Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

NASA scientists use satellites to distinguish human pollution from other atmospheric particles

18.09.2002


Driven by precise new satellite measurements and sophisticated new computer models, a team of NASA researchers is now routinely producing the first global maps of fine aerosols that distinguish plumes of human-produced particulate pollution from natural aerosols.



In the current issue of the journal Nature, atmospheric scientists Yoram Kaufman, at NASA’s Goddard Space Flight Center, Greenbelt, Md., Didier Tanré and Olivier Boucher from CNRS (Centre National de la Recherche Scientifique) at the University of Lille, reported in a review paper that these global maps are an important breakthrough in the science of determining how much aerosol pollution comes from human activities. Aerosols are tiny solid or liquid particles suspended in the atmosphere. The authors stated that the next step is to quantify more precisely the roles human aerosol pollution plays in Earth’s weather and climate systems.

"Plumes of smoke and regional pollution are distinguished by their large concentrations of small particles (less than 1 micrometer) downwind of biomass burning sites and urban areas," Kaufman said. "These particles are important because, depending upon the type of particles produced, human pollution can either have a warming or cooling influence on climate, and they can either increase or decrease regional rainfall."


Distinguishing small from large aerosol particles requires good understanding of how aerosols reflect sunlight at key wavelengths of the solar spectrum. For the first time ever, the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument flying aboard NASA’s Terra and Aqua satellites measures precisely the sunlight reflected by aerosols back to space every day over almost the entire planet at wavelengths spanning across the solar spectrum (from 0.41 to 2.2 micrometers).

Aerosol plumes comprised of smaller particles (less than 1 micrometer) reflect light at shorter wavelengths (blue light) much more strongly than plumes comprised of larger particles (greater than 1 micrometer) which scatter and reflect light roughly equally at short and long wavelengths (blue, green, red and near-infrared light). It is this basic understanding that helps scientists use MODIS data to distinguish human-produced aerosol.

However, there are exceptions to this rule. Kaufman noted that nature produces small particles too, while humans can generate large particles by changing land surface cover through agricultural practices and deforestation. Therefore, scientists need additional information-such as land use and fire activities, which are also observed by satellites, as well as information on population and economic activities-that is fed into advanced new computer aerosol models.

"Natural aerosols like salt particles from sea spray are typically widespread over larger areas and not particularly concentrated downwind of urban areas," Kaufman observed. "Or, they are particularly concentrated downwind of obviously natural sources, such as the streams of dust originating from the Sahara Desert."

Conversely, aerosols produced by humans are the result of urban pollution, industrial combustion, or burning vegetation. These plumes of pollutants appear in punctuated bursts of thick and concentrated plumes comprised of small particles. Or, they are concentrated downwind of regions obviously altered by human activities, such as deforested regions.

The authors find surprisingly good agreement between a new aerosol model (developed jointly by NASA Goddard and Georgia Tech) and the measurements now being made by the MODIS sensors. Examining global satellite images in concert with global-scale models and globally distributed ground-based measurements gives scientists the best tools they have ever had to estimate the effects of aerosols on climate and weather patterns around the world.

The new aerosol measurements collected by the Terra and Aqua satellites provide dramatic improvements over the measurements made by previous satellites over the last two decades. Another instrument on Terra, the Multi-angle Imaging SpectroRadiometer (MISR), observes aerosols by looking at the radiation reflected and scattered by aerosols in nine different directions. This multi-angle technique complements the multi-wavelength approach by NASA. NASA plans to further expand global aerosol research with the launch of satellite-based light imaging radars (lidars) that sends bursts of light to Earth and, like a radar signal, provide a measure of the altitude and vertical structure of aerosol plumes and clouds.

The Terra and Aqua satellites are part of NASA’s Earth Science Enterprise, a long-term research effort to understand our home planet.

Lynn Chandler | EurekAlert!
Further information:
http://www.gsfc.nasa.gov/topstory/20020917pollutionpart.html
http://modis.gsfc.nasa.gov
http://earthobservatory.nasa.gov/Library/RemoteSensingAtmosphere/remote_sensing3.html

More articles from Ecology, The Environment and Conservation:

nachricht Loss of habitat causes double damage to species richness
02.04.2019 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig

nachricht Deep decarbonization of industry is possible with innovations
25.03.2019 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

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

Im Focus: Quantum gas turns supersolid

Researchers led by Francesca Ferlaino from the University of Innsbruck and the Austrian Academy of Sciences report in Physical Review X on the observation of supersolid behavior in dipolar quantum gases of erbium and dysprosium. In the dysprosium gas these properties are unprecedentedly long-lived. This sets the stage for future investigations into the nature of this exotic phase of matter.

Supersolidity is a paradoxical state where the matter is both crystallized and superfluid. Predicted 50 years ago, such a counter-intuitive phase, featuring...

Im Focus: Explosion on Jupiter-sized star 10 times more powerful than ever seen on our sun

A stellar flare 10 times more powerful than anything seen on our sun has burst from an ultracool star almost the same size as Jupiter

  • Coolest and smallest star to produce a superflare found
  • Star is a tenth of the radius of our Sun
  • Researchers led by University of Warwick could only see...

Im Focus: Quantum simulation more stable than expected

A localization phenomenon boosts the accuracy of solving quantum many-body problems with quantum computers which are otherwise challenging for conventional computers. This brings such digital quantum simulation within reach on quantum devices available today.

Quantum computers promise to solve certain computational problems exponentially faster than any classical machine. “A particularly promising application is the...

Im Focus: Largest, fastest array of microscopic 'traffic cops' for optical communications

The technology could revolutionize how information travels through data centers and artificial intelligence networks

Engineers at the University of California, Berkeley have built a new photonic switch that can control the direction of light passing through optical fibers...

Im Focus: A long-distance relationship in femtoseconds

Physicists observe how electron-hole pairs drift apart at ultrafast speed, but still remain strongly bound.

Modern electronics relies on ultrafast charge motion on ever shorter length scales. Physicists from Regensburg and Gothenburg have now succeeded in resolving a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

Fraunhofer FHR at the IEEE Radar Conference 2019 in Boston, USA

09.04.2019 | Event News

 
Latest News

Simple and Fast Method for Radiolabelling Antibodies against Breast Cancer

23.04.2019 | Life Sciences

Quantum gas turns supersolid

23.04.2019 | Physics and Astronomy

New automated biological-sample analysis systems to accelerate disease detection

18.04.2019 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>