With the upgrading of geostationary meteorological satellites, their capabilities in Convective Initiation (CI) identification have been enhanced. To improve the applicability of the ARGI-based CI algorithm in central and eastern China, this study uses Fengyun-4A data, integrates radar and precipitation data to construct a TrueCI dataset, and defines FalseCI events (satellite-identified events without radar or precipitation signals) for comparative analysis. The results show that TrueCI events tend to have longer durations, larger cloud cluster areas, and lower central cloud-top brightness temperature (BT) during development. It exhibits distinct features such as reduced differences between water vapor and infrared channels, increased cloud optical thickness, and ice-phase transformation 30 minutes before CI occurrence—features absent in FalseCI events. Based on these comparisons, a new CI definition on satellite cloud imagery is proposed, and a set of reference thresholds is formulated, targeting cloud-top cooling, increased optical thickness, and ice-phase transitions. The evaluation of the DefinedCI events (defined using the CI definition) via TrueCI events indicates that the CI definition on satellite cloud imagery proposed in this study is reliable, and suggests that further research on the pre-CI environmental conditions of weak convection is needed. Supported by hyperspectral data or numerical model products, such research will help clarify which cloud clusters are prone to developing into convective weather.
Peng et al. (Wed,) studied this question.