Friday, April 10, 2015

Scientists Investigate Mysterious Methane Hot Spot Over U.S.

Researchers from several scientific institutions are in the Four Corners region of the U.S. Southwest with airborne and ground-based instruments to try to determine what is causing a mysterious methane "hot spot" anomaly detected from space.

Last fall, researchers reported that a small region around the Four Corners intersection of Arizona, Colorado, New Mexico and Utah had the highest concentration of methane over background levels of any part of the United States. An instrument on a European Space Agency satellite measuring greenhouse gases showed a persistent atmospheric hot spot in the area between 2003 and 2009.



But the satellite observations were not detailed enough to reveal the actual sources of the methane in the Four Corners. Scientists believe that likely causes include venting from oil and gas activities, which are primarily coalbed methane exploration and extraction in this region; active coal mines; and natural gas seeps.

So researchers from the Cooperative Institute for Research in Environmental Sciences (CIRES) in Boulder, Colorado; the National Oceanic and Atmospheric Administration (NOAA) Earth Systems Research Laboratory; and the University of Michigan, Ann Arbor are conducting a field campaign called TOPDOWN (Twin Otter Projects Defining Oil Well and Natural gas emissions) 2015, bringing airborne and ground-based instruments to investigate possible sources of the methane hot spot.

"With all the ground-based and airborne resources that the different groups are bringing to the region, we have the unique chance to unequivocally solve the Four Corners mystery," said Christian Frankenberg, a scientist at NASA's Jet Propulsion Laboratory (JPL), Pasadena, California, who is heading NASA's part of the effort.

Shiprock, New Mexico, is in the Four Corners region where an atmospheric methane "hot spot" can be seen from space. Credit: Bowie Snodgrass via Wikimedia Commons
JPL will fly two complementary remote sensing instruments on two Twin Otter research aircraft. The Next-Generation Airborne Visible/Infrared Imaging Spectrometer (AVIRISng), which observes spectra of reflected sunlight, flies at a higher altitude and will be used to map methane at fine resolution over the entire region. Using this information and ground measurements from the other research teams, the Hyperspectral Thermal Emission Spectrometer (HyTES) will fly over suspected methane sources, making additional, highly sensitive measurements of methane. Depending on its flight altitude, the NASA aircraft can image methane features with a spatial resolution better than three feet (one meter) square.

Using their combined resources, the scientific teams hope to quantify the region's overall methane emissions and pinpoint contributions from different sources. They will track changes over the course of the month-long effort and study how meteorology transports those emissions through the region.

SOURCE: NASA