# A 3D Numerical Model to Estimate Lightning Types for PyroCb Thundercloud
## 3 Simulation Results and Discussion
### Impact of Wind Shear on PyroCb Thundercloud  
To examine the consequences of wind shear on a pyroCb thundercloud and how the displacement of its charge layers influences potential lightning strike areas, the parameters \(x_{0n}\) and \(r_{xn}\) of both SC and UP charge layers are altered while keeping the MN and LP charge structures the same as configuration 2 in Table 1. The vertical cross-sectional view in Figure 7 illustrates how strong wind shear displaced the charge layers in pyroCb \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \(r_{x}\) **and \(r_{y}\)** & \(r_{z}\) **of LP** & **Charge of LP** & **Range of \(x\)** & **Polarity of \(\sigma\)** & **Peak** & **Probable** \\ **of LP (km)** & **(km)** & **LP (C)** & **and \(y\) (km)** & **\(\sigma\)** & **Value of \(\sigma\)** & **Lightning** \\ \hline \hline \multirow{4}{*}{3} & \multirow{4}{*}{1} & \multirow{4}{*}{18} & 3.5 \(\leq\text{x}\leq\) & \multirow{4}{*}{Positive} & 0.2087 & \multirow{4}{*}{\(-\)CG} \\  & & & 26.5 km, & & & nC/m\({}^{2}\) at & \\ \cline{1-1} \cline{4-5}  & & & 3.5 \(\leq\text{y}\leq\) & 26.5 km & & \(x=14\), 14.5 & \\ \cline{1-1} \cline{4-5}  & & & & 26.5 km & & \(\leq\text{y}\leq\) & \\ \hline \hline \multirow{2}{*}{4} & \multirow{2}{*}{1.2} & \multirow{2}{*}{30} & \multirow{2}{*}{\(0\leq x,y\leq\) 30 km} & \multirow{2}{*}{Negative} & 0.2454 nC/m\({}^{2}\) & \multirow{2}{*}{\(+\)CG} \\  & & & 30 km & & & at \(x,y=15\) km & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Possible lightning categories for simulated pyroCb thundercloud with tripole charge configuration. Figure 6: Plots of surface charge density \(\sigma\) for: (**a**) configuration 1 and (**b**) configuration 2 to identify probable CG lightning types in pyroCb thunderclouds. Detailed views of the temporal changes in \(\sigma\) on Earth’s surface (_xy_ plane) are presented for two tripole charge configurations. thunderclouds, causing an impact on the overall distribution of thundercloud-generated potential and electric field (see Figure 8). In Figure 7a-c, the extension parameter \(d\) is varied by 2, 4, and 8 km, respectively, while maintaining the value of \(\rho_{n}(0)\) constant to ensure the overall charge of the affected charge regions remains constant. With the wind shear extension in the SC and UP regions, growth in negative potential is observed, particularly in the middle region of the pyroCb thundercloud, as depicted in Figure 8(a1-a3). Furthermore, the magnitude of the electric field (Figure 8(b1-b3)) within the thundercloud decreases with the rightward lateral extension of SC and UP charge layers, aligning with the principles of the electrostatic field. Figure 9(a1-a3) and Figure 9(b1-b3) depict the variations in the electric potential \(V\) (measured at maximum field point) and longitudinal electrical field \(E_{z}\) at the thundercloud's core with the effect of wind shear extension. Figure 9(a1-a3) shows that as the UP charge layer shifts horizontally, the maximum potential decreases gradually, whereas the minimum potential experiences a concurrent rise. Consequently, the point at which discharge initiation occurs shifts negatively. The potential at the initiation point of the lightning flash is 178.81 MV for \(d=2\) km as seen in Figure 9(a1). Then, a noticeable change in the potential value at the point of flash initiation becomes evident with an increase in the value of \(d\) and ends up at \(-64.07\) MV for \(d=8\) km (Figure 9(a3)). Moreover, the extension of wind shear leads to a reduction in the absolute peak value of the vertical field at the top, while it increases the absolute peak value of the vertical field at the bottom of the pyroCb thundercloud as observed in Figure 9(b1-b3). For various values of extension parameter \(d\), the fluctuations in the simulated surface charge density \(\sigma\) on the ground surface beneath the pyroCb thundercloud are illustrated in Figure 10a-c.