The aerosol optical depth processing includes the spectral de-convolution algorithm (SDA) described in O'Neill et al. (2003). This algorithm yields fine (sub-micron) and coarse (super-micron) aerosol optical depths at a standard wavelength of 500 nm (from which FMF*, the fraction of fine mode to total aerosol optical depth can be computed).

The aerosol optical depth processing includes the spectral de-convolution algorithm (SDA) described in O'Neill et al. (2003). This algorithm yields fine (sub-micron) and coarse (super-micron) aerosol optical depths at a standard wavelength of 500 nm (from which FMF*, the fraction of fine mode to total aerosol optical depth can be computed).

The aerosol optical depth processing includes the spectral de-convolution algorithm (SDA) described in O'Neill et al. (2003). This algorithm yields fine (sub-micron) and coarse (super-micron) aerosol optical depths at a standard wavelength of 500 nm (from which FMF*, the fraction of fine mode to total aerosol optical depth can be computed).

The aerosol optical depth processing includes the spectral de-convolution algorithm (SDA) described in O'Neill et al. (2003). This algorithm yields fine (sub-micron) and coarse (super-micron) aerosol optical depths at a standard wavelength of 500 nm (from which FMF*, the fraction of fine mode to total aerosol optical depth can be computed).

This High-Resolution (0.1 x 0.1 degree) Level 3 daily Aerosol Optical Depth (AOD) product is generated by combining two Visible Infrared Imaging Radiometer Suite (VIIRS) operational algorithms, namely Deep Blue (DB) and Dark Target (DT), on board the Suomi National Polar-Orbiting Partnership (SNPP) satellite. This dataset is provided in daily files ranging from 2012-03-04 to the present. The spatial coverage is global and the dataset is gridded at 0.1 x 0.1 degree spatial resolution. The data are generated using Level 2 AOD retrieved using DT and DB algorithms. The product provides multiple options for using data either from DT or DB or combined. Depending on user need and application, they can choose one or more relevant parameter. The pixels with highest quality as recommended by science teams are only considered in these averaging. In addition to averaged AOD at 0.1 x 0.1 degree resolution, standard deviation and number of pixels averaged from each algorithm are also provided. Average sensor zenith angle is also provided for additional filtering of the data. If you have any questions, please read the README document first and post your question to the NASA Earthdata Forum (forum.earthdata.nasa.gov) or email the GES DISC Help Desk (gsfc-dl-help-disc@mail.nasa.gov).

The MCD19A2 Version 6.1 data product is a Moderate Resolution Imaging Spectroradiometer (MODIS) Terra and Aqua combined Multi-angle Implementation of Atmospheric Correction (MAIAC) Land Aerosol Optical Depth (AOD) gridded Level 2 product produced daily at 1 kilometer (km) pixel resolution. The MCD19A2 product provides the atmospheric properties and view geometry used to calculate the MAIAC Land Surface Bidirectional Reflectance Factor (BRF) or surface reflectance, MCD19A1 product.The MCD19A2 AOD data product contains the following Science Dataset (SDS) layers: blue band AOD at 0.47 µm, green band AOD at 0.55 µm, AOD uncertainty, fine mode fraction over water, column water vapor over land and clouds (in cm), smoke injection height (m above ground), AOD QA, AOD model at 1km, cosine of solar zenith angle, cosine of view zenith angle, relative azimuth angle, scattering angle, and glint angle at 5km. A low-resolution browse image is also included showing AOD of the blue band at 0.47 µm created using a composite of all available orbits.Each SDS layer within each MCD19A2 Hierarchical Data Format 4 (HDF4) file contains a third dimension that represents the number of orbit overpasses. This factor could affect the total number of bands for each SDS layer.Known Issues* Known issues are described in Section 6 of the User Guide.* For complete information about known issues please refer to the [MODIS/VIIRS Land Quality Assessment website](https://landweb.modaps.eosdis.nasa.gov/knownissue?sensor=MODIS&sat=TerraAqua&as=61).Improvements/Changes from Previous Versions* The Version 6.1 Level-1B (L1B) products have been improved by undergoing various calibration changes that include: changes to the response-versus-scan angle (RVS) approach that affects reflectance bands for Aqua and Terra MODIS, corrections to adjust for the optical crosstalk in Terra MODIS infrared (IR) bands, and corrections to the Terra MODIS forward look-up table (LUT) update for the period 2012 - 2017.* A polarization correction has been applied to the L1B Reflective Solar Bands (RSB).* The MCD19 Version 6.1 products have added 250 m resolution bands.* The previous BRDF product (MCD19A3) was reported once every eight days and the new MCD19A3D is a daily product.* MCD19A3D introduces gap-filled NDVI and gap-filled 250 m NBAR. * Snow Fraction, Snow Fit, and Snow Grain size layers were moved from MCD19A1 to the MCD19A3D.* There are four additional Climate Modeling Grid (CMG) products: MCD19A1CMGL, MCD19A1GO, MCD19A2CMG, and MCD19A3CMG.

This High-Resolution (0.1 x 0.1 degree) Level 3 monthly Aerosol Optical Depth (AOD) product is generated by combining two Visible Infrared Imaging Radiometer Suite (VIIRS) operational algorithms, namely Deep Blue (DB) and Dark Target (DT), on board the Suomi National Polar-Orbiting Partnership (SNPP) satellite. This dataset is provided in monthly files ranging from March 2012 to the present. The spatial coverage is global and the dataset is gridded at 0.1 x 0.1 degree spatial resolution. The data are generated using Level 2 AOD retrieved using DT and DB algorithms. The product provides multiple options for using data either from DT or DB or combined. Depending on user need and application, they can choose one or more relevant parameter. The pixels with highest quality as recommended by science teams are only considered in these averaging. In addition to averaged AOD at 0.1 x 0.1 degree resolution, standard deviation and number of pixels averaged from each algorithm are also provided. Average sensor zenith angle is also provided for additional filtering of the data. If you have any questions, please read the README document first and post your question to the NASA Earthdata Forum (forum.earthdata.nasa.gov) or email the GES DISC Help Desk (gsfc-dl-help-disc@mail.nasa.gov).

Entura accumulated Level 3 data over 10 year period and interpolated to 5 km grid. Values of 'Deep Blue Aerosol Optical Depth' (AOT) from the MODIS Aqua data set are used in the analysis. These values are non-dimensional, with a valid range of -0.5 to +5.0 (negative readings are not physically valid but are retained for consistency of the algorithm). Typical values are between 0 and 1, with 0.0 representing clear sky; 0.0 to 0.5 representing moderate levels of aerosols; and 0.5 to 1.0 representing relatively high aerosol concentrations (typical of heavy industrialisation).Values over 1.0 are less common and represent considerable levels of aerosols). The methodology is contained within the report prepared by Entura which is downloadable here: https://gsv.vic.gov.au/downloader/Downloader?ID=documentation/geovic_3/energy_division/E300128-TR01%20Solar%20Atlas%20Victoria%20(public%20release)%20with%20calibration%20certificates.pdf

The Moderate Resolution Imaging Spectroradiometer (MODIS) Near Real Time (NRT) Combined Terra and Aqua Multi-Angle Implementation of Atmospheric Correction (MAIAC) Land Aerosol Optical Depth gridded Level 2 product (MCD19A2N) produced daily at 1 kilometer (km) pixel resolutions. The MCD19A2N product provides the atmospheric properties and view geometry used to calculate the MAIAC Land Surface Bidirectional Reflectance Factor (BRF) or surface reflectance, MCD19A1N product.