|
NSF PR 99-6 - January 29, 1999
This material is available primarily for archival
purposes. Telephone numbers or other contact information
may be out of date; please see current contact information
at media
contacts.
Scientists To Kick Off Major Field Experiment On Role
Of Aerosols In Climate Change
Pollutants known as aerosols play a role in cooling
the planet and mitigating the effects of global warming.
Scientists from around the world are now trying to
find out how; the intensive field phase of an experiment
sponsored in part by the National Science Foundation
(NSF) is beginning next week.
The $25-million Indian Ocean Experiment, or INDOEX,
will be coordinated by the Center for Clouds, Chemistry
and Climate (C4) at the Scripps Institution of Oceanography
(SIO). "C4", an NSF Science and Technology Center,
is based at the University of California at San Diego.
Paul J. Crutzen, director of the Max Planck Institute
for Chemistry and a 1995 Nobel Laureate in Chemistry,
and V. Ramanathan, director of C4 at the Scripps Institution
of Oceanography, will serve as INDOEX co-chief scientists.
Aerosol cooling is one of the largest remaining sources
of uncertainty in predicting future climate. Data
collected during INDOEX will provide scientists with
crucial information needed to develop more accurate
global climate prediction models.
"INDOEX scientists will document the chemical and
physical properties of natural and human-produced
atmospheric aerosols and use these observations to
study and model the complex interactions among atmospheric
aerosols, clouds and climate," says Jay Fein, program
director in NSF's division of atmospheric sciences,
which funds INDOEX. "The project is addressing one
of the key remaining issues regarding potential climate
change. This knowledge is essential to improve climate
forecasts."
Aerosols are tiny particles of about a micron (one
millionth of a meter) or so in diameter that scatter
sunlight back to space and, thus, cause a regional
cooling effect. The particles also can have an indirect
cooling effect on climate by acting as seeds for cloud
condensation and, thus, increasing the reflectivity,
or albedo, of clouds. The effect of sulfate aerosols
is equivalent to that of trillions of tiny mirrors
floating in the sky, reflecting sunlight back to space.
Concentrated predominantly over the industrial areas
of the northern hemisphere, sulfates contribute to
acid rain and haziness. In addition to sulfates, aerosols
also include pollutants such as soot, organic carbon
and mineral dust, and are produced both naturally
and by human activities.
"This is one of the first comprehensive experiments
aimed at understanding the magnitude of the cooling
effect of sulfates and other aerosols on climate,"
says Ramanathan. "We hope to learn the extent to which
aerosol cooling has offset global warming due to human-produced
greenhouse gases, and how that may change with increased
regulation of aerosol emissions in the United States
and Europe."
The scientists chose the Indian Ocean region as the
site for INDOEX because the Indian subcontinent and
surrounding nations are rich sources for many kinds
of aerosols, including those produced from industrial
and auto emissions, biomass burning and soil dust.
With Asia's population rising at a dramatic rate,
the amount of sulfur dioxide released is expected
to increase.
The Republic of Maldives will serve as headquarters
for the intensive field investigation. Scientists
will use ships, aircraft and land stations to collect
data from the sea surface through the lower stratosphere
on aerosol composition, reactive atmospheric gases,
solar radiation fluxes, winds and water vapor distribution.
| |