ERA5–Drought: Global drought indices based on ECMWF reanalysis

Droughts are increasingly intensified by human-induced climate change and pose a growing threat to society. Thus, enhancing our capabilities to monitor drought occurrence and intensity is crucial. This paper introduces a new dataset of drought indices derived from the 5th generation ECMWF reanalysis system (ERA5), which offers long-term monitoring of the global climate in both deterministic and probabilistic forms. This global dataset is freely accessible through an ECMWF-hosted data store, and it entails two prominent drought indices: the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI). Both indices are calculated over a range of accumulation periods from 1 month to 4 years and are available for the full ERA5 climatology from 1940 to today. It also contains validation data that indicates the quality of these drought indices. The ERA5-Drought dataset serves as a valuable tool for environmental agencies and supports sectors such as water management and agriculture, thus contributing to efforts that monitor water and food security.