During recent years, severe droughts and floods have caused billions of dollars in property damage within China, and other countries.Changes in extreme weather and climate events have significant impacts and are among the most serious challenges to society in coping with a changing climate.Many extremes and their associated impacts are now changing, and heavy downpours have become more frequent and intense.The increase in heavy precipitation events is associated with an increase in water vapor, and the latter has been attributed to human-induced warming.Climate models are important tools for understanding the causes of observed changes in extremes, as well as projecting future changes.However, most GCMs simulation of extreme events is problematic due to the limitation of resolution, imperfect representation of sub-grid scale processes and lack of realistic amplitude of natural variability given the model tuning being focused on getting the mean and simple standard variation correct.In the future, with continued global warming, severe droughts and heavy downpours are very likely to further increase in frequency and intensity.To help climate modelers to improve their future prediction in extreme events, we will investigate the variability of regional hydrological extremes over China across the intraseasonal to inter-decadal time scales, and identify the linkage between changes in the characteristics of these extremes (e.g., frequency, duration, intensity and sequencing), clouds, radiation, atmospheric variables, and the regional climate change from widely used datasets (e.g., PDSI, GPCP, MERRA, etc).Furthermore, we will investigate how these trends are associated with changes of clouds, radiation and other atmospheric variables, and to what extent the regional extremes are associated with various climate/weather phenomena, such as monsoon systems and teleconnections.An improved understanding of these key processes will ultimately contribute to advances in the simulation, prediction and projection of extreme events with both regional and global climate models.Eventually, this study will translate better observations and improved understanding of hydrological extremes into practically relevant information for multiple stakeholders in sectors such as agriculture, energy, water resource and risk management.