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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 mineralogical 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 1 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) is calculated for each of the EMIT-10 minerals as the simple average of relevant 60 m pixels within each 0.5 degree grid cell in the EMITL3ASA product, after controlling for the estimated fractional cover of bare soil within the pixel.

The EMITL3ASA data product contains 22 Science Dataset (SDS) layers. There are two layers for each of the EMIT-10 minerals: mineral spectral abundance and mineral spectral abundance uncertainty. The latitude and longitude layers contain the coordinates for the upper left corner of each pixel.

Known Issues

  • The current version of the spectral unmixing algorithm may retrieve spuriously high non-photosynthetic vegetation values over bare playas. Algorithmic fixes are underway and will be integrated during the first data reprocessing cycle. As such, some bare playas are excluded from the current L3 aggregation.
  • Spectral abundance is a measure of optical abundance, not of mass fraction. Conversion to mass or volume fraction requires leverage on particle grain size, which is not incorporated into the current model. Given this limitation, this product should not be used directly as a measure of mass fraction.

Version Description

Version 1

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 2023-07-30
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
C2408752948-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. (2023). EMIT L3 Aggregated Mineral Spectral Abundance and Uncertainty 0.5 Deg V001 [Data set]. NASA Land Processes Distributed Active Archive Center. https://doi.org/10.5067/EMIT/EMITL3ASA.001 Date Accessed: 2025-11-02

File Naming Convention

EMIT_L3_ASA_001.nc

The file name begins with the Sensor (EMIT) followed by the Processing Level (L3), Product Type (ASA), and Product Version Number (001).

Documents

Data collected by NASA's Earth Surface Mineral Dust Source Investigation (EMIT) on April 23, 2024, indicates the location of a variety of planet communites across a swath of the mid-Atlantic United States.

EMIT Tutorial Series

In this three-part tutorial series, learn how to use Python to process EMIT reflectance data.
Tutorial
June 14, 2023
SHOWING 1 OF 1

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 Percent float32 -9999 -9999 N/A
Calcite_uncert Aggregated mineral spectral abundance uncertainty of calcite Percent float32 -9999 -9999 N/A
Chlorite Aggregated mineral spectral abundance of chlorite Percent float32 -9999 -9999 N/A
Chlorite_uncert Aggregated mineral spectral abundance uncertainty of chlorite Percent float32 -9999 -9999 N/A
Dolomite Aggregated mineral spectral abundance of dolomite Percent float32 -9999 -9999 N/A
Dolomite_uncert Aggregated mineral spectral abundance uncertainty of dolomite Percent float32 -9999 -9999 N/A
Goethite Aggregated mineral spectral abundance of goethite Percent float32 -9999 -9999 N/A
Goethite_uncert Aggregated mineral spectral abundance uncertainty of goethite Percent float32 -9999 -9999 N/A
Gypsum Aggregated mineral spectral abundance of gypsum Percent float32 -9999 -9999 N/A
Gypsum_uncert Aggregated mineral spectral abundance uncertainty of gypsum Percent float32 -9999 -9999 N/A
Hematite Aggregated mineral spectral abundance of hematite Percent float32 -9999 -9999 N/A
Hematite_uncert Aggregated mineral spectral abundance uncertainty of hematite Percent float32 -9999 -9999 N/A
Illite+Muscovite Aggregated mineral spectral abundance of illite+muscovite Percent float32 -9999 -9999 N/A
Illite+Muscovite_uncert Aggregated mineral spectral abundance uncertainty of illite+muscovite Percent float32 -9999 -9999 N/A
Kaolinite Aggregated mineral spectral abundance of kaolinite Percent float32 -9999 -9999 N/A
Kaolinite_uncert Aggregated mineral spectral abundance uncertainty of kaolinite Percent float32 -9999 -9999 N/A
latitude Latitude Degree float32 -9999 -9999 N/A
longitude Longitude Degree float32 -9999 -9999 N/A
Montmorillonite Aggregated mineral spectral abundance of montmorillonite Percent float32 -9999 -9999 N/A
Montmorillonite_uncert Aggregated mineral spectral abundance uncertainty of montmorillonite Percent float32 -9999 -9999 N/A
Vermiculite Aggregated mineral spectral abundance of vermiculite Percent float32 -9999 -9999 N/A
Vermiculite_uncert Aggregated mineral spectral abundance uncertainty of vermiculite Percent float32 -9999 -9999 N/A
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