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 Dispersal of Fish Eggs by Water Birds – Just a Myth?
19.02.2018 | Universität Basel

nachricht Removing fossil fuel subsidies will not reduce CO2 emissions as much as hoped
08.02.2018 | International Institute for Applied Systems Analysis (IIASA)

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: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

Im Focus: Computer-Designed Customized Regenerative Heart Valves

Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.

Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...

Im Focus: Light-induced superconductivity under high pressure

A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.

Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Supersonic waves may help electronics beat the heat

18.05.2018 | Power and Electrical Engineering

Keeping a Close Eye on Ice Loss

18.05.2018 | Information Technology

CrowdWater: An App for Flood Research

18.05.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>