The U.S. space agency
is adapting tools it has used to learn about water on the moon, minerals on
Mars and the composition of exoplanets to analyze ecosystems on planet Earth.
NASA this week finished a month of preliminary high-altitude tests of a new
Earth-imaging instrument package, which the agency plans to launch into orbit.
The instruments have
been flying on NASA’s ER-2, an aircraft that skirts the edge of space at
an altitude of 20,000 meters, nearly two times the cruising altitude of
commercial jetliners.
The imaging tools
gather data about how different wavelengths of light interact with landscape
molecules and particles to produce a spectral fingerprint. According to Robert
Green, a scientist with NASA’s Jet Propulsion Laboratory and principal
investigator on the Hyperspectral Infrared Imager or airborne campaign (HyspIRI),
sensors for an instrument called the Airborne Visible/Infrared Imaging
Spectrometer precisely measure the light and temperature characteristics of
each ecosystem the plane overflies.
“We can see the
interaction of the molecules that are present in the earth’s atmosphere, such
as water vapor and carbon dioxide, and on the earth’s surface in plants such as
cellulous and leaf water and the other constituents of plants," he said.
The tool, whose imaging
spectroscopy technology was tested over California’s varied landscape, can also
measure the impact of surface events such as volcanic eruptions, wildfires and
droughts.
“We have snow-covered
mountains, we have coasts, we have agriculture, we have deserts, we have
forested areas," Green said of the testing region along the nation's
western edge. "So in one fairly small region of the country, we can
capture a tremendous diversity of ecosystems and environments found on the
surface of the Earth.”
Green says each pixel
captured by the imager holds a wealth of information invisible to the human
eye. “We can map the species type. We can look at the bio-geochemistry of the
plants, [and determine] the state of the chemicals in the leaves of the plant
to tell us about their health and productivity," he said. "In the
geology area, we can look at the different mineral signatures, which tell us
the molecules in the rocks to know exactly what those minerals are.”
The test flights, he
adds, are part of preparations for an eventual satellite mission that will
provide global coverage from low-Earth orbit, about 700 kilometers above the
planet.
“This would give us
global direct measurements of molecules and temperatures of the Earth’s
surface, repeated each year, so we could see seasonal and temporal
variations," he said.
The HyspIRI satellite
mission is still in the study phase, with ER-2 test-flights continuing through
2014.
Green says the new
images of the planet could help scientists better assess how Earth is changing
and possibly help policymakers and the public make better-informed decisions
about how humans can adapt to the changes.
Sources :
http://www.voanews.com/content/nasa-jp-high-resolution-earth-imaging-ecosystems-er2-hyspiri/1648985.html
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