Lightning strikes in the Arctic tripled from 2010 to 2020, a finding 91Ě˝»¨ researchers attribute to rising temperatures due to human-caused climate change. The results, researchers say, suggest Arctic residents in northern Russia, Canada, Europe and Alaska need to prepare for the danger of more frequent lightning strikes.

The , published March 22 in Geophysical Research Letters, used data from the UW-based to map lightning strikes across the globe from 2010 to 2020. WWLLN sensors detect the short burst of radio waves emitted during a lightning strike.

The new study found the number of lightning strikes above 65 degrees north latitude during the summer months tripled from 2010 to 2020 as compared to the total number of lightning strikes over the entire globe during the same period.

“With long periods of ice-free ocean and increasing shipping in the Arctic, you’re going to have the same problem you have at lower latitudes — when there’s a lot of people and they don’t know about the lightning threat and it becomes a problem,” said lead author , a 91Ě˝»¨professor emeritus of Earth and space sciences.

Holzworth and his colleagues analyzed the frequency of Arctic lightning strikes occurring during the summer months of June, July and August from 2010 to 2020. They found the percentage of lightning strikes occurring in the Arctic tripled from 0.2% of global lightning strikes in 2010 to 0.6% in 2020. The actual number of lightning strikes above 65 degrees north increased from about 18,000 in 2010 to over 150,000 in 2020.

During the same time period, Arctic temperatures increased from 0.65 to 0.95 degrees Celsius above pre-industrial times. Holzworth and his colleagues attribute the increased lightning strikes to these rising temperatures, as warmer summers mean more chances for intense thunderstorms to develop and create lightning.

Lightning in the Arctic is historically rare, as it usually isn’t warm enough to generate the right thunderstorm conditions during which lightning occurs. But researchers have recently noticed more strikes occurring in the northernmost latitudes and they even reported several lightning strikes near the north pole in August 2019. Lightning strikes that do occur in the Arctic tend to happen in the summer when thunderstorms are most likely to form.

The Arctic is warming faster than any other region on Earth, and the study authors found the uptick in lightning strikes matched rising temperatures in the region over the past decade. Arctic temperatures increased by 0.3 degrees Celsius from 2010 to 2020; that warming has created more favorable conditions for intense summer thunderstorms that produce lightning, according to the authors.

Arctic sea ice is declining by about 13% every decade, . Less ice means more ocean will be available for shipping through the Arctic, especially in the summer months. Countries like Russia, China, Canada and the United States are already preparing to use the Arctic Ocean as a viable shipping route in the future.

The new study suggests shipping vessels throughout the Arctic could be more vulnerable to lightning strikes, in addition to those who call the Arctic home.

Co-authors are Michael McCarthy, Abram Jacobson, Craig Rodger and Todd Anderson at the UW; and James Brundell at the University of Otago in New Zealand.

For more information, contact Holzworth at bobholz@uw.edu. This was adapted from a from the AGU. An interactive embeddable graphic is available .

The lightning season in the Southeastern U.S. is almost finished for this year, but the peak season for the most powerful strokes of lightning won’t begin until November, according to a newly published global survey of these rare events.

A 91Ě˝»¨ maps the location and timing of “superbolts” — bolts that release electrical energy of more than 1 million joules, or a thousand times more energy than the average lightning bolt, in the in which lightning is most active. Results show that superbolts tend to hit the Earth in a fundamentally different pattern from regular lightning, for reasons that are not yet fully understood.

The study was published Sept. 9 in the , a journal of the American Geophysical Union.

“It’s very unexpected and unusual where and when the very big strokes occur,” said lead author , a 91Ě˝»¨professor of Earth and space sciences who has been tracking lightning for almost two decades.

Holzworth manages the , a UW-managed research consortium that operates about 100 lightning detection stations around the world, from Antarctica to northern Finland. By seeing precisely when lightning reaches three or more different stations, the network can compare the readings to determine a lightning bolt’s size and location.

The network has operated since the early 2000s. For the new study, the researchers looked at 2 billion lightning strokes recorded between 2010 and 2018. Some 8,000 events — one in 250,000 strokes, or less than a thousandth of a percent — were confirmed superbolts.

“Until the last couple of years, we didn’t have enough data to do this kind of study,” Holzworth said.

The authors compared their network’s data against lightning observations from the Maryland-based company Earth Networks and from the New Zealand MetService.

The new paper shows that superbolts are most common in the Mediterranean Sea, the northeast Atlantic and over the Andes, with lesser hotspots east of Japan, in the tropical oceans and off the tip of South Africa. Unlike regular lightning, the superbolts tend to strike over water.

“Ninety percent of lightning strikes occur over land,” Holzworth said. “But superbolts happen mostly over the water going right up to the coast. In fact, in the northeast Atlantic Ocean you can see Spain and England’s coasts nicely outlined in the maps of superbolt distribution.”

“The average stroke energy over water is greater than the average stroke energy over land — we knew that,” Holzworth said. “But that’s for the typical energy levels. We were not expecting this dramatic difference.”

The time of year for superbolts also doesn’t follow the rules for typical lightning. Regular lightning hits in the summertime — the three major so-called “lightning chimneys” for regular bolts coincide with summer thunderstorms over the Americas, sub-Saharan Africa and Southeast Asia. But superbolts, which are more common in the Northern Hemisphere, strike both hemispheres between the months of November and February.

The reason for the pattern is still mysterious. Some years have many more superbolts than others: late 2013 was an all-time high, and late 2014 was the next highest, with other years having far fewer events.

“We think it could be related to sunspots or cosmic rays, but we’re leaving that as stimulation for future research,” Holzworth said. “For now, we are showing that this previously unknown pattern exists.”

Co-authors are research associate professor and senior research scientist at the UW; and and at the University of Otago in New Zealand. The research was funded by the UW.

For more information, contact Holzworth at bobholz@uw.edu or 206-685-7410.

Humans have always been frightened and fascinated by lightning. This month, NASA is scheduled to launch a new satellite that will provide the first nonstop, high-tech eye on lightning over the North American section of the planet.

91Ě˝»¨ researchers have been tracking global lightning from the ground for more than a decade. Lightning is not only about public safety — lightning strike information has recently been introduced into weather prediction, and a 91Ě˝»¨study shows ways to apply it in storm forecasts.

“When you see lots of lightning you know where the convection, or heat-driven upward motion, is the strongest, and that’s where the storm is the most intense,” said co-author , a 91Ě˝»¨professor of Earth and space sciences. “Almost all lightning occurs in clouds that have ice, and where there’s a strong updraft.”

The recent , published in the American Meteorological Society’s Journal of Atmospheric and Oceanic Technology, presents a new way to transform lightning strikes into weather-relevant information. The U.S. National Weather Service has begun to use lightning in its most sophisticated forecasts. This method, however, is more general and could be used in a wide variety of forecasting systems, anywhere in the world.

The authors tested their method on two cases: the summer 2012 thunderstorm system that swept across the U.S., and a 2013 that killed several people in the Midwest.

“Using lightning data to modify the air moisture was enough to dramatically improve the short-term forecast for a strong rain, wind and storm event,” said first author , a former 91Ě˝»¨graduate student who now works for The Weather Company. His simple method might also improve medium-range forecasts, for more than a few days out, in parts of the world that have little or no ground-level observations.

The study used data from the UW-based , which has a global record of lightning strikes going back to 2004. Director Holzworth is a plasma physicist who is interested in what happens in the outer edges of the atmosphere. But the network also sells its data to commercial and government agencies, and works with scientists at the 91Ě˝»¨and elsewhere.

A few years ago Holzworth joined forces with colleagues in the 91Ě˝»¨Department of Atmospheric Sciences to use lightning to improve forecasts for convective storms, the big storms that produce thunderstorms and tornadoes.

Apart from ground stations, weather forecasts are heavily dependent on weather satellites for information to start or “initialize” the numerical weather prediction models that are the foundation of modern weather prediction.

What’s missing is accurate, real-time information about air moisture content, temperature and wind speed in places where there are no ground stations.

“We have less skill for thunderstorms than for almost any other meteorological phenomenon,” said co-author , a 91Ě˝»¨professor of atmospheric sciences. “This paper shows the promise of lightning information. The results show that lightning data has potential to improve high-resolution forecasts of thunderstorms and convection.”

The new method could be helpful in forecasting storms over the ocean, where no ground instruments exist. Better knowledge of lightning-heavy tropical ocean storms could also improve weather forecasts far from the equator, Mass said, since many global weather systems originate in the tropics.

The study was funded by NASA and the National Oceanic and Atmospheric Administration. , a 91Ě˝»¨professor of atmospheric sciences, is the other co-author.

The UW-based Worldwide Lightning Location Network began in 2003 with 25 detection sites. It now includes some 80 at universities or government institutions around the world, from Finland to Antarctica.

The latest thinking on how lightning occurs is that ice particles within clouds separate into lighter and heavier pieces, and this creates charged regions within the cloud. If strong updrafts of wind make that altitude separation big enough, an electric current flows to cancel out the difference in charges.

A bolt of lightning creates an electromagnetic pulse that can travel a quarter way around the planet in a fraction of a second. Each lightning network site hosts an 8- to 12-foot antenna that registers frequencies in the 10 kilohertz band, and sends that information to a sound card on an Internet-connected laptop. When at least five stations record a pulse, computers at the 91Ě˝»¨register a lightning strike, and then triangulate the arrival times at different stations to pinpoint the location.

The network’s shows lightning strikes for the most recent 30 minutes in Google Earth. An alternate shows the last 40 minutes of lightning in different parts of the world on top of NASA cloud maps, which are updated from satellites every 30 minutes. The program is the longest-running real-time global lightning location network, and it is operated by the research community as a global collaboration.

Lightning already kills hundreds of people every year. That threat may be growing — a recent study projected that lightning will become with climate change.

“The jury’s still out on any long-term changes until we have more data,” Holzworth said. “But there is anecdotal evidence that we’re seeing lightning strikes in places where people are not expecting it, which makes it more deadly.”

On Nov. 19, NASA is scheduled to launch the new satellite that will be the first geostationary satellite to include an to continuously watch for lightning pulses. Holzworth will help calibrate the new instrument, which uses brightness to identify lightning, against network data. NASA also funded the recent research as one of the potential applications for lightning observations.

“GOES-R will offer more precise, complete lightning observations over North and South America, which will supplement our global data,” Holzworth said. “This launch has been long anticipated in the lightning research community. It has the potential to improve our understanding of lightning, both as a hazard and as a forecasting tool.”

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For more information, contact Holzworth at 206-685-7410 or bobholz@uw.edu, Mass at 206-685-0910 or cmass@uw.edu and Dixon at ken.dixon@weather.com.

This scientific mission, led and funded by the U.S. Naval Research Laboratory, will simultaneously create and observe “dusty plasmas” in Earth’s outer atmosphere. These hot, charged clouds of ions, electrons and dust form and dissipate naturally when swift-moving objects move through the atmosphere — from a satellite launching into orbit to a meteorite burning up in the atmosphere. Dusty plasmas are thought to be a common source of interference for radar and radio communications.

“From a practical standpoint, normal atmospheric dynamics can get completely disrupted for a period of time,” said 91Ě˝»¨professor of Earth and space sciences , who is working on this project along with his departmental colleague professor .

Dusty plasmas are complex, transient mixtures of gas and dust that have been difficult to observe and characterize when they arise naturally. The mission of the Charged Aerosol Release Experiment II — or CAREII — is to use rocket engines to generate a dusty plasma and simultaneously measure its characteristics using sensors on the rocket itself. 91Ě˝»¨researchers designed and constructed instruments in the rocket that will measure the dusty plasma’s electrical field. Collaborators with NASA provided launch and support services, while scientists at the , under the project lead investigator Paul Bernhardt, provided additional instruments and the CRV7 rockets that will create the dusty plasma. The U.S. Department of Defense Space Test Program provided payload integration and launch services.

Plasmas are gases in a superheated and charged state. Scientists can predict the behavior of plasmas with a known composition based on the types of gases and other particles present. But dusty plasmas are too intricate to predict using current theories of plasma physics, said Holzworth.

“Most plasmas in the atmosphere are actually ‘dusty’ in that they have extra stuff in them like dust and aerosols,” said Holzworth. “That’s a problem because our descriptions of plasmas and how they behave really don’t apply to much of anything that we study in the real world. So as we learn more we’re hoping we can improve our models and understand how dusty plasmas work in the atmosphere.”

The CAREII mission follows up on the success of in 2009, which used a rocket launched from NASA’s Wallops Flight Facility to create a dusty plasma in the skies above Virginia, which scientists observed using ground-based equipment.

The CAREII rocket will launch from the , a rocket launch facility above the Arctic Circle near Andenes, Norway.

“You want the dusty plasma illuminated but you want it dark on the ground,” said Holzworth. “That’s a narrow window that’s typically longer at higher latitudes — about a half hour every day.”

The CAREII mission has a two-week window starting on Sept. 7 to launch the rocket. The team will wait for ideal visibility and atmospheric conditions to send the rocket up into the atmosphere, McCarthy said.

After it ascends over 160 miles into the atmosphere, the rocket will begin to fall back to Earth. At about 145 miles above the Norwegian Sea, the forward section of the rocket — which contains most of the scientific instruments — will detach and aim its instruments toward the aft section. The aft section will then simultaneously fire 37 small CRV7 rocket engines, designed by Bristol Aerospace in Canada, creating a dusty plasma of known gas, ion and dust composition that will envelop the forward section of the rocket. Probes and sensors in the forward section — including the UW’s electric field instruments — will soak up information about the dusty plasma. Radar and stations on the ground and a nearby plane packed with cameras and sensors will also track and measure the artificial plasma.

“From start to finish, it will take 10 minutes,” McCarthy said.

The electric field instruments that Holzworth and McCarthy designed reside on four mechanical arms — or booms — that will be deployed outward from the rocket once the forward and aft sections separate. The booms keep the eight electric field sensors 6 to 10 feet apart so they can gather accurate information about electric fields within the dusty plasma.

“The sensors are separated far apart to get them away from the rocket body, which perturbs the plasma you’re trying to measure,” said McCarthy. “Also, we’re trying to measure small electric fields, so if we have things farther apart we can get a better signal.”

Holzworth and McCarthy hope that this project will give them a glimpse at how complex plasmas truly behave. The data they and their colleagues collect could illuminate how dusty plasmas in the atmosphere disrupt radio-based communications and tracking systems. But on a more fundamental level, CAREII could reveal basic characteristics about a common phenomenon.

“We don’t know what we’re going to see,” said Holzworth. “It’s very much an experiment of investigation.”

Holzworth and McCarthy have already started thinking of the types of sensors and equipment they would like on a future dusty plasma mission, should there be funding to get a CAREIII endeavor off the ground.

Funding for the CAREII project comes from the U.S. Naval Research Laboratory and the Department of Defense Space Test Program.

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For more information, contact Holzworth at 206-685-7410 or bobholz@uw.edu or McCarthy, who is currently in Norway for the launch, at mccarthy@u.washington.edu.

Update: the CAREII rocket was launched successfully on Sept. 16, .