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Posts Tagged ‘electromagnetic’

The Megaflash

Posted in Uncategorized, tagged , , , , on May 25, 2022| 4 Comments »

Photo: NOAA (National Oceanic and Atmospheric Administration).
Lightning as seen from the Geostationary Lightning Mapper on NOAA’s GOES-16 satellite from April 29, 2020. The World Meteorological Organization has found that one of the lightning flashes within this thunderstorm complex was the longest flash on record, covering a horizontal distance of 477 miles.

Let’s talk about natural phenomena. Let’s talk about lightning. Can you imagine one flash covering 477 miles? That’s the record, set in 2020. Here’s Matthew Cappucci‘s January article for the Washington Post about such megaflashes.

Capupucci wrote, “The World Meteorological Organization announced on Monday that it had confirmed two new mind-blowing lightning ‘megaflash’ records. The findings, which come after careful data-checking and rigorous certification processes, include one record event that occurred over the Lower 48 states.

“On April 29, 2020, a sprawling mass of strong to severe thunderstorms produced a 477.2-mile-long lightning strike over the southern United States. It stretched from near Houston to southeast Mississippi, a distance equivalent to that between Columbus, Ohio, and New York City. …

“The WMO also identified a new world record for the long-lasting lightning flash. It lit up the skies over Uruguay and northern Argentina for 17.1 seconds on June 18, 2020. …

“ ‘These are extraordinary records from single lightning flash events,’ wrote Randall Cerveny, rapporteur of Weather and Climate Extremes for WMO, in a statement.

“Megaflashes dwarf ordinary lightning strikes. As Earth dwellers, we’re accustomed to seeing what’s going on near the ground, including conventional cloud-to-ground lightning bolts. …

“Megaflashes are different. They’re enormous. They snake through regions of high electric field and can travel for hundreds of miles while lasting more than 10 seconds. Since most storm clouds are fewer than 10 miles high, lightning can’t grow terribly long in the vertical direction. But megaflashes have plenty of space to sprawl in the horizontal.

“All megaflashes accompany MCSs, or mesoscale convective systems. MCSs are clusters of thunderstorms that often rage overnight and can occupy an area the size of several states, last for hours and stretch 750 miles or more end-to-end. They’re a staple of the spring and early summer across the southern and central United States, and are also common in Brazil, Argentina and Uruguay. South America’s ‘Altiplano,’ or high Andean Plateau, also brews prolific lightning-producing storms.

“Megaflashes crawl through the clouds but can produce or induce ground connections at various points. Sometimes MCSs merge, leading to amplified and more chaotic electric fields that can also be supportive of megaflashes. Covering so much real estate means megaflashes flicker for an extended duration.

“While atmospheric electrodynamicists had long since theorized about the existence of megaflashes, the scale and duration of said flashes was not well-understood until recently. …

“ ‘Detecting these extreme lightning events is very difficult due to their exceptional rarity and scale,’ wrote Michael J. Peterson of the Space and Remote Sensing Group at Los Alamos National Laboratory, in an email. ‘Your sensor has to be in just the right place at perfectly the right time to be able to see it — and the instrument has to be capable of measuring something as large as a megaflash.’ …

“That changed with the Nov. 19, 2016, launch of the GOES East weather satellite, soon followed by GOES West. Both peer down on North America from 22,236 miles above Earth and have ‘Geostationary Lighting Mappers,’ or instruments that are able to discern the infrared signal associated with a lightning flash. That allows for the tracking of cloud-to-cloud and intracloud flashes from above. …

“Megaflashes may be more common than once believed. Now that scientists are able to spot and resolve them over North America, they’re able to begin constructing a catalogue of events. One particularly impressive discharge, which eventually spanned 300 miles but was not evaluated by the WMO, occurred on the morning of Oct. 23, 2017. A thunderstorm was raging near Thackerville, Okla., a little more than an hour’s drive north of the Dallas-Fort Worth Metroplex. A lightning strike illuminated skies near the Red River — Oklahoma’s southern border — at 12:13 a.m.

“At the same time, the landscape was also aglow near Burlington, Kansas; the same massive 300 mile-long lightning bolt had illuminated an area four times larger than the state of Connecticut.”

More at the Post, here. I wonder what Philip Pullman, author of the amazing Golden Compass fantasy series, could do with this. His powerful imagination already has done a lot with electromagnetic waves.

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Northern Lights Make Music

Posted in Uncategorized, tagged , , , , on December 27, 2020| 5 Comments »

Have you ever gotten a glimpse of the aurora borealis, maybe from an airplane? It’s something I’ve always wanted to see. My sense of the northern lights comes only from pictures and from the fantasy trilogy His Dark Materials, in which the electricity generated is harnessed for travel to other worlds.

In an article at the Guardian by Patrick Barkham, we learn of a different way to get a sense of the aurora borealis.

“There’s a hypnotic crackle before a whoosh of sound flies from ear to ear,” he writes. “It’s followed by a heavenly chorus that might be whales whistling, frogs calling or the chirping of an alien bird. It sounds celestial because that’s what it is. The noise is the aurora borealis: the northern lights.

“The vivid green lights that trace across the Arctic sky emit electromagnetic waves when the solar shower meets the Earth’s magnetic field, and these can be translated into sounds that are made audible to human ears by a small machine.

“These mysterious, sweeping noises are celebrated by a new Radio 3 documentary following the biologist Karin Lehmkuhl Bodony into the wilderness on her dog sleigh to record the soundscape, which has now been turned into music by an Alaskan composer.

“Bodony lives in the remote Alaskan village of Galena. She can see the lights from her porch, and 16 years ago she discovered she could also record the sound of the lights using a very low frequency (VLF) receiver.

“ ‘To hear those “whoosh-whoosh” sounds, which are so like what you see, is really special,’ she says. …

‘There are times when it’s just normal background chattery, crackly sounds and then there’ll be other times when it’s really cool – beautiful whooshing sounds and a chorus that sounds like frogs calling. If it was always the same it wouldn’t be as fun to go out and listen.’

“For Songs of the Sky … Radio 3 commissioned the composer Matthew Burtner, who works with natural sounds and scientific environmental data, to make a piece of music derived from the sounds of the aurora.

“Northern lights listeners must get at least four miles away from human-made sounds and other electrical sources such as power lines to avoid interference on the VLF receivers, so Burtner had to hike into the wilds with his daughter. …

“Burtner found that the recordings from the [VLF recorder] weren’t very clear and so mapped the sounds’ frequency and amplitude profile onto a high-quality synthesiser. ‘You can then alter the timbre of the sound and have the northern lights play different instruments. That let me really orchestrate with the northern lights, using their input as a controller,’ he says. …

“Burtner created a six-minute piece that he hopes expresses the dialectic between humans and the natural world. ‘That’s what I’m always looking for in music – there’s something of the real natural system in there that’s untouched by a person.’ …

“The programme also explores the traditional meanings of the aurora borealis in the rapidly changing Arctic environment, where temperatures are rising faster than in many parts of the world.

“According to Bodony, traditional Inuit interpretations of the northern lights are often benevolent, with the lights signalling to hunters how they will find food or reassuring the bereaved that their loved ones have passed to a better place.

“But there are more sinister mythologies connected with the northern lights, which have symbolised danger in certain stories as well. ‘Our atmosphere shields us from the sun’s radiation and manages to warm the planet but not too much – it’s a shield – and this display of the northern lights is a representation of the sun’s fearsome force on our planet that could make it uninhabitable,’ says Burtner. …

“For Bodony, the perspective derived from her rural subsistence culture – and the experience of the aurora borealis – can correct the wider human attitude to the planet, which is ‘like impudent children whose parent is away and we’re destroying the house’ “

More at the Guardian, here.

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