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World Map of Lightning Activity
Ian writes "NewScientist.com is >reporting that you can now see the lightning activity on the entire planet Earth at one time. The article states, "The NASA map also shows that lightning very rarely occurs at sea and is almost never seen at the Earth's poles." Anyone care to speculate on why that is?"
My estimation is that the extremely low lightning at sea is caused by a general lack of geographic anomalies to disturb airflow.
You'll notice in the map a wide swath of sea to the west of South America which follows the equator and then curves south following the coast. This is approximately the path of the Humbolt and equatorial currents in the South Pacific. Winds and sea currents have a strong influence on each other, and so we may presume that the winds over these strong ocean currents are less turbulent than those over the Polynesians or the Carribean islands. This is consistent with the hypothesis that a lack of turbulence is the cause of low lightning occurrence at sea.
At the poles, the temperature is very low. I'm not sure of the mechanics involved, but I do know that regions with surfaces heated by the sun experience more lightning in general, so we could reasonably presume the opposite about regions of cold surfaces, explaining the lack of lightning at the poles.
I like to play children's songs in minor keys.
"We're all sons of bitches now." --J. Robert Oppenheimer
NASA used different contractors for the top and bottom halves of the lightning scale. These contractors used different units ... with hilarious results.
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My preferences can't be that screwed up. Or can they?
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Yeah, I know it's sort of egocentric for we Americans, but you can visit http://www.lightningstorm.com/ls2/gpg/lex1/mapdisp lay_free.jsp?jrunsessionid=1007697160371304360 to see recent lightening activity in the continental US. When things are lively, you can see a lot of really nifty patterns with the fronts.
Thunderstorms are the thing I miss most about the midwest (I'm from Illinois, live in California), but it looks like the "third coast" (TX, LA, MS, AL, FL) is the place to be in the US for lightning. I think I once read that Lakeland, FL (I believe between Tampa and Orlando) gets the most lightning of any locale in the US. And property is probably really cheap. :-)
Anyone find a high res version of the map in the New Scientist article?
People in Australia with Teletext (Austext, broadcast on Channel 7) can get live info on lightning strikes in Queensland. It even has a map, of sorts. Page 179.
Yes! Connect a 20 foot iron pole to a ground loop. Stand in a bucket of water holding the iron pole. This is guaranteed to let you know when there is lightning in the area.
The TinWeasle: "Worming Out of Culpability since 1978" - Opinions expressed are mine alone, yadda, yadda, yadda
> The NASA map also shows that lightning very rarely occurs at sea and is almost never seen at the Earth's poles. Anyone care to speculate on why that is?
Far fewer blasphemers in those regions, of course.
Sheesh, evil *and* a jerk. -- Jade
One really crude way is to just turn on an AM radio during a storm and listen for the brief pops caused by lightning. One page you should look at is here:
http://www.altair.org/natradio.htm
It talks about the different types of EM radiation created by lightning. I think if you wind some wire around an iron core, connect the wires to a battery and transistor to boost the power and connect it to the speaker you should get some interesting pops during lightning. If you are familiar with band pass filters in electronics you could probably filter it so that you only pick up the frequencies you hear lightning on (which is a very broad range). It isn't hard to hear it. Now lightning prediction...I can't vouch for that.
btw, this is a really cool site Wavelet Compression of Lightning Signatures.
t.
Maybe it's because lightning wants to be perpendicular to the magnetic field lines of the earth. Therefore, toward the poles, the magnetic field lines are too "curvy" so that the lightning would be forced to go horizontal, resulting in it never being grounded. Who knows though, eh?
It has everything to do with the behavior of static electricity. What were you taught as a kid, should you find yourself in a lightning storm?
Get out in the open. Stay away from trees.
Ever look at a lightning rod?
Static electricity collects at points. The overall lack of geographic features over the ocean pretty much negates most opportunities for static charges to balance themselves between earth and sky, without any points to collect at.
- billn
No lightning at the poles, and very little at sea? Obviously lightning is herbivorous, and tends to roam areas where there are trees to eat.
Nothing to see here. Move along.
Remember, than electromagnetic radiation travels with the speed of light! The time it takes for the electromagnetic signal from a lightning strike 10 km away to travel to the receiver is only 33 micro seconds. if you use the sonic signal, however, you would be able to do the triangulation fairly easily with relatively cheap watches. Your only concern would be that you and your friends should be certain that you measure the arrival time for the same lightning strike.
Yours Yazeran
Plan: To go to Mars one day with a hammer.
Large drops falls through the cloud and collides with smaller drops going up. These collisions transfer charge from the down-going drops to the up-going drops, and thus a larde charge difference between top and bottom of the cloud develops. The large charge in the bottom of the cloud results in the formation of a 'mirror charge' in the ground beneath it and these charges are responsible for the lightning.
Yours Yazeran
Plan: To go to Mars one day with a hammer.
Sufficiently strong convection currents are much more common over land, where the sun can heat ground rapidly.
Another factor is global circulation patterns. Convection causes air to rise at the equator, and to sink at the poles. (actually we get three convection cells, so we also get descending air at 30 degrees latitude, and rising air at 60 degrees). This means that we tend to get high rainfall, storms, and lightning at the equator and at 60 degrees, low rainfall and few storms at 30 degrees and at the poles.
As long as you're not in a raging lightning storm, you can correlate lightning strikes recorded at different computers by using a large error tolerance. e.g. the EM burst from this strike was recorded on three different computers within a span of 15 seconds. We can assume that this was the same event if the lightning was spaced several minutes apart during the storm.
The time for the EM burst to travel is considered to be zero for ease of computation. Not to mention the impossiblity of keeping things accurate for that to even be useful.
Also my initial test showed EM bursts that were o.w. undetectable which is pretty cool. Maybe the first step is an early detection system for lightning storms.
t.
On the other hand, I know from being at sea during any type of storm, you can get some seriously big waves. I imagine that in the middle of the ocean, you'll have wave on the order of 10m high, at least. This seems like enough of a height variation.
I guess there's two reasons I can think of that you wouldn't have strikes over water: first, any charge on the "ground" would tend to disperse more rapidly than it would when you're on land, and second, there's less convection due to the night/day cycle, so the clouds over the ocean rub together a bit less.
I also noticed that the point most hit on the US seemed to be my hometown, New Orleans... I always expected that, baby!
Come on, give it up, that's
sPh
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