News that doesn't receive the necessary attention.

Friday, May 15, 2015

Central America biomass burning increased severity of Southeast US tornadoes in 2011 per AGU study. Such fires are set every year in Central America to clear land for farming-National Geographic

2/11/15, "Deadliest Tornado Outbreak in Decades Was Fueled by Smoke From Land Clearing. April 2011 saw the worst day of US tornadoes since 1974, and a new analysis points to fires in Central America as part of the cause." National Geographic, Devin Powell 







"A 2011 tornado that ravaged Tuscaloosa, Alabama (shown in this aerial photo), may have owed some of its destructive power to particles of smoke that traveled more than a thousand miles from fires set in Central America. Photograph by Dave Martin, AP"

"Even experienced weather forecasters were taken aback by the ferocity of the 2011 tornado outbreak. On its worst day, April 27, more than 120 twisters touched down in the Southeast, doing $4.2 billion of damage and killing 316 people. Now a computer simulation of the day's events suggests that smoke drifting into the United States from fires set to clear farmland in Central America helped intensify the fatal wind funnels

Researchers publishing the finding in an upcoming Geophysical Research Letters hope that meteorologists will begin to consider air pollution a risk factor when making tornado forecasts. "I never expected to see an April like that," says Greg Carbin, a meteorologist at the the National Oceanic and Atmospheric Administration (NOAA) Storm Prediction Center in Norman, Oklahoma, who wasn't involved in the research. "Everything came together to produce an outbreak the likes of which hadn't been seen for nearly 40 years."

Smoke and other tiny airborne particles called aerosols have been linked to severe weather events before. Aerosols may quiet tropical storms and ramp up the amount of lightning dished out by thunderstorms, for instance. One study blamed human-made haze for an uptick in summer tornadoes and hailstorms, which are more common on weekdays along with exhaust-belching traffic.

Still, you won't hear about aerosols in local news coverage of storms; the science remains controversial. "There's a lot of debate in this area," says David Lerach, an atmospheric scientist at the University of North Colorado, in Greeley. "Some people think that the effects of aerosols on storms are insignificant, while others have staked their careers on it."

Even global climate change simulations struggle with "aerosols, which along with clouds remain the single greatest source of uncertainty in those models.

To pin down smoke's influence on tornadoes, Pablo Saide, an atmospheric scientist at the University of Iowa, in Iowa City, and his colleagues first turned to NASA's Aqua satellite. Its payload includes an infrared camera that in 2011 detected the heat of fires in Central America. Such fires are set every year, before the summer monsoons, to clear land for farming.

The spacecraft also measures sunlight reflected by aerosols, giving shape to the plume of smoke belched out by the fires. Estimates of the amount of smoke that reached the United States were fed into a computer simulation that included the weather conditions on April 27.

Even without any air pollution, the computer called for violent tornadoes. "We're not saying that the outbreak happened because of the smoke," says Saide. "We're saying that, given the conditions already in place, the smoke intensified the tornadoes.".Warm air rolling off plateaus in Mexico colliding with cold air from Canada had set the stage by destabilizing the atmosphere. And severe thunderstorms earlier in the season had left behind dangerous amounts of moisture.
But the smoke, particularly the black soot it contained, made a bad situation worse. Like a dark car interior, soot soaks up the sun and then radiates that energy as heat. Heating the atmosphere in the simulation led to cloud formation at lower heights, which is a common risk factor for tornadoes. Winds at low altitudes also became more variable in speed and direction, setting up wind shear, also an ingredient in tornado formation.

Jun Wang, an atmospheric scientist at the University of Nebraska-Lincoln who develops tornado simulations, said that the new study provides the most comprehensive look yet at smoke's influence on tornadoes.

The new findings are only one case study, though, a peek into an usually rare and destructive event. "This case is such an outlier in so many ways, it makes it difficult for me to believe the findings," says NOAA's Carbin.
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In the hopes of convincing Carbin and the forecasting community of the power of aerosols, Saide plans to test his simulations on other tornado outbreaks."

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"Abstract"

"Tornadoes in the Southeast and central U.S. are episodically accompanied by smoke from biomass burning in Central America. Analysis of the 27 April 2011 historical tornado outbreak shows that adding smoke to an environment already conducive to severe thunderstorm development can increase the likelihood of significant tornado occurrence. Numerical experiments indicate that the presence of smoke during this event leads to optical thickening of shallow clouds while soot within the smoke enhances the capping inversion through radiation absorption. The smoke effects are consistent with measurements of clouds and radiation before and during the outbreak. These effects result in lower cloud bases and stronger low-level wind shear in the warm sector of the extratropical cyclone generating the outbreak, two indicators of higher probability of tornado genesis and tornado intensity and longevity. These mechanisms may contribute to tornado modulation by aerosols, highlighting the need to consider aerosol feedbacks in numerical severe weather forecasting."

"Funded by


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Comment: There's no money in telling the truth about aerosol air pollution which is a completely different issue than the notion of excess human CO2. The two have different causes and different solutions. As to CO2, even though China controls global CO2 and the US has no ability to reduce global CO2, US politicians tell us because the US emitted more CO2 in our shameful past we must pay for this in perpetuity. No amount of money will ever make it right of course, but we must pay and keep silent. It was US politicians--not scientists or the UN--who in 1990 set up permanent mechanisms in the Executive branch to fund the climate scare industry by stealing taxpayer dollars. US industry must be reduced to zero and we must sign a so-called climate treaty to formalize even greater transfer of US taxpayer wages to the UN and others. The multi-trillion dollar crime exists today only because the US political class wants it to. The poor and needy are starved of needed tax dollars in favor of millionaire and billionaire "climate" investors, cronies, potentates and of course "climate science" which has to come up with new excuses for politicians to keep stealing taxpayer money and funneling it to them. Aerosols put the focus on "air pollution as a risk factor" in severe weather events as the National Geographic article says in paragraph 2. Not a new idea, "Smoke and other tiny airborne particles called aerosols have been linked to severe weather events before....Still, you won't hear about aerosols in local news coverage of storms." ...










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