In all the explanations of how global electric circuit on Earth works, I've always encountered statements like "thunderstorms generate ionospheric potential" (which is about 250 kV). E.g. here: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2009JA014758

But how is that possible? Thunderstorm (or, more specifically, a lightning strike) is inherently a discharge rather than a generator. It's the breakdown of an abstract capacitor rather than the charging of it. For all intents and purposes, thunderstorms should reduce any potential difference that exists around them rather than sustain it.

Can somebody explain, what actually drives the upward current that is observed above thunderstorms? Surely it cannot be lightning itself, so what then?

(I'm perfectly aware that there is also a downward current in fair weather; but the same question remains - where is the generator that causes it?)

  • $\begingroup$ The lightning strike is the result of generating too much potential during thunderhead development and evolution. The thunderhead builds the potential, and some may be discharged. $\endgroup$ – Jon Custer Sep 12 at 23:14
  • $\begingroup$ Thank you. That is perfectly understandable. But that doesn't explain the upward current in and above the thunderstorms, which is what I'm asking about. $\endgroup$ – Eugene B. Sep 12 at 23:20
  • $\begingroup$ Have you noticed that thunderheads grow upwards? Earth Sciences may be a better place to ask about specifics of thunderstorm environments, growth, etc. $\endgroup$ – Jon Custer Sep 12 at 23:27
  • $\begingroup$ Start with, e.g., earthscience.stackexchange.com/questions/1011/… $\endgroup$ – Jon Custer Sep 12 at 23:29
  • $\begingroup$ OK, thanks. I didn't know of its existence. I'll repeat my question there. $\endgroup$ – Eugene B. Sep 12 at 23:33

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