extracted and kindly provided by Ian Harris and David Viner (CRU). The authors would like to acknowledge Dr. Jean Palutikof and Ms. Célia Gouveia for their helpful suggestions.


  1. Anderson JL (1993) The climatology of blocking in a numerical forecast model. J Clim 6: 1041–1056CrossRefGoogle Scholar
  2. Austin JF (1980) The blocking of middle latitude westerly winds by planetary waves. Q J R Meteorol Soc 106: 327–350CrossRefGoogle Scholar
  3. Barry RG, Chorley RJ (1998) Atmosphere, weather and climate. Routledge, London, pp 409Google Scholar
  4. Blender RK (1997) Identification of cyclone track regimes in the North Atlantic. Q J R Meteorol Soc 123: 727–741CrossRefGoogle Scholar
  5. Charney JG, Devore JG (1979) Multiple flow equilibria in the atmosphere and blocking. J Atmos Sci 36: 1205–1216CrossRefGoogle Scholar
  6. Christensen WC, Wiin-Nielsen A (1996) Blocking as a wave-wave interaction. Tellus 48A: 254–271Google Scholar
  7. Colucci SJ, Alberta TL (1996) Planetary-scale climatrology of explosive cyclogenisis and blocking. Mon Weather Rev 124: 2509–2520CrossRefGoogle Scholar
  8. Cox AT, Cardone V, Swail VR (2000) Proc 2nd Int Conf on Reanalyse, Reading, United Kingdom. World Meteorological Organization, Geneva Switzerland. WCRP-109 (WMO/TD876), 73–76Google Scholar
  9. D’Andrea F, Tibaldi S, Blackburn M, Boer G, DéquéM, Dix RM, Dugas B, Ferranti L, Iwasaki T, Kitoh A, Pope V, Randall D, Roeckner E, Strauss D, Stern W, van Den Dool H, Williamson D (1998) Northern Hemisphere atmospheric blocking as simulated by 15 atmospheric general circulation models in the period 1979–1988. Clim Dyn 14: 385–407CrossRefGoogle Scholar
  10. DaCamara CC, Kung EC, Baker WE, Lee BC, Corte-Real JAM (1991) Long-term analysis of planetary wave activities and blocking circulation in the Northern Hemisphere winter. Beitr Phys Atmos 64: 285–298Google Scholar
  11. Dole RM (1986) Persistent anomalies of the extratropical Northern Hemisphere wintertime circulation: structure. Mon Weather Rev 114: 178–207CrossRefGoogle Scholar
  12. Egger J (1978) Dynamics of blocking highs. J Atmos Sci 35: 1788–1801CrossRefGoogle Scholar
  13. Elliot RD, Smith TB (1949) A study of the effect of large blocking highs on the general circulation in the northern hemisphere westerlies. J Meteorol 6: 67–85Google Scholar
  14. Frederiksen JS (1982) A unified three-dimensional instability theory of the onset of blocking and cyclogenisis. J Atmos Sci 39: 969–987Google Scholar
  15. Green JSA (1977) The weather during July 1976: some dynamical considerations of the drought. Weather 32: 120–126Google Scholar
  16. Gulev SK, Zolina O, Grigoriev S (2001) Extratropical cyclone variability in the Northern Hemisphere winter from the NCEP/NCAR reanalysis data. Clim Dyn 17: 795–809CrossRefGoogle Scholar
  17. Hansen AR, Pandolfo JP, Sutera A (1993) Midtropospheric flow regimes and persistent wintertime anomalies of surface-layer pressure and temperature. J Clim 6: 2136–2143CrossRefGoogle Scholar
  18. Kalnay E, Kanamitsu M, Kistler R, Colins W, Deaven D, Gandin L, Iredell M, Saha S, White G, Wollen J, Zhu Y, Leetmaa A, Reynolds R, Chelliah M, Ebisuzaki W, Higgins W, Janowiak J, Mo KC, Ropelewski C, Wang J, Jenne R, Joseph D (1996) The NCEP/NCAR 40-years reanalyses project. Bull Am Meteorol Soc 77: 437–471CrossRefGoogle Scholar
  19. Kung EC, DaCamara CC, Baker WE, Susskind J, Park CK (1990) Simulations of winter blocking episodes using observed sea surface temperatures. Q J R Meteorol Soc 116: 1053–1070CrossRefGoogle Scholar
  20. Lejenäs H, Øakland H (1983) Characteristics of northern hemisphere blocking as determined from long time series of observational data. Tellus 35A: 350–362Google Scholar
  21. Liu Q (1994) On the definition and persistence of blocking. Tellus 46A: 286–290Google Scholar
  22. Lupo AR, Smith PJ (1994) Climatological features of blocking anticyclones in the Northern Hemisphere. Tellus 47A: 439–456Google Scholar
  23. Michelangeli PA, Vautard R (1998) The dynamics of Euro-Atlantic blocking onsets. Q J R Meteorol Soc 124: 1045–1070CrossRefGoogle Scholar
  24. Mullen SL (1987) Transient eddy forcing of blocking flows. J Atmos Sci 44: 3–22CrossRefGoogle Scholar
  25. Murray RJ, Simmonds I (1991) A numerical scheme for tracking cyclones centres from digital data. Part I. Development and operation of the scheme. Aust Meteorol Mag 39: 155–166Google Scholar
  26. Nakamura H, Wallace JM (1990) Observed changes in baroclinic wave activity during the life cycles of low-frequency circulation anomalies. J Atmos Sci 47: 1100–1116CrossRefGoogle Scholar
  27. Nakamura H, Nakamura M, Anderson JL (1997) The role of high- and low-frequency dynamics in blocking formation. Mon Weather Rev 125: 2074–2093 CrossRefGoogle Scholar
  28. Quadrelli R, Pavan V, Molteni F (2001) Wintertime variability of Mediterranean precipitation and its links with large-scale circulation anomalies. Clim Dyn 17: 457–466CrossRefGoogle Scholar
  29. Quiroz RS (1984) The climate of 1983–84 winter. A season of strong blocking and severe cold in North America. Mon Weather Rev 112: 1894–1912CrossRefGoogle Scholar
  30. Reid PA, Jones PD, Brown O, Goodess CM, Davies TD (2001) Assessments of the reliability of NCEP circulation data and relationships with surface climate by direct comparisons with station based data. Clim Res 17: 247–261Google Scholar
  31. Reinhold BB, Pierrehumbert RT (1982) Dynamics of weather regimes: quasi-stationary waves and blocking. Mon Weather Rev 110:1105–1145CrossRefGoogle Scholar
  32. Rex DF (1950a) Blocking action in the middle troposphere and its effect upon regional climate. Part I. An aerological study of blocking action. Tellus 2: 196–211Google Scholar
  33. Rex DF (1950b) Blocking action in the middle troposphere and its effect upon regional climate. Part II. The climatology of blocking action. Tellus 2: 275–301Google Scholar
  34. Rex DF (1951) The effect of Atlantic blocking action upon European climate. Tellus 3: 1–16Google Scholar
  35. Sausen R, König W, Sielmann F (1995) Analysis of blocking events observation and ECHAM model simulations. Tellus 47A: 421–438Google Scholar
  36. Serreze MC, Carse F, Barry RG, Rogers JC (1997) Icelandic Low cyclone activity: climatological features, linkages with the NAO, and relationships with recent changes in the Northern Hemisphere circulation. J Clim 10: 453–464 CrossRefGoogle Scholar
  37. Shutts GJ (1983) The propagation of eddies in diffluent jet streams: eddy forcing of “blocking” flow fields. Q J R Meteorol Soc 109: 737–762CrossRefGoogle Scholar
  38. Shutts GJ (1986) A case study of eddy forcing during an Atlantic blocking episode. In: Benzi R, Saltzman B, Wiin-Nielsen AC (eds) Anomalous atmospheric flows and blocking. Advances in Geophysics, vol 29, Academic Press, New-York, pp 135–162Google Scholar
  39. Sinclair MR (1994) An objective cyclone climatology for Southern Hemisphere. Mon Weather Rev 122: 1156–1167CrossRefGoogle Scholar
  40. Simmons AJ, Wallace JM, Branstator GW (1983) Barotropic wave propagation and instability, and atmospheric telleconnection patterns. J Atmos Sci 40: 1363–91CrossRefGoogle Scholar
  41. Stein O (2000) The variability of Atlantic-European blocking as derived from long SLP time series. Tellus 52A: 225–236Google Scholar
  42. Tibaldi S, Molteni F (1990) On the operational predictability of blocking. Tellus 42A: 343–365Google Scholar
  43. Tibaldi S, Tosi E, Navarra A, Pedulli L (1994) Northern and Southern Hemisphere seasonal variability of blocking frequency and predictability. Mon Weather Rev 122: 1971–2003CrossRefGoogle Scholar
  44. Tibaldi S, D’Andrea F, Tosi E, Roeckner E (1997) Climatology of Northern Hemisphere blocking in the ECHAM model. Clim Dyn 13: 649–666CrossRefGoogle Scholar
  45. Treidl RA, Birch EC, Sajecki P (1981) Blocking action in the Northern Hemisphere: a climatological study. Atmosphere-Ocean 19: 1–23Google Scholar
  46. Trigo IF, Davies TD, Bigg GR (1999) Objective climatology of cyclones in the Mediterranean region. J Clim 12: 1685–1696CrossRefGoogle Scholar
  47. Trigo IF, Bigg GR, Davies TD (2002) Climatology of cyclogenesis mechanisms in the Mediterranean. Mon Weather Rev 130: 549–569CrossRefGoogle Scholar
  48. Trigo RM, DaCamara CC (2000) Circulation weather types and their impact on the precipitation regime in Portugal. Int J Climatol 20: 1559–1581CrossRefGoogle Scholar
  49. Trigo RM, Osborn TJ, Corte-Real JM (2002) The North Atlantic Oscillation influence on Europe: climate impacts and associated physical mechanisms. Clim Res 20: 9–17Google Scholar
  50. Tsou CH, Smith PJ (1990) The role of synoptic/planetary-scale interactions during the development of a blocking anticyclone. Tellus 42A: 174–193Google Scholar
  51. Tung KK, Lindzen RS (1979) A theory of stationary long waves. 1 A simple theory of blocking. 2. Resonant Rossby waves in the presence of realistic vertical shears. Mon Weather Rev 107: 735–750CrossRefGoogle Scholar
  52. Verdecchia M, Visconti G, D’Andrea F, Tibaldi S (1996) A neural network approach for blocking recognition. Geophys Res Lett 23: 2081–2084CrossRefGoogle Scholar
  53. Widmann M, Bretherton CS (2000) Validation of mesoscale precipitation in the NCEP reanalysis using a new gridcell dataset for the northwestern United States. J Clim 13: 1936–1950CrossRefGoogle Scholar
  54. Wilby RL, O’Hare G, Barnsley N (1997) The North Atlantic Oscillation and the British Isles climate variability 1865–1995. Weather 52: 266–276Google Scholar
  55. White G (2000) Long-term trends in NCEP/NCAR Reanalysis. Proc 2nd Int Conf on Reanalyse, Reading, United Kingdom. World Meteorological Organization, Geneva Switzerland. WCRP-109 (WMO/TD985), 54–57Google Scholar
  56. Xie P, Arkin PA (1997) Global precipitation: a 17-year monthly analysis based on gauge observations, satellite estimates and numerical model outputs. Bull Am Meteorol Soc 78: 2539–2558CrossRefGoogle Scholar
  57. Zolina O, Gulev SK (2002) Improving accuracy of mapping cyclone numbers and frequencies. Mon Weather Rev 129: 748–759CrossRefGoogle Scholar

Copyright information

© Springer-Verlag  2004

Authors and Affiliations

  • R. M. Trigo
    • 1
    • 2
  • I. F. Trigo
    • 1
    • 3
  • C. C. DaCamara
    • 1
    • 3
  • T. J. Osborn
    • 4
  1. 1.Centro de Geofísica da Universidade de LisboaDepartamento de Física, Faculdade de Cièncias Campo GrandeLisbonPortugal
  2. 2.Departamento de Eng. Civil da Universidade LusófonaLisbonPortugal
  3. 3.Instituto de MeteorologiaLisbonPortugal
  4. 4.Climatic Research UnitUniversity of East AngliaNorwichUK

Personalised recommendations