First Global Maps from Orbiting Carbon Observatory
 
Dec. 19, 2014: The first global maps of atmospheric carbon dioxide from NASA's
new Orbiting Carbon Observatory-2 mission show elevated carbon dioxide
concentrations across the Southern Hemisphere from springtime biomass burning
and hint at potential surprises to come.
 
At a media briefing  at the American Geophysical Union meeting in San
Francisco, scientists from NASA's Jet Propulsion Laboratory, Pasadena,
California; Colorado State University (CSU), Fort Collins; and the California
Institute of Technology, Pasadena, presented the maps of carbon dioxide and a
related phenomenon known as solar-induced chlorophyll fluorescence and
discussed their potential implications.
 
http://tinyurl.com/nom85mu
 
Global atmospheric carbon dioxide concentrations from Oct. 1 through Nov. 11,
as recorded by NASA's Orbiting Carbon Observatory-2. Carbon dioxide
concentrations are highest above northern Australia, southern Africa and
eastern Brazil. Image Credit: NASA/JPL-Caltech
 
A global map covering Oct. 1 through Nov. 17 shows elevated carbon dioxide
concentrations in the atmosphere above northern Australia, southern Africa and
eastern Brazil.
 
"Preliminary analysis shows these signals are largely driven by the seasonal
burning of savannas and forests," said OCO-2 Deputy Project Scientist Annmarie
Eldering, of JPL. The team is comparing these measurements with data from
other satellites to clarify how much of the observed concentration is likely
due to biomass burning.
 
The time period covered by the new maps is spring in the Southern Hemisphere,
when agricultural fires and land clearing are widespread. The impact of these
activities on global carbon dioxide has not been well quantified. As OCO-2
acquires more data, Eldering said, its Southern Hemisphere measurements could
lead to an improved understanding of the relative importance in these regions
of photosynthesis in tropical plants, which removes carbon dioxide from the
atmosphere, and biomass burning, which releases carbon dioxide to the
atmosphere.
 
The early OCO-2 data hint at some potential surprises to come. "The agreement
between OCO-2 and models based on existing carbon dioxide data is remarkably
good, but there are some interesting differences," said Christopher O'Dell, an
assistant professor at CSU and member of OCO-2's science team. "Some of the
differences may be due to systematic errors in our measurements, and we are
currently in the process of nailing these down. But some of the differences
are likely due to gaps in our current knowledge of carbon sources in certain
regions -- gaps that OCO-2 will help fill in."
 
http://tinyurl.com/ms99nlm
 
This map shows solar-induced fluorescence, a plant process that occurs during
photosynthesis, from Aug. through Oct. 2014 as measured by NASA's Orbiting
Carbon Observatory-2. This period is springtime in the Southern Hemisphere and
fall in the Northern Hemisphere. Image Credit: NASA/JPL-Caltech
Carbon dioxide in the atmosphere has no distinguishing features to show what
its source was. Elevated carbon dioxide over a region could have a natural
cause -- for example, a drought that reduces plant growth -- or a human cause.
At today's briefing, JPL scientist Christian Frankenberg introduced a map
using a new type of data analysis from OCO-2 that can help scientists
distinguish the gas's natural sources.
 
Through photosynthesis, plants remove carbon dioxide from the air and use
sunlight to synthesize the carbon into food. Plants end up re-emitting about
one percent of the sunlight at longer wavelengths. Using one of OCO-2's three
spectrometer instruments, scientists can measure the re-emitted light, known
as solar-induced chlorophyll fluorescence (SIF). This measurement complements
OCO-2's carbon dioxide data with information on when and where plants are
drawing carbon from the atmosphere.
 
"Where OCO-2 really excels is the sheer amount of data being collected within
a day, about one million measurements across a narrow swath," Frankenberg
said. "For fluorescence, this enables us, for the first time, to look at
features on the five- to 10-kilometer scale on a daily basis." SIF can be
measured even through moderately thick clouds, so it will be especially useful
in understanding regions like the Amazon where cloud cover thwarts most
spaceborne observations.
 
The changes in atmospheric carbon dioxide that OCO-2 seeks to measure are so
small that the mission must take unusual precautions to ensure the instrument
is free of errors. For that reason, the spacecraft was designed so that it can
make an extra maneuver. In addition to gathering a straight line of data like
a lawnmower swath, the instrument can point at a single target on the ground
for a total of seven minutes as it passes overhead. That requires the
spacecraft to turn sideways and make a half cartwheel to keep the target in
its sights.
 
The targets OCO-2 uses are stations in the Total Carbon Column Observing
Network (TCCON), a collaborative effort of multiple international
institutions. TCCON has been collecting carbon dioxide data for about five
years, and its measurements are fully calibrated and extremely accurate. At
the same time that OCO-2 targets a TCCON site, a ground-based instrument at
the site makes the same measurement. The extent to which the two measurements
agree indicates how well calibrated the OCO-2 sensors are.
 
Additional maps released today showed the results of these targeting maneuvers
over two TCCON sites in California and one in Australia. "Early results are
very promising," said Paul Wennberg, a professor at Caltech and head of the
TCCON network. "Over the next few months, the team will refine the OCO-2 data,
and we anticipate that these comparisons will continue to improve."
 
Credits and more information:
Production editor: Dr. Tony Phillips | Credit: Science@NASA
 
To learn more about OCO-2, visit: http://oco2.jpl.nasa.gov/
 
Caltech manages JPL for NASA.
 
NASA monitors Earth's vital signs from land, air and space with a fleet of
satellites and ambitious airborne and ground-based observation campaigns. NASA
develops new ways to observe and study Earth's interconnected natural systems
with long-term data records and computer analysis tools to better see how our
planet is changing. The agency shares this unique knowledge with the global
community and works with institutions in the United States and around the
world that contribute to understanding and protecting our home planet.
 
For more information about NASA's Earth science activities this year, see:
http://www.nasa.gov/earthrightnow
 
 
Regards,
 
Roger

--- D'Bridge 3.99
 * Origin: NCS BBS - Houma, LoUiSiAna (1:3828/7)