Skill of an Aircraft Wake-Vortex Model Using Weather Prediction and Observation

The performance of the two-phase probabilistic wake-vortex transport and decay model using numerical weather prediction and weather observations as input is analyzed using data from a wake measurement campaign carried out at Frankfurt airport during fall 2004. The wake-vortex observations include wakes evolving in and out of ground effects. The best forecast quality is achieved for wakes evolving in ground effect. We include the simplified hazardarea prediction model to compute the time to clear the corridor from hazardous wakes and to assess the potential capacity gain for single-runway operations. The highest-capacity potential can be expected when weather observations are employed for wake predictions. The limiting factor for capacity are wakes evolving in ground effect. Out of ground effect, the self-induced vertical transport of the wake vortex proves to be a robust mechanism to clear the approach corridor in an efficient way. This is found independently from the source of meteorological input. In contrast, the consideration of lateral wake transport alone leads to marginal-capacity potential. The analysis also shows that weather data along the glide path can be provided by numerical weather prediction for safe wake prediction.