Abstract
Researching future changes in rainfall variability is critical to mitigating the possible effects of global warming, especially in areas where vulnerability is higher, such as South Asia. While changes in mean and extreme rainfall have received a great deal of attention, rainfall variability has received very little research, despite its substantive importance. This study endeavors to delve into the anticipated modifications in rainfall variability during the mainland Indochina southwest monsoon (MSWM) utilizing data derived from five ensemble models participating in the Coupled Model Inter-comparison Project Phase 6 (CMIP6). Employing band-pass filtering techniques on daily rainfall data, we discerned variability across an expansive spectrum of temporal scales. Our research indicates that, in the event of global warming, MSWM rainfall variability is expected to increase by roughly 10–25% throughout the whole region. Notably, this increased unpredictability appears uniformly throughout a wide range of time intervals. We find that changes in average rainfall significantly aid in explaining the majority of intermodel variances in the predicted MSWM rainfall variability. In order to get further insight into this phenomenon, we examine the effects of elevated atmospheric moisture content through the estimation of modifications resulting from an idealized local thermodynamic enhancement. We show that the increased atmospheric moisture, as suggested by the connection between Clausius and Clapeyron, accounts for most of the predicted changes in rainfall variability at all-time scales.