Navigation Links
Forward step in forecasting global warming
Date:8/7/2008

TEMPE, Ariz. Arizona State University researchers have made a breakthrough in understanding the effect on climate change of a key component of urban pollution. The discovery could lead to more accurate forecasting of possible global-warming activity, say Peter Crozier and James Anderson.

Crozier is an associate professor in ASU's School of Materials, which is jointly administered by the College of Liberal Arts and Sciences and the Ira A. Fulton School of Engineering. Anderson is a senior research scientist in the engineering school's Department of Mechanical and Aerospace Engineering.

As a result of their studies of aerosols in the atmosphere, they assert that some measures used in atmospheric science are oversimplified and overlook important factors that relate to climatic warming and cooling.

The research findings are detailed in the Aug. 8 issue of Science magazine, in the article "Brown Carbon Spheres in East Asian Outflow and Their Optical Properties," co-authored by Crozier, Anderson and Duncan Alexander, a former postdoctoral fellow at ASU in the area of electron microscopy, and the paper's lead author.

So-called brown carbons a nanoscale atmospheric aerosol species are largely being ignored in broad-ranging climate computer models, Crozier and Anderson say.

Studies of the greenhouse effect that contribute directly to climate change have focused on carbon dioxide and other greenhouse gases. But there are other components in the atmosphere that can contribute to warming or cooling including carbonaceous and sulfate particles from combustion of fossil fuels and biomass, salts from oceans and dust from deserts. Brown carbons from combustion processes are the least understood of these aerosol components.

The parameter typically used to measure degrees of warming is radiative forcing, which is the difference in the incoming energy from sunlight and outgoing energy from heat and reflected sunlight. The variety of gasses and aerosols that compose the atmosphere will, under different conditions, lead to warming (positive radiative forcing) or cooling (negative radiative forcing).

The ASU researchers say the effect of brown carbon is complex because it both cools the Earth's surface and warms the atmosphere.

"Because of the large uncertainty we have in the radiative forcing of aerosols, there is a corresponding large uncertainty in the degree of radiative forcing overall," Crozier says. "This introduces a large uncertainty in the degree of warming predicted by climate change models."

A key to understanding the situation is the light-scattering and light-absorbing properties called optical properties of aerosols.

Crozier and Anderson are trying to directly measure the light-absorbing properties of carbonaceous aerosols, which are abundant in the atmosphere.

"If we know the optical properties and distribution of all the aerosols over the entire atmosphere, then we can produce climate change models that provide more accurate prediction," Anderson says.

Most of the techniques used to measure optical properties of aerosols involve shining a laser through columns of air.

"The problem with this approach is that it gives the average properties of all aerosol components, and at only a few wavelengths of light," Anderson says.

He and Crozier have instead used a novel technique based on a specialized type of electron microscope. This technique monochromated electron energy-loss spectroscopy can be used to directly determine the optical properties of individual brown carbon nanoparticles over the entire visible light spectrum as well as over the ultraviolet and infrared areas of the spectrum.

"We have used this approach to determine the complete optical properties of individual brown carbon nanoparticles sampled from above the Yellow Sea during a large international climate change experiment," Crozier says.

"This is the first time anyone has determined the complete optical properties of single nanoparticles from the atmosphere," Anderson says.

It's typical for climate modelers to approximate atmospheric carbon aerosols as either non-absorbing or strongly absorbing. "Our measurements show this approximation is too simple," Crozier says. "We show that many of the carbons in our sample have optical properties that are different from those usually assumed in climate models."

Adds Anderson: "When you hear about predictions of future warming or changes in precipitation globally, or in specific regions like the Southwestern United States, the predictions are based on computer model output that is ignoring brown carbon, so they are going to tend to be less accurate."


'/>"/>

Contact: Joe Kullman
joe.kullman@asu.edu
480-965-8122
Arizona State University
Source:Eurekalert

Related biology technology :

1. Instrumentation Laboratory to Celebrate 50th Anniversary With 50 and Forward Program
2. Record Venture Capital and Heated Deal Environment Propel Global Biotechnology Industry Forward in 2007
3. Innovative and Forward-Thinking Experts to Deliver Keynote Presentations at IBCs 13th Annual Drug Discovery & Development of Innovative Therapeutics World Congress
4. CellCyte Genetics Corp. Continues to Move Its Technology Forward in Light of Plaintiff Law Firm Press Releases
5. Verenium Corporation to Present at Canaccord Adams 28th Annual Global Growth Conference
6. Thousands Rally in Mexico City and Call for Human Rights Protections in Global AIDS Response
7. Ondine to Present at Canaccord Adams 28th Annual Global Growth Conference
8. Sangamo BioSciences to Present at the Canaccord Adams Global Growth Conference
9. Atrium Innovations to Present at Upcoming 28th Annual Canaccord Adams Global Growth Conference
10. Shengtai Pharmaceutical Retains Grayling Global As Investor Relations Counsel
11. Body Shaping Fuels Growth of $5.2 Billion Global Medical Aesthetic Market
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/28/2017)... ... April 28, 2017 , ... Cynvenio Biosystems, Inc. a leader ... neoadjuvant breast cancer monitoring (NEAT) study in partnership with Allentown, PA-based TME Research ... patients to be monitored over two years with Cynvenio’s ClearID Breast Cancer blood test. ...
(Date:4/27/2017)... MD (PRWEB) , ... April 27, 2017 , ... ... solutions provider for digital pathology, today announced their digital pathology technology has the ... images provided by five medical centers in The Netherlands as part of the ...
(Date:4/27/2017)... , ... April 27, 2017 , ... ... explaining why mass flow controllers based on capillary thermal mass flow technology provide ... mass flow control applications. Over 80% of all industrial processes—such as those ...
(Date:4/27/2017)... , April 27, 2017  Kinexum, a distinguished ... products, today announces the appointment of Thomas C. ... Alexander ("Zan") Fleming, M.D., Kinexum founder, who becomes Executive ... advisor to Kinexum clients. Thomas Seoh ... on the Kinexum mission and lead the firm,s remarkable ...
Breaking Biology Technology:
(Date:3/30/2017)... , March 30, 2017 Trends, opportunities ... (physiological and behavioral), by technology (fingerprint, AFIS, iris recognition, ... recognition, and others), by end use industry (government and ... immigration, financial and banking, and others), and by region ... , Asia Pacific , and ...
(Date:3/27/2017)... N.Y. , March 27, 2017  Catholic ... Information and Management Systems Society (HIMSS) Analytics for ... EMR Adoption Model sm . In addition, CHS ... of U.S. hospitals using an electronic medical record ... for its high level of EMR usage in ...
(Date:3/23/2017)... -- The report "Gesture Recognition and Touchless Sensing Market by Technology ... Forecast to 2022", published by MarketsandMarkets, the market is expected to be worth ... and 2022. Continue Reading ... ... ...
Breaking Biology News(10 mins):