Abstract
Detection and reconstruction of early instrumental series is an interdisciplinary activity that allows us to extend climate data records to periods prior to the mid‐19th century, extending the overlapping periods with climate proxies and characterizing extreme events. In this work, the collection of several data sources corresponding to different periods and locations, obtained with a wide range of methods and instruments by institutions or private observers, provides the following results: Barcelona has a continuous rainfall series with monthly resolution since 1786 and with daily resolution since 1850. It is worth mentioning that the records from Barcelona provide the longest continuous monthly series available on rainfall in the Iberian Peninsula. The monthly records have been homogenized by using a relative homogenization approach, HOMER . The results highlight the existence of five breaks, most of them due to relocations or instrumentation changes documented in the metadata, which have been adjusted to remove non‐climatic factors. The homogenized annual and winter precipitation series in Barcelona show a statistically significant increase from 1786 to 2014, although this increase is mainly due to the concentration of negative anomalies during the first half of the 19th century, which is also clearly visible in the seasonal series. Specifically, an extreme mega‐drought episode was observed from the 1810s to the 1830s, which is supported by different proxy data. For a better dissemination of the homogenized monthly series developed in this study, the data set is freely available to the research community.