Researchers predict impacts of wildfire smoke after climate change

Above: Illustration from Harvard/Yale paper about the impacts of wildfire smoke following climate change. The colors indicate the number of smoke waves based on the primary smoke wave definition (cutoff= 6 μg/m3). The map on the left represents the present day (based on 2004-2009 data). The map on the right represents the future under climate change (based on projected data for the years 2046-2051). 

(Originally published at 11:39 a.m. MDT August 16, 2016; edited at 6 p.m. MDT August 17 to include this link to the research paper.)

Researchers at Harvard and Yale Universities have written a paper predicting the quantities of wildfire smoke that will be impacting residents of the United States in the years 2046 through 2051. Unfortunately it will cost you $40 to get a copy of the complete results of their research. Open Access to publically funded research is apparently not a priority at Harvard and Yale. (UPDATE: on August 17 we obtained a copy of the paper from one of the authors. But it would still cost $40 to buy it from the journal.)

The information here is obtained from the abstract and one document with supplementary material that was available.

To identify the highest-risk areas, the team used a fire prediction model and advanced atmospheric modeling to separate pollution caused by wildfires from other pollution sources and track the likely movement of smoke. The authors estimate that under future climate change, more than 82 million individuals will experience a 57 percent and 31 percent increase in the frequency and intensity, respectively, of Smoke Waves, which they define as ≥2 consecutive days with high wildfire-specific PM2.5.

Northern California, Western Oregon and the Great Plains are likely to suffer the highest exposure to wildfire smoke in the future. Results point to the potential health impacts of increasing wildfire activity on large numbers of people in a warming climate and the need to establish or modify U.S. wildfire management and evacuation programs in high-risk regions. The study also adds to the growing literature arguing that extreme events in a changing climate could have significant consequences for human health.

A call to Loretta J. Mickley, one of the authors, to ask about access to the publically funded research, was not immediately returned. UPDATE, August 17, 2016: Ms. Mickley did call the following day, and said she was disappointed that Harvard chose a non-Open Access journal in which to place the paper. She said she will send us a copy of the paper and it will also be posted on her web site in the next day or two. We will link to it later. The research was funded, she said, by the Environmental Protection Agency and the National Institutes of Health. In our opinion government agencies that fund research should only do so if the findings are made public at no additional charge.

The paper’s authors are J.C. Liu, L.J. Mickley, M.P Sulprizio, et al.

Scientists discover a new kind of fire whirl

The “blue whirl” can greatly reduce pollution

Above: A “blue whirl”.

Scientists attempting to develop a new method for mitigating oil spills by burning the oil were hoping to find a way to reduce the air pollution as the petroleum product burns. We’ve all see the thick, black smoke at an oil fire. They may be a step closer to their goal with the discovery of a new type of fire behavior — a previously unseen type of flame. They call it a “blue whirl”.

A paper published online August 4, 2016, in the peer-reviewed journal Proceedings of the National Academy of Sciences describes this previously unobserved flame phenomenon.

A yellow flame is a sign of very incomplete combustion and produces more particulates and air pollution than a blue flame like you see on a gas fueled stove.

So far they have only created the blue whirl in a chamber which has slits in the side that cause the air to rotate as it enters. Over a layer of water they injected a liquid fuel, n-heptane, and then ignited it. The flame at first is yellow but eventually transitions to a small, swirling blue flame.

“Blue whirls evolve from traditional yellow fire whirls. The yellow color is due to radiating soot particles, which form when there is not enough oxygen to burn the fuel completely,” said Elaine Oran, Glenn L. Martin Institute Professor of Engineering and co-author of the paper. “Blue in the whirl indicates there is enough oxygen for complete combustion, which means less or no soot, and is therefore a cleaner burn.”

“This is the first time fire whirls have been studied for their practical applications,” said Michael Gollner,  co-author of the paper and assistant professor of fire protection engineering at the A. James Clark School of Engineering at the University of Maryland.

One of the principles that reduces the pollution in the blue whirl is that plenty of oxygen is available for the fuel, helping it to burn more completely. Another is that the partially burned fuel remains in the flame longer, burning more completely.

An air curtain used near Custer, SD in 2013 produced very little visible smoke. Photo by Bill Gabbert.

Land managers sometimes use an “air curtain” to burn woody debris from fuel reduction operations. We wrote about this in 2013 after visiting one near Custer, South Dakota. The one we saw was trailer-mounted. The key to the system is pumping large amounts of compressed air into the fire box or open trench. Some of the devices create a vortex which traps the particulates keeping them in the burn zone longer, causing them to more completely burn while reducing their size and the visible smoke.

air curtain
Air Burner Inc.

Some oil spill remediation techniques include corralling the crude oil to create a thick layer on the water surface that can be burned in place, but the resulting combustion is smoky, inefficient, and incomplete. However, the Clark School researchers say blue whirls could improve remediation-by-combustion approaches by burning the oil layer with increased efficiency, reducing harmful emissions into the atmosphere around it and the ocean beneath it.

“Fire whirls are more efficient than other forms of combustion because they produce drastically increased heating to the surface of fuels, allowing them to burn faster and more completely. In our experiments over water, we’ve seen how the circulation fire whirls generate also helps to pull in fuels. If we can achieve a state akin to the blue whirl at larger scale, we can further reduce airborne emissions for a much cleaner means of spill cleanup,” explained Gollner.

Beyond improvements to fuel efficiency and oil spill remediation, there are currently few easy methods to generate a stable vortex in the lab, so the team hopes their discovery of the ‘blue swirl’ can serve as a natural research platform for the future study of vortices and vortex breakdown in fluid mechanics.

“A fire whirl is usually turbulent, but this blue whirl is very quiet and stable without visible or audible signs of turbulence,” said Huahua Xiao, assistant research scientist in the Clark School’s Department of Aerospace Engineering and corresponding author of the paper. “It’s really a very exciting discovery that offers important possibilities both within and outside of the research lab.”

NOAA experiments with forecasts for wildfire smoke

Wildfire smoke forecast
Wildfire smoke forecast for 6 p.m. MDT August 4, 2016

The National Oceanic and Atmospheric Administration is experimenting with a system that produces forecasts for the distribution of smoke from wildfires.

The examples of their products created at 6 a.m. MDT August 4 for near-surface smoke are included here — predicting conditions for 6 p.m. MDT August 4 (above) and 6 p.m. August 5 (below). Click the images to see larger versions.

Developers are collecting feedback from users to improve the model before it is considered for transfer into operations.

The HRRR-Smoke air quality modeling system simulates the emissions and transport of smoke from wildfires detected by the VIIRS/JPSS satellite fire product in high spatial resolution (3km) over the CONUS domain. Currently the model is run every 6 hours (00, 06, 12 and 18 UTC) to produce smoke forecasts for next 36 hours. The forecast products of near-surface and vertically integrated smoke concentrations are visualized on a GSD web-site in real time:

Wildfire smoke forecast
Wildfire smoke forecast for 6 p.m. MDT August 5, 2016

NASA’s report on developing an improved fire shelter is like the last episode of The Sopranos

In this video that NASA published today the agency explains their role in working with the U.S. Forest Service in developing a fire shelter that would hopefully increase the survival chances of a wildland firefighter entrapped in a vegetation fire. NASA is looking at materials they have used or plan to use on spacecraft that could reflect heat, provide some insulation from the outside temperatures which can exceed 2,000 degrees F, is thin and flexible enough to be folded and easily carried, is durable enough to be carried by tactical athletes for years, and weighs less than five pounds. That’s tough criteria.

They have been working on this for about a year, which we have covered here and here. When I saw that they had just published this video, I assumed they would report on their progress, saying perhaps that they had selected a new very promising space age material and would be make a bunch of prototypes for rigorous testing. But no. In the five-minute video they simply say they are looking at materials.

Maybe I’m naive, thinking that when the vast resources of NASA are used to design a fairly straightforward product with no circuit boards or interplanetary radios, after a year their scientists could report at least SOME progress.

The video simply stops after five minutes and 18 seconds. There is no conclusion, no timetable is laid out, and there is no cause for celebration or hope. The video just ends. Like the final episode of The Sopranos.

The Sopranos
The last scene in “The Sopranos” series finale.

More research confirms insect damage reduces wildfire severity

pine beetle damageAdditional research about the effects of insect outbreaks on fires confirms that generally, insect damage reduces burn severity.

Researchers from the University of Vermont and Oregon State University studied 81 Pacific Northwest fires that burned in areas affected by infestations of two prevalent bark beetle and defoliator species, mountain pine beetle (Dendroctonus ponderosae) and western spruce budworm (Choristoneura freemani). The fires spanned the years 1987 to 2011.

Insect fire severity

Few of the 81 fires occurred in forests while the needles were still on the trees in the red highly flammable stage of the outbreak shortly after the trees were killed by mountain pine beetles. The researchers recommend more studies in this area.

Aside from the transient red stage the burn severity decreased for more than 20 years following a MPB attack. Forests affected by western spruce budworm (WSB) exhibited a sharp decrease in fire severity immediately after an attack. This decrease is likely due to the fact that the WSB defoliates the tree, removing fuel from the canopy. The MPB kills the tree from the inside, leaving the dying needles on the tree until they fall off in one to two years. It makes sense that fewer fine fuels in the canopy would reduce the fire intensity and make it less prone to transition from a ground fire to a crown fire. But in the WSB-affected forests, the fire intensity slowly increased after 20 years to a neutral condition, then continued to increase in the 5 to 10 subsequent years. The researchers elaborated on that effect:

The relatively rapid increase of the budworm-fire coefficient with time indicates that the thinning effect on fuel profiles is less persistent for the defoliator (WSB) than for the bark beetle (MPB). In addition to relatively lower per-unit-area tree mortality impacts, WSB affects host forests that are more productive than those affected by MPB in the study region , leading to more rapid accumulation of live overstory and understory vegetation. Thus, as time elapses following WSB outbreaks, fuel density and connectivity likely increase in multiple strata, including dead surface fuels and total live biomass, the latter of which is associated with higher burn severity.

The research was conducted by Garrett W. Meigs, Harold S. J. Zald, John L. Campbell, William S. Keeton, and Robert E. Kennedy. The paper is titled, Do insect outbreaks reduce the severity of subsequent forest fires?

Our analysis

There is legitimate cause to be concerned about fires during the one or two year red needle stage after an insect attack, although I think more research studying actual fires is needed in this area. And there is danger from falling snags 5 to 20 years after an attack. Snags are dangerous for firefighters and any structures, hikers, traffic on roads, and any improvements that could be damaged by the falling trees. But as numerous researchers have found, after the needles are on the ground fire behavior, intensity, and severity decrease.

We first wrote about a post-attack decrease in burn intensity in a 2010 article titled Firefighters should calm down about beetle-killed forests.

Rather than panicking and rushing out to cut every tree affected by insects, preventive measures to keep forests healthy could be more effective, such as prescribed fire and thinning.

Group creates fire effects on soil network

FESPinThe group that has put on five conferences about the effects fire on soil has created a network to facilitate the sharing of information. You can find out more about the Fire Effects on Soil Properties International Network at their website and Facebook page.

Their next conference will be in Kruger National Park (South Africa) August 14-18, 2017. The previous conferences were in Spain, Turkey, Portugal, Lithuania, and Ireland.