International Science Team Measures Arctic’s Atmosphere

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 ecosystems.

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.