This article describes the development of a monthly
precipitation dataset for the Spanish mainland, covering the period between
December 1915 and December 2020. The dataset combines ground observational
data from the National Climate Data Bank (NCDB) of the Spanish
meteorological service (AEMET) and new data rescued from meteorological
yearbooks published prior to 1951 that were never incorporated into the
NCDB. The yearbooks' data represented a significant improvement of the
dataset, as it almost doubled the number of weather stations available
during the first decades of the 20th century, the period when the
data were more scarce. The final dataset contains records from 11 312 stations, although the number of stations with data in a given month varies
largely between 674 in 1939 and a maximum of 5234 in 1975. Spatial
interpolation was used on the resulting dataset to create monthly
precipitation grids. The process involved a two-stage process: estimation of
the probability of zero precipitation (dry month) and estimation of
precipitation magnitude. Interpolation was carried out using universal
kriging, using anomalies (ratios with respect to the 1961–2000 monthly
climatology) as dependent variables and several geographic variates as
independent variables. Cross-validation results showed that the resulting
grids are spatially and temporally unbiased, although the mean error and the
variance deflation effect are highest during the first decades of the
20th century, when the observational data were more scarce. The
dataset is available at https://doi.org/10.20350/digitalCSIC/15136 under an open license and can
be cited as Beguería et al. (2023)....

MOPREDAScentury: a long-term monthly precipitation grid for the Spanish mainland

10.5194/essd-15-2547-2023