Recognition of multi-scale processes and a physical model for extreme rainfall mechanisms in North China and the Huanghuai region

In recent years, extreme rainfall events such as the "21·7" Henan and "23·7" Beijing-Tianjin-Hebei storms have frequently impacted North China and the Huanghuai region (North China-Huanghuai region). These events exposed significant gaps in our understanding of their physical mechanisms. This article summarizes recent researches on spatial-temporal features, synoptic patterns, mesoscale convective systems (MCSs), and microphysical structures of extreme rainfall. By combining multi-source observations and model simulations, the study highlights the multiscale processes—from large-scale circulation to microphysics—that jointly shape rainfall intensity. A multiscale pattern recognition method is proposed to improve the identification of extreme events. Two distinct MCS types—warm-type and deep-convective-type—are characterized, especially in terms of raindrop spectra and hydrometeor composition. A multiscale conceptual model tailored to North China is presented, offering insights to improve forecasting and model representation of extreme rainfall processes.