Natural proxies, documentary evidence and instrumental data are the main sources used to reconstr... more Natural proxies, documentary evidence and instrumental data are the main 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, methodologies 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 Furthermore, previously unpublished data for 1783-1784 has allowed analysing the consequences of the Laki eruption in Portugal: foggy and haze days are referred to in summer 1783, but unlike the hot summer observed in ...
Resumo-As observações meteorológicas instrumentais, em Portugal, têm início nos anos 70 do século... more Resumo-As observações meteorológicas instrumentais, em Portugal, têm início nos anos 70 do século XVIII. O clima de Portugal anterior àquela década tem vindo a ser reconstituído exclusivamente com base em fontes documentais descritivas, em que, de um modo geral, são os extremos climáticos que surgem registados. Dada a subjectividade que este tipo de informação encerra, a análise crítica do maior número de fontes possível é um procedimento essencial. Analisa-se aqui o temporal ocorrido em grande parte do território de Portugal continental, entre 3 e 6 de Dezembro de 1739. À violência do vento do quadrante Sul, que pelos efeitos relatados poderá ter atingido velocidades da ordem dos 120km/h, associaram-se chuvas contínuas e intensas, que originaram cheias nas bacias dos rios Tejo, Mondego e Douro. Os prejuízos foram muito avultados, havendo referências à perda de vidas humanas e à morte de muitos animais. Tal como na actualidade, também no passado estes episódios de ventos fortes e de chuvas intensas ocorreram em situação de fluxo do quadrante Sul.
The year 1816 was characterized by unusual weather conditions, in particular, by a cold and wet s... more The year 1816 was characterized by unusual weather conditions, in particular, by a cold and wet summer season ('year without a summer') on both the European and North American continents. The eruption of Tambora, an active stratavolcano, on the Island of Sumbaya (Indonesia) in April 1815 has been identified as the main driving force for the strong 1816 temperature anomaly. This climate anomaly has been relatively well studied in central Europe, France, Scandinavia and the United Kingdom. The unusual unsettled weather and climate at mid-latitudes in 1816 and 1817 had major socioeconomic impacts, particularly in terms of a poor yield of agricultural production, malnutrition and consequentially an increased potential for diseases and epidemics. The Iberian Peninsula was also affected by the intense climate anomalies during those years. Documentary sources describe the impact that the cold and wet summer of 1816 had on agriculture, namely the bad quality of fruits, delayed ripening of vineyards and cereals.
Natural proxies, documentary evidence and instrumental data are the main sources used to reconstr... more Natural proxies, documentary evidence and instrumental data are the main 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, methodologies 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 has allowed analysing the consequences of the Laki eruption in Portugal: foggy and haze days are referred to in summer 1783, but unlike the hot summer observed in ...
Resumo-As observações meteorológicas instrumentais, em Portugal, têm início nos anos 70 do século... more Resumo-As observações meteorológicas instrumentais, em Portugal, têm início nos anos 70 do século XVIII. O clima de Portugal anterior àquela década tem vindo a ser reconstituído exclusivamente com base em fontes documentais descritivas, em que, de um modo geral, são os extremos climáticos que surgem registados. Dada a subjectividade que este tipo de informação encerra, a análise crítica do maior número de fontes possível é um procedimento essencial. Analisa-se aqui o temporal ocorrido em grande parte do território de Portugal continental, entre 3 e 6 de Dezembro de 1739. À violência do vento do quadrante Sul, que pelos efeitos relatados poderá ter atingido velocidades da ordem dos 120km/h, associaram-se chuvas contínuas e intensas, que originaram cheias nas bacias dos rios Tejo, Mondego e Douro. Os prejuízos foram muito avultados, havendo referências à perda de vidas humanas e à morte de muitos animais. Tal como na actualidade, também no passado estes episódios de ventos fortes e de chuvas intensas ocorreram em situação de fluxo do quadrante Sul.
The year 1816 was characterized by unusual weather conditions, in particular, by a cold and wet s... more The year 1816 was characterized by unusual weather conditions, in particular, by a cold and wet summer season ('year without a summer') on both the European and North American continents. The eruption of Tambora, an active stratavolcano, on the Island of Sumbaya (Indonesia) in April 1815 has been identified as the main driving force for the strong 1816 temperature anomaly. This climate anomaly has been relatively well studied in central Europe, France, Scandinavia and the United Kingdom. The unusual unsettled weather and climate at mid-latitudes in 1816 and 1817 had major socioeconomic impacts, particularly in terms of a poor yield of agricultural production, malnutrition and consequentially an increased potential for diseases and epidemics. The Iberian Peninsula was also affected by the intense climate anomalies during those years. Documentary sources describe the impact that the cold and wet summer of 1816 had on agriculture, namely the bad quality of fruits, delayed ripening of vineyards and cereals.
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Papers by João Taborda