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NASA's EMIT Collects Mineral Maps, Spectral Fingerprints From Nevada

Oct. 12, 2022
NASA's EMIT mission recently gathered mineral spectra in northwest Nevada that match what the agency's AVIRIS instrument found in 2018, helping to confirm EMIT's accuracy.

Since NASA's Earth Surface Mineral Dust Source Investigation (EMIT) imaging spectrometer was installed on the International Space Station in late July 2022, the EMIT science team has been validating its data against data gathered in 2018 by NASA's Airborne Visible/Infrared Imaging Spectrometer (AVIRIS).

EMIT recently collected data from a mountainous area of Nevada about 130 miles (209 kilometers) northeast of Lake Tahoe. The instrument measures reflected solar energy from Earth across hundreds of wavelengths from the visible to the infrared range of the spectrum. The intensity of the reflected light varies by wavelength based on the material. Scientists use these patterns, called spectral fingerprints, to pinpoint the locations of surface minerals on a map.

The top left map shows the region both the EMIT and AVIRIS data sets cover. The center image is a mineral map featuring AVIRIS data. At right is a map generated with EMIT data. The center and right images reveal portions of the landscape dominated by kaolinite, a light-colored clay mineral that scatters sunlight. This comparison, which shows a close match of the data, was one of many that confirmed the accuracy of EMIT's data.

The bottom row features an AVIRIS spectral fingerprint, left, beside EMIT data for the same location. The graphs show agreement in the kaolinite fingerprint region, which is marked in blue.

Over the course of its 12-month mission, EMIT will collect measurements of 10 important surface minerals – kaolinite, hematite, goethite, illite, vermiculite, calcite, dolomite, montmorillonite, chlorite, and gypsum – in arid regions between 50-degree south and north latitudes in Africa, Asia, North and South America, and Australia. The data EMIT collects will help scientists better understand the role of airborne dust particles in heating and cooling Earth's atmosphere on global and regional scales.

EMIT was developed at NASA's Jet Propulsion Laboratory, which is managed for NASA by Caltech in Pasadena, California.

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