SINOPTICA: A project of analysis of hail affectation on Air Traffic Management

The H2020 SINOPTICA Project (2020-2022) aims at exploiting the untapped potential of assimilating remote sensing as well as GNSS-derived datasets and in-situ weather stations data. The main goal is getting very high-resolution, very short-range numerical weather forecasts to improve the prediction of extreme weather events to the benefit of Air Traffic Control (ATC) operations. SINOPTICA weather forecast results will be integrated into ATC decision-support tools, visualizing weather information on the controller's display, and generating 4D trajectories to avoid severe weather areas, including hailstorms. Within this context, the preliminary results of the radar analysis on three hail events affecting Italian airports are presented. The cases have been selected for their relevant impact on the international airports of Milan-Malpensa, Marco Polo-Venice and Bergamo-Orio al Serio. The analysis is based on the mosaic radar images provided by the Italian Civil Protection, which included relevant data such as the top of the clouds, vertically integrated liquid (VIL), and VIL density products. The proposed early warning system distinguish four periods: non-storm alert, pre-alert, alert level 1, alert level 2. The proposed domain to be monitored would have a radius of 75 km from the airport. The storm alert level 2 period would be considered when VIL radar echoes are above 1 mm within an area about 20 km from the airport, considering 1 km2 of spatial resolution and 5 min. of temporal resolution. The storm alert level 1 period start two hours before the alert period, covering an area of 500 km2, with a spatial resolution of 3 km2 and temporal resolution of 15 min. The pre-alert period would correspond to the period between the first appearance of radar echoes on the Italian radar mosaic until the storm alert level 1 period starts. To monitor this period, the proposed spatial resolution is 5 km2 and temporal resolution would be 30 min. for the whole radar mosaic. This procedure would help to identify and track convective storm structures responsible for ATM difficulties. VIL density variable is considered the most suitable candidate to compare the different episodes since they can occur in different seasons. The application of the proposed methodology to the selected cases has shown good ability to efficiently quantify the severity of the thunderstorms. Additionally, various VIL density thresholds have been tested as severity indicators. Maximum VIL density values in the affected region exceed 4 g/m3, however, on some occasions, they exceed 8 g/m3. VIL density showed a weak seasonal dependency with slightly higher values for summer events.