MODIS Atmosphere L2 Aerosol Product
Dataset Short Name:
MOD04_L2 (Terra Platform)
MYD04_L2 (Aqua Platform)
Dataset Long Name:
MODIS/Terra Level-2 (L2) Aerosol Product
MODIS/Aqua Level-2 (L2) Aerosol Product
(Swath, 1km and 5km Resolution)
(5 minute time-period HDF files)
Terra (Day Overpass: ~1030 LST, Descending Node, Equator ... Night Overpass: ~2230 LST, Ascending Node, Equator)
Aqua (Day Overpass: ~1330 LST, Ascending Node, Equator ... Night Overpass: ~0130 LST, Descending Node, Equator)
MODIS (Moderate Resolution Imaging Spectroradiometer)
The MODIS Level-2 Atmospheric Aerosol Product (04_L2) provides full global coverage of aerosol properties from the Dark Target (DT) and Deep Blue (DB) algorithms. The DT algorithm is applied over ocean and dark land (e.g., vegetation), while the DB algorithm in Collection 6 (C6) covers the entire land areas including both dark and bright surfaces. Both results are provided on a 10x10 pixel scale (10 km at nadir). Each MYD04_L2 product file covers a five-minute time interval. The output grid is 135 pixels in width by 203 pixels in length. Every tenth file has an output grid size of 135 by 204 pixels. MOD04_L2 and MYD04_L2 product files are stored in Hierarchical Data Format (HDF-EOS).
Based on C5 validation studies, a number of Science Data Sets (SDSs) have been deleted with C6 from the DT product (Angstrom_Exponent_Land, Optical_Depth_Small_Land, etc.) while a number of SDSs have been renamed or added. A number of algorithm changes have lead to significant changes in regional aerosol product statistics. For C6, the DT algorithm team now provides a new 3 km spatial resolution product intended for the air quality community; this is provided in a separate file (M*D04_3K).
In C5, the DB algorithm was limited to only bright targets. With C6, the DB team has expanded coverage to include both bright targets and vegetated regions, using NDVI information in addition to a precalculated surface reflectance database. New DB products for C6 include an estimate on the aerosol retrieval uncertainty to assist with error analyses as well as a best estimate SDS containing the aerosol optical thickness data with quality assurance flags already applied (SDS names Deep_Blue_Aerosol_Optical_Depth_550_Land_Estimated_Uncertainty and Deep_Blue_Aerosol_Optical_Depth_550_Land_Best_Estimate respectively). In addition to separate DT and DB retrievals, the C6 product now provides a merged (SDS) that combines both types of retrievals (SDS name AOD_550_Dark_Target_Deep_Blue_Combined). This SDS uses a combination of scene NDVI and retrieval Quality Assessment (QA) assignments to select one of the retrievals (if any) or an average of the two retrievals. Ocean retrievals from the DT algorithm are also provided if they have a sufficiently high retrieval QA value.
~144 files per day
10x10 km at nadir
~6 MB (maximum)
(MODIS Atmosphere Aerosol Product site)
Dr. Rob Levy (Dark Target)
Dr. Christina Hsu (Deep Blue)
MODIS Atmosphere Science Team / Aerosol Retrieval Group
MODIS Adaptive Processing System (MODAPS)
When Using Collection 6.0 Data: Collection 006 (C6)
To determine the Collection version of the data you used or are using, look at the HDF filename. If there is a ".006." field in the HDF filename, then it's Collection 6.0 data.
Dataset DOI: (Data Object Identifier)
Citation: (We kindly request that you cite the use of any Collection 6.0 MODIS Cloud data in a publication using the following wording)
Levy, R., C. Hsu, A. Sayer, S. Mattoo, J. Lee, 2015. MODIS Atmosphere L2 Aerosol Product. NASA MODIS Adaptive Processing System, Goddard Space Flight Center, [doi:10.5067/MODIS/MOD04_L2.006; doi:10.5067/MODIS/MYD04_L2.006]
When Using Collection 6.1 Data: Collection 061 (C61)
To determine the Collection version of the data you used or are using, look at the HDF filename. If there is a ".061." field in the HDF filename, then it's Collection 6.1 data.
Dataset DOI: (Data Object Identifier)
Citation: (We kindly request that you cite the use of any Collection 6.1 MODIS Cloud data in a publication using the following wording)
Levy, R., C. Hsu, A. Sayer, S. Mattoo, J. Lee, 2015. MODIS Atmosphere L2 Aerosol Product. NASA MODIS Adaptive Processing System, Goddard Space Flight Center, [doi:10.5067/MODIS/MOD04_L2.061; doi:10.5067/MODIS/MYD04_L2.061]
Note the DOI (Data Object Identifier) system was not used previous to Collection 6.0 (006).