Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

NASA's Fermi catches gamma-ray flashes from tropical storms

25.04.2017

About a thousand times a day, thunderstorms fire off fleeting bursts of some of the highest-energy light naturally found on Earth. These events, called terrestrial gamma-ray flashes (TGFs), last less than a millisecond and produce gamma rays with tens of millions of times the energy of visible light. Since its launch in 2008, NASA's Fermi Gamma-ray Space Telescope has recorded more than 4,000 TGFs, which scientists are studying to better understand how the phenomenon relates to lightning activity, storm strength and the life cycle of storms.

Now, for the first time, a team of NASA scientists has analyzed dozens of TGFs launched by the largest and strongest weather systems on the planet: tropical storms, hurricanes and typhoons. A paper describing the research was published March 16 in the Journal of Geophysical Research: Atmospheres.


Storm clouds produce some of the highest-energy light naturally made on Earth: terrestrial gamma-ray flashes (TGFs). Using data from NASA's Fermi Gamma-ray Space Telescope and ground-based lightning detection networks, scientists tracking these fleeting outbursts are beginning to learn more about how conditions in hurricanes, typhoons and other tropical weather systems set the stage for TGFs. (Video)

Credit: NASA's Goddard Space Flight Center

"One result is a confirmation that storm intensity alone is not the key factor for producing TGFs," said Oliver Roberts, who led the study at the University College Dublin, Ireland, and is now at NASA's Marshall Space Flight Center in Huntsville, Alabama. "We found a few TGFs were made in the outer rain bands of major storms, hundreds of kilometers from the powerful eye walls at their centers, and one weak system that fired off several TGFs in a day."

Scientists suspect TGFs arise from the strong electric fields near the tops of thunderstorms. Under certain conditions, these fields become strong enough to drive an "avalanche" of electrons upward at nearly the speed of light. When these accelerated electrons race past air molecules, their paths become deflected slightly. This change causes the electrons to emit gamma rays.

Fermi's Gamma-ray Burst Monitor (GBM) detects TGFs occurring within about 500 miles (800 kilometers) of the location directly beneath the spacecraft. In 2012, GBM scientists employed new techniques that effectively upgraded the instrument, increasing its sensitivity and leading to a higher rate of TGF detections.

This enhanced discovery rate helped the GBM team show that most TGFs also generate a strong pulse of very low frequency radio waves, signals previously attributed only to lightning. Facilities like the Total Lightning Network operated by Earth Networks in Germantown, Maryland, and the World Wide Lightning Location Network, a research collaboration run by the University of Washington in Seattle, can pinpoint lightning- and TGF-produced radio pulses to within 6 miles (10 km) anywhere on the globe.

"Combining TGF data from GBM with precise positions from these lightning detection networks has opened up our ability to connect the outbursts to individual storms and their components," said co-author Michael Briggs, assistant director of the Center for Space Plasma and Aeronomic Research at University of Huntsville (UAH).

The team studied 37 TGFs associated with, among other storms, typhoons Nangka (2015) and Bolaven (2012), Hurricane Paula (2010), the 2013 tropical storms Sonia and Emang and Hurricane Manuel, and the disturbance that would later become Hurricane Julio in 2014.

"In our study, Julio holds the record for TGFs, firing off four within 100 minutes on Aug. 3, 2014, another the day after, and then no more for the life of the storm," Roberts said. "Most of this activity occurred as Julio underwent rapid intensification into a tropical depression, but long before it had even become a named storm."

What the scientists have learned so far is that TGFs from tropical systems do not have properties measurably different from other TGFs detected by Fermi. Weaker storms are capable of producing greater numbers of TGFs, which may arise anywhere in the storm. In more developed systems, like hurricanes and typhoons, TGFs are more common in the outermost rain bands, areas that also host the highest lightning rates in these storms.

Most of the tropical storm TGFs occurred as the systems intensified. Strengthening updrafts drive clouds higher into the atmosphere where they can generate powerful electric fields, setting the stage for intense lightning and for the electron avalanches thought to produce TGFs.

TGFs were discovered in 1992 by NASA's Compton Gamma-Ray Observatory, which operated until 2000.

The Fermi Gamma-ray Space Telescope is an astrophysics and particle physics partnership managed by NASA's Goddard Space Flight Center in Greenbelt, Maryland. Fermi was developed in collaboration with the U.S. Department of Energy, with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden and the United States.

The GBM Instrument Operations Center is located at the National Space Science Technology Center in Huntsville. The GBM team includes a collaboration of scientists from UAH, NASA's Marshall Space Flight Center, the Max Planck Institute for Extraterrestrial Physics in Germany, University College Dublin in Ireland and other institutions.

###

For more information on Fermi, visit:
https://www.nasa.gov/fermi

Francis Reddy | EurekAlert!

More articles from Physics and Astronomy:

nachricht Turning entanglement upside down
22.05.2018 | Universität Innsbruck

nachricht Astronomers release most complete ultraviolet-light survey of nearby galaxies
18.05.2018 | NASA/Goddard Space Flight Center

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

PR of MCC: Carbon removal from atmosphere unavoidable for 1.5 degree target

22.05.2018 | Earth Sciences

Achema 2018: New camera system monitors distillation and helps save energy

22.05.2018 | Trade Fair News

LZH showcases laser material processing of tomorrow at the LASYS 2018

22.05.2018 | Trade Fair News

VideoLinks
Science & Research
Overview of more VideoLinks >>>