Stratospheric Joule heating by lightning continuing current inferred from radio remote sensing

The mean lightning current waveform of particularly intense lightning discharges is inferred from 52,510 radio wave recordings in the frequency range 1–200 Hz. The current waveform decays initially with a time constant of ∼2 ms, and the current lowers ∼60 C from cloud to ground within the first ∼10 ms of the discharge. The subsequent continuing current exhibits a decay time constant of ∼40 ms and lowers ∼170 C from cloud to ground within the next ∼100 ms of the discharge. The total charge transfer ∼230 C from cloud to ground deposits electrical energy into the stratosphere resulting from quasi‐static (Joule) heating. The energy deposition is dominated by the lightning continuing current, and it is ∼10 −5 J/m 3 at 30 km height. It is speculated that the initiation of blue jets and gigantic jets in the stratosphere may result from lightning continuing current ≳100 ms which can be observed with radio waves at frequencies ≲10 Hz.