An international team of scientists embarked this week on a journey to
improve modeling of global-scale air quality and climate change predictions by
conducting high quality measurements of the Arctic region’s atmosphere.

The Polar Aura Validation Experiment (PAVE) will gather information to validate
data from NASA’s Aura satellite, launched in July 2004. PAVE is the third in a
series of planned Aura validation and science missions. These missions will help
understand the transport and transformation of gases and aerosols in the lower
atmosphere (troposphere), and their exchange with those in the lower
stratosphere, the layer just above the troposphere. PAVE takes place from Jan. 24
to Feb. 9.

“In addition to providing important validation for the various Aura data
products, PAVE brings together a full NASA complement of space-based and
suborbital measurements to study the atmospheric chemistry and transport of gases
and aerosols in this sensitive region of our planet,” said Dr. Michael Kurylo,
Program Scientist for PAVE, at NASA Headquarters in Washington. “The information
from this campaign will aid in understanding how changing atmospheric
composition, associated with climate change, might affect the recovery of the
Earth’s ozone layer that is anticipated to occur over the next several decades,”
he said.

In particular, PAVE focuses on the Arctic region of the Northern Hemisphere,
where winter chemistry has led to significant seasonal reduction of the
stratospheric ozone layer in many years, over more than a decade. The ozone layer
restricts the amount of the sun’s ultraviolet radiation that reaches the Earth.
Depletion of this protective layer can have harmful effects on humans and other

NASA’s DC-8 flying laboratory and high-altitude balloons are collecting valuable
science data, especially on ozone and ozone-destroying chemicals, using a suite
of atmospheric remote sensing and “in situ” instruments. The aircraft, operated
by NASA’s Dryden Flight Research Center, Edwards, Calif., is flying the PAVE
mission from Pease International Tradeport, Portsmouth, N.H. Balloons are being
launched from the European Sounding Rocket Range (ESRANGE) facility in Sweden.

The study is focusing on obtaining in situ and remote sensing measurements of the
arctic region for validation of the Aura satellite. Information gathered during
PAVE will be combined with data from Aura to improve modeling of global-scale air
quality, ozone and climate change predictions.

Instruments on board the DC-8 are characterizing upper tropospheric and
stratospheric gases inside and outside the Arctic polar region to study ozone
depletion chemistry. Such flights also permit measurement of the outflow of gases
from the North American continent, thereby contributing to an understanding of
how regional pollutants are distributed in the hemisphere.

Scientists will make remote sensing measurements (extending many kilometers away
from the aircraft) of tropospheric and stratospheric ozone, aerosols,
temperature, nitric acid, HCl, ClO and other ozone-related chemicals. These are
complemented by measurements of components such as ozone, methane, water vapor,
carbon monoxide, nitric acid and nitrous oxide, in the atmosphere immediately
surrounding the aircraft.

Major PAVE partners include the University of New Hampshire, Durham; University
of California-Berkeley; University of Bremen, Germany; National Center for
Atmospheric Research (NCAR), Boulder, Colo.; the U.S. Naval Research Laboratory
in Washington; Koninklijk Netherlands Meteorological Institute; and Los Gatos
Research, Inc., Mountain View, Calif.

For more information about the Aura mission on the Internet, visit:

For more information about PAVE on the Internet, visit: