Coupling and coordination of rainfall erosivity and aerosols in the Pearl River Basin under multiple shared socio-economic pathways

Aerosols can influence the size, quantity, and other characteristics of raindrops, subsequently altering the precipitation pattern and modifying rainfall erosivity (RE). To explore the relationship between RE and aerosols, this study analyzed the spatiotemporal distribution characteristics of RE and aerosols in the Pearl River Basin. Utilizing GPM rainfall data from 2001 to 2022, future 100-year rainfall prediction data, and aerosol data, the study investigated the potential relationship between these indicators. The findings are as follows: (1) RE exhibited a spatial distribution decreasing from southeast to northwest, showing a declining trend; Aerosol Optical Depth (AOD) demonstrated a similar decreasing spatial distribution and trend. (2) RE and AOD displayed a highly significant positive correlation, with a coordinated distribution within the basin, as indicated by a multi-year average coupling coordination index of 0.7054. (3) Over the next century, RE in various scenarios remained lower than current RE and exhibited a highly significant negative correlation with current AOD. (4) Aerosol particle size emerged as the most significant indicator correlated with RE, and among all RE indicators, rainfall quantity exhibited the strongest correlation with aerosols. (5) RE for rainfall across all magnitudes demonstrated a highly significant correlation with aerosols, with the strongest correlation observed in heavy rain. This study unveils the interrelationship between RE and aerosols, providing a theoretical basis for land managers and governments to formulate measures aimed at reducing the impact of rainfall erosion on farmland and ecosystems.