An orbital NASA instrument designed primarily to advance studies of airborne dust and its effects on climate change has proven adept at another important Earth science function.
A NASA orbital instrument primarily designed to advance studies of airborne dust and its effects on climate change has proven adept at another important Earth science function — detecting large, global emissions of methane, a potent greenhouse gas.
The device, called an imaging spectrometer, has identified more than 50 methane “super emitters” in Central Asia, the Middle East and the southwestern United States since its installation in July, NASA said Tuesday.
The newly measured methane hotspots — some previously known and others just discovered — include sprawling oil and gas facilities and large landfills.
The spectrometer was built primarily to identify the mineral composition of dust blown from Earth’s deserts and other arid regions into the atmosphere by measuring the wavelengths of light reflected from the surface soil in those regions.
That study, NASA’s Earth Surface Mineral Dust Investigation, or EMIT, will help scientists determine whether dust in the air in different parts of the world is likely to trap or deflect heat from the sun, thus contributing to warming or cooling the planet. .
It turns out that methane absorbs infrared light in a unique pattern that EMIT’s spectrometer can easily detect, according to scientists at NASA’s Jet Propulsion Laboratory (JPL) near Los Angeles, where the instrument was designed and built.
EMIT orbits Earth every 90 minutes from its position aboard the space station, about 420 km high, and can scan vast swathes of the planet tens of kilometers across, while also focusing on areas as small as a football field. .
“Some of the (methane) plumes that EMIT has detected are among the largest ever seen — unlike anything ever seen from space,” said Andrew Thorpe, a JPL research technologist who leads the methane studies.
A byproduct of decomposing organic matter and the main component of natural gas used in power plants, methane is responsible for a fraction of all human-caused greenhouse gas emissions, but has about 80 pounds more heat-holding capacity than carbon dioxide.
Compared to CO2, which lingers in the atmosphere for centuries, methane lasts for only about ten years, meaning reductions in methane emissions have a more direct effect on global warming.
Examples of newly imaged methane super-radiators shown by JPL on Tuesday included a cluster of 12 plumes from oil and gas infrastructure in Turkmenistan, some plumes stretching for more than 20 miles (32 km).
Scientists estimate that the Turkmenistan plumes collectively spew methane at a rate of 111,000 pounds (50,400 kilograms) per hour, which corresponds to the peak flow of the 2015 Aliso Canyon gas field eruption near Los Angeles, which ranks as one of the the largest accidental methane release in US history.
Two other major emitters were an oil field in New Mexico and a waste processing complex in Iran, which together emit nearly 60,000 pounds (29,000 kg) of methane per hour. JPL officials said neither had been previously known to scientists.
EMIT, one of 25 Earth science instruments in orbit, could potentially find hundreds of methane super-radiators before the year-long mission ends, NASA said.