The selection of pixels was carried out in four steps. First,we only
used pixels within a 5-km buffer and within an altitude range
of 100 m around 13 meteorological stations (RAIF and SIVA
Networks, Fig. 1). Then, we used the vegetation map of Andalusia
(scale: 1:10,000, years: 1996e2006) and the land-use information
system of Spain (SIOSE2005 for Andalusia, scale: 1:10,000, years:
2004e2006) to select only those pure pixels at the both maps
that corresponded to scrublands and alpha steppes. For each pure
pixel, we identified the dominant (>90%) lithological substrate
according to the lithological map of Andalusia (scale: 1:50,000,
year: 2004, Spanish Institute for Geology and Mining)