PAVE To Validate NASA Data
An international team of scientists has embarked on a journey
this week 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) is gathering
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 to 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 mission began Jan. 24 and continues through 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, DC. "The information
obtained 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."
In particular, PAVE is focusing on the high latitude (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 thus 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 at Edwards, CA., is flying the PAVE
mission from Pease International Tradeport, Portsmouth, NH.
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 onboard the DC-8 are characterizing upper
tropospheric and stratospheric gases inside and outside the Arctic
polar region to study ozone depletion chemistry. Such flights will
also permit measurement of the outflow of gases from the North
American continent thereby contributing to an understanding of how
regional pollutants are distributed on a hemispheric basis.
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 (such as ozone, methane, water vapor, carbon monoxide,
nitric acid, and nitrous oxide) in the atmosphere immediately
surrounding the aircraft.
"The DC-8 will perform a number of specialized maneuvers to
permit concurrent flights under the path of the Aura satellite and
to sample the concentration of ozone at very high latitudes," said
Walter Klein, Dryden's mission manager for the project. "The
aircraft is carrying 13 instruments, weighing more than 20,000
pounds, and a complement of 40 scientists, engineers and
technicians in support of PAVE."
"PAVE is designed to validate satellite data from the newly
launched Aura mission," added Mark Schoeberl, PAVE co-project
scientist and Aura project scientist at NASA's Goddard Space Flight
Center, Greenbelt, MD. "Aura contains four instruments including
the Dutch Ozone Monitoring Instrument and the joint US-U.K. High
Resolution Dynamics Limb Sounder. Both Dutch and U.K.
representatives will be in the field as part of the validation
program."
NASA scientists from Dryden, Goddard, Ames Research Center,
Moffett Field, CA, Langley Research Center, Hampton, VA, and the
Jet Propulsion Laboratory, Pasadena, CA, are participating in PAVE.
Major PAVE partners include the University of New Hampshire,
University of California-Berkley, University of Bremen, National
Center for Atmospheric Research (NCAR), the US Naval Research
Laboratory, Koninklijk Netherlands Meteorological Institute and Los
Gatos Research Inc.