Using fast-time simulation to assess weather forecast accuracy requirements for air traffic flow management

We present the concept and initial results of using fast-time air traffic simulation modeling to assess requirements for convective weather forecast accuracy from a Traffic Flow Management (TFM) standpoint. For strategic TFM applications with longer lead time (2-8 hours), such requirements can be relaxed compared with tactical (0-1 hours) weather avoidance applications. A gradual increase in forecast error does not always cause commensurate gradual changes in operational costs (e.g. delays) associated with a given TFM action (for example, a ground delay program or strategic reroute) which was implemented based on that forecast. But, while such modest inaccuracies in forecast may not initially require any adjustments to TFM actions, at some point when the discrepancy between forecast and actual weather exceeds a certain threshold, it may prompt a different weather avoidance strategy to be initiated. This, in turn, may cause a significant increase in operational costs. This paper demonstrates how such thresholds, indicative of forecast accuracy requirements for TFM, can be determined using parametric forecast accuracy changes in a series of simulations.