Electrical Structure and Dynamics of a Thunderstorm with Hail in the North-West of the Russian Federation by Three-Dimensional Simulation data

Abstract

A numerical study of thunderstorm development using 3D model is presented. An investigation of evolution features of cloud parameters and spatial distribution of the cloud characteristics during development is carried out. It is shown that maxima of studied parameters (cloud top height, vertical velocities, hydrometeor specific contents, lightning frequency, etc.) are reached at 50 min of simulation. The cloud appears in simulation domain after 26 min of simulation, maxima are reached in 25 min of cloud development. It is shown that most intensive convective processes take place during 50–60 min of simulation and reduce thereafter. Multilayer electrical charge structure is formed in the cloud. A polarity of the cloud inverts shortly after lightning activity beginning and returns back to the structure with main positive charge in the upper part of the cloud at mature stage of Cb development. A coincidence is established between location of regions with main volume charge and regions with highest specific hail content when discharges begin. A predominance of updrafts in velocity field of the studied thunderstorm during development stage is demonstrated. Downdrafts are formed in precipitation regions under the cloud base. At mature stage downdrafts are formed inside cloud and first appears in an anvil.