Summer Surface Rainfall Deviations From Convective Cold‐Cloud Shields Over China

Abstract The surface rainfall regions of convective systems do not always align spatially with the overlying cold‐cloud shields, posing challenges to satellite quantitative precipitation estimates. A novel index of convective rainfall deviation is defined in this study to quantify the spatial discrepancy between surface rainfall and cold‐cloud shields, utilizing the FY‐4A brightness temperature data and surface rainfall observation data from across China. The results show that systems with larger deviations are more prevalent in southern China. For small‐deviation systems, surface rainfall closely coincides with the coldest center of the cloud shields. However, in medium‐deviation systems, rainfall occurs southwest of the coldest center, with relatively expanded but weakened rainfall beneath the cloud shields. Retaining a pronounced southwestern deviation signature, large‐deviation systems also present a secondary northeastern rainfall center. This complex spatial pattern is associated with increased cloud tilting driven by the configuration of environmental updrafts and low‐level southwesterly wind shears.