NASA’s Earth Surface Mineral Dust Source Investigation (EMIT) mission maps the occurrence of key minerals in the planet’s dust-producing deserts—information that advances our understanding of the effects of airborne dust on climate. However, EMIT has demonstrated another crucial capability: detecting the presence of methane, a potent greenhouse gas. In data collected by EMIT since its installation on the International Space Station in July, the science team identified more than 50 “super-emitters” in Central Asia, the Middle East and the southwestern United States. Superemitters are facilities, equipment and other infrastructure, typically in the fossil fuel, waste or agriculture sectors, that emit high levels of methane.
“Cutting methane emissions is the key to limiting global warming. This exciting new development will not only help researchers better determine where methane leaks are coming from, but also provide insight into how they can be quickly addressed,” said NASA Administrator Bill Nelson. “The International Space Station and more than two dozen NASA satellites and instruments in space have long been invaluable in determining changes in Earth’s climate. EMIT is proving to be a critical tool in our toolkit for measuring this powerful greenhouse gas – and stopping it at the source.”
Methane absorbs infrared light in a unique pattern – called a spectral fingerprint – that the EMIT imaging spectrometer can discern with high accuracy and precision. The device can also measure carbon dioxide. The new observations come from the wide coverage of the planet provided by the space station’s orbit, as well as EMIT’s ability to scan swathes of Earth’s surface tens of miles wide while distinguishing areas as small as a football field.
“These results are exceptional and demonstrate the value of combining a global-scale perspective with the resolution needed to identify point sources of methane down to the facility scale,” said David Thompson, EMIT instrument scientist and NASA Jet Propulsion Principal Investigator. The laboratory in Southern California that manages the mission. “It’s a unique capability that will raise the bar for efforts to attribute methane sources and mitigate emissions from human activities.”
Compared to carbon dioxide, methane accounts for a fraction of human-caused greenhouse gas emissions, but is estimated to be 80 times more effective, tonne for tonne, at trapping heat in the atmosphere within 20 years of release. Furthermore, where carbon dioxide persists for centuries, methane persists for about a decade, meaning that if emissions are reduced, the atmosphere will respond in a similar timeframe, leading to slower short-term warming.
Identifying point sources of methane may be a key step in the process. By knowing the location of large emitters, operators of gas-emitting facilities, equipment and infrastructure can act quickly to reduce emissions. The EMIT methane observations came as the scientists verified the accuracy of the imaging spectrometer’s mineral data. During its mission, EMIT will collect measurements of surface minerals in arid regions of Africa, Asia, North and South America, and Australia. The data will help researchers better understand the role of airborne dust particles in heating and cooling the Earth’s atmosphere and surface.
“We were eager to see how EMIT’s mineral data would improve climate modeling,” said Kate Calvin, NASA’s principal scientist and senior climate advisor. “This additional methane detection capability offers a remarkable opportunity to measure and monitor greenhouse gases that contribute to climate change.”
Detection of methane plumes
The mission’s study area coincides with known methane hotspots around the world, allowing researchers to search for gas in these areas and test the imaging spectrometer’s capability. “Some of the plumes detected by EMIT are among the largest ever observed — unlike anything ever seen from space,” said Andrew Thorpe, a research technologist at JPL who leads EMIT’s methane effort. “What we have found in a short period of time already exceeds our expectations.”
For example, the instrument detected a plume about 3.3 km southeast of Carlsbad, New Mexico, in the Permian Basin. The Permian, one of the largest oil fields in the world, covers parts of southeastern New Mexico and western Texas. In Turkmenistan, EMIT identified 12 plumes from oil and gas infrastructure east of the Caspian Sea port city of Hazar. Some west-blowing plumes extend more than 20 miles (32 kilometers). The team also identified a methane plume south of Tehran, Iran, at least 3 miles (4.8 kilometers) long from a large waste processing complex. Methane is a by-product of decomposition and its main source can be landfills.
The researchers estimate flows of about 40,300 pounds (18,300 kilograms) per hour in the Permian locality, 111,000 pounds (50,400 kilograms) per hour in total for the resources in Turkmenistan, and 18,700 pounds (8,500 kilograms) per hour in the Iran field. The Turkmenistan resources collectively have a similar flow rate to the 2015 Aliso Canyon gas leak, which at times exceeded 110,000 pounds (50,000 kilograms) per hour. The disaster in the Los Angeles area was among the largest methane releases in US history.
With wide and repeated coverage from its vantage point on the space station, EMIT has the potential to find hundreds of superemitters – some of which have previously been observed by measurements in air, space or on the ground, and others which were unknown. “As the exploration of the planet continues, EMIT will look in places where no one has thought to look for greenhouse gas emitters before, and they will find plumes that no one expects,” said Robert Green, EMIT principal investigator at JPL. EMIT is the first of a new class of space-based imaging spectrometers for Earth studies. One example is the Carbon Plume Mapper (CPM), an instrument under development at JPL designed to detect methane and carbon dioxide. JPL is working with the nonprofit Carbon Mapper and other partners to launch two CPM-equipped satellites in late 2023.
Source : https://www.nasa.gov/feature/jpl/methane-super-emitters-mapped-by-nasa-s-new-earth-space-mission
