Fig. 7: Spatial and regional contributions of temperature-driven PET and precipitation to observed scPDSI trends.
From: Regional responses to oceanic variability constrain global drought synchrony
Panels (A−D) show the percentage contribution of temperature and precipitation to observed changes in monthly self-calibrating PDSI (scPDSI) over two periods: 1961–1990 (A, B) and 1991–2020 (C, D). PET was computed using the Thornthwaite method to isolate the role of temperature alone. Contributions are calculated by comparing scPDSI trends from the observed simulation to two sensitivity experiments: one where precipitation is held fixed at its 1961–1990 climatology (P-CLIM) and another where PET is held fixed (PET-CLIM). Panel (E) summarizes the regional and global average contributions of temperature and precipitation across continents for both time periods These trends are influenced by the evolving balance between temperature-driven evaporative demand and precipitation variability, with the role of temperature increasing after 1990, especially in the mid-latitudes, but precipitation remains the dominant driver globally.
