Meteorology and Atmospheric Physics

, Volume 131, Issue 5, pp 1367–1386 | Cite as

Changes in summer temperatures and rainfall in the northeastern Iberian Peninsula in the late 1960s and the weakening of the Iberian thermal low

  • V. FavàEmail author
  • J. J. Curto
  • M. C. Llasat
Original Paper


Changes in a number of important climatic variables in the northeastern part of the Iberian Peninsula (NE IP) were detected in summers around the end of the 1960s. From 1950 to 1966, we found significant correlations between the Summer North Atlantic Oscillation (SNAO) and frontal precipitation. This could be explained, on the one hand, by the withdrawal of the Azores High to the west which enhanced the frequency of cold advections in the north IP, and, on the other hand, by a high occurrence of an anticyclonic pattern over the west Mediterranean that enhanced the precipitation in NE IP by advecting moist air which, in turn, reinforced the storms linked to the frontal activity coming from the Atlantic. This pattern was also linked in this period to the strengthening of the Iberian Peninsula summer thermal low and to the increase in second-quadrant wind at the Ebro Observatory. Nevertheless, an abrupt rise of the vorticity at sea level in the western Mediterranean was detected around 1967. This rise was related to the steep increase in the SNAO, the expansion of the Azores High to central Europe in summer, and an increase of the anticyclonic regime. This contributes to explaining the simultaneous drop in frontal precipitation in NE IP, the weakening of the IP summer thermal low, the drop of the second-quadrant daily wind run, and the steep rise of the diurnal temperature range (DTR) at the Ebro Observatory.



We want to acknowledge the great contribution of the meteorological observers of the Ebro Observatory for their huge commitment over the years to recording and digitising the wind data used in this work. We further extend our gratitude to AEMET as well as the Santander Meteorological group (Universidad de Cantabria-CSIC) for elaborating the Spain02 dataset and making it available. The authors extend their appreciation to UCAR (University Corporation for Atmospheric Research) NCEP/NCAR for allowing us access to their huge meteorological data base and the extremely powerful and versatile software (NCL). The authors thank Brian and Silvia for their accurate translation and for improving the grammar and the quality of the text. Finally, we extend our appreciation to the anonymous reviewer for their valuable suggestions.


  1. Alonso-Garcia M, Kleiven HF, McManus JF, Moffa-Sanchez P, Broecker WS, Flower BP (2017) Freshening of the Labrador Sea as a trigger for Little Ice Age development. Clim Past. Google Scholar
  2. Arakawa A, Fujita T, Masuda Y, Matsumoto S, Murakami T, Ozawa T, Suzuki E, Takeuchi M, Tomatsu K (1955) Climatic abnormalities as related to the explosions of volcano and hydrogen-bomb. J Meteorol Soc Jpn Ser II. Google Scholar
  3. Baines PG, Folland CK (2007) Evidence for a rapid global climate shift across the late 1960s. J Clim. Google Scholar
  4. Bladé I, Liebmann B, Fortuny D, van Oldenborgh GJ (2011) Observed and simulated impacts of the summer NAO in Europe: implications for projected drying in the Mediterranean region. Clim Dyn. Google Scholar
  5. Brunet M, Aguilar E, Saladié O, Sigró J, López D (1999) Variaciones y tendencias contemporáneas de la temperatura máxima, mínima y amplitud térmica diaria en el NE de España. In: Raso Nadal JM, Martín Vide J (eds) La climatología española en los albores del siglo XXI. Asociación Española de Climatología, Barcelona, pp 103–112 (Serie A, 1) Google Scholar
  6. Brunet M, Aguilar E, Saladié O, Sigró J, López D (2001) A differential response of northeastern Spain to asymmetric trends in diurnal warming detected on a global scale. In: Brunet M, López D (eds) Detecting and modelling regional climate change. Springer, New York, pp 95–107CrossRefGoogle Scholar
  7. Brunet M, Jones PD, Sigró J, Saladié O, Aguilar E, Moberg A, Della-Marta PM, Lister D, Walther A, López D (2007) Temporal and spatial temperature variability and change over Spain during 1850–2005. J Geophys Res. Google Scholar
  8. Chronis T, Raitsos DE, Kassis D, Sarantopoulos A (2011) The summer North Atlantic oscillation influence on the eastern Mediterranean. J Clim. Google Scholar
  9. Curto JJ, Also E, Pallé E, Solé JG (2009) Sunshine and synoptic cloud observations at Ebro Observatory, 1910–2006. Int J Climatol. Google Scholar
  10. Dickson RR, Meincke J, Malmberg S, Lee AJ (1988) The “great salinity anomaly” in the northern North Atlantic 1968–1982. Prog Oceanog. Google Scholar
  11. Dima M, Lohmann G (2011) Causes and consequences of the late 1960s great salinity anomaly. In: Carayannis E (ed) Planet earth 2011—global warming challenges and opportunities for policy and practice. InTech, London, p 17, ISBN: 978-953-307-733-8.
  12. Esteban-Parra MJ, Pozo-Vázquez D, Rodrigo FS, Castro-Díez Y (2003) Temperature and precipitation variability and trends in Northern Spain in the context of the Iberian Peninsula climate. Reg Clim Stud. Google Scholar
  13. Favà V, Curto JJ, Llasat MC (2015) Relationship between the summer NAO and maximum temperatures for the Iberian Peninsula. Theor Appl Climatol. Google Scholar
  14. Favà V, Curto JJ, Llasat MC (2016) Regional differential behaviour of maximum temperatures in the Iberian Peninsula regarding the summer NAO in the second half of the twentieth century. Atmos Res. Google Scholar
  15. Favà V, Curto JJ, Llasat MC (2018) Changes in summer pressure patterns across the late 1960s and their influence on temperature trends on the eastern coast of the Iberian Peninsula. Atmosphere. Google Scholar
  16. Fischer EM, Luterbacher J, Zorita E, Tett SFB, Casty C, Wanner H (2007) European climate response to tropical volcanic eruptions over the last half millennium. Geophys Res Lett. Google Scholar
  17. Folland CK, Knight J, Linderholm HW, Fereday D, Ineson S, Hurrell JW (2009) The summer North Atlantic oscillation: past, present and future. J Clim. Google Scholar
  18. Font I (1983) Climatología de España y Portugal. Instituto Nacional de Meteorología, MadridGoogle Scholar
  19. Friedman AR, Hwang Y-T, Chiang JCH, Frierson DMW (2013) The interhemispheric temperature asymmetry over the 20th century and in future projections. J Clim. Google Scholar
  20. Fujii Y (2011) The role of atmospheric nuclear explosions on the stagnation of global warming in the mid 20th century. J Atmos Sol Terr Phys. Google Scholar
  21. Gaertner MA, Fernández C, Castro M (1993) A two-dimensional simulation of the Iberian summer thermal low. Mon Weather Rev 121:2740–2756CrossRefGoogle Scholar
  22. Gong DY, Drange H, Gao YQ (2007) Reconstruction of Northern Hemisphere 500 hPa geopotential heights back to the late 19th century. Theor Appl Climatol. Google Scholar
  23. Haylock MR, Hofstra N, Klein Tank AMG, Klok EJ, Jones PD, New M (2008) A European daily high-resolution gridded dataset of surface temperature and precipitation. J Geophys Res (Atmos). Google Scholar
  24. Herrera S, Gutiérrez JM, Ancell R, Pons MR, Frías MD, Fernández J (2012) Development and analysis of a 50-year high-resolution daily gridded precipitation dataset over Spain (Spain02). Int J Climatol. Google Scholar
  25. Hertig E, Seubert S, Jacobeit J (2010) Temperature extremes in the Mediterranean area: trends in the past and assessments for the future. Nat Hazards Earth Syst Sci. Google Scholar
  26. Hoinka KP, Castro MD (2003) The Iberian Peninsula thermal low. Q J Royal Meteorol Soc. Google Scholar
  27. Holton JR (1992) An introduction to dynamic meteorology. International geophysics series, 3rd edn, vol 48. Elsevier, CambridgeGoogle Scholar
  28. Hurrell JW, Folland CK (2002) A change in the summer circulation over the North Atlantic. CLIVAR Exchanges No. 25, International CLIVAR Project Office, Southampton, pp 52–54Google Scholar
  29. Ionita M, Scholz P, Lohmann G, Dima M, Prange M (2016) Linkages between atmospheric blocking, sea ice export through Fram Strait and the Atlantic meridional overturning circulation. Nature. Google Scholar
  30. Kondratyev KY (1988) Climate shocks: natural and anthropogenic (climate and biosphere). Wiley, New YorkGoogle Scholar
  31. Lenderink G, Haarsma H (1994) Variability and multiple equilibria of the thermohaline circulation associated with deep water fromation. J Phys Oceanogr.;2 Google Scholar
  32. Linderholm HW, Folland CK (2017) Summer North Atlantic oscillation (SNAO) variability on decadal to paleoclimate time scales. PAGES Magazine. (CLIVAR Exchanges N72) Google Scholar
  33. Linderholm HW, Folland CK, Hurrell JW (2008) Reconstructing summer North Atlantic oscillation (SNAO) variability over the last five centuries. In: Elferts D, Brumelis G, Gärtner H, Helle G, Schleser G (ed) TRACE—Tree rings in archaeology, climatology and ecology, Vol. 6: Proceedings of the Dendrosymposium 2007, 3–6 May 2007, Riga, Latvia (scientific technical report STR 08/05). GFZ Potsdam, Potsdam, pp 6–13Google Scholar
  34. Linés A (1970) The climates of the Iberian Peninsula. In: Wallén CC (ed) Climates of northern and western Europe. World Meteorological Organization, Geneva, pp 195–226Google Scholar
  35. Llebot J (2010) El canvi Climàtic a Catalunya. 2n informe del grup d’experts en canvi climàtic de Catalunya. Generalitat de Catalunya, Barcelona, pp 1–32Google Scholar
  36. Manabe S, Stouffer RJ (1995) Simulation of abrupt climate change induced by freshwater input to the North Atlantic Ocean. Nature. Google Scholar
  37. Martin-Vide J et al (2016) Tercer Informe sobre el Canvi Climàtic a Catalunya. Generalitat de Catalunya i Institut d’Estudis Catalans. ISBN 9788499653174 (IEC). ISBN 9788439394488 (Generalitat de Catalunya)Google Scholar
  38. Martínez MD, Lana X, Burgueño A, Serra C (2006) Spatial and temporal daily rainfall regime in Catalonia (NE Spain) derived from four precipitation indices, years 1950–2000. Int J Climatol. Google Scholar
  39. Martin-Vide J, López-Bustins JA (2006) The western Mediterranean oscillation and rainfall in the Iberian Peninsula. Int J Climatol. Google Scholar
  40. Miller S, Keim B (2002) Synoptic-scale controls on the sea breeze of the Central New England Coast. Weather Forecast.;2 Google Scholar
  41. Miró J, Estrela MJ, Millan M (2006) Summer temperature trends in a Mediterranean area (Valencia region). Int J Climatol. Google Scholar
  42. National Centers for Environmental Prediction/National Weather Service/NOAA/U.S. Department of Commerce. 1994, updated monthly. NCEP/NCAR global reanalysis products, 1948-continuing. Research Data Archive at the National Center for Atmospheric Research, Computational and Information Systems Laboratory. Accessed 6 Sept 2013
  43. Politis DN, Romano JP (1992) A circular block-resampling procedure for stationary data. In: LePage R, Billard L (eds) Exploring the limits of bootstrap. Wiley, New York, pp 236–270Google Scholar
  44. Portela A, Castro M (1991) Primera aproximación a una climatología de las depresiones térmicas en la Península Ibérica. Rev de Geofísica 47:205–215Google Scholar
  45. Portela A, Castro M (1996) Summer thermal lows in the Iberian Peninsula: a three-dimensional simulation. Q J R Meteorol Soc 122:1–22CrossRefGoogle Scholar
  46. Rahmstorf S, Box JE, Feulner G, Mann ME, Robinson A, Rutherford S, Schaffernicht EJ (2015) Exceptional twentieth-century slowdown in Atlantic Ocean overturning circulation. Nat Clim Change. Google Scholar
  47. Robock A, Oman L, Stenchikov GL (2007) Nuclear winter revisited with a modern climate model and current nuclear arsenals: still catastrophic consequences. J Geophys Res Atmos 47:47. Google Scholar
  48. Rodó X, Baert E, Comin FA (1997) Variation in seasonal rainfall in southern Europe during the present century: relationships with the North Atlantic oscillation and the El Niño–southern oscillation. Clim Dyn. Google Scholar
  49. Rowell DP, Folland CK, Maskell K, Owen JA, Ward MN (1992) Modeling the influence of global sea surface temperature on the variability and predictability of seasonal Sahel rainfall. Geophys Res Lett 19:905–908CrossRefGoogle Scholar
  50. Sigró J, Brunet M, Aguilar E (2008) Evolución de la temperatura máxima estival en España. Parte II: Relación con la circulacion atmosferica y la temperatura superficial del mar. In: Sigró, J., Brunet, M., Aguilar, E. (eds), Cambio Climatico Regional y Sus Impactos. Publicaciones de la Asociacion Española de Climatologia (AEC). Serie A, no. 6, pp 319–331 ISBN: 978-84-612-6051-5Google Scholar
  51. The NCAR Command Language (Version 6.1.1) (Software) (2013), UCAR/NCAR/CISL/VETS, Boulder.
  52. Thompson DWJ, Wallace JM, Kennedy JJ, Jones PD (2010) An abrupt drop in Northern Hemisphere sea surface temperature around 1970. Nature. Google Scholar
  53. Turco M, Llasat MC (2011) Trends in indices of daily precipitation extremes in Catalonia (NE Spain), 1951–2003. Nat Hazards Earth Syst Sci. Google Scholar
  54. Turco RP, Toonv OB, Ackerman TP, Pollack JB, Sagan C (1983) Nuclear Winter: global consequences of multiple nuclear explosions. Science. Google Scholar
  55. Turco RP, Toon OB, Ackerman TP, Pollack JB, Sagan C (1984) The climatic effects of nuclear war. Sci Am 251:23–33CrossRefGoogle Scholar
  56. Turco M, Marcos R, Quintana-Seguí P, Llasat MC (2012) Testing instrumental and downscaled reanalysis time series for temperature trends in NE of Spain in the last century. Reg Environ Change. Google Scholar
  57. Vose RS, Easterling DR, Gleason B (2005) Maximum and minimum temperature trends for the globe: An update through 2004. Geophys Res Lett. Google Scholar
  58. Wilks DS (2006) Principal component (EOF) analysis. In: Dmowska R, Hartmann D, Rossby HT (eds) Statistical methods in the atmospheric sciences. International geophysics series. Elsevier, Cambridge, pp 463–508Google Scholar
  59. Zoubir AM, Boashash B (1998) The bootstrap and its application in signal processing. IEEE Signal Process Mag 15:56–76CrossRefGoogle Scholar

Copyright information

© Springer-Verlag GmbH Austria, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Ebro Observatory (OE)CSIC-Ramon Llull UniversityRoquetesSpain
  2. 2.Department of Applied PhysicsUniversity of BarcelonaBarcelonaSpain

Personalised recommendations