2021-02-23, 23:45
Another issue is the apparent visual size of a multi-stroke lightning flash. The subsequent strokes of a multi-stroke flash are displaced by the wind and give the appearance of a much wider channel - you can see the same effect on photographs.
One of my late Johannesburg colleagues and lightning researcher, Dr. David Proctor, told me a story about this years ago. A researcher moved from England to South Africa and commented that the lightning there was much thicker or wider than in Britain. David was skeptical, because we all now that channel width is a centimeter or two at most and should be the same everywhere. Then, on a European trip, David encountered a British thunderstorm. "The British lightning looked really thin and wimpy" compared to South African lightning, he confirmed. The only difference he noted was that in northern latitudes such as Britain, there are typically fewer strokes per flash than in more equatorial areas, such as South Africa. He postulated the difference in apparent size was due to the movement between strokes, with flashes of high multiplicity appearing much bigger than single-stroke flashes. Having viewed lightning in Britain, South Africa and the USA, I can confirm the apparent size difference and think David's explanation is likely correct.
Mike
One of my late Johannesburg colleagues and lightning researcher, Dr. David Proctor, told me a story about this years ago. A researcher moved from England to South Africa and commented that the lightning there was much thicker or wider than in Britain. David was skeptical, because we all now that channel width is a centimeter or two at most and should be the same everywhere. Then, on a European trip, David encountered a British thunderstorm. "The British lightning looked really thin and wimpy" compared to South African lightning, he confirmed. The only difference he noted was that in northern latitudes such as Britain, there are typically fewer strokes per flash than in more equatorial areas, such as South Africa. He postulated the difference in apparent size was due to the movement between strokes, with flashes of high multiplicity appearing much bigger than single-stroke flashes. Having viewed lightning in Britain, South Africa and the USA, I can confirm the apparent size difference and think David's explanation is likely correct.
Mike
Stations: 1246