Spatio-temporal Characteristics of Meteorological Drought based on the MCI of Penman-Monteith

Abstract The severity of global climate change is increasing, resulting in more frequent occurrences of drought disasters. Accurate evaluation of Spatio-temporal changes in drought using drought indices is of significant practical importance. This study employed the MCI based on Penman-Monteith, in combination with Kriging spatial interpolation, linear trend analysis, Mann-Kendall mutation test, and the EOF analysis to analyze annual and seasonal variations of different drought level days, drought station ratio, drought impact range, and drought cumulative intensity, and to study their interrelationships. The focus of this article is on the Spatio-temporal characteristics of meteorological drought in the Pearl River Basin over the past 60 years. The findings indicate that the annual average number of drought days exhibits a decreasing trend from the central to the eastern and western parts of the basin, with the western region experiencing more drought days than the eastern region. Furthermore, the highest frequency of drought occurs in winter, followed by spring and autumn, while summer experiences the lowest frequency. Additionally, there is a positive correlation between the drought impact range and drought cumulative intensity. Based on the EOF decomposition, the drought cumulative intensity can be primarily divided into two modes, the drought consistently changes throughout the entire basin, and the wet-dry distribution is opposite in the western and eastern parts. Studying the drought conditions in the Pearl River Basin based on the MCI can not only provide reference for drought research in different regions of the world but also provide a scientific basis for global climate change response and drought management and forecasting.