Researchers fly into convection columns to study wildfire smoke

Below are excerpts from an article at Scienceline.org:

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“It’s a hot day in central Washington as a twin turboprop plane cruises southward. Through the cabin window, the jagged peaks of the Cascades rise in the west; to the east, a lush carpet of green vineyards and yellow wheat fields. But an hour into this flight, the blue skies give way to a white haze that rapidly turns to an alarming burnt orange.

The cabin begins to reek of smoke. The plane’s vibrations increase until the entire vessel is rocking and rolling. For a few seconds, the plane is literally free falling. All the while, outside the window, the sky grows darker and darker.

It’s another day at work for Arthur Sedlacek, an atmospheric chemist who is trying to solve one of the biggest mysteries in global climate change: the role that wildfires play when they spew millions of tons of soot skyward each year.

For five months in 2013, Sedlacek was part of a thrill-seeking team that flew into wildfire plumes in the Pacific Northwest and then Tennessee to measure exactly what’s in the soot. “Biomass burns are just this incredibly rich soup of raw material,” said Sedlacek, who is based at Brookhaven National Laboratory in New York.

[…]

It’s a tricky scientific problem because fires exert both warming and cooling effects on the climate.

Black smoke billowing up from a fire’s center has a warming effect because dark aerosols absorb light, keeping that energy trapped in our atmosphere. But as winds push aerosols away from the fire, the particles gather a reflective coating of organic matter, which has a cooling effect. White aerosols scatter light, sending that energy back into space.

[…]

So the smoke from wildfires can impact the climate directly, by reflecting and absorbing sunlight, and also indirectly, by influencing the formation of clouds. But how will these effects change as the frequency of wildfires increases in a warmer, drier world?

“That’s the million-dollar question,” Lewis said.

To try to answer that question as precisely as possible, Sedlacek, Lewis and their colleagues sampled 17 wildfires, seven urban plumes, and more than three dozen agricultural burns during 120 hours of flight time in 2013. Their research project is funded by the U.S. Department of Energy.

[…]

Sedlacek recalls one mid-summer flight that got especially hairy. “I remember about this time, hanging on, and thanking God I listened to the pilot when he said ‘buckle up’ because one of my colleagues had not and he went flying.” But that wasn’t the worst of it. In the thick of the plume the flight got even bumpier. Sedlacek overheard his pilot pleading with his engine, saying “stay with me baby, stay with me.”

As soon as the aircraft safely landed, Sedlacek pulled the pilot aside to ask why he was so worried about the engine. The pilot explained that aircraft engines need oxygen to burn fuel, and there’s very little oxygen in a smoke plume.”

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Vegetation fires affect snow melt

Wildfire, climate change and declining snowpacks are intricately connected. As temperatures rise, moisture-stressed forests can lead to bigger, hotter, longer and more frequent wildfires. In turn, wildfires can impact the amount and timing of snowmelt runoff according to a study by Anne Nolin and her Ph.D. student Kelly Gleason. The two researchers have presented new evidence showing that particles and burned woody debris from charred forests increase snowmelt and impact the hydrologic cycle — illustrated in this animation.

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Study finds firefighters more likely to get two types of cancer

According to a recently published study, firefighters in three major municipal fire departments were more likely to be diagnosed with lung cancer and leukemia than the general population.

Researchers examined the firefighting exposure and medical histories of 20,000 firefighters with over 1,300 cancer-related deaths and 2,600 cancer incidence cases in Chicago, Philadelphia, and San Francisco who were on duty between the years 1950 and 2009. This was one of the largest studies of its kind, and was the first to relate the time elapsed during fire runs to cancer risk.

Among eight types of cancers examined, they found slight, but statistically significant positive exposure–responses for lung cancer and leukemia risk. The researchers wrote:

These findings contribute to the evidence of a causal association between firefighting exposures and cancer.

The study did not address the health effects on wildland firefighters who, unlike structural firefighters, do not have access to an effective breathing apparatus to provide them clean air to inhale into their lungs. There could also be significant differences between the harmful effects of vegetation smoke and that produced by materials in structure fires.

Some wildland firefighters, especially those on hand crews, are routinely exposed to smoke-filled air for hours each day when assigned to a large fire, sometimes for 14 days. At other times they can be stationed in a smoky environment 24 hours a day for weeks at a time when inversions trap smoke. This frequently occurs in northwestern California, for example on the Six Rivers, Klamath, and Shasta-Trinity National Forests. In those cases even non-firefighters working in administrative positions at the Incident Base have been adversely affected by breathing contaminated air.

As we wrote in January, 2011:

There needs to be a concerted effort to conduct a similar study on wildland firefighters. It should be led by a physician/epidemiologist and should evaluate the long term health and occurrence of cancer and other diseases among wildland firefighters. There is a lot of grant money out there and it should be possible to get some of it pointed towards this overlooked niche of firefighting.

Other articles on Wildfire Today tagged cancer and firefighter health.

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Long-term changes in dead wood reveal new forest dynamics

Healthy forest ecosystems need dead wood to provide important habitat for birds and mammals, but there can be too much of a good thing when dead wood fuels severe wildfires. A scientist with the U.S. Forest Service’s Pacific Southwest Research Station (PSW) compared historic and recent data from a forest in California’s central Sierra Nevada region to determine how logging and fire exclusion have changed the amounts and sizes of dead wood over time. Results were recently published in Forest Ecology and Management.

DeadwoodPSW Research Ecologist Eric Knapp and a field crew visited three research plots initially established in 1929 in old-growth, mixed conifer stands on the Stanislaus National Forest. The stands had not burned since 1889 and were logged with a variety of methods later in 1929, shortly after the first survey of the plots. In this study, Knapp and a research crew first used digitized maps to locate and re-measure all live and dead trees in the plots. They later used old plot maps to reconstruct the number and size of downed logs in the 1929 plots and also surveyed logs in the present-day plots.

The research crew compared their present-day data with those from 1929 and documented a more than nine-fold increase in the density of standing dead trees (snags) coupled with a decrease in the average diameter of the snags. Additionally, they observed nearly three times as many logs on the ground (coarse woody debris), but found a substantial decrease in the size of these logs. The majority of downed logs in the present-day re-measurement were highly decayed.

“Because larger-sized dead wood is preferred by many wildlife species, the current condition of more, smaller, and more decayed woody pieces may have a lower ratio of habitat value relative to potential fire hazard,” says Knapp. Long-term dead wood changes in these forests pose a challenge for forest managers who must balance concerns for wildlife habitat with reducing the chance for damaging wildfires.

But dead trees, like live trees, can be managed. “To restore dead wood to conditions more like those found historically will require growing larger trees and reducing the addition of dead wood from small and intermediate-sized trees,” says Knapp. “Forest thinning, through mechanical means and/or fire has been shown to slow the mortality rate of the remaining trees. In addition, using prescribed fire and low-intensity wildfire, which preferentially consume smaller and more decayed wood, would shift the balance to larger and less decayed pieces of dead wood, and help reduce fuels that contribute to uncharacteristically severe wildfires.”

To read the paper, view or download the publication from Treesearch, the U.S. Forest Service online system for sharing free, full text publications by Research and Development scientists.

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Researchers link smoke from fires to tornado intensity

Some university and federal government scientists have concluded there is a link between smoke generated by vegetation fires in Central America and the intensity of tornadoes in the southeast United States. Their research was funded primarily by the federal government, but if you want a copy of their results it will cost you $38 — rather than making the government funded product available to taxpayers as an Open Access document.

Below are some highlights of their research.

Can smoke from fires intensify tornadoes?

“Yes,” say University of Iowa researchers, who examined the effects of smoke—resulting from spring agricultural land-clearing fires in Central America—transported across the Gulf of Mexico and encountering tornado conditions already in process in the United States.

The UI study, published in the journal Geophysical Research Letters, examined the smoke impacts on a historic severe weather outbreak that occurred during the afternoon and evening of April 27, 2011. The weather event produced 122 tornadoes, resulted in 313 deaths across the southeastern United States, and is considered the most severe event of its kind since 1950.

The outbreak was caused mainly by environmental conditions leading to a large potential for tornado formation and conducive to supercells, a type of thunderstorm. However, smoke particles intensified these conditions, according to co-lead authors Gregory Carmichael, professor of chemical and biochemical engineering, and Pablo Saide, Center for Global and Regional Environmental Research (CGRER) postdoctoral fellow.

They say the smoke lowered the base of the clouds and increased wind shear, defined as wind speed variations with respect to altitude. Together, those two conditions increased the likelihood of more severe tornadoes. The effects of smoke on these conditions had not been previously described, and the study found a novel mechanism to explain these interactions.

“These results are of great importance, as it is the first study to show smoke influence on tornado severity in a real case scenario. Also, severe weather prediction centers do not include atmospheric particles and their effects in their models, and we show that they should at least consider it,” says Carmichael.

“We show the smoke influence for one tornado outbreak, so in the future we will analyze smoke effects for other outbreaks on the record to see if similar impacts are found and under which conditions they occur,” says Saide. “We also plan to work along with model developers and institutions in charge of forecasting to move forward in the implementation, testing and incorporation of these effects on operational weather prediction models.”

In order to make their findings, the researchers ran computer simulations based upon data recorded during the 2011 event. One type of simulation included smoke and its effect on solar radiation and clouds, while the other omitted smoke. In fact, the simulation including the smoke resulted in a lowered cloud base and greater wind shear.

Future studies will focus on gaining a better understanding of the impacts of smoke on near-storm environments and tornado occurrence, intensity, and longevity, adds Carmichael, who also serves as director of the Iowa Informatics Initiative and co-director of CGRER.

Paper co-authors are Scott Spak ofthe UI Departments of Urban and Regional Planning and Civil and Environmental Engineering; Bradley Pierce and Andrew Heidinger of National Oceanic and Atmospheric Administration Satellite and Information Service Center for Satellite Applications and Research; Jason Otkin and Todd Schaack of the Cooperative Institute for Meteorological Satellite Studies, University of Wisconsin-Madison; Arlindo da Silva of NASA Goddard Space Flight Center; and Meloë Kacenelenbogen and Jens Redemann of NASA.

The paper “Central American biomass burning smoke can increase tornado severity in the U.S.” can be found online [for a fee of up to $38].

The research was funded by grants from NASA, U.S. Environmental Protection Agency, National Institutes of Health, National Oceanic and Atmospheric Administration, and the Fulbright-CONICYT scholarship program in Chile.

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National Ecological Observatory Network studies the High Park Fire

This video was published June 6, 2013.
In response to one of the worst wildfires in Colorado history, scientists from the Warner College of Natural Resources at Colorado State University (CSU) are leading a first of its kind, large-scale wildfire impact study on the High Park Fire in partnership with Colorado’s newest research facility, the National Ecological Observatory Network (NEON). The study will provide critical data to communities still grappling with how to respond to major water quality, erosion and ecosystem restoration issues in an area spanning more than 136 square miles.

Supported by a National Science Foundation (NSF) RAPID grant, the collaboration will integrate airborne remote sensing data collected by NEON’s Airborne Observation Platform (AOP) with ground-based data from a targeted field campaign conducted by CSU researchers. RAPID, short for Grants for Rapid Response Research, are used for proposals having a real urgency, including quick-response research on natural disasters. This effort is the first time a comprehensive airborne remote sensing system of this caliber will be used to enhance research on wildfire causes and impacts. The system will be able to detect remaining vegetation, identify plant species, ash cover, soil properties and other details to help illustrate how the fire burned–over the span of the entire fire scar.

“The NEON Airborne Observatory is transforming research by providing data to researchers and resource managers at temporal and geographic scales that could not previously be captured,” says Elizabeth Blood, NSF program director for NEON. “By combining ground measurements with data gathered from cutting-edge instruments in NEON airplanes, scientists are gathering potentially pivotal information about small scale and large scale processes that affect the spread of fires through forests and subsequent forest recovery.”

NEON will be to ecological health what an EKG is to heart health. Like an EKG generates snapshots of heart health by measuring heart activity at strategic locations on a patient’s body, NEON will generate snapshots of ecosystem health by measuring ecological activity at strategic locations throughout the U.S. Resulting ecological data will enable scientists to generate the first apples-to-apples comparisons of ecosystem health throughout large regions of the U.S. and the entire country over multiple decades.

Some of NEON’s data collection and educational operations have already begun, and others will begin incrementally until NEON becomes fully functional in 2017. All of NEON’s data, synthesized data products and associated educational materials will be made freely available on the Internet. These materials will thereby provide grist for groundbreaking analyses and educational activities by researchers, students, decision-makers, educators and the public.

NEON will be fully operational for some 30 years.

Articles at Wildfire Today tagged “High Park Fire”.

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