The use of radar information for improving the knowledge about landslides and floods events: an application to Calabria region (Italy)

Floods and landslides are common natural phenomena that threaten society and ecosystems causing significant losses in term of human lives and financial damages. An in-depth investigation about the past occurrences of these events is of paramount importance for providing advances in the knowledge of natural and anthropogenic factors responsible for their generation. Considering rainfall as one of the key drivers for triggering physical mechanisms responsible for the occurrences of floods and landslides, a proper description of its characteristics needs to contemplate the intrinsic spatial and temporal variability. Despite the importance of such elements, rainfall monitoring often relies on sparse rain gauges, which lead to uncertainty in the identification of real rainfall patterns, making difficult to link precipitation records with observed damages. Meteorological radar represents a relevant tool for detecting rainfall spatiotemporal variability and providing ancillary information about the evolution of the events.

Goal of the work is to develop a methodology that aims in reconcile records of landslides and floods events with the rainfall structures obtained by the joint use of data recorded by rain gauge network and radar data. The research has been carried out by moving from a consolidated catalogue of damaging events occurred in correspondence of floods and landslides in Calabria region (Italy) in 2019 and 2020. Rainfall was investigated integrating rain gauge data and maps of Surface Rainfall Intensity with resolution of 1x1 km².

Exploiting the availability of an accurate spatiotemporal reconstruction of precipitation structures, our investigation allowed to improve the specific knowledge about dynamics responsible of selected floods and landslides events. Preliminary results are supportive of the use of the proposed approach for integrating different sources of information in the assessment of the real dynamics of damaging events and for enhancing the use of their joint scientific content in the framework of risk assessment and mitigation.