NASA sensor produces first global maps of surface minerals in arid regions

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NASA’s EMIT mission has created the first comprehensive maps of mineral dust resource areas on Earth, pinpointing the precise locations of 10 key minerals based on the way they reflect and absorb light. When wind blows these materials into the air, they cool or warm the atmosphere and Earth’s surface, depending on their composition. Understanding their abundance around the world will help researchers predict future climate impacts.

EMIT, short for Earth Surface Mineral Dust Source Investigation, will be launched to the International Space Station in 2022 and is an imaging spectrometer developed by NASA’s Jet Propulsion Laboratory in Southern California. The mission fulfills climate scientists’ critical need for more detailed information about the mineral composition of the Earth’s surface. EMIT surveys the Earth’s surface from an altitude of about 410 kilometers (250 miles), surveying large areas that would be impossible for a ground geologist or aircraft instruments to explore.

So far, the mission has captured more than 55,000 “views,” 50-by-50-mile images of the surface, in the study area, which includes barren regions within a 7,000-mile-wide belt around the center of the Earth. Together, the views comprise billions of measurements, more than enough to create detailed maps of surface composition. The mission also demonstrated a number of additional capabilities during its 17 months in orbit, including detecting methane and carbon dioxide plumes emanating from landfills, oil facilities and other infrastructure.

“Anywhere we need chemistry to understand something on the surface, we can do that using imaging spectroscopy,” says Roger Clark, an EMIT science team member and senior scientist at the Planetary Science Institute in Tucson, Arizona. “Now, with EMIT, we will see the big picture and this will definitely open some eyes.”

Dust and climate

Scientists have long known that mineral dust in the air affects climate. They know that dark materials rich in iron oxide absorb the sun’s energy and warm the surrounding air, while bright, non-iron materials reflect light and heat and cool the air. However, whether these effects have a net warming or cooling effect has remained uncertain.

Researchers have an idea of ​​how dust moves through the atmosphere, but the missing piece was the composition of the surface where dust typically comes from, which so far has been obtained from fewer than 5,000 sample sites worldwide. world. EMIT maps are based on billions of samples and provide much more detail. “We’re taking the new maps and putting them into our climate models,” said Natalie Mahowald, deputy principal investigator at EMIT and an Earth systems scientist at Cornell University in Ithaca, New York. “Consequently, we know the ratio of aerosols that absorb versus reflect heat to a much greater extent than we did in the past.”

EMIT, a NASA mission launching to the International Space Station in 2022, contains hematite, goethite and kaolinite.
It is located in North Africa and the Arabian Peninsula. The three minerals belong to 10
The main materials studied by the mission and believed to be the basic material
Impact on climate change – Image: NASA

Dust and ecosystems

In addition to using EMIT’s mineral data to improve Earth’s climate modeling, scientists can also use the information to study the impact of dust on the ecosystems it introduces. There is strong evidence that particles entering the ocean can cause phytoplankton blooms, potentially affecting aquatic ecosystems and the planet’s carbon cycle. Scientists have also shown that dust from the Andes in South America and parts of northern and sub-Saharan Africa provides nutrients for the growth of the Amazon rainforest.

The EMIT data could allow researchers to pinpoint the sources of the mineral dust and take a more detailed look at its composition, allowing them to estimate the movement of key elements such as phosphorus, calcium and potassium, which are thought to play a role over this long period. – Remote fertilization. “EMIT can help us build more complex and accurate mass transport models to track the movement of these nutrients over long distances,” says Eric Slesarev, a soil researcher at Yale University in New Haven, Connecticut. “This will help us better understand the chemical composition of soil in places far from dust-producing areas.”

A new generation of science

In addition to detecting the 10 key minerals that are part of the core mission, EMIT data is used to identify a range of other minerals, plant species, snow, ice and even human-produced materials on or near the Earth’s surface. With many measurements available, researchers can find statistical relationships between surface features and other features of interest.

For example, they can detect signals in the EMIT data consistent with the presence of rare earth elements and lithium-bearing minerals, said Robert Green, a senior research scientist at JPL and a principal investigator at EMIT. This new information can be used to search for these materials in previously unknown places. “Until now, we simply didn’t know the distribution of surface minerals over large parts of the planet,” said Phil Broderick, a data scientist at JPL who led the effort to create the mineral maps. With the EMIT data, “a new generation of science is likely to emerge that we don’t know anything about yet, and that’s really cool.”

More about the mission

EMIT was selected from the Earth Venture Instrument-4 solicitation within the Earth Sciences Division of NASA’s Science Mission Directorate and was developed at NASA’s Jet Propulsion Laboratory, which is operated by the California Institute of Technology in Pasadena, California. Instrument data are available at NASA’s Earth Operations Distributed Active Archive Center for use by other researchers and the public.

source: NASA