Warming in the Desert?
By Don Comis
August 27, 2001
The Chihuahuan Desert is a perfect
outdoor lab for using satellites to spot changes in vegetation due to global
warming or other climate change.
There is preliminary evidence that global warming may have sped up the pace
at which grasslands are being overtaken by mesquite, creosote and other shrubs
at desert sites around the world.
Scientists at the Agricultural Research
Services Jornada Experimental
Range in Las Cruces, N.M., in the heart of the Chihuahuan Desert, have been
working with the U.S. National Aeronautics and
Space Administration and the Henry A.
Wallace Beltsville Agricultural Research Center since 1995, gathering data
on global climate change as part of NASAs Mission to Planet
Earth. NASAs program is a long-term environmental health checkup of
Earth from space. ARS has a lead role in the hydrology part of the project.
The 100,000-plus-acre Jornada desert site is a good stand-in for similar
semiarid areas where desertification has been aggravated by overgrazing and
drought. Twice a year, ARS physical scientist Tom Schmugge and others from
Beltsville join Kris Havstad, head of the Jornada Experimental Range, and
colleagues in an aircraft and satellite flyover campaign to test remote sensors
by air, space and land.
The Jornada work helps NASA and USDA
evaluate the interaction between desert landscapes and climate change.
Schmugge and colleagues are testing sensors to distinguish bare soil from
vegetation by their natural emissions of light or colors. They are also testing
thermal infrared sensors to measure surface temperature. Surface temperature
variations are key to defining regions of high and low evaporation that
More details are available in a feature story in the August 2001 issue of
Agricultural Research magazine.
ARS is USDAs chief scientific research agency.