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Description

The Earth Surface Mineral Dust Source Investigation (EMIT) instrument measures surface mineralogy, targeting the Earth’s arid dust source regions. EMIT is installed on the International Space Station (ISS) and uses imaging spectroscopy to take measurements of the sunlit regions of interest between 52° N latitude and 52° S latitude. An interactive map showing the regions being investigated, current and forecasted data coverage, and additional data resources can be found on the VSWIR Imaging Spectroscopy Interface for Open Science (VISIONS) EMIT Open Data Portal.

The EMIT Level 3 Aggregated Mineral Spectral Abundance and Uncertainty (EMITL3ASA) Version 2 data product provides an aggregated mineral spectral abundance of the 10 minerals that are the focus of the EMIT mission. These minerals, referred to as the EMIT-10 minerals, are calcite, chlorite, dolomite, goethite, gypsum, hematite, illite+muscovite, kaolinite, montmorillonite, and vermiculite. The EMITL3ASA granule consists of one Network Common Data Format 4 (netCDF-4) file at a spatial resolution of 0.5 degrees. The data in EMITL3ASA relies heavily on the EMIT L2B Estimated Mineral Identification and Band Depth and Uncertainty (EMITL2BMIN) data. Using the EMITL2BMIN data, aggregated spectral abundance (ASA) and uncertainty is calculated within each 0.5 degree grid cell in the EMITL3ASA product for each of the EMIT-10 minerals. Grainsize was determined to be the strongest contributor to abundance variation, and as such layers calculated using the 2.5 and 97.5 percentile confidence interval of the grainsize are provided for use in uncertainty quantification.

The EMITL3ASA data product contains 30 Science Dataset (SDS) layers. There are three layers for each of the EMIT-10 minerals: one layer containing mineral spectral abundance and two layers for uncertainty quantification containing mineral spectral abundance at 2.5 and 97.5 percentile confidence intervals of grainsize. The latitude and longitude layers contain the coordinates for the upper left corner of each pixel.

Known Issues

  • Minor Abundance Estimate Discrepancy. A transcription error in the grain-size median prediction caused a minor discrepancy in the EMITL3ASA Version 2 mineral spectral abundance estimates. The issue caused deviations well within the uncertainty estimates, typically far below 1%. The most affected estimate is calcite, with maximum deviations reaching 2% for a very small number of pixels. Iron oxides are virtually unaffected.

Improvements/Changes from Previous Versions

  • Version 2 data produced using a fundamentally new model to obtain spectral abundance from L2BMIN data.
  • Added grainsize dependency into the new model.

Version Description

Version 2

Product Summary

Platforms
ISS
Instruments
EMIT Imaging Spectrometer
Spatial Extent
N: 55 S: -54.5 E: 179.5 W: -165
Spatial Resolution
0.5 Decimal Degrees x 0.5 Decimal Degrees
Geographic Region
GLOBAL LAND
Coordinate System
CARTESIAN
Granule Spatial Representation
CARTESIAN
Temporal Extent
2022-08-10 to 2024-01-20
Temporal Resolution
Varies
Data Partner
Land Processes Distributed Active Archive Center (LP DAAC)
Earth Surface Mineral Dust Source Investigation, Jet Propulsion Laboratory, NASA (NASA/JPL/EMIT)
Concept ID
C3147269019-LPCLOUD
Data State
COMPLETE
Processing Level
3
Published
Updated
Science Keywords
Soil Chemistry

Citation

Citation is critically important for dataset documentation and discovery. This dataset is openly shared, without restriction, in accordance with the EOSDIS Data Use and Citation Guidance.

Copy Citation

Brodrick, P., Okin, G., Ochoa, F., Thompson, D., Clark, R., Ehlmann, B., Keebler, A., Miller, R., Mohawald, N., Ginoux, P., Garcia-Pando, C., Goncalves, M., & Green, R. (2025). EMIT L3 Aggregated Mineral Spectral Abundance and Uncertainty 0.5 Deg V002 [Data set]. NASA Land Processes Distributed Active Archive Center. https://doi.org/10.5067/EMIT/EMITL3ASA.002 Date Accessed: 2025-11-02

File Naming Convention

EMIT_L3_ASA_002.nc

The file name begins with the Sensor (EMIT) followed by the Processing Level (L3), Product Type (ASA), and Product Version Number (002), and Data Format (nc).

Documents

Variables

Variables are a set of physical properties whose values determine the characteristics or behavior of something. For example, temperature and pressure are variables of the atmosphere. Parameters and variables can be used interchangeably. Variable level attributes provide individual information for each variable.

The Name in this table is the variable name. Fill value indicates missing or undefined data points in a variable. Valid range is the range of values the variable can store. Scale factor is used to increase or decrease the size of an object and can be used to correct for distortion. For questions on a specific variable, please use the Earthdata Forum.

Name Description Units Data Type Fill Value Valid Range Scale Factor
Calcite Aggregated mineral spectral abundance of calcite N/A float32 -9999 -9999 N/A
Calcite_UQ_high_grainsize Aggregated mineral spectral abundance of calcite at 97.5 percentile grainsize for uncertainty quantification N/A float32 -9999 -9999 N/A
Calcite_UQ_low_grainsize Aggregated mineral spectral abundance of calcite at 2.5 percentile grainsize for uncertainty quantification N/A float32 -9999 -9999 N/A
Chlorite Aggregated mineral spectral abundance of chlorite N/A float32 -9999 -9999 N/A
Chlorite_UQ_high_grainsize Aggregated mineral spectral abundance of chlorite at 97.5 percentile grainsize for uncertainty quantification N/A float32 -9999 -9999 N/A
Chlorite_UQ_low_grainsize Aggregated mineral spectral abundance of chlorite at 2.5 percentile grainsize for uncertainty quantification N/A float32 -9999 -9999 N/A
Dolomite Aggregated mineral spectral abundance of dolomite N/A float32 -9999 -9999 N/A
Dolomite_UQ_high_grainsize Aggregated mineral spectral abundance of dolomite at 97.5 percentile grainsize for uncertainty quantification N/A float32 -9999 -9999 N/A
Dolomite_UQ_low_grainsize Aggregated mineral spectral abundance of dolomite at 2.5 percentile grainsize for uncertainty quantification N/A float32 -9999 -9999 N/A
Goethite Aggregated mineral spectral abundance of goethite N/A float32 -9999 -9999 N/A
Goethite_UQ_high_grainsize Aggregated mineral spectral abundance of goethite at 97.5 percentile grainsize for uncertainty quantification N/A float32 -9999 -9999 N/A
Goethite_UQ_low_grainsize Aggregated mineral spectral abundance of goethite at 2.5 percentile grainsize for uncertainty quantification N/A float32 -9999 -9999 N/A
Gypsum Aggregated mineral spectral abundance of gypsum N/A float32 -9999 -9999 N/A
Gypsum_UQ_high_grainsize Aggregated mineral spectral abundance of gypsum at 97.5 percentile grainsize for uncertainty quantification N/A float32 -9999 -9999 N/A
Gypsum_UQ_low_grainsize Aggregated mineral spectral abundance of gypsum at 2.5 percentile grainsize for uncertainty quantification N/A float32 -9999 -9999 N/A
Hematite Aggregated mineral spectral abundance of hematite N/A float32 -9999 -9999 N/A
Hematite_UQ_high_grainsize Aggregated mineral spectral abundance of hematite at 97.5 percentile grainsize for uncertainty quantification N/A float32 -9999 -9999 N/A
Hematite_UQ_low_grainsize Aggregated mineral spectral abundance of hematite at 2.5 percentile grainsize for uncertainty quantification N/A float32 -9999 -9999 N/A
Illite+Muscovite Aggregated mineral spectral abundance of illite+muscovite N/A float32 -9999 -9999 N/A
Illite+Muscovite_UQ_high_grainsize Aggregated mineral spectral abundance of illite+muscovite at 97.5 percentile grainsize for uncertainty quantification N/A float32 -9999 -9999 N/A
Illite+Muscovite_UQ_low_grainsize Aggregated mineral spectral abundance of illite+muscovite at 2.5 percentile grainsize for uncertainty quantification N/A float32 -9999 -9999 N/A
Kaolinite Aggregated mineral spectral abundance of kaolinite N/A float32 -9999 -9999 N/A
Kaolinite_UQ_high_grainsize Aggregated mineral spectral abundance of kaolinite at 97.5 percentile grainsize for uncertainty quantification N/A float32 -9999 -9999 N/A
Kaolinite_UQ_low_grainsize Aggregated mineral spectral abundance of kaolinite at 2.5 percentile grainsize for uncertainty quantification N/A float32 -9999 -9999 N/A
Montmorillonite_UQ_high_grainsize Aggregated mineral spectral abundance of montmorillonite at 97.5 percentile grainsize for uncertainty quantification N/A float32 -9999 -9999 N/A
Montmorillonite_UQ_low_grainsize Aggregated mineral spectral abundance of montmorillonite at 2.5 percentile grainsize for uncertainty quantification N/A float32 -9999 -9999 N/A
Montomorillonite Aggregated mineral spectral abundance of montmorillonite N/A float32 -9999 -9999 N/A
Vermiculite Aggregated mineral spectral abundance of vermiculite N/A float32 -9999 -9999 N/A
Vermiculite_UQ_high_grainsize Aggregated mineral spectral abundance of vermiculite at 97.5 percentile grainsize for uncertainty quantification N/A float32 -9999 -9999 N/A
Vermiculite_UQ_low_grainsize Aggregated mineral spectral abundance of vermiculite at 2.5 percentile grainsize for uncertainty quantification N/A float32 -9999 -9999 N/A
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