GDO Standardized Precipitation Index MERRA, 48-month accumulation period (SPI-48) (version 1.0.0)

The 48-month Standardized Precipitation Index (SPI-48) is an indicator used to monitor meteorological drought based on precipitation anomalies over 48-month accumulation periods. SPI-48 serves as a proxy indicator for long-term impacts, such as reduced reservoir and groundwater recharge. The input data for calculating the SPI-48 is MERRA (Modern-Era Retrospective analysis for Research and Applications) global precipitation, provided by the USA NASA (National Aeronautics and Space Administration) GMAO (Global Modeling and Assimilation Office).