April 01, 2008
PASADENA, Calif. - This month, NASA begins the most extensive field campaign
ever to investigate the chemistry of the Arctic's lower atmosphere. The mission
is poised to help scientists identify how air pollution contributes to climate
changes in the Arctic.
The recent decline of sea ice is one indication the Arctic is undergoing significant
environmental changes related to climate warming. NASA and its partners plan to
investigate the atmosphere's role in this climate-sensitive region with the Arctic
Research of the Composition of the Troposphere from Aircraft and Satellites
(ARCTAS) field campaign.
"It's important that we go to the Arctic to understand the atmospheric contribution
to warming in a place that's rapidly changing," said Jim Crawford, manager of the
Tropospheric Chemistry Program at NASA Headquarters in Washington. "We are in a
position to provide the most complete characterization to date for a region that is
seldom observed but critical to understanding climate change."
The campaign begins this week in Fairbanks, Alaska. NASA's DC-8, P-3 and B-200
aircraft will serve as airborne laboratories for the next three weeks, carrying
instruments to measure air pollution gases and aerosols and solar radiation. Of
particular interest is the formation of the springtime "arctic haze." The return of
sunlight to the Arctic in the spring fuels chemical reactions of pollutants that have
accumulated over the winter after traveling long distances from lower latitudes.
"The Arctic is a poster child of global change and we don't understand the processes
that are driving that rapid change," said Daniel Jacob, an ARCTAS project scientist
at Harvard University, Cambridge, Mass. "We need to understand it better and that's
why we're going."
ARCTAS is NASA's contribution to an international series of Arctic field experiments
that is part of the International Polar Year, a two-year event focusing science and
education on Earth's remote polar regions. The National Oceanic and Atmospheric
Administration and the Department of Energy also are sponsoring research flights
from Fairbanks this month in collaboration with NASA.
The wealth of data collected also will improve computer models used to study
global atmospheric chemistry and climate. This ultimately will provide scientists
with a better idea of how pollutants are transported to and around the Arctic and
their impact on the environment and climate.
"We haven't looked at pollution transport in a comprehensive fashion," said Hanwant
Singh, an ARCTAS project scientist at NASA Ames Research Center, Moffett Field, Calif.
"We can see Arctic haze coming in but we don’t know its composition or how it got there.
One goal of ARCTAS is to provide a comprehensive understanding of the aerosol composition,
chemistry and climate effects in the Arctic region."
The aircraft observations also will help researchers interpret data from NASA satellites
orbiting over the Arctic, such as Aura and its Tropospheric Emission Spectrometer instrument,
developed and managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif.; Terra; and
Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation. Interpreting satellite
data can be difficult in the Arctic because of extensive cloud cover, bright reflective
surfaces from snow and ice, and cold surface temperatures. For example, it's difficult for
researchers to look at satellite data and distinguish between light reflected by clouds
and light reflected from white ice cover.
"NASA has invested a lot of resources in satellites that can be of value for diagnosing
effects of climate change,” Jacob said. "Satellites orbit over poles with good coverage
and good opportunity, but you really need to have aircraft observations supporting those
to make good interpretations of what satellites are telling you."
The new airborne view of the Arctic atmosphere combined with satellite data will provide
scientists with a better understanding of the atmospheric side of the climate question.
"We're interested in data that will help models better characterize the current state of
the atmosphere, to set a benchmark for them so we can gain confidence in their ability to
predict future warming in the Arctic," Crawford said.
A second phase of the ARCTAS campaign, involving JPL scientists using data from the
Tropospheric Emission Spectrometer on Aura, takes place this summer from Cold Lake in Alberta,
Canada, where flights will focus on measurements of emissions from forest fires. Researchers
want to know how the impact of naturally occurring fires in the region compares to the pollution
associated with human activity at lower latitudes. Understanding the relative influence of
each is important to predictions of the Arctic's future climate.
"What we've found before is that there's sometimes a significant amount of ozone produced
from these fires and sometimes there's not," said John Worden, an ARCTAS project scientist at
JPL. "We need to understand that, because ozone in the Arctic region is a significant greenhouse
gas, where it will be involved in part of the warming of the Arctic region. Because the plumes
from these fires can stretch across the globe, the ozone and other pollutants they produce
such as aerosols and carbon monoxide can have an impact on local pollution in higher latitude cities."
For more on ARCTAS on the Web, visit: http://www.nasa.gov/mission_pages/arctas . For more on
the Tropospheric Emission Spectrometer on the Web, visit: http://tes.jpl.nasa.gov/ .
JPL is managed for NASA by the California Institute of Technology in Pasadena.
Media contact: Alan Buis 818-354-0474
Jet Propulsion Laboratory, Pasadena, Calif.
Alan.buis@jpl.nasa.gov
Steve Cole 202-358-0918
NASA Headquarters, Washington
Stephen.e.cole@nasa.gov
2008-051