Persistent plume

Analysis of massive 2017 cloud of wildfire smoke will help calibrate climate models, including modeling of nuclear winter, geoengineering

University of Colorado at Boulder

A towering cloud of smoke billows in the Willow Fire near Payson, Arizona on July 8, 2004. Credit: Eric Neitzel/ Wikimedia Commons

A towering cloud of smoke billows in the Willow Fire near Payson, Arizona on July 8, 2004. Credit: Eric Neitzel/ Wikimedia Commons

Thunderstorms generated by a group of giant wildfires in 2017 injected a small volcano’s worth of aerosol into the stratosphere, creating a smoke plume that lasted for almost nine months. CIRES and NOAA researchers studying the plume found that black carbon or soot in the smoke was key to the plume’s rapid rise: the soot absorbed solar radiation, heating the surrounding air and allowing the plume to quickly rise.

The billowing smoke clouds provided researchers with an ideal opportunity to test climate models that estimate how long the particulate cloud would persist–after achieving a maximum altitude of 23 km, the smoke plume remained in the stratosphere for many months.

These models are also important in understanding the climate effects of nuclear war or geoengineering.

“We compared observations with model calculations of the smoke plume. That helped us understand why the smoke plume rose so high and persisted so long, which can be applied to other stratospheric aerosol injections, such as from volcanoes or nuclear explosions,” said NOAA scientist Karen Rosenlof, a member of the author team that also included scientists from CU Boulder, Naval Research, Rutgers and other institutions. The findings were published today in the journal Science.

During the summer of 2017, wildfires raged across the Pacific Northwest. On August 12 in British Columbia, a group of fires and ideal weather conditions produced five near-simultaneous towering clouds of smoke or pyrocumulonimbus clouds that lofted smoke high into the stratosphere. Within two months, the plume rose from its initial height of about 12 km up to 23 km and persisted in the atmosphere for much longer–satellites could spot it even after eight months.

“The forest fire smoke was an ideal case study for us because it was so well observed by satellites,” said lead author Pengfei Yu, a former CIRES scientist at NOAA, now at the Institute for Environment and Climate Research at Jinan University in Guangzhou, China.

Instruments on two satellites–the International Space Station and NASA’s CALIPSO–and on NOAA’s balloon-borne Printed Optical Particle Spectrometer, or POPS, provided the aerosol measurements the researchers needed.

Yu and his colleagues compared those observations with results from a global climate and chemistry model to get a match for how high up the smoke rose and how long it lasted in the atmosphere. With measurements of the rise rate and evolution of the smoke plume, the researchers could estimate the amount of black carbon in the smoke and how quickly the organic particulate material was destroyed in the stratosphere.

They found that the plume’s rapid rise could only be explained by the presence of black carbon or soot, which comprised about 2 percent of the total mass of the smoke. The soot absorbed solar radiation, heated the surrounding air and forced the plume high into the atmosphere.

Next, the team modeled the degradation of the smoke plume in the atmosphere. They found that to mimic the smoke’s observed rate of decay over the multi-month plume, there had to be a relatively slow loss of organic carbon (through photochemical processes) that previous nuclear winter studies had assumed to be very rapid.

“We have a better understanding of how our models represent smoke. And because we can model this process, we know we can model other aerosol-related processes in the atmosphere,” said Ru-Shan Gao, a NOAA scientist and one of the paper’s co-authors.

CU Boulder’s Brian Toon and Rutgers University’s Alan Robock, also co-authors of the new paper, are particularly interested in what the findings mean for the climate impacts of nuclear explosions, which include a severe cooling impact dubbed “nuclear winter.” In modeling the climate impacts of nuclear war, Toon, Robock and others have long expected that massive fires would create smoke plumes that could also be lofted well up into the stratosphere.

“While the rise of the smoke was predicted in the 1980s, the 2017 fire in British Columbia is the first time it has been observed,” Toon said.

“It was exciting to get confirmation,” Robock added.

Moreover, the detailed observations made during the 2017 fire–such as the somewhat longer-than-expected persistence of organic matter–are fueling more modeling, the two noted. It’s possible that the cooling impacts of a nuclear winter could last somewhat less long than models have predicted to date, Toon said, but work is ongoing.

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From EurekAlert!

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43 thoughts on “Persistent plume

    • The greenies won’t like it because its really science for tackling climate change in ways other than the green pet emission control. Green blob attack on the paper in 5 .. 4 .. 3

    • Wait, wait. If the models cannot model normal climate, how in heck are they going to doing anything useful regarding smoke and volcanic plumes? Wow. Truly the totally blind leading the blind and claiming clear sight.

  1. ““While the rise of the smoke was predicted in the 1980s, the 2017 fire in British Columbia is the first time it has been observed,” Toon said.

    “It was exciting to get confirmation,” Robock added.”

    So lets get this straight, they made a prediction in the 1980s and waited around all this time for a bunch of fires
    to start under the right conditions to test their model.

    Gosh, they just should have set off a nuke or started some fires to test their models. Like real science.

    same with C02, lets drive it up to 1000 ppm and really test things.

    • There is the matter of having the satellites and balloon based spectrometers, and furthermore it is quite common for scientists to test predictions made by others.

    • Well it’s going to keep rising for at least next 30 years so I guess we will see part of your desired test.

    • “same with C02, lets drive it up to 1000 ppm and really test things.”

      Erm, shouldn’t we be conducting that research on Planet B?

      • ?? Planet B is the control planet, with only a few, scattered compounds for uber-wealthy elites to enjoy the solitude and natural beauty. You can’t go doing tests on planet B! You would ruin it!

      • It’s already been over 1000ppm and life at the time flourished throughout the Triassic, Jurassic, and Cretaceous. No runaway greenhouse, no hothouse Earth, and large leaf greenery with ultra mega fauna thriving

        • For the record, the Earth has two basic geological states, Ice-house conditions & Tropical conditions, we are in Ice-house conditions with ice at the Poles, & the atmosphere is relatively C02 starved from what I have read in non-alarmist (therefore due to be banned anytime soon) literature! However, Bryan A, as you already know, they don’t like “Inconvenient Truths”!

    • The natural level of CO2 was close to 2000 ppm in the Jurasic era, and 1000ppm is what market gardeners run their tunnel houses at, so your suggestion is not as silly as you thought it was.

      • Yes, that experiment worked so well for growing plants in real greenhouses that it’s used all the time now.

    • IIRC, a serious proposal was made at the time to validate the nuclear winter theory by making a detailed survey of an area of boreal forest within a military test and training range in Canada then torch it and observe. Vigorous protests by the Union of Concerned Scientists and environmentalists put a stop to it. An untested theory has more political clout than a failed one. I guess they could not take the risk.

    • Steven Mosher: “same with C02, lets drive it up to 1000 ppm and really test things.”

      WR: Agree. The avoidence of real tests / experiments in regard to climate is more than remarkable.

      Real measurements of coastal sea level rise can be performed by combining GPS measurements for the stations that are measuring sea level rise. In this way the influence of rise/subsidence of the stations themselves can be measured and added/subtracted to the observed change in sea level. A perfect way to get better and more reliable measurements. On my question how many European sea level stations had such a device installed Tom Wysmuller answered me: only one, in England.

      Not putting the GMS devices on all sea level measuring stations avoids the discovery of the reality of sea level rise.

      • Satellite measurements are not the “gold standard” because they are subject to the same tidal variations as sea stations. As the satellites scan one region, the sea level has shifted in adjacent and far-flung regions, making any “global volume” meaningless. Satellites must be calibrated with the sea stations to correct for drift in the satellite measurements.

    • same with C02, lets drive it up to 1000 ppm and really test things.

      Or we could drive it back down to 280 when the world was perfect. Of course we’d have to go back to the stone age to do it, but that’s OK, we know exactly how stone works, no need for experiment, we know exactly what life would be like because we’ve done it before.

      The 5 Billion people who die in the first 2 months are on your hands…

  2. “Within two months, the plume rose from its initial height of about 12 km up to 23 km and persisted in the atmosphere…”

    I don’t think the smoke plume was still intact after 2 months, so not sure if there is more to this story than this brief post. The smoke plume would disperse in the upper level winds or the jet stream as we see on satellite photo’s and there would no longer be any attachment of the black carbon or soot to the smoke plume so how would the Sun warm the soot and take the entire plume from 12 km to 23 km and then persist there? The story as written doesn’t make a lot of sense to me, so am wondering if this was actually a model interpretation they were viewing? Or maybe this is just plain racist climatism, with the evil black carbon and soot soaking up ‘heat’.

    When we used to slash burn logged clear cut blocks 25-30 years ago, there would be a mushroom cloud that could be up to 40,000-50,000 feet high within a few hours with jet liners modifying their route to go around them which the big ones having lightening/thunder activity. I doubt it was the Sun warming the soot in the mushroom cloud that first few hours, more like the thermal heat in the cloud from the intensely hot burn that caused the cloud to rise up to those heights nearly instantly. Even if you think about this for a minute, the cloud would be impenetrable by sunlight to cause much heating other than the surface, so what was that about?

    I am not sure what the point of this study was or is, but I don’t think they will be able to accurately jig their models to represent anything of any value from the conclusions they are drawing.

  3. They found that the plume’s rapid rise could only be explained by the presence of black carbon or soot, which comprised about 2 percent of the total mass of the smoke.

    Two percent? That’s a surprise. None of the references I googled gave a percentage of soot for forest fires. Anyway, the low percentage of soot seems to indicate more efficient combustion than I thought would be the case for a forest fire.

    Water vapor makes up the majority of smoke. even for forest fires

    As the smoke rises, the water vapor will give off energy by condensing. That should also contribute to the rise of the plume. Mind you, that would be limited by the same process that sets a limit to cloud height. Hmmm. Clouds absorb solar energy, yet their height is limited.

    It seems dodgy to claim that the only explanation of why the plume rose so high was due to solar heating of the soot. That’s the same kind of logic that says, all the other explanations are bunk, so CO2 must be the global thermostat. How about admitting that you don’t actually understand what’s going on.

  4. From my observation of burning large tracts of relatively dry vegetation, the mixture of smoke and moisture from the burning vegetation separates at a certain altitude with the heated moisture condensing and going higher and being a brighter white than the smoke.

    It seems to me that most of the initial energy going into the lofting of the smoke and moisture comes from the actual combustion of the vegetation. Has it been shown that when small black particles of carbon are released in air in the absence of a combusting source, their absorbed photons create a localized thermal updraft?

  5. “……predicted in the 1980s, the 2017 fire in British Columbia is the first time it has been observed…”. If they’ve been watching for the effect, and it occurred only once in 30 years, it sounds more like a random result that happened to match their expectations.

    • Well, like they tree of Yamal, their backwards scientific methods only require one sample that proves their hypothesis regardless of how many exist to refute it.

  6. “They found that to mimic the smoke’s observed rate of decay over the multi-month plume, there had to be a relatively slow loss of organic carbon (through photochemical processes)

    – that previous nuclear winter studies had assumed to be very rapid.”
    _________________________________________________

    “It’s possible that the cooling impacts of a

    – nuclear winter could last somewhat less long than models have predicted to date,

    Toon said, but work is ongoing.”

    _________________________________________________

    Kind’a contradictory, ain’t it. But work is ongoing.

  7. So how does all this differ from the Kuwaiti oil fires lit be retreating Iraqi soliders in the first Gulf War?

    Carl Sagan suggested disaster, see https://www.baltimoresun.com/news/bs-xpm-1991-01-23-1991023131-story.html

    In fact, the fires were put out in eight months, and there was no analog to nuclear winter, see https://go.galegroup.com/ps/anonymous?id=GALE%7CA10393540&sid=googleScholar&v=2.1&it=r&linkaccess=abs&issn=00368075&p=HRCA&sw=w

    It’s protected by paywall, but the article preview says:

    AS WAR LOOMED IN THE MIDDLE EAST EARLY in January, atmospheric scientists in the United States and Britain went scurrying to their computers to check out a potential nightmare scenario: Could a major conflagration in Kuwait’s oil fields trigger a climate catastrophe akin to the hypothesized “nuclear winter” that got so much attention in the 1980s? They had reason to worry because back in 1986 and 1987, computer modelers had indicated that if bombs ignited enough oil refineries, the pall of dense smoke could cause a significant change in the weather, perhaps shutting down the Asian monsoon cycle. On the very day war erupted, however, the scientists came up with a reassuring preliminary answer: A local chill might be triggered, but there is scant likelihood that global cooling would result.

    Among the scientists who raised the specter that soot from a huge fire in the Gulf would block out sunlight and cause a big chill were Richard Turco, a builder of atmospheric models at the University of California at Los Angeles, and Brian Toon, an atmospheric researcher at the National Aeronautics and Space Administration’s Ames Research Center. Both collaborated with Carl Sagan of Cornell University on the original nuclear winter…

    • Wildfires are “Covers the ENTIRE top of the World!”. Yeah, right.

      Or were they referring to the “very unusual event” of CO blowing around?

  8. “The billowing smoke clouds provided researchers with an ideal opportunity to test climate models ”

    An ideal opportunity to show how as a wildfire creates a heated air mass with elevated levels of CO2, back radiation is impacted. Where is the chart of back-radiation over time during and after this fire?

    Why aren’t they measuring back-radiation?

    Did they squander “an ideal opportunity to test climate models “?

  9. I wonder if that 2% carbon soot has anything to do with the remarkable altitude of the smoke-plume top: There are a few other things to consider. First of all the location and date, the Gulf of California monsoon and its low-level humidity probably is just beginning to reach AZ, pushing into a very hot, at the surface, and very dry Continental-Tropical air mass. So, the lapse rate on the dry side is probably close to dry-adiabatic all the way up to the 500 mb level and beyond. So, the heat of moisture condensation in the cloud is lifting the top to the unusually high, 23 km altitude.

    What seems to be interesting is at what altitude does the atmosphere begin to abruptly be very slow at cleansing itself of fine particles. Smoke is usually gone after several days. Volcanic ash usually does not hang around for very long. An unusually violent eruption, such as Pinatubo, does inject ash above this threshold altitude, so ash and droplets persisted for at least three years. And, I recall reading a paper where the February 2013 asteroid explosion over Russia left fine particles high in the atmosphere for a long time. And now this article demonstrates that forest fire smoke, injected high into the atmosphere, persisted.

    So, the question seems to be, what altitude in the stratosphere is critical such that fine particles to linger?

  10. Steven Mosher: “same with C02, lets drive it up to 1000 ppm and really test things.”

    We can already project what will happen.

    Humans will be given another 12 years to “save the planet” (-:
    The new tipping points, will be adjusted appropriately to just higher than whatever the the current global temperature and CO2 level is.

    Al Gores trillionaire great, great grandson will be telling us how great great grandpa Gore predicted everything that has happened so far, even though it was 100 years ago, so we can believe him that the polar bears will soon die off when the Arctic sea ice all melts away in the Summer of 2120.

    The United Nations led Climate Accord, that was initially passed over 100 years ago will pass version #13, with world powers, India and China continuing to agree to consider reducing CO2 emissions, this time by the year 2130.

    The United States, which passed the Green New Deal in 2025 and joined back up with the Climate Accord, will be allowed to increase CO2 emissions again under this latest agreement, as their status has been downgraded/revised to a poor country. The US will then be eligible for climate reparations from rich countries like India and China that are destroying the planet with their CO2 pollution.

    The Severe Storm Forecast Center in the United States, is forced to close operations after funding from the collapsing government is only available for the most important life threatening services related to natural disasters. This had been widely expected for some time, since the US had not experienced a tornado in almost 10 years.
    Numerous lawsuits from storm chasers remain unsettled based on their claims of losses.

    Energy prices, which immediately quadrupled in the US after it imposed the Green New Deal plan, continue to keep it in a continual depressed state.

    The good news is that food prices have continued to stay at historic lows, thanks to a world wide glut in food production caused by photosynthetic, atmospheric fertilization of crops which have experienced stratospheric yields, never imagined before(outside of the greenhouses, which are saving tons of money because they no longer need to run carbon dioxide enrichment generators……….they can just bathe plants in the glorious, ambient atmospheric level of CO2 at 1,000 parts per million)

  11. ” . . . will help calibrate climate models, including modeling of nuclear winter.”

    Can anybody explain the reason for doing that? And morbid curiosity doesn’t count.

  12. “Thunderstorms generated by a group of giant wildfires in 2017……..” I assume this is meant to read A group of giant wildfires generated by thunderstorms in 2017

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