Journal cover Journal topic
Climate of the Past An interactive open-access journal of the European Geosciences Union
Clim. Past, 8, 353-371, 2012
https://doi.org/10.5194/cp-8-353-2012
© Author(s) 2012. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
29 Feb 2012
Early Portuguese meteorological measurements (18th century)
M. J. Alcoforado1, J. M. Vaquero2,3, R. M. Trigo3,4, and J. P. Taborda5 1Centro de Estudos Geográficos, IGOT, Universidade de Lisboa, Lisbon, Portugal
2Departamento de Física, Universidad de Extremadura, Mérida, Spain
3CGUL, Instituto Dom Luiz (IDL), Lisbon, Portugal
4Departamento de Eng. Civil da Universidade Lusófona, Lisbon, Portugal
5Escola Secundária Gabriel Pereira, Évora, Portugal
Abstract. Natural proxies, documentary evidence and instrumental data are the only sources used to reconstruct past climates. In this paper, we present the 18th century meteorologists (either Portuguese or foreigners) who made the first observations at several sites in Continental Portugal, Madeira Island and Rio de Janeiro (Brazil), from 1749 until 1802. Information is given concerning observation site, variables observed, measurement period, methods of measurements and sources (both manuscript and printed). Some examples from the data usefulness are given: rainfall variability in Madeira (1749–1753) and in continental Portugal (1781–1793) was reconstructed, allowing to extend towards the late 18th century the well known negative correlation between the NAO index and seasonal rainfall. Furthermore, previously unpublished data for 1783–1784 have allowed analysing the consequences of the Lakagígar eruption in Portugal: foggy and haze days are referred to in summer 1783, but unlike the hot summer observed in northern and central Europe, temperatures in Portugal were lower than average. Additionally, observations from Rio de Janeiro in Brazil show that the Lakagígar consequences may well have spread to sectors of the Southern Hemisphere. Although the series are short, the data have been used for climate reconstruction studies and may also be useful to improve the quality of large scale reconstruction datasets.

Citation: Alcoforado, M. J., Vaquero, J. M., Trigo, R. M., and Taborda, J. P.: Early Portuguese meteorological measurements (18th century), Clim. Past, 8, 353-371, https://doi.org/10.5194/cp-8-353-2012, 2012.
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