Tracking Lightning - how do news stations show lightning strikes?

[spidey07]

I'm talking about the local news thunderstorm coverage. They brag about "storm tracker" radar or whatever system they have/use/promote. Then they show actual lightning strikes as small icons on the map/radar.

Is there some national system? Or are they just calculating this based on radar?

Also, please feel free to post/discuss any and all high-tech weather devices as it's fascinating to me. I thought we just had radar. And how can they "predict" the size of hail?

 

[bobsmith1492]

Hm... are you sure they don't just put lil' icons in areas where there are thunderstorms? I doubt they'd show actual locations of strikes; it would be some dozens in a small area in rapid succession, and rather useless.

On a side note, one of the senior project teams at school built a device to test airplane lightning strike detection equipment (Automated WX-500 Stormscope Final Unit) - here: http://www.gvsu.edu/engineering/index.cfm?id=000C8FAB-2F53-1F5E-820980C44E1C028A - can't find much info about it online, though. One of the guys is in my class right now; I'll ask him about it tomorrow. 🙂

EDIT: D'oh, I forgot; he did the Helmholtz coil project. Oh well; I'm sure he knows about the lightning machine anyway.

 

[ScottMac]

If you go to www.intellicast.com, they were advertising a handheld device you can buy that will track severe (= storms with lightning) out to (advertised) 75 miles.

General aviation aircraft have "stormscopes" available that will give you a visual of lightning hits out to 20-50 miles, maybe more.

NASA (I think) also just announced that they have discovered a correlation of in-cloud ice (like hail) to lightning. The initial research was done via satellite, but it can be migrated to ground-based detection systems, and it works both ways (X amount of lightning means Y amount of ice or vice-versa). I read about it a couple weeks ago on www.spaceweather.com

I believe the traditional aviation "storm scopes" are picking up the electrical pulse and comparing it against a profile of the EMP characteristics (greater distance, greater dispersion I suppose). That would be a way to get a general feeling of distance, regardless of the intensity of the lightning strike. I'm pretty sure the GA strikefinders have multiple antennas/probes.

The Weather Service strikefinders are probably satellite based systems.

Mostly speculation on my part, I pretty just accept it as magic and move on to other ponderances.

FWIW

Scott

 

[spidey07]

Well that's the thing...

Is their data accurate? I think I recall some national system to track lightning, don't know.

The reason I pose this question is there was a very active storm in my area with TONS of lightning visibly. And believe it or not, their radar/"system" showed a remarkable similarity.

 

[BrownTown]

yes, you can track individual lightning strikes. There is some website I've been to before that shows it for the whole US, and for local news they obviously jsut show the one small area. I'm not sure exactly how hte systems work, but lightning create a large elecgtromagnetic pulse when it strikes, if you have multiple location set up to sense EM disturbances you could triangulate the position of the lightning.

 

[Gibsons]

I can see how they could detect lightning, but how do they know if it's a ground strike or not?

 

[Mark R]

Originally posted by: Gibsons
I can see how they could detect lightning, but how do they know if it's a ground strike or not?

Lightning strikes cause a burst of EMI - which can be detected by an antenna at a radio station.

By using an array of antennas, it is possible to determine the direction of the strike.

Cloud-ground and cloud-cloud strikes seem to have different EMI characteristics, so it is possible to tell them apart with reasonable confidence.

The distance is estimated by the strength of the signal. Most lightning strikes have an energy within a certain range. If a strike is significantly weaker it's assumed to be further away - if strong it's assumed to be close.

 

[spidey07]

Got it!

It for sure is a national program, very, very good read here from NOAA/NASA with good pictures and clear an concise explations. A must read for anybody into weather and storms.

http://thunder.msfc.nasa.gov/primer/primer3.html

"National and regional lightning networks which use magnetic direction finders, time of arrival techniques, or VHF interferometry, provide important lightning and storm information. For a number of years, the Federal Government assisted in the financing of a national lightning data service combining independently operated systems into one network. Used primarily for operational evaluation by NOAA, it evolved into a product with substantial value for both private industry and by other Federal agencies. By 1991, recognition of the importance of lightning detection had become apparent with economically viable commercially-sponsored systems coming into existence.

The National Lightning Detection Network (NLDN) which is operated by Global Atmospherics, Inc. (GAI) in Tucson, Arizona, is a network of at least 130 magnetic direction finders which covers the entire United States. Each direction finder determines a direction toward a detected electromagnetic lightning discharge. The location of the lightning discharge is determined by triangulation. Each of these sensors is capable of detecting cloud-to-ground lightning flashes at a distance of 400 km away and greater. Processed information is transmitted to the Network Control Center (NCC) in the form of a grid map showing lightning across the U.S.

"

NASA (works with NOAA) home page on lightning. good stuff.
http://thunder.msfc.nasa.gov/

 

[Rubycon]

We have an LLP system that shows where dangerous cloud to water strikes are occuring so the Captain can alter course if necessary to avoid the obvious inconvience. 🙂

There's also a directional device that can be pointed into an active cummulonimbus cloud that can record active sferics in real time and derive all sorts of parameters of the system but that's still very experiemental.