# EMIT L3 Aggregated Mineral Spectral Abundance and Uncertainty
*data products*

## Specifications
- **level**: L3
- **distributor**: nasa
- **spectral range nm**: {"min":381,"max":2493}
- **gsd m**: {"native":60}
- **file format**: netCDF-4
- **access endpoint**: https://search.earthdata.nasa.gov
- **access model**: open
- **licence**: NASA EOSDIS open data (no restrictions on use or redistribution; NASA Earthdata account required for download)
- **primary data portal url**: https://www.earthdata.nasa.gov/data/catalog/lpcloud-emitl3asa-002
- **use cases**: ["Global mineral dust source characterisation, deriving the surface mineral composition of arid regions (Sahara, Arabian Peninsula, Gobi, Atacama, Australian outback) to constrain atmospheric mineral dust radiative forcing in Earth system models","Earth system model boundary condition input, supplying gridded fractional abundances of iron-bearing minerals (goethite, hematite) and carbonate minerals (calcite, dolomite) that drive dust optical property parameterisations in GCMs","Cross-reference mineralogy anchor for exploration datasets, validating regional-scale mineral abundance maps produced from airborne or spaceborne hyperspectral surveys against a global open-access baseline","Climate-minerals community cross-reference, identifying which arid regions have anomalously high concentrations of specific minerals (gypsum, kaolinite, illite+muscovite) relevant to both dust radiative forcing and mineral exploration landscape context","Baseline iron oxide distribution mapping; the goethite and hematite layers provide a global open reference for surface iron oxide abundance in dust source regions"]
- **practical limitations**: ["Static dataset covering the EMIT ISS coverage window (2022-08-10 to 2024-01-20); not an operational rolling product. V002 is the current and final version as of 2025-08-27; no updates beyond the January 2024 temporal bound have been announced.","0.5-degree grid resolution (approximately 55 km at the equator) is not suitable for deposit-scale or outcrop-scale mineral mapping; use EMIT L2B Surface Mineralogy (60 m per-pixel) or airborne hyperspectral data for local-scale work.","Spectral abundance is an optical (reflectance-derived) fractional measure, not a mass fraction. Conversion to mass fraction requires grain-size data that are not included in the product; users requiring mass-based abundances must apply independent grain-size models.","Geographic coverage constrained to 52 N to 52 S latitude by ISS inclination (51.6 degrees); polar regions and sub-polar latitudes above approximately 52 degrees are not represented.","Coverage prioritised arid dust-source regions; vegetated and densely clouded areas may have sparse 0.5-degree cells. Bare soil mask applied during aggregation excludes non-mineral surfaces.","NASA Earthdata account registration required for download via Earthdata Search; free but requires registration.","NetCDF-4 format requires CF-convention-aware readers (xarray, netCDF4-python, GDAL); no pre-packaged COG or STAC delivery."]
- **known artefacts**: ["V002 grain-size transcription error: a minor error in the grain-size median used in the uncertainty model causes deviations typically well below 1%, with calcite reaching a maximum of approximately 2% in select pixels. Iron oxides are virtually unaffected. Deviations are within the stated uncertainty bounds.","Spectral unmixing may produce spuriously elevated spectral abundance values over bare salt playas and some highly reflective surfaces; some such areas are excluded via the bare soil mask but residual artefacts are possible.","V001 (22 SDS layers, DOI 10.5067/EMIT/EMITL3ASA.001, temporal through 2023-07-30) is superseded by V002 (30 SDS layers, extended temporal through 2024-01-20, grain-size percentile uncertainty split into 2.5th and 97.5th confidence interval layers). Users should use V002."]
- **last verified date**: "2026-05-19T00:00:00.000Z"
- **verified by**: agency-doc
- **claim status**: agency-verified
- **deployment context**: orbital

## Compositional position
- minerals (topics) --[topic_capabilities]--> EMIT L3 Aggregated Mineral Spectral Abundance and Uncertainty

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Source: https://eo-atlas.org/data_products/emit-l3-mineralogy
Maintainer: SpectraWorks B.V. (CC-BY 4.0)