Journal cover Journal topic
Climate of the Past An interactive open-access journal of the European Geosciences Union
Clim. Past, 11, 825-834, 2015
© Author(s) 2015. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
05 Jun 2015
New insights into the reconstructed temperature in Portugal over the last 400 years
J. A. Santos1, M. F. Carneiro1, A. Correia2, M. J. Alcoforado3, E. Zorita4, and J. J. Gómez-Navarro5 1Centre for the Research and Technology of Agro-Environmental and Biological Sciences, CITAB, Universidade de Trás-os-Montes e Alto Douro, UTAD, 5000-801 Vila Real, Portugal
2Department of Physics and Geophysical Centre of Évora, University of Évora, Évora, Portugal
3Centro de Estudos Geográficos, IGOT, Universidade de Lisboa, Ed. Faculdade de Letras, 1600-214 Lisboa, Portugal
4Institute for Coastal Research, Helmholtz-Zentrum Geesthacht, Geesthacht, Germany
5Climate and Environmental Physics, Physics Institute and Oeschger Centre for Climate Change Research, University of Bern, 3012 Bern, Switzerland
Abstract. The consistency of an existing reconstructed annual (December–November) temperature series for the Lisbon region (Portugal) from 1600 onwards, based on a European-wide reconstruction, with (1) five local borehole temperature–depth profiles; (2) synthetic temperature–depth profiles, generated from both reconstructed temperatures and two regional paleoclimate simulations in Portugal; (3) instrumental data sources over the twentieth century; and (4) temperature indices from documentary sources during the late Maunder Minimum (1675–1715) is assessed. The low-frequency variability in the reconstructed temperature in Portugal is not entirely consistent with local borehole temperature–depth profiles and with the simulated response of temperature in two regional paleoclimate simulations driven by reconstructions of various climate forcings. Therefore, the existing reconstructed series is calibrated by adjusting its low-frequency variability to the simulations (first-stage adjustment). The annual reconstructed series is then calibrated in its location and scale parameters, using the instrumental series and a linear regression between them (second-stage adjustment). This calibrated series shows clear footprints of the Maunder and Dalton minima, commonly related to changes in solar activity and explosive volcanic eruptions, and a strong recent-past warming, commonly related to human-driven forcing. Lastly, it is also in overall agreement with annual temperature indices over the late Maunder Minimum in Portugal. The series resulting from this post-reconstruction adjustment can be of foremost relevance to improve the current understanding of the driving mechanisms of climate variability in Portugal.

Citation: Santos, J. A., Carneiro, M. F., Correia, A., Alcoforado, M. J., Zorita, E., and Gómez-Navarro, J. J.: New insights into the reconstructed temperature in Portugal over the last 400 years, Clim. Past, 11, 825-834, doi:10.5194/cp-11-825-2015, 2015.
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