Scientists are working to reveal the source of a methane mass half the size of Connecticut currently hovering over the Four Corners region of the American Southwest.

Researchers with the University of Colorado, the University of Michigan, NASA, and the National Oceanic and Atmospheric Administration are , the Associated Press reports.

Last year, researchers with NASA and the University of Michigan released a studywas the largest concentration of the greenhouse gas in the U.S.

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Now, these scientists are coming together to piece together how the "hot spot" formed.

When NASA discovered the methane mass last year, they were basing their observations on satellite imagery taken from the European Space Agency. That imagery, however, didn't carry enough detail to point to the source of the methane.

A year later, the above ground and on land.

"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," NASA scientist Christian Frankenberg said in a statement.

According to NASA, the likely sources of the hot spot include the region's many coal mines and the oil and gas activities in the area. Methane, which is the main component of natural gas, is extracted from coalbeds regularly, and accidental releases into the atmosphere aren't uncommon.

On top of that, methane is released into the air naturally from those same coal beds over time.

As the Associated Press reports, scientists in Durango, Colorado, will fly over the coalbed-heavy San Juan Basin with instruments to detect methane. Crews on the ground will communicate with the aerial teams and follow up on their discoveries.

Since last year's findings were based on images taken in 2009, it's possible that methane levels have gone down and the findings from the current study will give a more accurate representation of the hot spot.

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Ecologist Katey Walters Anthony, right, ignites a large methane bubble that was trapped by the fall freeze. (Mark Thiessen/National Geographic Creative/Caters News Agency)