Spatiotemporal variability in annual drought severity, duration, and frequency from 1901 to 2020

Drought is currently one of the most severe natural disasters affecting the world. Therefore, characterizing the temporal and spatial characteristics of droughts is critical to managing drought disasters and coping with global climate change. In this study, we apply the ensemble empirical mode decomposition (EEMD), empirical orthogonal function (EOF) decomposition, and the drought event division method of run theory to analyze the temporal and spatial characteristics of meteorological droughts across the globe from 1901 to 2020 using the self-calibrated Palmer drought severity index (scPDSI). We found that the world was gradually becoming wetter from 1901 to 2020, but the severity and duration of severe and extreme drought events also increased. In contrast to the PDSI, which showed no obvious short-period changes, the annual drought severity (ADS) had short cycle changes of 8 and 17 yr. Based on the EOF decomposition results of drought characteristics, dry and wet trends of local PDSI are inconsistent with increasing or decreasing trends of severe and extreme drought events. This research on the temporal and spatial decomposition of severe and extreme drought events provides a new perspective on drought research and analysis, which is critical for the further characterization of drought and the prevention and management of drought disasters.