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Climate: Pollution causing drop in monsoon rains

A classic monsoonal flow of moisture, moving clockwise around a

A classic North American monsoonal flow of moisture, moving clockwise around an area of high pressure.

‘Human activity has played a significant role in altering the seasonal monsoon rainfall on which billions of people depend’

Staff Report

FRISCO — A 10 percent drop in overall monsoon rainfall in the northern hemisphere during past 50 years is outside the range of natural climate variability, Scottish researchers said after a detailed analysis of weather data.

After accounting for all the variables, the scientists said that emissions produced by human activity caused the drop. Tiny air particles from man-made sources — known as anthropogenic aerosols — were the cause. Continue reading

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Climate: Bioparticles in dusty air may be key to rain and snow formation

Tiny bioparticles in atmospheric dust play a big role in the formation of raindrops and snowflakes. bberwyn photo.

Tiny bioparticles in atmospheric dust play a big role in the formation of raindrops and snowflakes. bberwyn photo.

Researchers starting to take nuanced look at chemical composition of aerosols

Staff Report

FRISCO —Scientists have long known that tiny grains of airborne dust are key players in the formation of rain and snow, driving precipitation patterns across the drought-stricken western U.S. and other areas.

New research suggests that  the exact chemical make-up of that dust, including microbes found in it, is the key to how much rain and snow falls from clouds.  The information could help better predict rain events, as well as explain how air pollution from a variety of sources influences regional climate in general.

“We’ve learned that not all of the particles in the air at high altitudes have the same influence on clouds. We’re starting to think that these differences contribute to how rain gets distributed,” said Dr. Kim Prather, who presented her findings at the 248th National Meeting & Exposition of the American Chemical Society last week in San Francisco. Continue reading

Climate: Historic paintings offer atmospheric clues

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Many of J.M. Turner’s famed impressionist sky scenes were painted shortly after the 1815 eruption of the Tambora Volcano in Indonesia.

Study traces pollution levels by analyzing 500 years of art

Staff Report

FRISCO — Looking closely at some of the world’s great paintings from the past 500 years has enabled scientists to track the history of atmospheric pollution, based on the colors the artists used to depict the sky.

For example, when he Tambora volcano in Indonesia erupted in 1815, painters in Europe could see the colors of the sky changing. The volcanic ash and gas spewed into the atmosphere traveled the world and, as these aerosol particles scattered sunlight, they produced bright red and orange sunsets in Europe for up to three years after the eruption.

Continue reading

Forest fumes play big role in global climate

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What’s the role of coniferous trees in regulating climate?

Fast growth of particles from pine tree fumes surprises researchers

By Summit Voice

FRISCO — Forests may play a much bigger role in global climate than previously believed. In addition to cycling carbon, it appears that gases wafting from conifers quickly form small particles that can reflect sunlight and promote cloud formation, according to a new study that looked at forest aerosols at the molecular level.

“In many forested regions, you can go and observe particles apparently form from thin air. They’re not emitted from anything, they just appear,” said Joel Thornton, a University of Washington associate professor of atmospheric sciences. Continue reading

Study helps unravel the secret life of clouds

Air pollution can be a big factor in development of thunderclouds

Thundercloud over Peak 1

Air pollution can have a significant impact on the development of thunderclouds, causing cloud remnants to persist longer. bberwyn photo.

FRISCO — Air pollution can have a significant effect on the development of thunderhead clouds, causing the cloud remnants to persist high in the atmosphere long after thunderstorms dissipate. This, in turn, can affect daily temperature ranges, as the lingering clouds partially cool the Earth during the day with their shadows, but trap heat to keep nighttime temperatures warmer.

The new study, from the Department of Energy’s Pacific Northwest National Laboratory, helps answer long-running questions about how airborne pollutants affect climate warming. The findings will help provide a gauge for the accuracy of weather and climate models.

“This study reconciles what we see in real life to what computer models show us,” said atmospheric scientist Jiwen Fan. “Observations consistently show taller and bigger anvil-shaped clouds in storm systems with pollution, but the models don’t always show stronger convection. Now we know why.” Continue reading

Aerosols still a big missing piece of climate puzzle

sdfgsdfNew study suggests natural aerosols may be a bigger factor than previously thought

By Summit Voice

FRISCO — In their quest to better understand the role of aerosols in the Earth’s climate, researchers may have to try and find the cleanest parts of the atmosphere.

Knowing to what degree both human-caused and natural aerosols mask the effects of heat-trapping greenhouse gases is crucial to making accurate climate predictions, according to a new study that assessed 28 factors that could affect the uncertainties in cloud brightness.

Natural aerosols, such as emissions from volcanoes or plants, may contribute more uncertainty than previously thought to estimates of how the climate might respond to greenhouse gas emissions. Continue reading

Climate: Tracking atmospheric aerosols

New satellite data shows volcanoes are a bigger factor than industrial emissions, at least high in the atmosphere

Alaska's Redoubt Volcano erupting in 1990. Photo courtesy USGS/R.J. Clucas.

Alaska’s Redoubt Volcano erupting in 1990. Photo courtesy USGS/R.J. Clucas.

By Summit Voice

FRISCO — Scientists have long known that aerosols can have a major effect on climate, and with measurements from sensitive satellite-based instruments, they’re getting a better handle on the formation, distribution and sources of various sulfur compounds in the atmosphere.

In a new study, researchers with the Karslruhe Institute of Technology say they’ve compiled one of the most comprehensive overview of sulfur dioxide measurements.

“Sulfur compounds up to 30 km altitude may have a cooling effect,” said KIT researcher Michael Höpfner, explaining that sulfur dioxide and water vapor react to sulfuric acid that forms aerosols, that reflect solar radiation back into universe. Continue reading

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