Missions aims to sharpen climate-change predictions
By Summit Voice
FRISCO — Climate scientists have a clear understanding of how greenhouse gas physics work in the lower atmosphere, but there are still a lot of unanswered questions about how global warming will play out in the upper layers, where water vapor and ozone have an as-yet unquantified impact on climate changes.
Starting this month, NASA will use unmanned aircraft flying as high as 65,000 feet to gather data that could provide some answers. The research missions will start at Edwards Air Force Base in California, with 30-hour flight out across the Pacific.
The Airborne Tropical Tropopause Experiment (ATTREX) missions will study moisture and chemical composition in the upper regions of the troposphere, the lowest layer of Earth’s atmosphere. The tropopause layer between the troposphere and stratosphere, from about eight miles to 11 miles above Earth’s surface, is the point where water vapor, ozone and other gases enter the stratosphere.
Studies have shown even small changes in stratospheric humidity may have significant climate impacts. ATTREX will use the Global Hawk to carry instruments to sample this layer near the equator off the coast of Central America.
“The ATTREX payload will provide unprecedented measurements of the tropical tropopause,” researcher said Eric Jensen, based at NASA’s Ames Research Center in Moffett Field, Calif. “This is our first opportunity to sample the tropopause region during winter in the northern hemisphere when it is coldest and extremely dry air enters the stratosphere.”
Instruments aboard the NASA Global Hawk include remote sensors for measuring clouds, trace gases and temperatures above and below the aircraft, as well as instruments to measure water vapor, cloud properties, meteorological conditions, radiation fields and numerous trace gases around the aircraft.
Six science flights are planned between Jan. 16 and March 15. The ATTREX team also is planning remote deployments to Guam and Australia in 2014. Scientists hope to use the acquired data to improve global model predictions of stratospheric humidity and composition.
For more information about the ATTREX mission, visit: http://espo.nasa.gov/missions/attrex.