Array · collection · 2025
NOAA20 VIIRS Dark Target Aerosol Level-2 6-Minute Swath 6 km V2.1
Listed in NASA Earthdata CMR and NASA Data Portal — shown once because both records carry DOI 10.5067/viirs/aerdt_l2_viirs_noaa20.021
The NOAA-20 Visible Infrared Imaging Radiometer Suite (VIIRS) NASA Standard Level-2 (L2) Dark Target (DT) Aerosol product provides satellite-derived measurements of Aerosol Optical Thickness (AOT) and aerosol properties over land and ocean.
Description
It delivers spectral AOT measurements and their size parameters over oceans every 6 minutes globally. This aerosol product uses the same dark target algorithm originally developed for the Terra and Aqua missions' Moderate Resolution Imaging Spectroradiometer (MODIS) instruments.
It includes two separate and distinct algorithms:
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- One retrieves aerosol information over ocean (which appears dark in visible and longer wavelengths).
- The second retrieves aerosol data over vegetated and dark-soiled land (which appears dark in visible wavelengths). This orbit-level product (Short-name: AERDT_L2_VIIRS_NOAA20) has an at-nadir resolution of 6 km x 6 km and progressively increases away from nadir due to the sensor's scanning geometry and Earth's curvature. The product uses 8 x 8 native VIIRS moderate-resolution (M-band) pixels that nominally have approximately 750 m horizontal pixel size at nadir. Therefore, the Level-2 Dark Target Aerosol Optical Thickness data product incorporates 64 (750 m) pixels over a 6-minute period. As of December 2025, Version 2.1 is the latest collection of the NOAA-20 VIIRS L2 Dark Target Aerosol product and contains improvements over its previous collection (v2.0): **Level-2 Dark Target Aerosol: NOAA20 VIIRS v2.1 Improvements over v2.0**
- **Data Quality Fixes:** Corrected write error in Mean_Reflectance_Land and STD_Reflectance_Land.
- **Enhanced Dust Detection:** New Dust_Flag_Ocean Science Data Sets (SDS) and additional retrieval model for dust detection.
- **Improved Cloud Filtering:** Multiple updates to cloud mask over ocean to prevent cloud-contaminated retrievals.
- **Cross Platform Calibration:** Cross-calibration coefficients for SNPP, NOAA-20, and NOAA-21.
- **Surface Reflectance Updates:** Revised surface reflectance parameterization and urban correction.
- **Updated Meteorological Data:** Transitioned Global Modeling and Assimilation Office (GMAO) ancillary data from Global Earth Observing System Forward Processing for Instrument Teams (GEOS-FPIT) to its successor, Global Earth Observing System Instrument Teams (GEOS-IT).
- **Quality Assurance Fix:** Fixed a bug that incorrectly included land Aerosol Optical Depth (AOD) values and replaced these values with Quality Assurance values of 1 and 2 in the Optical_Depth_Land_And_Ocean dataset. The Level-2 netCDF product's geophysical data contains 38 Science Data Set (SDS) layers: 1. Aerosol_Cldmask_Land_Ocean 2. Aerosol_Cloud_Fraction_Land 3. Aerosol_Cloud_Fraction_Ocean 4. Aerosol_Type_Land 5. Angstrom_Exponent_1_Ocean 6. Angstrom_Exponent_2_Ocean 7. Asymmetry_Factor_Average_Ocean 8. Average_Cloud_Pixel_Distance_Land_Ocean 9. Backscattering_Ratio_Average_Ocean 10. Cloud_Pixel_Distance_Land_Ocean 11. Corrected_Optical_Depth_Land 12. Dust_Flag_Ocean 13. Effective_Optical_Depth_Average_Ocean 14. Effective_Radius_Ocean 15. Error_Flag_Land_And_Ocean 16. Fitting_Error_Land 17. Image_Optical_Depth_Land_And_Ocean 18. Land_Ocean_Quality_Flag 19. Land_Sea_Flag 20. Least_Squares_Error_Ocean 21. Mass_Concentration_Land 22. Mass_Concentration_Ocean 23. Mean_Reflectance_Land 24. Mean_Reflectance_Ocean 25. Number_Pixels_Used_Land 26. Number_Pixels_Used_Ocean 27. Optical_Depth_By_Models_Ocean 28. Optical_Depth_Land_And_Ocean 29. Optical_Depth_Large_Average_Ocean 30. Optical_Depth_Ratio_Small_Land 31. Optical_Depth_Ratio_Small_Ocean_0p55micron 32. Optical_Depth_Small_Average_Ocean 33. PSML003_Ocean 34. STD_Reflectance_Land 35. STD_Reflectance_Ocean 36. Surface_Reflectance_Land 37. Topographic_Altitude_Land 38. Wind_Speed_GMAO_Ocean The geolocation data group includes Glint Angle, Geodetic Latitude and Longitude, Scattering Angle, Sensor Azimuth and Zenith Angles, and Solar Azimuth and Zenith Angles. The Dark Target Aerosol Product User Guide provides additional information regarding these SDS parameters.
Links
Get the data
- Data product documentation darktarget.gsfc.nasa.gov/pubs ↗
documentation · download · from NASA CMR, data nasa gov
- PDF ladsweb.modaps.eosdis.nasa.gov/api/v2/content/archives/Document%20Archive/Science%20Data%20Pr… ↗
A pdf version User's Guide for VIIRS dark target products.
documentation · download · from NASA CMR, data nasa gov
- Resource darktarget.gsfc.nasa.gov/atbd/overview ↗
An Agorithm Theoretical Basis Document (ATBD) for MODIS and VIIRS dark target products.
documentation · download · from NASA CMR, data nasa gov
- Original Metadata cmr.earthdata.nasa.gov/search/concepts/C3703051596-LAADS.iso19115 ↗
download · from data nasa gov
- Search and order products from LAADS website. ladsweb.modaps.eosdis.nasa.gov/search/order/2/AERDT_L2_VIIRS_NOAA20--5201 ↗
download · from NASA CMR
- search.earthdata.nasa.gov /search/granules?p=C3703051596-LAADS ↗
Earthdata Search allows users to search, discover, visualize, refine, and access NASA Earth Observation data.
download · from NASA CMR
- Resource ladsweb.modaps.eosdis.nasa.gov/opendap/RemoteResources/laads/allData/5201/AERDT_L2_VIIRS_NOAA… ↗
download · from data nasa gov
Where it is published
- NASA Data Portal dataset page data.nasa.gov/dataset/noaa20-viirs-dark-target-aerosol-level-2-6-minute-swat… ↗
landing page · from data nasa gov
- DOI doi.org/10.5067/viirs/aerdt_l2_viirs_noaa20.021 ↗
DOI / persistent id · from NASA CMR
Catalogue records · 3
- CMR UMM-JSON cmr.earthdata.nasa.gov/search/concepts/C3703051596-LAADS.umm_json ↗
metadata API · from NASA CMR
- CKAN API data.nasa.gov/api/3/action/package_show?id=7a6da7de-4e4e-4cd2-9ad8-f746d5cb0… ↗
metadata API · from data nasa gov
- CMR record cmr.earthdata.nasa.gov/search/concepts/C3703051596-LAADS.html ↗
catalogue entry · from NASA CMR
Topics
- Stated by source
- Aerosol Optical Depth/Thickness · Aerosol Particle Properties · Aerosols · Angstrom Exponent · National Oceanic & Atmospheric Administration-20 · Visible-Infrared Imager-Radiometer Suite
- From keywords
- Astronomy & Astrophysics · Earth & Environmental Science · Ocean & Atmospheric Science · Physics
- Inferred from text
- Atmospheric sciences 71% · Imaging 75%
Provenance · 2 source records, 22 field assertions
| Source | Key | Last seen | Raw |
|---|---|---|---|
| NASA Earthdata CMR | C3703051596-LAADS | 12 d ago | JSON v1 |
| NASA Data Portal | 7a6da7de-4e4e-4cd2-9ad8-f746d5cb07a7 | 9 d ago | JSON v1 |
| Field | Assertion | Extractor | Evidence |
|---|---|---|---|
| access_level | source · NASA CMR | connector:nasa_cmr@1.0.0 | |
| concepts[field].anzsrc:group:3701 | enrichment · NASA CMR | taxonomy-embedding@1.0.0 | title+keywords+description (71%) |
| concepts[field].local:field:astronomy | mapping · data nasa gov | connector:data_nasa_gov@1.0.0 | |
| concepts[field].local:field:earth-environmental | mapping · data nasa gov | connector:data_nasa_gov@1.0.0 | |
| concepts[field].local:field:ocean-atmospheric | mapping · data nasa gov | connector:data_nasa_gov@1.0.0 | |
| concepts[field].local:field:physics | mapping · data nasa gov | connector:data_nasa_gov@1.0.0 | |
| concepts[instrument].gcmd_instrument:viirs | source · NASA CMR | connector:nasa_cmr@1.0.0 | |
| concepts[measured_variable].gcmd:earth-science/atmosphere/aerosols | source · NASA CMR | connector:nasa_cmr@1.0.0 | |
| concepts[measured_variable].gcmd:earth-science/atmosphere/aerosols/aerosol-optical-depth-thickness | source · NASA CMR | connector:nasa_cmr@1.0.0 | |
| concepts[measured_variable].gcmd:earth-science/atmosphere/aerosols/aerosol-optical-depth-thickness/angstrom-exponent | source · NASA CMR | connector:nasa_cmr@1.0.0 | |
| concepts[measured_variable].gcmd:earth-science/atmosphere/aerosols/aerosol-particle-properties | source · NASA CMR | connector:nasa_cmr@1.0.0 | |
| concepts[modality].local:modality:imaging | enrichment · NASA CMR | keyword-concept-rules@1.0.0 | title+description (75%) |
| concepts[platform].gcmd_platform:noaa-20 | source · NASA CMR | connector:nasa_cmr@1.0.0 | |
| created_date | source · NASA CMR | connector:nasa_cmr@1.0.0 | |
| description | source · NASA CMR | connector:nasa_cmr@1.0.0 | /umm/Abstract |
| license_text | source · data nasa gov | connector:data_nasa_gov@1.0.0 | |
| publication_date | source · NASA CMR | connector:nasa_cmr@1.0.0 | |
| spatial | source · NASA CMR | connector:nasa_cmr@1.0.0 | /umm/SpatialExtent |
| temporal | source · NASA CMR | connector:nasa_cmr@1.0.0 | /umm/TemporalExtents |
| title | source · NASA CMR | connector:nasa_cmr@1.0.0 | /umm/EntryTitle |
| updated_date | source · data nasa gov | connector:data_nasa_gov@1.0.0 | |
| version_label | source · NASA CMR | connector:nasa_cmr@1.0.0 |