Spatio-temporal characteristics of meteorological drought based on the MCI of Penman–Monteith

The increasing global climate change has resulted in more frequent drought disasters, and using the drought index to assess spatial and temporal changes accurately is of practical importance. In this study, the Spatio-temporal evolution characteristics of different drought indicators at annual and seasonal scales were analyzed by combining spatial interpolation, correlation analysis, trend tests, and the empirical orthogonal function based on the meteorological drought composite index (MCI) of Penman–Monteith. The study focused on drought research in the Pearl River basin from 1961 to 2020. The results indicated that (1) on the annual scale, drought exhibited a high spatial distribution in the west and low in the east, as well as high in the south and low in the north. The frequency, intensity, and extent displayed a non-significant decreasing trend, with the drought degree being mild in the past ten years. (2) On the seasonal scale, drought exhibited seasonal variability, particularly in spring and autumn, which were inversely distributed. Summer drought was the least severe, with the drought range mostly below 10%, while winter drought was the severest, exceeding 50%, indicating an areawide drought. (3) The consistent change of drought intensity across the basin is the primary mode, and the reverse distribution of east–west and north–south is the secondary mode. The overall higher year of drought intensity is close to 24 years, and the overall lower year is close to 28 years. The study based on the MCI can provide a reference for drought research and management in different regions.