Detectable anthropogenic influence on the changes in structure of precipitation over China using CMIP6 models

Abstract In the context of global warming, both droughts and extreme precipitation events occur frequently over China. Precipitation, being a major driving factor and a crucial component of the water cycle, is highly sensitive to the human activities. This study uses high-resolution gridded daily precipitation, categorizing precipitation into 20 equal intervals, to analyze the changes in precipitation structure across the region. The investigation reveals a significant transition from light to heavy precipitation in China from 1961 to 2014, characterized by a notable decrease in light precipitation and a substantial increase in heavy precipitation. Employing the latest generation of CMIP6 models, it is found that the models can accurately replicate this change, with GHG forcing exacerbating this trend, particularly noticeable, whereas results under AER forcing are contrary to observational outcomes. Simultaneously, the study notes that CMIP6 models exhibit limitations in simulating the spatial distribution of trends in light precipitation but perform well in reproducing the trend pattern for heavy precipitation. Attribution results suggest that the observed shift from light to heavy precipitation is predominantly a result of the combined influence of GHG and AER forcing. However, significant regional variations exist in this transition. In the future, this transition is expected to persist, with heavy precipitation showing a more pronounced increasing trend.