NASA's Global Hawk 872 on a checkout flight from
Dryden Flight Research Center, Edwards, Calif., in preparation for the 2014
ATTREX mission over the western Pacific Ocean.
Image Credit: NASA/Tom Miller
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NASA's uncrewed Global Hawk research aircraft is in the western Pacific
region on a mission to track changes in the upper atmosphere and help
researchers understand how these changes affect Earth's climate.
Deployed from NASA's Dryden Flight Research Center in Edwards, Calif., the
Global Hawk landed at Andersen Air Force Base in Guam Thursday at approximately
5 p.m. EST and will begin science flights Tuesday, Jan. 21. Its mission, the
Airborne Tropical Tropopause Experiment (ATTREX), is a multi-year NASA airborne
science campaign.
ATTREX will measure the moisture levels and chemical composition of upper
regions of the lowest layer of Earth's atmosphere, a region where even small
changes can significantly impact climate. Scientists will use the data to better
understand physical processes occurring in this part of the atmosphere and help
make more accurate climate predictions.
"We conducted flights in 2013 that studied how the atmosphere works and how
humans are affecting it," said Eric Jensen, ATTREX principal investigator at
NASA’s Ames Research Center in Moffett Field, Calif. "This year, we plan to
sample the western Pacific region which is critical for establishing the
humidity of the air entering the stratosphere."
Studies show even slight changes in the chemistry and amount of water vapor
in the stratosphere, the same region that is home to the ozone layer, which
protects life on Earth from the damaging effects of ultraviolet radiation, can
affect climate significantly by absorbing thermal radiation rising from the
surface. Predictions of stratospheric humidity changes are uncertain because of
gaps in the understanding of the physical processes occurring in the tropical
tropopause layer.
ATTREX is studying moisture and chemical composition from altitudes of 55,000
feet to 65,000 feet in the tropical tropopause, which is the transition layer
between the troposphere, or the lowest part of the atmosphere, and the
stratosphere, which extends up to 11 miles above Earth's surface. Scientists
consider the tropical tropopause to be the gateway for water vapor, ozone and
other gases that enter the stratosphere. For this mission, the Global Hawk
carries instruments that will sample the tropopause near the equator over the
Pacific Ocean.
ATTREX scientists installed 13 research instruments on NASA's Global Hawk
872. Some of these instruments capture air samples while others use remote
sensing to analyze clouds, temperature, water vapor, gases and solar
radiation.
"Better understanding of the exchange between the troposphere and
stratosphere and how that impacts composition and chemistry of the upper
atmosphere helps us better understand how, and to what degree, the upper
atmosphere affects Earth’s climate," Jensen said.
In 2013, for the first time, ATTREX instruments sampled the tropopause region
in the Northern Hemisphere during winter, when the region is coldest and
extremely dry air enters the stratosphere. Preparations for this mission started
in 2011 with engineering test flights to ensure the aircraft and its research
instruments operated well in the extremely cold temperatures encountered at high
altitudes over the tropics, which can reach minus 115 degrees Fahrenheit. ATTREX
conducted six science flights totaling more than 150 hours last year.
Jensen and Project Manager Dave Jordan of Ames lead the ATTREX mission. It
includes investigators from Ames and three other NASA facilities: Langley
Research Center in Hampton, Va., Goddard Space Flight Center in Greenbelt, Md.,
and the Jet Propulsion Laboratory in Pasadena, Calif. The team also includes
investigators from the National Oceanic and Atmospheric Administration, the
National Center for Atmospheric Research, universities and private industry.
ATTREX is one of the first research missions of NASA's new Earth Venture
project. These small and targeted science investigations complement NASA's
broader science research satellite missions. The Earth Venture missions are part
of NASA's Earth System Science Pathfinder Program managed by Langley.
For more information about the ATTREX mission, visit:
An ATTREX press kit is available at
NASA
Guillermo Gonzalo Sánchez Achutegui
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