Wind Speed Forecasting from 1 to 30 Minutes

Summary The long lifetime and high intensity of vortex trails generated by landing large-capacity aircraft may cause a risk to subsequently landing planes. A wake vortex warning system can help to avoid such hazards by forecasting the time intervals permitting safe operation on the landing strip. This information provides the basis for an appropriate landing schedule based on reduced succession distances. An essential element of the warning system is the prediction of wind across the landing strip and this is commonly determined by a method based on the principle of persistence. This study shows that autoregressive (AR) modelling can improve the accuracy of crosswind forecasts. To this end, the measurements are analysed in order to estimate model parameters. Unlike the more simplistic previously used method, AR forecasting, as part of the vortex trail warning system, allows longer intervals for safe operation and can avoid forecast discontinuities (leaps) which are inherent problems of all forecasts in which boundary layer processes have to be considered. Received June 10, 1997 Revised October 6, 1997