Abstract. In the northeast of the Iberian Peninsula, few studies have reconstructed
drought occurrence and variability for the pre-instrumental period using
documentary evidence and natural proxies. In this study, we compiled a
unique dataset of rogation ceremonies – religious acts asking God for rain –
from 13 cities in the northeast of Spain and investigated the annual
drought variability from 1650 to 1899 CE. Three regionally different
coherent areas (Mediterranean, Ebro Valley, and Mountain) were detected. Both
the Barcelona and the regional Mediterranean drought indices were compared
with the instrumental series of Barcelona for the overlapping period
(1787–1899), where we discovered a highly significant and stable correlation
with the Standardized Precipitation Index of May with a 4-month lag
(r=-0.46 and r=-0.53; p<0.001, respectively). We found common
periods with prolonged droughts (during the mid and late 18th century)
and extreme drought years (1775, 1798, 1753, 1691, and 1817) associated with
more atmospheric blocking situations. A superposed epoch analysis (SEA) was
performed showing a significant decrease in drought events 1 year after
the volcanic events, which might be explained by the decrease in
evapotranspiration due to reduction in surface temperatures and,
consequently, the higher availability of water that increases soil moisture.
In addition, we discovered a common and significant drought response in the
three regional drought indices 2 years after the Tambora volcanic
eruption. Our study suggests that documented information on rogation ceremonies
contains important independent evidence to reconstruct extreme drought
events in areas and periods for which instrumental information and other
proxies are scarce. However, drought index for the mountainous areas (denoted Mountain later in the text) presents
various limitations and its interpretation must be treated with caution.