Tuesday, 13 January 2009: 11:45 AM
The complexities of thunderstorm avoidance due to turbulence and implications for traffic flow management
Room 132A (Phoenix Convention Center)
Managing traffic flow in the vicinity of thunderstorms has traditionally been done by avoidance, based in part on FAA guidelines that establish safety buffers around and over thunderstorms. However, recent advances in our understanding of out-of-cloud convectively-induced turbulence (CIT) processes have pointed to deficiencies in these guidelines, and the need for their revision. This talk will review case studies of turbulence encounters near cloud and statistical analyses of the relation of turbulence levels to radar-derived cloud boundaries. It is shown that the CIT formation process is complex, and often due to processes in which the storm itself significantly modifies its environment. This complicates the CIT prediction problem since some of these processes may be subgrid scale relative to standard numerical weather prediction (NWP) model resolutions. Given this state-of-affairs, avoidance guidelines must necessarily be situationally dependent and probabilistic, and could only be reliably provided by automated real-time CIT diagnostic (DCIT) and prediction tools. In the context of air traffic route management, it is clear that these CIT prediction tools must be used in making routing decisions so that the probability of encountering elevated turbulence regions both within and outside the cloud are minimized. In particular, future automated traffic flow management (TFM) systems must account for turbulence hazards within, above and around thunderstorms, in the routing process.