Global Assessment of Sand and Dust Storms. Atmospheric Aerosol Eddies NASA Animated Map: 10km GEOS-5 Aerosol Optical Depth (AOD). Models are used to assess the current and future impacts of mineral dust.
Is Mineral Dust Heating or Cooling the Planet?
Does mineral dust blown into the atmosphere cause it to warm or cool? This is the fundamental question that researchers hope a new space-based instrument will help them answer. Since much of the Earth’s desert regions are remote and inhospitable, the best way to study them may be from space.
In February 2018, NASA selected the JPL-led Earth Surface Mineral Dust Source Investigation (EMIT) as an Earth Venture Instrument for development and deployment to the International Space Station. EMIT will use advanced JPL imaging spectroscopy to measure the mineral composition of the Earth’s dust source regions. This will determine the optical and chemical properties of the dust aerosols emitted into the atmosphere during high wind conditions, providing accurate boundary conditions for today’s state-of-the-art Earth system models. With accurate initialization, these models will be used to understand the global dust cycle and predict the future role of mineral dust in the Earth’s climate system.
Mineral dust impacts the atmosphere, oceans, terrestrial ecosystems, cryosphere, and inhabited lands. The EMIT instrument uses a set of technologies invented at JPL for advanced imaging spectrometer instruments and science missions, including: a three-octave, high-uniformity Dyson imaging spectrometer design; submicron adjustable detector mounts; an e-beam fabricated grating; a silicon nitride slit; and a black silicon zero-order light trap. The grating, slit, and light trap are fabricated at MDL. A prototype of the EMIT imaging spectrometer has been developed and used to advance the readiness of these key technologies. High-throughput imaging spectrometers of the EMIT type are relevant to a broad range of future NASA missions to address new science questions on the moon, Mars, and throughout the solar system. EMIT’s scheduled launch is in 2021 to proceed and address these objectives. The principal investigator for the EMIT mission at JPL is MDL’s Robert O. Green.
The EMIT Instrument Draws from a Long History of Imaging Spectrometer Development
- First Imaging Spectrometer AIS proposed in 1979 first flights in 1982
- AVIRIS imaging spectrometer > 1000 refereed journal articles
- NIMS imaging spectrometer to Jupiter
- VIMS imaging spectrometer to Saturn
- MICAS Miniature Integrated Camera and Imaging Spectrometer to Comet
- Enabling partner in Hyperion-Earth, CRISM-Mars and ARTEMIS-Earth imaging spectrometers (gratings, designs, calibration, and science)
- Proposed and Developed NASA Moon Mineralogy Mapper (M3)
- > 7 Airborne/Rover-type Imaging Spectrometer operating at cryogenic temperature and in a vacuum (2005-2015)
MDL-e-beam fabricated structured blaze concave grating technology for the EMIT prototype imaging spectrometer with atomic force micrograph of achieved structured blaze.
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Detector mounts: JPL technology cryogen detector array mount with six degrees of freedom adjustment to submicron tolerances.
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EMIT will constrain the sign and magnitude of dust-related Radiative Forcing at regional and global scales by acquiring, validating and delivering updates of surface mineralogy used to initialize Earth system models. The next objective is to predict the increase or decrease of available dust sources under future climate scenarios. EMIT achieves this objective by initializing ESM forecast models with the mineralogy of soils exposed within at-risk lands bordering arid dust source regions.
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