Lightning spurs hurricanes - Link shows storms in Africa can cause havoc in the United States.

news@nature.com ^ | 11 May 2007 | Harvey Leifert

[neverdem]

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Published online: 11 May 2007; | doi:10.1038/news070508-12

Lightning spurs hurricanes

Link shows storms in Africa can cause havoc in the United States.

What creates an Atlantic hurricane? The most devastating ones are spurred by intense thunderstorms in the Ethiopian highlands, according to new research.

The link between lightning strikes and hurricane formation should give researchers a heads-up about when a nasty hurricane might form, weeks before it could make landfall in the United States, says Colin Price of Tel Aviv University in Israel. Today, scientists apply various models to predict storm tracks and strength, but only once they form over the Atlantic Ocean. "This is what is unique about our work," Price says. "We look at the initial stages of these devastating storms before they have become hurricanes."

Price and his colleagues at Israel's Open University studied the 2005 and 2006 hurricane seasons, which were markedly different from each other. In 2005 there were a record 28 named storms, including the catastrophic Hurricane Katrina, while 2006 brought only 10 named storms — a 64% reduction. Summertime lightning activity in eastern Africa, mainly in the Ethiopian highlands, was also quite different in each of the years, the researchers found, with 23% less activity in 2006 over 2005.

The two phenomena are linked, says Price, an atmospheric scientist who has long studied lightning.

Wind interrupted

Heavy lightning in eastern Africa apparently perturbs the westward trade winds across the African continent, Price writes in Geophysical Research Letters¹. He likens the process to the effect of boulders in a stream: "The boulder produces undulations and turbulence downstream, and the bigger the boulder, the larger the turbulence. Over Africa, thunderstorms act as our boulders."

So the larger the thunderstorm, the greater the atmospheric turbulence, says Price. This turbulence, in turn, creates low-pressure areas known as African easterly waves (AEW). About half of these systems are known to generate tropical storms as they head westwards over the Atlantic. Various factors, including sea surface temperature, dust and wind shear above the Atlantic, then determine whether those storms strengthen into hurricanes.

The team mined data about lightning strikes from the World Wide Lightning Location Network, whose ground stations monitor the very low-frequency electromagnetic signals that lightning emits. They found that all periods of intense lightning in eastern Africa monitored in both 2005 and 2006 were followed by an AEW low-pressure area.

Striking impact

Only a fraction of these AEWs go on to make hurricanes or cause damage in the United States. But of the big hurricanes that do form, the vast majority seem to have been born of lightning.

At least 85% of intense hurricanes and two-thirds of all Atlantic hurricanes in the study developed from AEWs that formed after thunderstorms in eastern Africa, the researchers found.

Price suggests that forecasters and emergency response personnel keep an eye on major thunderstorms in eastern Africa during the upcoming hurricane season, in order to gauge its likely severity.

Earle Williams, a lightning expert at the Massachusetts Institute of Technology in Cambridge, who was not involved in the study, says the study highlights the benefits of having global lightning data available on a continuous basis.

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References

1. Price C., Yair Y. & Asfur M. Geophys. Res. Lett. 34 , L09805 doi:10.1029/2006GL028884 (2007).

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[neverdem]

A Walk In The Country May Beat Depression

Governor Seeks Vast DNA Base for New York

FReepmail me if you want on or off my health and science ping list.

[Dutchguy]

Reminds me of the Quantum Weather Butterfly from Pratchett’s fantasy novels:

The Quantum Weather Butterfly is a butterfly which has evolved the curious trait of weather control. This is used as a defence mechanism and a sexual characteristic. The insect is yellow, with Mandelbrot patterned wings: these wings have an infinite wing perimeter, but only a finite area. Its classification is Papilio tempestae, and it appears mainly in Interesting Times. It is based on the illustration of chaos theory that the air movement caused by a butterfly flapping its wings in America could eventually cause a storm in China.

[Budge]

Somebody call Owlgore, Hitlery, the ACLU, the enviro-nazis. We must ban lightning or we’ll all die!

[SunkenCiv]

What creates an Atlantic hurricane? The most devastating ones are spurred by intense thunderstorms in the Ethiopian highlands, according to new research.

Ah, but the Ethiopian thunderstorms are caused by smokestacks and auto exhaust in North America, so you see, heads they win, tails we lose. Global warming is the new Lysenkoism. Thanks NeverDem.

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[SunkenCiv]

Thanks neverdem.

To all -- please ping me to other topics which are appropriate for the GGG list. Thanks.

Please FREEPMAIL me if you want on or off the
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[MNJohnnie]

So if we simply buy eastern Africa and turn it into a desert the United States would never have hurricanes? How tough can that be? Most of the Somalis are all ready here!

[twhitak]

Lightning spurs hurricanes

I'm confused. I thought it was Bush's fault.

[conservatism_IS_compassion]

Lightning spurs hurricanes

I'm confused. I thought it was Bush's fault.

LOL!

But you see, it was - Rove knew this all along, and he created the humongous African thunderstorm which spawned Katrina. And how did he do that? SunkenCiv has it right: "Ethiopian thunderstorms are caused by smokestacks and auto exhaust in North America."

Rove, the SOB, drove an SUV!

[SlowBoat407]

Link shows storms in Africa can cause havoc in the United States.

Shouldn't this be in breaking news?

[Jeffrey_D.]

Oh man !!!! Say it ain’t so. I so expected it to be blamed on all those helicopters we’ve got in the military!

[sheik yerbouty]

We must demand reparations!

[RightWhale]

The butterfly theory does not apply to a sufficiently damped system such as earth’s meteorological system. It might apply to an unstable system such as a star or a nuclear explosive device at the point where the reaction blooms into the new regime. That point might be called the critical point or the tipping point. The Mandelbrot butterfly theory might be applied to the coastline of Alaska, which I maintain is infinite or perhaps indefinite down to the Planck length. The Universe itself appears to be finite and unbounded, which might be confusing Poincare topology with Mandelbrot iteration.

[Mr. K]

thats easy for you to say...

[Mike Darancette]

The butterfly effect?

[Hegemony Cricket]

Hmmm. OK. Let’s see now - lightening creates ozone. We have severely limited or outright banned ozone-depleting substances here in the U.S. Therefore, if hurricanes are on the increase it is directly the fault of those who pushed for the ban on ODS’s...

[Berosus]

Once upon a time they caused the Nile to flood in the summer, now they cause hurricanes. Dang those SUV-driving Ethiopians!

[gcruse]

“give researchers a heads-up about when a nasty hurricane might form, weeks before it could make landfall in the United States”

Heh. It’s not like the strike us by surprise, you know.
The stock market is accused of predicting more recessions than occur. Can you imagine getting hurricane warnings ‘weeks before’ based on a lot of lightning in Ethiopia? Har.

[GOPJ]

Thanks for the ping.

[grey_whiskers]

The butterfly theory does not apply to a sufficiently damped system such as earth’s meteorological system.

Speak for yourself. Phoenix is anything *but* damp! ;-)

Seriously, what is being damped here, and what is doing the damping?

(...by analogy to driven pendulums w/friction, etc.)

Cheers!