A simple guide to predicting aircraft spray drift

A sensitivity analysis has been performed on a simple Gaussian Diffusion Model used to predict spray drift deposition from agricultural aircraft at far wake distances. It is intended that the model be used as a training tool to demonstrate clearly the basic effects of windspeed, turbulence intensity, release height, droplet size and uniformity on far downwind spray drift deposition i.e. at distances greater than 50 m. Overlapping the model outputs has also provided a useful benchmark against which experimentally obtained spray drift values may be compared. This information has assisted in the preparation of guidelines regarding required buffer zone distances and the best ways in which aircraft pesticide spray drift can be effectively reduced and managed.