Analysis of the spatial and temporal properties of rain cells for rainfall modeling purposes

The propagation of electromagnetic waves through the atmosphere at frequencies above 10 GHz is strongly influenced by oxygen, water vapor, clouds and, most importantly, by rain. The scarcity of worldwide reliable rainfall data has pushed towards the development of models that could adequately reproduce real rain fields. This contribution presents a preliminary analysis of some spatial and temporal characteristics of rain cells for rainfall modeling purpose, based on weather radar images collected at the experimental station of Spino d’Adda. Specifically, the work investigates the spatial organization of rain cells, by taking into account their natural aggregative process into more extended structures, as well as the spatial distribution of such clusters on the map. The work also investigates the temporal evolution of real rain cells. A simple cell tracking algorithm is presented, which allows to examine the temporal variation of some fundamental descriptors of the rain cells, such as the area and average rain intensity. The trend of such descriptors is analyzed and modeled both separately and jointly. The results obtained in this study are of key importance in the development of advanced cellular space-time rainfall models that aim to properly reproduce the spatial and temporal features of real rain fields.