Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Sun-warmed air pollution flows east from Asia

15.03.2007
Most of the atmosphere-warming soot transported at high altitudes over the West Coast in spring comes from Asia, a new study estimates. That continent generates more than 75 percent of the high-flying contamination, which is a type of particulate pollution known as black carbon.

By absorbing sunlight, black-carbon particles heat the upper atmosphere while also reducing radiation at the surface. The new data indicates that the warming is winning out.

"The soot heating of the atmosphere exceeds the surface dimming and, as a result, the long-range, transported soot amplifies the global warming due to increase in carbon dioxide," says Professor V. Ramanathan at the Scripps Institution of Oceanography, UC San Diego. He and Scripps graduate student Odelle Hadley led the study, published online today in the Journal of Geophysical Research (Atmospheres). Other scientists at Scripps and the University of Iowa, Iowa City, also contributed to the study.

The black carbon transported from Asia in spring equals 77 percent of the black carbon emitted into the troposphere from North America during that season, the team also finds. The researchers used computer simulations and measurements of pollution taken in March and April of 2004 at the surface and at various elevations. Mostly soot, black carbon comes from automobile exhaust, agricultural burning and other sources.

Although the transported black-carbon pollution is an extremely small component of air pollution at land surface levels, it has a significant heating effect on the atmosphere at altitudes above two kilometers (7,000 feet). The particles influence the Pacific Ocean region, which drives much of Earth’s climate. "That’s the primary concern we have with these aerosols," said Hadley. "They can really affect global climate."

In a follow-on study funded by the California Energy Commission (CEC), Hadley, Ramanathan, and fellow Scripps climate scientist Craig Corrigan--who is also a coauthor on the black-carbon transport study--are now investigating how much carbon might be incorporated into precipitation. The study will also examine potential consequences for melt rates of snowpack in California’s Sierra Nevada mountains. Results from that study are expected by the end of this year.

The newly reported measure of black-carbon influx from Asia "is a startling finding by itself, but its potential importance is magnified by the fact that black carbon is believed to have a disproportional impact on regional climate," said Guido Franco, technical lead for climate-change research at the CEC’s Public Interest Energy Research (PIER) program.

The black-carbon investigators compared predictions from a computer model called the Chemical Weather Forecast System (CFORS) to rarely available, in-flight data collected over the Eastern Pacific Ocean and to surface data from 30 West Coast meteorological stations.

Transport of Asian black carbon peaks in the spring when cold Arctic fronts dip to lower latitudes and loft warmer air to higher levels in the atmosphere. The eastward flow of the contaminants is part of a worldwide transport of aerosols, which remain aloft at high altitudes for up to two weeks.

Black carbon concentrations diminish as the pollution moves farther away from its sources in cities and farmlands in countries like China and India. However, over the Pacific Ocean, the particles are in sufficient concentration to have a warming effect on the upper atmosphere of between 2.04 and 2.55 watts per square meter, a prediction based on output from other computer models besides CFORS. By contrast, the black-carbon-induced dimming at the surface amounts to only -1.45 to -1.47 watts per square meter.

On a regional level, the amount of warming, or positive radiative forcing, the black carbon causes in the skies over the Pacific is about 40 percent of that attributed to the carbon dioxide increase of the last century, said Ramanathan. It likely has measurable effects on a variety of other physical and biological conditions in the areas of the Pacific over which the particulate pollution passes.

"We have to find out if this amplification is just restricted to spring time or is happening through out the year," Ramanathan says.

Scripps Oceanography researchers Greg Roberts and Guillaume Mauger, and Iowa’s Gregory Carmichael and Youhua Tang also took part in the study.

The National Science Foundation, the National Oceanic and Atmospheric Administration (NOAA), and the California Energy Commission funded the work.

Peter Weiss | AGU
Further information:
http://www.agu.org

More articles from Earth Sciences:

nachricht Massive impact crater from a kilometer-wide iron meteorite discovered in Greenland
15.11.2018 | Faculty of Science - University of Copenhagen

nachricht The unintended consequences of dams and reservoirs
14.11.2018 | Uppsala University

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: UNH scientists help provide first-ever views of elusive energy explosion

Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.

Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

Purdue cancer identity technology makes it easier to find a tumor's 'address'

16.11.2018 | Health and Medicine

Good preparation is half the digestion

16.11.2018 | Life Sciences

Microscope measures muscle weakness

16.11.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>