Free Newsletters - Space News - Defense Alert - Environment Report - Energy Monitor
. Earth Science News .




WATER WORLD
Research shows pollution doesn't change the rate of droplet formation
by Staff Writers
Atlanta GA (SPX) Feb 22, 2013


Clouds can hold in heat emitted from the Earth's surface, contributing to climate warming. But they can also reflect incoming sunlight back to space, producing a climate cooling effect. Predicting how cloud cover will change in the future is therefore essential to good climate modeling.

When it comes to forming the droplets that make up clouds, a little oily and viscous organic material apparently doesn't matter that much. And that's good news for reducing the uncertainty of climate model predictions.

Understanding cloud formation is essential for accurate climate modeling, and understanding cloud formation begins with the droplets that make up clouds. Droplets form when water vapor is attracted to particles floating in the atmosphere. These particles include dust, sea salt from the ocean, microorganisms, soot, sulfur - and organic material that can be both viscous and oily.

For years, scientists had believed that particles coated with this organic "goop" - produced by combusted petroleum and biomass - could form droplets more slowly than other particles. That would have had a significant impact on the formation of clouds.

But a study being reported this week in the journal Proceedings of the National Academy of Science suggests that the long-held belief isn't true. Based on aerial and ground-based measurements of droplet formation from ten different areas of the northern hemisphere, researchers at the Georgia Institute of Technology report that organic coatings on particles don't seem to significantly affect the rate at which droplets form. The researchers studied a wide range of particles, including organic, hydrocarbon-rich particles from the 2010 Deepwater Horizon oil spill in the Gulf of Mexico.

"It turns out that it doesn't matter how much goop you have - or don't have - the droplets take the same time to form," said Athanasios Nenes, a professor in the School of Earth and Atmospheric Sciences and the School of Chemical and Biomolecular Engineering at Georgia Tech. "Even in extreme environments like Deepwater Horizon, the rate of droplet formation on particles found over the spill doesn't differ from that of typical sea salt particles."

The research was scheduled to be published in the early online edition of the journal during the week of February 18th. The research was supported by the National Science Foundation (NSF), NASA, the Department of Energy, the National Oceanic and Atmospheric Administration (NOAA) and the Office of Naval Research (ONR).

Clouds can hold in heat emitted from the Earth's surface, contributing to climate warming. But they can also reflect incoming sunlight back to space, producing a climate cooling effect. Predicting how cloud cover will change in the future is therefore essential to good climate modeling.

"The reason we care about droplet formation rates is because the more slowly the droplets form, the more droplets you end up having in clouds," Nenes said.

"This, in turn, affects cloud properties and their climate impacts. For many years, there was the perception that having a lot of oily organic compounds from pollution would make water uptake a lot slower and might make droplets take longer to form. If that were true, it would mean that the impact pollution could have on clouds and climate would be much larger than we thought." And that created a large question mark in climate models.

To address that issue, Nenes and his collaborators began a series of studies using a mini cloud formation chamber small enough to be operated aboard an aircraft.

The chamber consists of a long metal tube that is heated at one end and cooled at the other. The walls of the chamber are kept moist, and air containing particles from outside the aircraft is flowed through.

Droplets form on the particles when air in the chamber becomes cool enough that it can no longer retain the moisture. The droplets then exit the chamber where they can be studied.

"With the chamber, we essentially create a cloud in a tube," Nenes said. "The difference between the cloud in the tube and the cloud outside is that the tube allows us to precisely control the temperature and the amount of water vapor available. We know exactly what is going on with that cloud, and this allows for very accurate measurements of cloud formation."

Beginning in 2004, Nenes and his graduate students took the chamber along on ten missions operated by NASA, NSF, NOAA and ONR. They flew through the pristine air of the Arctic, smoke from forest fires in Canada, and polluted air masses over the United States.

They also sampled polluted air over Mexico City, clean air over the forests of Finland, and dust-laden air over the Mediterranean. Though the particles flowing through the cloud chamber were different each time, the rate at which they formed droplets, the condensation coefficient, remained the same.

"We have literally hundreds of hours of data studying cloud formation from areas all over the globe," Nenes said. "We didn't see any changes in the droplet nucleation time scale."

In future studies, Nenes would like to study particles from other areas of the world, especially Africa and China. He'd also like to see what happens when the temperature of the air flowing through the cloud chamber is cold enough to form ice. There is some evidence that the kinetics of ice formation may be different in particles that are rich in "goop."

The study of droplet formation provides one small step toward reducing the uncertainty in climate modeling.

"This is good for atmospheric and climate scientists, because some of the uncertainty of droplet formation and aerosol impacts goes away," Nenes added. "With careful measurements and global deployment of measuring instruments, you can actually resolve outstanding questions in cloud physics and help simplify the descriptions of clouds in climate models."

.


Related Links
Georgia Institute of Technology
Water News - Science, Technology and Politics






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





WATER WORLD
Key to cleaner environment may be right beneath our feet
University Park PA (SPX) Feb 22, 2013
While many people recognize that clean water and air are signs of a healthy ecosystem, most do not realize that a critical part of the environment is right beneath their feet, according to a Penn State hydrologist. The ground plays an important role in maintaining a clean environment by serving as a natural water filtration and purification system, said Henry Lin, professor of hydropedolog ... read more


WATER WORLD
British PM sparks concern with aid budget proposals

Swiss Re posts 61% profit rise in 2012

Four guilty of manslaughter in Italy quake trial

Warning of emergency alert system hacks

WATER WORLD
DARPA Seeks to Defuse the Threat of Ionizing Radiation

Engineers show feasibility of superfast materials

Sony bills PS4 console as gaming's future

Lessons from nature could lead to the creation of new materials

WATER WORLD
Research shows pollution doesn't change the rate of droplet formation

Key to cleaner environment may be right beneath our feet

Study of world's richest marine area shows size matters

Indonesia announces shark, manta ray sanctuary

WATER WORLD
Reduced sea ice disturbs balance of greenhouse gases

Flow of research on ice sheets helps answer climate questions

Extreme winters impact fish negatively

ArcticNet will help improve standard of living in Canada's north

WATER WORLD
Monsanto to appeal Brazil GM seed ruling

Malawi's bountiful harvests and healthier children

Food science expert: Genetically modified crops are overregulated

US Court tilts toward Monsanto in battle with farmer

WATER WORLD
Gold gifts mystify tsunami-wracked Japan city

10 dead as Cyclone Haruna lashes Madagascar

Thousands isolated by Australian floodwaters

Flood research shows human habits die hard

WATER WORLD
Guinea soldiers quit I.Coast village in border dispute

Rising Islamist threat in West Africa

Life expectancy surges in AIDS-hit SAfrican region

ICoast, Guinea vow peaceful resolution to border dispute

WATER WORLD
Stay cool and live longer?

Zuckerberg, Brin join forces to extend life

Thick hair mutation emerged 30,000 years ago in humans

Tiny mutation had big evolutionary impact




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement