MODIS/Aqua Surface Reflectance 8-Day L3 Global 500m SIN Grid V006

The MYD09A1 Version 6 data product was decommissioned on July 31, 2023. Users are encouraged to use the [MYD09A1 Version 6.1](https://doi.org/10.5067/MODIS/MYD09A1.061) data product.The Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua MYD09A1 Version 6 product provides an estimate of the surface spectral reflectance of Aqua MODIS Bands 1 through 7 corrected for atmospheric conditions such as gasses, aerosols, and Rayleigh scattering. Along with the seven 500 meter (m) reflectance bands are a quality variable and four observation bands. For each pixel, a value is selected from all the acquisitions within the 8-day composite period. The criteria for the pixel choice include cloud and solar zenith. When several acquisitions meet the criteria the pixel with the minimum channel 3 (blue) value is used.Known Issues* The Collection 6 MODIS Land Surface Reflectance product (MYD09) may [incorrectly flag retrievals as ‘High Aerosol’](https://landweb.modaps.eosdis.nasa.gov/displayissue?id=174) over brighter surfaces and at higher view angles. This will impact the downstream MODIS BRDF/Albedo (MCD43) and Vegetation Index (MOD13 and MYD13) data products which use the aerosol quantity flag to screen out high aerosol values.* [Corrections](https://landweb.modaps.eosdis.nasa.gov/data/userguide/LSRHighAerosolFlagFinal.pdf) were implemented in Collection 6.1 reprocessing.* 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=Aqua&as=6).Improvements/Changes from Previous Versions* Improvements to the aerosol retrieval and correction algorithm along with new aerosol retrieval look-up tables.* Refinements to the internal snow, cloud, and cloud shadow detection algorithms. Uses Bidirectional Reflectance Distribution Function (BRDF) database to better constrain the different threshold used.* Processes ocean bands to create a new Surface Reflectance Ocean product and provides Quality Assurance (QA) datasets for these bands.* Improved discrimination of salt pans from cloud and snow, along with the inclusion of a salt pan flag in the QA band.

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  "026:00"
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  "026:000"
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  "Earth Science"
]