Electromagnetic waves linked to particle fallout in Earth's atmosphere, new study finds

In a new study that sheds light on space weather's impact on Earth, Dartmouth researchers and their colleagues show for the first time that plasma waves buffeting the planet's radiation belts are responsible for scattering charged particles into the atmosphere.

The study is the most detailed analysis so far of the link between these waves and the fallout of electrons from the planet's radiation belts. The belts are impacted by fluctuations in "space weather" caused by solar activity that can disrupt GPS satellites, communication systems, power grids and manned space exploration.

The results appear in the journal Geophysical Research Letters. A PDF is available on request.

The Dartmouth space physicists are part of a NASA-sponsored team that studies the Van Allen radiation belts, which are donut-shaped belts of charged particles held in place by Earth's magnetosphere, the magnetic field surrounding our planet. In a quest to better predict space weather, the Dartmouth researchers study the radiation belts from above and below in complementary approaches -- through satellites (the twin NASA Van Allen Probes) high over Earth and through dozens of instrument-laden balloons (BARREL, or Balloon Array for Radiation belt Relativistic Electron Losses) at lower altitudes to assess the particles that rain down.

The Van Allen Probes measure particle, electric and magnetic fields, or basically everything in the radiation belt environment, including the electrons, which descend following Earth's magnetic field lines that converge at the poles. This is why the balloons are launched from Antarctica, where some of the best observations can be made. As the falling electrons collide with the atmosphere, they produce X-rays and that is what the balloon instruments are actually recording.

"We are measuring those atmospheric losses and trying to understand how the particles are getting kicked into the atmosphere," says co-author Robyn Millan, an associate professor in Dartmouth's Department of Physics and Astronomy and the principal investigator of BARREL. "Our main focus has been really on the processes that are occurring out in space. Particles in the Van Allen belts never reach the ground, so they don't constitute a health threat. Even the X-rays get absorbed, which is why we have to go to balloon altitudes to see them."

In their new study, the BARREL researchers' major objective was to obtain simultaneous measurements of the scattered particles and of ionoized gas called plasma out in space near Earth's equator. They were particularly interested in simultaneous measurements of a particular kind of plasma wave called electromagnetic ion cyclotron waves and whether these waves were responsible for scattering the particles, which has been an open question for years.

The researchers obtained measurements in Antarctica in 2013 when the balloons and both the Geostationary Operational Environmental Satellite (GOES) and Van Allen Probe satellites were near the same magnetic field line. They put the satellite data into their model that tests the wave-particle interaction theory, and the results suggest the wave scattering was the cause of the particle fallout. "This is the first real quantitative test of the theory," Millan says.

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Scientists eye longer-term forecasts of U.S. heat waves

Scientists have fingerprinted a distinctive atmospheric wave pattern high above the Northern Hemisphere that can foreshadow the emergence of summertime heat waves in the United States more than two weeks in advance.

The new research, led by scientists at the National Center for Atmospheric Research (NCAR), could potentially enable forecasts of the likelihood of U.S. heat waves 15-20 days out, giving society more time to prepare for these often-deadly events.

The research team discerned the pattern by analyzing a 12,000-year simulation of the atmosphere over the Northern Hemisphere. During those times when a distinctive "wavenumber-5" pattern emerged, a major summertime heat wave became more likely to subsequently build over the United States.

"It may be useful to monitor the atmosphere, looking for this pattern, if we find that it precedes heat waves in a predictable way," says NCAR scientist Haiyan Teng, the lead author. "This gives us a potential source to predict heat waves beyond the typical range of weather forecasts."

The wavenumber-5 pattern refers to a sequence of alternating high- and low-pressure systems (five of each) that form a ring circling the northern midlatitudes, several miles above the surface. This pattern can lend itself to slow-moving weather features, raising the odds for stagnant conditions often associated with prolonged heat spells.

The study is being published next week in Nature Geoscience. It was funded by the U.S. Department of Energy, NASA, and the National Science Foundation (NSF), which is NCAR's sponsor. NASA scientists helped guide the project and are involved in broader research in this area.

Predicting a lethal event

Heat waves are among the most deadly weather phenomena on Earth. A 2006 heat wave across much of the United States and Canada was blamed for more than 600 deaths in California alone, and a prolonged heat wave in Europe in 2003 may have killed more than 50,000 people.

To see if heat waves can be triggered by certain large-scale atmospheric circulation patterns, the scientists looked at data from relatively modern records dating back to 1948. They focused on summertime events in the United States in which daily temperatures reached the top 2.5 percent of weather readings for that date across roughly 10 percent or more of the contiguous United States. However, since such extremes are rare by definition, the researchers could identify only 17 events that met such criteria -- not enough to tease out a reliable signal amid the noise of other atmospheric behavior.

The group then turned to an idealized simulation of the atmosphere spanning 12,000 years. The simulation had been created a couple of years before with a version of the NCAR-based Community Earth System Model, which is funded by NSF and the Department of Energy.

By analyzing more than 5,900 U.S. heat waves simulated in the computer model, they determined that the heat waves tended to be preceded by a wavenumber-5 pattern. This pattern is not caused by particular oceanic conditions or heating of Earth's surface, but instead arises from naturally varying conditions of the atmosphere. It was associated with an atmospheric phenomenon known as a Rossby wave train that encircles the Northern Hemisphere along the jet stream.

During the 20 days leading up to a heat wave in the model results, the five ridges and five troughs that make up a wavenumber-5 pattern tended to propagate very slowly westward around the globe, moving against the flow of the jet stream itself. Eventually, a high-pressure ridge moved from the North Atlantic into the United States, shutting down rainfall and setting the stage for a heat wave to emerge.

When wavenumber-5 patterns in the model were more amplified, U.S. heat waves became more likely to form 15 days later. In some cases, the probability of a heat wave was more than quadruple what would be expected by chance.

In follow-up work, the research team turned again to actual U.S. heat waves since 1948. They recognized that some historical heat wave events are indeed characterized by a large-scale circulation pattern that indicated a wavenumber-5 event.

Extending forecasts beyond 10 days

The research finding suggests that scientists are making progress on a key meteorological goal: forecasting the likelihood of extreme events more than 10 days in advance. At present, there is very limited skill in such long-term forecasts.

Previous research on extending weather forecasts has focused on conditions in the tropics. For example, scientists have found that El Ni?o and La Ni?a, the periodic warming and cooling of surface waters in the central and eastern tropical Pacific Ocean, are correlated with a higher probability of wet or dry conditions in different regions around the globe. In contrast, the wavenumber-5 pattern does not rely on conditions in the tropics. However, the study does not exclude the possibility that tropical rainfall could act to stimulate or strengthen the pattern.

Now that the new study has connected a planetary wave pattern to a particular type of extreme weather event, Teng and her colleagues will continue searching for other circulation patterns that may presage extreme weather events.

"There may be sources of predictability that we are not yet aware of," she says. "This brings us hope that the likelihood of extreme weather events that are damaging to society can be predicted further in advance."

The University Corporation for Atmospheric Research manages the National Center for Atmospheric Research under sponsorship by the National Science Foundation. Any opinions, findings and conclusions, or recommendations expressed in this release are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

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Society not ready for heat waves coming with climate change

Health officials are better prepared for heat waves than they used to be, but they have more to do in the face of climate change, experts say.

Denny Simmons, Evansville Courier & Press/AP

Evelyn Levitt, 7, kneels in the waters of Old National Bank's fountain in Evansville, Ind., on June 25.

Denny Simmons, Evansville Courier & Press/AP

Evelyn Levitt, 7, kneels in the waters of Old National Bank's fountain in Evansville, Ind., on June 25.

"Nationally and internationally we are much more aware of the danger of extreme heat than we were in 1995," says sociologist Eric Klinenberg, author of Heat Wave: A social autopsy of disaster in Chicago, about the three-day heat wave that caused 739 excess deaths and thousands of hospitalizations in 1995.

"We're more prepared than we were in 1995. A lot of Americans are still vulnerable, and our power grid is vulnerable, too."

Medical workers reported few problems related to the past week's heat wave in parts of the USA that suffered extreme temperatures but were spared Friday night's storms that knocked out power to more than 3 million customers.

But in the District of Columbia, where heat and power outages struck together, sick patients at home who rely on electronic medical devices suffered doubly, and hospitals had to improvise, says Bill Frohna, chairman of the emergency department at MedStar Washington Hospital Center. "Before the storm came we saw some heat-related stuff, but once you throw the power issue on top of the heat, families didn't know what to do," Frohna said. "When no one has power they don't have a backup plan."

Even the Washington hospital had a plan for heat and a plan for outages, but not a plan for the two together, Frohna said.

After storms cut power to millions, hospital workers Saturday saw a spike in patients with chronic diseases who need electricity to operate home dialysis units and machines that deliver intravenous fluids, medications, tube feedings and oxygen, Frohna said.

Many arrived at the hospital with temperatures of 104 and could have been discharged after emergency cooling treatment and hydration, if they had a safe place to go, but they didn't, Frohna said.

Instead, hospital workers opened waiting spaces in part of the emergency room and the hospital's central registration area to let patients convalesce with their family members while caseworkers searched for cool, safe places with power where they can be sent.

Overall, the hospital saw a daily increase of 15% to 30% above normal during the weekend and Monday, Frohna said.

"Saturday (was) one of our biggest Saturdays in recent memory," he said.

Parts of the country that did not lose power because of the storm fared better.

In Indiana, where the heat wave has been going strong for a week, 153 emergency patients visited the state's emergency rooms for heat-related issues in all of last week, says Amy Reel, spokeswoman for the Indiana State Department of Health. The number of heat-related injuries has been relatively small because everyone is taking the heat seriously, says Wishard Hospital emergency physician John Boe. "There's more awareness of how dangerous this kind of weather can be," Boe said.

The news media have gotten better at getting the word out. Hospitals are better prepared. Public officials have made more cooling centers available and neighbors are checking on neighbors without air conditioning, Boe said.

Boe, who teaches at Indiana University's Department of Emergency Medicine, says the Chicago heat wave of 1995 was a turning point in his field.

"In our teachings, they always talk about the Chicago heat wave," he said.

Multiple factors led to the high death toll of the Chicago heat wave, Klinenberg says. High humidity combined with triple-digit heat and little nighttime cooling to turn the lakeside city into a furnace. Mayor Richard Daley and the city's fire and health commissioners were away on vacation. And the city failed to implement its plan for extreme heat, Klinenberg says.

High demand for electricity caused outages, and much of the city lost water as residents opened hydrants to cool off and then fought with city officials trying to close them. Most of the fatalities were elderly, isolated bachelors in the poorest sections of town, Klinenberg says.

Even worse disasters happened in Europe in 2003, when 70,000 excess deaths were caused by an extreme heat event that lasted three weeks, and in Russia in 2010, when a heat wave caused 50,000 excess deaths.

The USA has yet to experience such an extreme heat event, but some experts believe that with climate change it's only a matter of time.

Climate projections see global warming driving longer, warmer and more frequent heat waves for North America in coming years, says Princeton climate scientist Ngar-Cheung Lau.

Essentially, global warming raises the odds of heat waves, and at the same time worsens their effects due to the warmer temperature it brings on average, he says. "One cannot attach certainty to any one weather event being driven by climate change, but this heat wave is certainly striking in its size, severity and duration, similar to the sort of heat waves seen in climate projections," Lau says.

Klinenberg says cities such as Washington, Philadelphia and New York City are ill prepared.

"We need to make sure that cities can get through the worst heat wave," he says. "In New York City, police officers drive through streets using loudspeakers asking people to turn down their air conditioning during the day. The power grid can't handle it."

Contributing: Dan Vergano

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Strong winds whip up waves, down trees in Midwest (Reuters)

James Kelleher

CHICAGO (Reuters) – A gusty cold front sweeping into the Midwest from Canada triggered gale, rip current and shoreline flood warnings along Lake Michigan on Friday and whipped up waves as high a 23 feet, the National Weather Service said.

Areas of North and South Dakota, Minnesota, Iowa, Wisconsin, Illinois, Michigan, Indiana, Ohio and adjoining parts of Canada - were buffeted by winds as high a 70 miles an hour and downed trees, knocked out power and prompted the closure of waterfront parks in several states.

In Wisconsin's Door County, a picturesque peninsula that juts out into northern Lake Michigan popular this time of year with tourists seeking fall color, all state parks and trails were closed until next week. The state's Department of Natural Resources said this was because of closed roads, downed trees and unsafe conditions.

No injuries were reported.

"We have all available local crews at work clearing roads and more help is on the way," said Dan Schuller, director of the DNR's Wisconsin State Parks and Trails system.

"We are concentrating on damage assessment and clearing of roads to campgrounds and other high use areas. Campers currently in the parks are being asked to leave ... We will reopen all properties as soon as they can be declared safe for visitors."

Chicago lived up to its nickname as the "Windy City" on Friday as huge swells forced the closure of the city's 18.5 mile lakefront bike and running path.

Mark Bardou, a meteorologist with in the Chicago bureau of the NWS, said some of the strongest winds associated with the storm were measured over the Great Lakes, where gusts neared 65 knots an hour, about 75 miles an hour, and buoys in the middle of the lake measured swells as high as 23 feet.

(Editing by Greg McCune)

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21-Foot Waves, Wild Winds Assault West Michigan (ContributorNetwork)

It was a crazy day, weather-wise, in West Michigan and more is expected today and Saturday. Gale-force winds, 21-33 foot waves on Lake Michigan, torrential rains blasted the western counties. Temperatures are dropping into the 30s this evening. Over on the east side, Detroit gears up for 18-foot waves on Lake Huron and seven foot waves on little Lake St. Clair.

Michigan may not be seeing the hurricane winds and rains that plague Florida and the east coast, but gale force is enough to knock out the power and create hazards for locals. Most of Michigan is outlined in small craft advisories and all the lakes are pink, meaning gale-force winds on the lakes.

High winds and rain knocked down trees and damaged power lines in several areas in West Michigan. This came on top of storm damage along the lakeshore, earlier in the week, too. The Lake Express car ferry which shuttles passengers across Lake Michigan from Muskegon, Mich., to Milwaukee Wis., canceled scheduled passages on Friday, due to wind advisories on the lake. Ludington's S.S. Badger, a car and tourist ferry also canceled service.

Though not as large as Lake Superior up north, we locals have always referred to Lake Michigan as the "big lake." Winds and high waves on the lake, can be more difficult to navigate even than out on the ocean. Bill Moore, Sylva, N.C., is a seasoned boater. He also served on different ships in Vietnam.

He explains sailing on the Great Lakes is completely different than sailing on the ocean. For one thing, the Great Lakes are more like small seas, than lakes. On the ocean, high waves appear as swells. On the lake, there are shorter distances between waves especially close to shore and near harbors. Waves "crest" in a shorter space, creating white caps. 14-20 foot waves (the current highs) on the lake can be more treacherous because there are more of them in a smaller space.

Also, the majority of boats on the Great Lakes are speed boats, pleasure crafts, yachts, sailboats and fishing boats. These vessels aren't designed for rough seas. There are fewer safety requirements for these smaller boats. Life jackets, flares and safety equipment are mandatory, but skippers aren't made to take boater safety courses. Many do, but licenses aren't required.

When storms and rough waters hit, this means more amateur boaters are unprepared for conditions. It's essential that boaters respect the lake and it's capacity for danger. Boaters should keep a marine radio on board. Here are mobile weather alerts and cellphone apps for land and marine conditions.

Marilisa Kinney Sachteleben writes about wild weather from 25 years teaching science.

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Quote Roundup: Do Hurricane Predictions Make Waves with Tampa Residents? (ContributorNetwork)

Tampa, Fla., residents can't help but hear about hurricane season each year, and most wonder at our luck in this regard: the area hasn't seen a direct hit from a hurricane in over 90 years.

Last week, the National Oceanic Atmospheric Administration released its hurricane predictions for the 2011 Atlantic Basin season, which starts June 1. The agency's forecast indicates we're in for a bumpy ride this year, with higher-than-average numbers for named storms and major hurricanes. So, how do locals prepare for hurricane season? Do the NOAA predictions make people more likely to rethink their hurricane preparedness?

"I maintain the same level of preparedness all the time, to be honest. I always keep bottled water on hand, canned food, and food that doesn't require refrigeration or heat to prepare or eat. There are always batteries in my flashlights (I test them regularly) and jar candles in every room. If there's a storm coming, I'll get cash from the ATM and fill the tank on my car, just in case. I'll check our water supply and maybe buy an extra case when I shop, or fill a prescription early. Beyond that, I don't buy into the media frenzy that happens every time they name a storm. I stay prepared all the time because we live in Florida. It's smart to stay ready rather than fight crowds when it's allegedly 'go time.'" -- Angie Nash, teacher, Clearwater

"I really don't pay attention to them. They've been wrong more often than they've been right. I have supplies ready here, but it's nothing specifically for hurricanes." -- Ryan Opel, government contractor, Riverview

"I haven't lived in Tampa all my life, but it's been a long time. My husband's been dealing with it a lot longer, so I trust his judgment. I know he keeps a close eye on the tracking. One thing I do find annoying is that when we moved into this house we made an investment to put a coating on the windows that's supposed to help with breakage and eliminate the need to board up all the windows, and the insurance company didn't give any kind of discount for it." -- Sara Rashas, scopist, Lutz

"We get pretty concerned, but we're already pretty prepared. We have plenty of canned goods, gallons of water, but we do get a little complacent just because it hasn't happened to us yet, not directly anyway. In Puerto Rico, we used to get a lot of hurricanes, so we're pretty used to it. In all, though, I think people who have lived through hurricanes do heed the warnings, but get complacent regardless." -- Mave Christian, nurse, Tampa

"I really don't do anything differently until I have to. I have lived in Florida my entire life. I don't even really think about it at all unless we have to evacuate, then I get what we need." -- Melissa Webster Conway, daycare aide, Crystal River

"I hadn't heard that we're having a busier than average season, but I've been duped in the past. I'm one of those jaded Floridians who has a few canned goods and bottled water. I also have a phone you can plug into the wall. Everything seems to go around us. We're in this perfect little hidey hole in Florida. I've had more damage done to my house and around my house when they've predicted a sunny day." -- Lindsay Fisher, karate studio director, Lutz

"I have lived in Florida since 1973. For almost 30 years, I lived near the beach. The only time I get really nervous is if there's a specific storm headed our way. I'm always prepared. We have a generator, because any strong storm usually knocks out our power. We're in a good location. My daughter and her family plan to evacuate here if there's ever a storm headed to Tampa." -- Debbie Smith, retired nurse, Gainesville

"After living in Florida for over 20 years, I have to say that I'm rather laid back about the subject. It doesn't matter to me if they say it's going to be a bad hurricane season since I've heard it too many times before. Most times, the season passes without cause. I deal with one storm at a time and what it brings us. If a storm were to hit, I think we could manage quite well for a time. My husband and I have talked about where we'd go if a storm came close. We agree that we'd leave our house and get to safer ground if things were looking bad. We have a 4-year-old so I think this makes us think a bit differently than we would have in the past. I think the most important thing that you can do is just stay informed about the weather, because it could change at any moment." -- Susan Eidam, homemaker, Tampa

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