The Suomi National Polar-Orbiting Partnership (S-NPP) NASA Visible Infrared Imaging Radiometer Suite (VIIRS) Bidirectional Reflectance Distribution Function (BRDF) and Albedo Quality product (VNP43D40) is produced daily using 16 days of data at 30 arc second (1,000 meter) resolution. Data are temporally weighted to the ninth day, which is reflected in the file name. The VNP43D product suite is provided in a Climate Modeling Grid (CMG), which covers the entire globe for use in climate simulation models. Due to the large file size, each VNP43D product contains just one data layer for each of the parameters included in the VNP43MA2 product. VNP43D40 through VNP43D53 are the 30 arc second BRDF/Albedo Quality values, the Local Solar Noon values, the Valid Observations of the moderate resolution bands (M1 through M5, M7, M8, M10, and M11) plus the Day/Night Band (DNB), the Snow Status, and the Uncertainty. Details regarding methodology are available on the VNP43MA2 product page and in the Algorithm Theoretical Basis Document (ATBD).
VNP43D40 consists of BRDF/Albedo quality information representing the overall quality of each pixel for VIIRS moderate resolution bands M1 through M5, M7, M8, M10, M11, and DNB.
|File Size||~400 MB|
|Temporal Extent||2012-01-19 to Present|
|Coordinate System||Geographic Latitude and Longitude|
|Number of Science Dataset (SDS) Layers||10|
|Columns/Rows||43200 x 21600|
|Pixel Size||1000 m|
|SDS Name||Description||Units||Data Type||Fill Value||No Data Value||Valid Range||Scale Factor|
|BRDF_Albedo_Band_Quality_M1||BRDF/Albedo Quality for Band M1 (0.402 - 0.422 μm)||N/A||8-bit unsigned integer||255||N/A||0 to 3||N/A|
|BRDF_Albedo_Band_Quality_M2||BRDF/Albedo Quality for Band M2 (0.436 - 0.454 μm)||N/A||8-bit unsigned integer||255||N/A||0 to 3||N/A|
|BRDF_Albedo_Band_Quality_M3||BRDF/Albedo Quality for Band M3 (0.478 - 0.498 μm)||N/A||8-bit unsigned integer||255||N/A||0 to 3||N/A|
|BRDF_Albedo_Band_Quality_M4||BRDF/Albedo Quality for Band M4 (0.545 - 0.565 μm)||N/A||8-bit unsigned integer||255||N/A||0 to 3||N/A|
|BRDF_Albedo_Band_Quality_M5||BRDF/Albedo Quality for Band M5 (0.662 - 0.682 μm)||N/A||8-bit unsigned integer||255||N/A||0 to 3||N/A|
|BRDF_Albedo_Band_Quality_M7||BRDF/Albedo Quality for Band M7 (0.846 - 0.885 μm)||N/A||8-bit unsigned integer||255||N/A||0 to 3||N/A|
|BRDF_Albedo_Band_Quality_M8||BRDF/Albedo Quality for Band M8 (1.230 - 1.250 μm)||N/A||8-bit unsigned integer||255||N/A||0 to 3||N/A|
|BRDF_Albedo_Band_Quality_M10||BRDF/Albedo Quality for Band M10 (1.580 - 1.640 μm)||N/A||8-bit unsigned integer||255||N/A||0 to 3||N/A|
|BRDF_Albedo_Band_Quality_M11||BRDF/Albedo Quality for Band M11 (2.225 - 2.275 μm)||N/A||8-bit unsigned integer||255||N/A||0 to 3||N/A|
|BRDF_Albedo_Band_Quality_DNB||BRDF/Albedo Quality for Day/Night Band (0.5 - 0.9 μm)||N/A||8-bit unsigned integer||255||N/A||0 to 3||N/A|
|0||Best quality, full inversion (Weight of Determination (WoDs), Root Mean Square Error (RMSE) majority good)|
|1||Good quality, full inversion|
|2||Magnitude inversion (number of observations ≥ 7)|
|3||Magnitude inversion (number of observations ≥ 2 & < 7)|
Product accuracy/uncertainty information for the VIIRS BRDF/Albedo product suite can be found in section 4 of the ATBD.
The abnormally high activation of the high aerosol flag in the Collection 1 (C1) VNP09 product, has impacted downstream products. The VNP43 BRDF/Albedo/NBAR product is affected by reducing the number of otherwise acceptable observations used as input to characterize surface anisotropy. This effect (most obvious over arid bright surfaces), results in a reduced number of high quality full BRDF model inversions. Therefore, users should be aware that bright arid surfaces (normally associated with high quality BRDF/Albedo/NBAR retrievals) are likely to be somewhat represented by lower quality results in C1. VNP09 has been corrected for Collection 2 (C2). Therefore, users should avoid substantive use of C1 VNP43 over arid regions (and wait for C2 products). In any event, users are always strongly encouraged to download and use the extensive QA data provided in VNP43[I-M]A2, in addition to the briefer mandatory QA provided as part of the VNP43[I-M]A1, 3 and 4 products.
Additional known issues for VNP43 data products can be found on the VIIRS Land Quality Assessment website.