Fig. 4: N_d estimates from T2 lidar observation.

a The threshold ratio χ vs. height based on Fig. 1c. The white-gray boundary indicates the estimated cloud base height where the rate of increase in χ with height is maximized. The red dots for χ between 0.5% and 50% are used to independently estimate n_d via Eq. (12). b Best fitted curve suggests n_d ≈ 120 cm⁻³. The gray region indicates ±30 cm⁻³ from the best fit, where the upper bound associates with smaller n_d.