The Adverse Weather Diversion Model DIVMET – Concept and Applications

A new model approach DIVMET is presented which provides safe and short aircraft trajectories through a field of thunderstorms. The latter are given as 2-dimensional polygons on a flight level and are considered as no-go-zones for any aircraft. Adverse weather is in general considered as dynamic with radar-based update rates of 5 – 15 minutes. DIVMET proposes for each given planned route an alternative route which keeps a safety distance of typically 10 NM to each storm cell and which tries to minimize the additional detour. A conventional pathfinder algorithm based on a convex hull approach is used. DIVMET has various options to account for (i) various safety distances to study the safety-cost relationship, (ii) varying the assumed conical field of view to investigate the hypothesized beneficial information-cost relationship, respectively varying the receding horizon, ranging from a purely radar based field of view to a “God's” view of unlimited knowledge, (iii) varying the hazard recognition response time to clarify the role of a wait-and-see attitude, (iv) varying the risk acceptance of a pilot when flying between two storm cells. Results of various applications are shown: (1) coupling of DIVMET with a traffic model during a squall line passage over central EUROPE in July 2010, (ii) modeling the ATC sector occupancy workload during that event, (iii) controller assistance for guiding aircraft through a thunderstorm field during approach. Future work will focus on safe and efficient trajectory generation within the SESAR framework.