What 'thunder' looks like

Whoa, scientists have captured the first ever picture of thunder
This is what power looks like.

FIONA MACDONALD
8 MAY 2015



When it comes to thunderstorms, lightning tends to steal the show, dazzling everyone with its spectacular displays, and overshadowing the powerful long-distance rumbles that accompany the atmospheric energy release.
But now a team of scientists working at the Southwest Research Institute in the US has captured the world’s first detailed image of thunder, and it looks even more incredible than we ever imagined.

The image was created using acoustic wave maps, which were based on recordings from a range of microphones positioned around an artificially generated lightning strike.
Because sound waves from higher elevations take longer to travel to the microphones, these recordings allowed the scientists to visualise how the claps and rumbles emitted during a storm move in space.
University of Florida, Florida Institute of Technology, Southwest Research Institute
To understand how thunder works, you first need to understand lightning, which is created by electrical charges moving either within a cloud, or between the cloud and the surface of the Earth. As this charge travels, it heats up the surrounding air, triggering the dramatic release of energy, which causes thunder.
To map the process, the researchers shot a long, Kevlar-coated copper wire into an electrically charged cloud, as you can see in the Science News video below. The result is an impressive lighting strike and resulting thunder, captured by 15 ultra-sensitive microphones positioned 95 metres from the strike point.
The researchers found that the thunder was louder when more current flowed through the lightning, a discovery that could one day help scientists use thunder to work out how much energy is being conducted through lightning. This could potentially be useful if we work out how to harness the energy from lightning.
The results of the research (and this spectacular image) were presented at the meeting of the American Geophysical Union on May 5. Watch your back, lightning, who's the show pony now?
University of Florida, Florida Institute of Technology, Southwest Research Institute
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http://www.sciencealert.com/whoa-scientists-have-captured-the-first-ever-picture-of-thunder

 

Watch the world's lightning strikes mapped in real-time
SCIENCEALERT STAFF 2 JUL 2014

Image: Blitzortung
Made by German duo, Egon Wanke and Tobias Volgnandt, this new lightning map, called Blitzortung, is built on a foundation of amateur meteorologists who have connected their lightning receivers to the web.

According to Olivia Solon at Wired UK, the project was developed by Wanke two years ago, with the idea to democratise access
to information on lightning strikes. There are lightning receivers available for people to buy, but they’re expensive, and not particularly accurate.

And often the commercial networks that gather and store information about lightning strikes will charge people and organisations large fees
to access it. This includes airports and energy companies seeking information about possible power surges.

So Wanke decided to develop his system for lightning detection, and he wanted the focus to be on ‘time-of-arrival’ information.
"His goal was to create something really low-cost," Volgnandt told Solon over the phone.
"It is also about providing free maps for everyone and having some fun.”

The Blitzortung map currently relies on a network of around 800 volunteers, who calculate the exact positions of lighting
based on information gathered by the receiver and its built-in GPS locator.

Solon explains how it works at Wired:

"Once the receiver is built, users can connect it to the internet and Blitzortung's central processing servers receive the data
and can then calculate the exact positions of the discharges that have been detected, based on the intensity of the measurements
combined with the GPS location of the receiver. This data is then published in real-time to the website.

Individuals who supply data to the network are free to use the raw data for non-commercial purposes.”
Right now, the communities are strongest in Europe, the US and Australia, and Wanke and Volgnandt
are looking for more volunteers in Asia, Africa and South America to even out the coverage.

Anyone can join the Blitzortung network and start feeding their own data into the map by purchasing one of their receivers
for €200 (about AUD$290).

"It's really cool when you see the signals on the detector from thousands of kilometres away and then in a few seconds
you see the lightning strikes on the map,” said Volgnandt. "It's not a job, it's a hobby.
We are working every day. We try what we can, but we need days that are 100 hours long!"

Click here to watch the Blitzortung lightning map.

http://www.blitzortung.org/Webpages/index.php?lang=en&page_0=30

This is amazing
- Susan Lynne Schwenger

 

Image: Robert Arn/Earth Science Picture of the Day
Exploding stars could help predict lightning during thunderstorms
Cosmic rays could catch lightning in the act.

MYLES GOUGH
27 APR 2015

High-energy particles released by exploding stars in outer space can be used to probe thunderclouds
in order to better understand what triggers lightning, researchers say.

While astronomers usually hope for clear skies, a team in the Netherlands has capitalised on measurements taken during stormy weather
to discover a new method for measuring intense electric fields inside thunderclouds.

After re-evaluating 'messy' data relating to the radio emissions from charged particles originating from space - known as cosmic rays obtained during storms, the researchers say they can accurately determine the strength of the electric fields in thunderclouds.

The researchers say this method could help them gain insight into what triggers lightning, and enable more accurate predictions
of lightning activity.

The team responsible for the discovery was using the Low Frequency Array (LOFAR),
which is a network of radio antennae and particle detectors spread across five European countries.

It can detect radio waves from distant cosmic phenomena and from sources in Earth's atmosphere.
Cosmic rays originate from exploding stars and other astrophysical sources, and they continuously bombard Earth from space.

When these particles hit molecules in the atmosphere, they trigger a reaction in which millions of electrically charged particles
shower toward the ground, the researchers say.

These showers can be measured from the radio emission that's generated when their constituent particles
are deflected by the magnetic field of Earth.

Between June 2011 and September 2014, researchers at LOFAR measured 762 of the highest-energy showers.

When the weather was clear the radio waves descended in orderly patterns, the researchers said. But when there were thunderclouds overhead, the patterns looked like junk.

"We used to throw away LOFAR measurements taken during thunderstorms. They were too messy," said lead author
and astronomer Pim Schellart, from Radboud University Nijmegen in the Netherlands, in a press release.

"Well, we didn't actually throw them away of course, we just didn't analyse them."

But after letting some colleagues look at the anomalous data, the researchers decided they might be worth a closer look.

As Davide Castelvecchi explains for Nature News, "the team redesigned their models to include intense electric fields of the type
that usually form inside thunderclouds - in which negative electric charges in a lower layer are separate from positive charges higher up."

By incorporating electric fields in thunderclouds into their models, the team was able to decipher the different measurements.

"This worked very well. How the radio emission changes gives us a lot of information about the electric fields in thunderstorms.
We could even determine the strength of the electric field at a certain height in the cloud," said Schellart.

The study, which is published in Physical Review Letters, offers long-awaited proof that a radio-astronomy observatory
can be used to probe thunderclouds.

"This paper is groundbreaking since it demonstrates that the idea actually works," Joseph Dwyer, an atmospheric physicist
at the University of New Hampshire in the US, who wasn't involved in the research, told Castelvecchi from Nature News.

Lightning is a channel of electric conduction that opens up between layers of clouds, or between clouds and the grouns.

It can be both frightening and awe-inspiring, and it strikes on Earth with startling frequency - once every 40 or 50 seconds,
or about 1.4 billion times per year. But what causes these intense outbursts is still unclear.

Perhaps the key to their enigma lies in cosmic rays.
Source: Nature News


http://www.sciencealert.com/exploding-stars-could-help-predict-lightning-during-thunderstorms