Percentage anomaly of annual accumulated precipitation with respect to the normal value

Precipitation data are collected daily from observatories and meteorological stations of different types. These data undergo quality control procedures to ensure spatial and temporal consistency and to eliminate errors. Both the observation and validation processes are carried out in accordance with the international standards established by the World Meteorological Organization. Once the data have been validated, monthly aggregates are calculated for each station. Subsequently, using geographic information systems and spatial interpolation techniques, average aggregates are estimated for each province.