The thunderstorm cloud top height reaches up to ~12–13 km as inferred from lidar measurements on board the CALIPSO spacecraft
Figure 5. The thunderstorm cloud top height reaches up to ~12–13 km as inferred from lidar measurements on board the CALIPSO spacecraft. Above the maximum cloud top height, an ensemble of stratospheric ice particles occurs at ~13–14 km around the tropopause as inferred from temperature measurements during a preceding radiosonde ascent (inset figure). The mixed phase region of the thundercloud is found at ~6–7 km height where ice and water coexist. The convective storm might have entrained dust which is confined to a layer from the ground up to ~5–6 km.
The acceleration of electrons results in observable electromagnetic waves which can be used for remote sensing. Here, we make use of ~4 Hz–66 MHz radio waves emitted by two consecutive intense positive lightning discharges to investigate their impact on the atmosphere above a thundercloud. It is found that the first positive lightning discharge initiates a sprite where electrons are accelerated during the exponential growth and branching of the sprite streamers. This preconditioned plasma above the thundercloud is subsequently exposed to a second positive lightning discharge associated with a bouncing-wave discharge. This discharge process causes a re-brightening of the existing sprite streamers above the thundercloud and initiates a subsequent relativistic electron beam.