U.S. Methane 'Hot Spot' Bigger than Expected
 
Oct. 9, 2014: One small "hot spot" in the U.S. Southwest is
responsible for producing the largest concentration of the greenhouse gas
methane seen over the United States - more than triple the standard
ground-based estimate -- according to a new study of satellite data by
scientists at NASA and the University of Michigan.
 
Methane is very efficient at trapping heat in the atmosphere and, like
carbon dioxide, it contributes to global warming. The hot spot, near the
Four Corners intersection of Arizona, Colorado, New Mexico and Utah, covers
only about 2,500 square miles (6,500 square kilometers), or half the size
of Connecticut.
 
http://www.nasa.gov/sites/default/files/thumbnails/image/14-280.jpg
 
The Four Corners area (red) is the major U.S. hot spot for methane
emissions in this map showing how much emissions varied from average
background concentrations from 2003-2009 (dark colors are lower than
average; lighter colors are higher). Image Credit:
NASA/JPL-Caltech/University of Michigan
In each of the seven years studied from 2003-2009, the area released about
0.59 million metric tons of methane into the atmosphere. This is almost 3.5
times the estimate for the same area in the European Union's widely used
Emissions Database for Global Atmospheric Research.
 
In the study published online today in the journal Geophysical Research
Letters, researchers used observations made by the European Space Agency's
Scanning Imaging Absorption Spectrometer for Atmospheric Chartography
(SCIAMACHY) instrument. SCIAMACHY measured greenhouse gases from 2002 to
2012. The atmospheric hot spot persisted throughout the study period. A
ground station in the Total Carbon Column Observing Network, operated by
the Department of Energy's Los Alamos National Laboratory, provided
independent validation of the measurement.
 
To calculate the emissions rate that would be required to produce the
observed concentration of methane in the air, the authors performed
high-resolution regional simulations using a chemical transport model,
which simulates how weather moves and changes airborne chemical compounds.
 
Research scientist Christian Frankenberg of NASA's Jet Propulsion
Laboratory (JPL) in Pasadena, California, first noticed the Four Corners
signal years ago in SCIAMACHY data.
 
"We didn't focus on it because we weren't sure if it was a true signal
or an instrument error," Frankenberg said.
 
The study's lead author, Eric Kort of the University of Michigan, Ann
Arbor, noted the study period predates the widespread use of hydraulic
fracturing, known as fracking, near the hot spot. This indicates the
methane emissions should not be attributed to fracking but instead to leaks
in natural gas production and processing equipment in New Mexico's San Juan
Basin, which is the most active coalbed methane production area in the
country.
 
Natural gas is 95-98 percent methane. Methane is colorless and odorless,
making leaks hard to detect without scientific instruments.
 
"The results are indicative that emissions from established fossil
fuel harvesting techniques are greater than inventoried," Kort said.
"There's been so much attention on high-volume hydraulic fracturing,
but we need to consider the industry as a whole."
 
Coalbed methane is gas that lines pores and cracks within coal. In
underground coal mines, it is a deadly hazard that causes fatal explosions
almost every year as it seeps out of the rock. After the U.S. energy crisis
of the 1970s, techniques were invented to extract the methane from the coal
and use it for fuel. By 2012, coalbed methane supplied about 8 percent of
all natural gas in the United States.
 
Frankenberg noted that the study demonstrates the unique role space-based
measurements can play in monitoring greenhouse gases.
 
"Satellite data cannot be as accurate as ground-based estimates, but
from space, there are no hiding places," Frankenberg said.
 
Credits:
Production editor: Dr. Tony Phillips | Credit: Science{at}NASA
 
More information:
 
In March 2014 the Obama Administration announced a strategy to reduce
methane emissions under its Climate Action Plan. The strategy includes
improving the measurement and monitoring of methane emissions and assessing
current methane emissions data.
 
NASA monitors Earth's vital signs from land, air and space with a fleet of
satellites and 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 in 2014, visit:
http://www.nasa.gov/earthrightnow
 
 
Regards,
 
Roger

--- D'Bridge 3.99