Combined Modification of Urbanization and Monsoon in Meiyu Precipitation Changes in the Megacity Shanghai, China

The Meiyu season is a typical rainy in East Asia that controlled by summer monsoon. Despite extensive research on its impact, it unclear how urbanization modifies precipitation during the background of monsoon influence. To address this gap, study investigated effects and modification (PDM) megacity Shanghai, China. Through homogenization analysis original observational data, we assessed temporal spatial variation PDM Shanghai two stages urbanization. Our findings revealed both total extreme daily have significantly increased since 1961. heterogeneity has also enhanced rapid urban process occurred 1986. long-term trend increasing showed synchronous with Asian subtropical (EASM) 1961–2021. Over interannual time scale, significant positive correlation between EASM slow period (Stage 1: 1961–1985) changed to non-significant 2: 1986–2021), which was associated convective season. Urbanization induced more further weakened association over central city nearby areas Stage 2. resulted differences near-surface wind non-urban areas, facilitated due friction effect shear Furthermore, our suggests increase may be coupling cold air intrusion warmer climate heat occurring These contribute better understanding monsoons affect megacities serve as unique reference for prediction region.