1Departamento de Física, Universidad de Extremadura, Badajoz, Spain
2Departamento de Sistemas Físicos, Químicos y Naturales, Universidad Pablo de Olavide, Sevilla, Spain
3Agencia Estatal de Meteorología, Madrid, Spain
4Departamento de Física, Universidad de Extremadura, Mérida, Spain
5Department of Modern History, University of Barcelona, Spain
6Departamento de Geografía, Universidad de Zaragoza, Zaragoza, Spain
7Centro de Estudios del Estado de Feria, Zafra, Spain
Abstract. Among the different meteorological risks, droughts are the ones with the highest socio-economical impact in the Iberian Peninsula. Drought events have been largely studied in the instrumental period, but very little is known about the characteristics of droughts in the preinstrumental period. In this work, new series of rogation ceremonies identify severe droughts within the period 1750–1850. The overlapping of the rogation series with some instrumental series served to identify some climatic characteristics of rogation ceremonies: a) during spring, rainfall deficits needed to celebrate rogation ceremonies are smaller than in any other season; b) when the number of location celebrating rogations increases in a region the hydrological deficit on each location increases as well.
On the other hand, it was found that the periods 1750–1754 and 1779–1783 are probably the driest periods of the 101 analyzed years. Both show an important number of rogations all over the Iberian Peninsula and during all the seasons.
The most extended drought of this period occurred during the spring of 1817, affecting 15 of the 16 locations studied. This drought was influenced by the Tambora eruption (1815). The study of the climate footprint of this eruption and its comparison with similar situations in the series suggest that the spring drought of 1824 may be associated with the eruptions of the Galunggung and Usu volcanoes (1822). Further studies are required to confirm this fact and understand the atmospheric mechanisms involved.