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I have lightning data that contains individual strikes and their location, time, polarity, amplitude and type (cloud-to-ground, intracloud). I am trying to develop some metrics that will help me assess if a thunderstorm is intense or not. By intense, I mean if it has the potential to generate heavy rain, large hail and strong winds. I plan on using radar reflectivity as my best guess of storm intensity and building a statistical model between the two datasets.

By browsing through the litterature, it seems that a sharp increase in positive cloud-to-ground lightning frequency is a sign of storm intensification to come. I was wondering if there was anything else that I could work with. Is amplitude useful in any way? Is the ratio of IC to CG lightning relevant? Is there another metric I could develop?

Thanks!

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Is the ratio of IC to CG lightning relevant?

Yes. Primarily, severe storms tend to have very few cloud-to-ground (CG) strikes. Thus, the ratio of IC:CG is likely going to be very high.1 2 However, some severe storms do produce a significant amount of positive CG strikes. They would still have a high IC:CG ratio, but they would distinguish themselves by having more positive CG strikes. However, both of these types -- low-CG and some-positive-CG -- are potentially severe.2

It is important to note that the amount of CG strikes can be dependent both on where in the lifecycle a storm is, and the physical location of a storm (CG characteristics appear to be region-dependent). In tornadic supercells, the total amount of lightning seems to decrease during tornadogenesis, and the CG rate appears to increase after the tornadic stage of that supercell ends.3

There doesn't appear to be any existing literature on amplitude as a measure of severity. Perhaps, through this work, you might be able to identify whether this is an area which should be studied further.

References

1 Donald R. MacGorman, Donald W. Burgess, Vladislav Mazur, W. David Rust, William L. Taylor, and Brenda C. Johnson, 1989: Lightning Rates Relative to Tornadic Storm Evolution on 22 May 1981. J. Atmos. Sci., 46, 221–251, doi: 10.1175/1520-0469(1989)046<0221:LRRTTS>2.0.CO;2.

2 Timothy J. Lang and Steven A. Rutledge, 2002: Relationships between Convective Storm Kinematics, Precipitation, and Lightning. Mon. Wea. Rev., 130, 2492–2506, doi: 10.1175/1520-0493(2002)130<2492:RBCSKP>2.0.CO;2.

3 Scott M. Steiger, Richard E. Orville, and Lawrence D. Carey, 2007: Total Lightning Signatures of Thunderstorm Intensity over North Texas. Part I: Supercells. Mon. Wea. Rev., 135, 3281–3302, doi: 10.1175/MWR3472.1.

Further Reading

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