Contact: Dane Konop (NOAA) FOR IMMEDIATE RELEASE
Frank Raes (European Commission) 6/11/97
Some 200 scientists from Europe and the United States will join forces this summer to investigate how smog, smoke and other "atmospheric aerosols" affect climate and the extent to which they may offset the greenhouse effect, the Commerce Department's National Oceanic and Atmospheric Administration announced today.
"Atmospheric aerosols are tiny particles or droplets, most of them smaller than one micrometer in diameter, that are suspended in the atmosphere," said principal scientist Timothy Bates of NOAA's Pacific Marine Environmental Laboratory in Seattle, Wash. "The effect of these particles on radiation has been known for many decades, as they are responsible for colorful sunsets, hazes over the landscape and the less romantic smog in large cities. Only recently have scientists suspected these effects might also influence global climate.
"The global distribution of aerosols, their characteristics and the way they interact with solar radiation and clouds are all poorly known, which prevents both precise calculations of the effect of aerosols on climate and accurate predictions of future climate change," Bates said.
Manmade sources of atmospheric aerosols include smoke and fumes from industrial combustion, forest fires and automobile emissions. Natural sources include mineral dust, which is often transported over large distances, salt particles from sea spray, sulfur and other organic emissions from the ocean and land, and sulfur from volcanoes.
In the 2nd Aerosol Characterization Experiment (ACE-2) June 16-July 25, scientists within the International Global Atmospheric Chemistry Project will equip a ship, and coastal and mountaintop sites in Portugal and on the Canary Islands and Madeira with the most advanced observational equipment to study manmade aerosols from Europe and natural dust aerosols from the Sahara.
Six research aircraft will perform dedicated flights to make measurements within these aerosol plumes and the surrounding clouds. The area will also be monitored with the NOAA12, NOAA14, NOAA/k, Meteosat, and ER-2 satellites.
"The various measurements we make in ACE-2 can be considered parts of a complex puzzle, which scientists from around the world will piece together to explain the role of aerosol, particularly those produced by humankind, in climate change," Bates said.
Aerosol particles primarily reflect sunlight and can also enhance the reflective properties of clouds, both of which result in a cooling of the Earth system. Scientists believe that the cooling by aerosols may explain why the observed increase in the global temperature is lower than that calculated by climate models considering the greenhouse effect alone.
ACE-2 is sponsored by the European Commission DGXII Environment and Climate Programme, the National Environmental Research Council and the Meteorological Office, both of the United Kingdom, Mateo France, the U.S. National Science Foundation and NOAA. Meteorological and logistics support will be provided by the Spanish National Meteorological Institute and the European Commission's Joint Research Centre Ispra.
In an earlier experiment called ACE-1 in late 1995, scientists made similar measurements over the Pacific Ocean south of Australia, which is the least polluted area of the world and where the natural aerosol system could be studied in near-pristine condition.
ACE-3 is planned for the year 2000 and will focus on the region downwind of the rapidly increasing pollution sources in eastern Asia.
All NOAA press releases and links to other NOAA material can be found on the Internet at http://www.noaa.gov/public-affairs . Journalists who wish to be added to our press release distribution list, or who wish to switch from fax to e-mail delivery, can send an e-mail to releases@www.noaa.gov , or fax to (202) 482-3154. For more information about this project, see the ACE-2 home page: http://rea.ei.jrc.it/~vandinge/ace2/ace2main.htm.