Shipping causes lightning?

[Paul L]

Originally Posted by Paul Elliott

If you actually compare the plots of lightning strikes to ship tracks, there are some interesting patterns that I doubt could be explained by natural weather patterns (which had been my initial knee-jerk reaction). It wouldn't surprise me to find that combustion products had some effect on ionization and the resulting lightning strikes.

If so that's interesting, but not evidence of a problem.

Could this be why Cats get hit by lightning more frequently than monos? Two diesels instead of one.

[StuM]

Originally Posted by Jim Cate

Am I not correct in saying that they are not talking about lightning strikes on the ships themselves, but rather total strikes in the area? As seen by satellites which don't discriminate with respect to WHAT that strike hits...

If so, many of the above arguments fail.

Jim

Close, but no cigar.

They are not lightning "strikes" and it's not satellite based.
The data come from the World Wide Lightning Location Network :

"University of Washington in Seattle operating a network of lightning location sensors at VLF (3-30 kHz). Most ground-based observations in the VLF band are dominated by impulsive signals from lightning discharges called “sferics”. Significant radiated electromagnetic power exists from a few hertz to several hundred megahertz, with the bulk of the energy radiated at VLF.

With our network of sferic sensors we are producing regular maps of lightning activity over the entire Earth."

IOW, they are triangulating Very Low Frequency radio signals generated by "lightning discharges" from about 70 sensor locations dotted around the world.

A large percentage of these discharges (80-90%) are cloud based and never "strike" the surface.

Also it's worth noting that the quality of data in many areas is dubious at best.

"Each lightning stroke location requires the time of group arrival (TOGA) from a least 5 WWLLN sensors. These sensors may be several thousand km distant from the stroke. The geographical arrangement of the sensors is important: a lightning stroke which is enclosed by sensors is much more accurately located than one which is not so enclosed. Clearly a uniform spacing of sensors around the Earth is the ideal. Since the Earth is round, there are no edges: every lightning stroke is surrounded by sensors, but not necessarily by the sensors which sense it. Typically only about 15 to 30% of strokes detected by one sensor are detected by 5 or more. These strokes are usually the stronger ones. Recent research indicates our detection efficiency for strokes about 30 kA is approximately 30% globally."

[StuM]

While looking for the percentage of discharges which strike the ground, I came across this little snippet: "Lightning strikes most frequently in the Democratic Republic of the Congo." That's the real black spot on the map in the middle of Africa:

Data from NASA’s space-based optical sensors revealing the uneven distribution of worldwide lightning strikes. Units: flashes/km2/yr. Image credit: NSSTC Lightning Team.

Guess DRC needs to de-industrialise and stop all that nasty diesel pollution.

[newhaul]

Originally Posted by StuM

While looking for the percentage of discharges which strike the ground, I came across this little snippet: "Lightning strikes most frequently in the Democratic Republic of the Congo." That's the real black spot on the map in the middle of Africa:

Data from NASA’s space-based optical sensors revealing the uneven distribution of worldwide lightning strikes. Units: flashes/km2/yr. Image credit: NSSTC Lightning Team.

Guess DRC needs to de-industrialise and stop all that nasty diesel pollution.

Lots of cobalt and copper . ( great attractant )

[Jim Cate]

Originally Posted by StuM

Close, but no cigar.

They are not lightning "strikes" and it's not satellite based.
The data come from the World Wide Lightning Location Network :

"University of Washington in Seattle operating a network of lightning location sensors at VLF (3-30 kHz). Most ground-based observations in the VLF band are dominated by impulsive signals from lightning discharges called “sferics”. Significant radiated electromagnetic power exists from a few hertz to several hundred megahertz, with the bulk of the energy radiated at VLF.

With our network of sferic sensors we are producing regular maps of lightning activity over the entire Earth."

IOW, they are triangulating Very Low Frequency radio signals generated by "lightning discharges" from about 70 sensor locations dotted around the world.

A large percentage of these discharges (80-90%) are cloud based and never "strike" the surface.

Also it's worth noting that the quality of data in many areas is dubious at best.

"Each lightning stroke location requires the time of group arrival (TOGA) from a least 5 WWLLN sensors. These sensors may be several thousand km distant from the stroke. The geographical arrangement of the sensors is important: a lightning stroke which is enclosed by sensors is much more accurately located than one which is not so enclosed. Clearly a uniform spacing of sensors around the Earth is the ideal. Since the Earth is round, there are no edges: every lightning stroke is surrounded by sensors, but not necessarily by the sensors which sense it. Typically only about 15 to 30% of strokes detected by one sensor are detected by 5 or more. These strokes are usually the stronger ones. Recent research indicates our detection efficiency for strokes about 30 kA is approximately 30% globally."

Ah, so! Thanks for the education... and I agree that this data is pretty sketchy and can certainly not distinguish between cloud to cloud and ground strikes. And as a ham operator, mostly on the lower parts of the HF continuum, I'm well aware that the RF pulses from lightning can propagate for long distances and wreak havoc with communications. QRN in ham talk!

Jim

[Wotname]

Let's get back to basics for a moment. Lightning strikes (arcs etc) travel between opposite charged masses via a path of ionised air. Without the ionisation of the air and without sufficiently electrical charged masses, there is no lightning.

The fact that some arcs hit the ground or hit objects on the surface or in the air is pretty much inconsequential in the big picture.

Ionising air is not easy, it takes large voltages if the distant between the charged masses is great. I forget the numbers but it is directly proportional to the distance between the charged "poles". Think spark plugs, takes ~30,000V to arc across .1".

The other major factor in the ionisation process is the composition of the gases. It isn't difficult to speculate that cargo ship exhaust emissions affect the local atmosphere to the extent that there are more arcs occurring nearby. It probably hard to prove though .

[Wotname]

Originally Posted by Jim Cate

....... And as a ham operator, mostly on the lower parts of the HF continuum, I'm well aware that the RF pulses from lightning can propagate for long distances and wreak havoc with communications. QRN in ham talk!

Jim

Hehe and also be used positively for the detection of storm cells (both range and bearing). If you don't know of Paul Ryan of Stormscope fame, google him. While the techniques of storm cell detection have been around for a century or more, he is the father of the modern day storm cell detection / location and has taken the process to levels that were impossible even 20 years ago. He is responsible for most of the generational changes of this technology.

[Tetepare]

Originally Posted by Paul Elliott

I see a strong negative correlation here...

That is absolutely hillarious!!!

[Don C L]

Originally Posted by Paul Elliott

I see a strong negative correlation here...

Aha! Fake news! I know for a FACT that there are 18 pirates in our own marina! At least they dress up like it.

[newhaul]

Originally Posted by Don C L

Aha! Fake news! I know for a FACT that there are 18 pirates in our own marina! At least they dress up like it.

Are you counting yourself or does that make 19 ?

[markpierce]

Originally Posted by Lepke

Taller ships make it easier for lightning to go to ground. Also wind on big things can make static electric charges that have something to do with lightning.

Benjamin Franklin's experiment with a kite collected static electricity and was not struck by lightning.

[markpierce]

Correlation itself does not prove cause or effect.

[Wotname]

Originally Posted by markpierce

Benjamin Franklin's experiment with a kite collected static electricity and was not struck by lightning.

Is this just an interesting observation or are you suggesting that static electricity is not related to lightning or ....

[markpierce]

Originally Posted by Wotname

Is this just an interesting observation or are you suggesting that static electricity is not related to lightning or ....

My understanding is that air-borne static is related to lightning production.

[Pelagic]

Just wait until we have a major volcanic eruption spewing ionized volcanic ash over the huge windfarms