On the search for a representative drag coefficient law to be used in hail trajectory simulations

A new method to calculate the ice particle drag coefficient used in hailstone trajectory calculations is presented. The method takes into account the high variability of this parameter and also allows for the investigation of the different trajectories that equally initialized embryos may follow within a cloud due to non-deterministic changes in their surface texture. The method is applied in a hail trajectory simulation model. The results are compared with those obtained by means of curves fitted to the drag coefficient going through mean, low and high values. The aim of this work is to investigate the representativity of hail trajectories simulated using these curves for the assessment of the drag coefficient value.