A Numerical Study of the Influence of the Droplets Number Concentration on Supercell Tornadoes

Numerical simulations with the Advanced Regional Prediction System (ARPS) model were performed to investigate the impact of DNC (droplets number concentration) on tornadogenesis in the supercell tornado over Wuwei County, Anhui Province on 8 July 2003. The three different droplets number concentrations were 3000 cm^-3, 1000 cm^-3, and 100 cm^-3. Results showed that features of supercell tornado such as hook echo and V-type inflow gap were found in all experiments. However, the thunderstorm in the high DNC experiment with the strongest updraft and vortex developed first and lasted for a significant time. Four tornado vortices were found in the three numerical experiments. Two cases in the high DNC experiment lasted for nearly 30 min, with a maximum near-surface wind speed of 46.93 m s^-1 and a maximum vortex of 0.42 s^-1. These findings suggest that higher droplets number concentration have a positive effect on the occurrence and development of tornadoes due to the attendant weaker cold pool.