Description
The NASA/NOAA Suomi National Polar-orbiting Partnership (Suomi NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) Nadir Bidirectional Reflectance Distribution Function (BRDF) Adjusted Reflectance (NBAR) Version 1 product provides NBAR estimates at 500 meter (m) resolution. The VNP43IA4 product is produced daily using 16 days of VIIRS data and is weighted temporally to the ninth day, which is reflected in the file name. The view angle effects are removed from the directional reflectances, resulting in a stable and consistent NBAR product. The VNP43 data products are designed to promote the continuity of NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) BRDF/Albedo data product suite.
The VNP43 algorithm uses the RossThick/Li-Sparse-Reciprocal (RTLSR) semi-empirical kernel-driven BRDF model, with the three kernel weights from (VNP43IA1) (https://doi.org/10.5067/VIIRS/VNP43IA1.001) to reconstruct surface anisotropic effects, correcting the directional reflectance to a common view geometry (VNP43IA4), while also computing integrated black-sky albedo (BSA) at local solar noon and white-sky albedo (WSA) (VNP43IA3) (https://doi.org/10.5067/VIIRS/VNP43IA3.001). Researchers can use the BRDF model parameters with a simple polynomial, to obtain black-sky albedo at any solar illumination angle. Likewise, both the BSA and WSA Science Dataset (SDS) layers can be used with a simple polynomial, to manually estimate instantaneous actual albedo (blue-sky albedo). Additional details regarding the methodology are available in the Algorithm Theoretical Basis Document (ATBD) (https://lpdaac.usgs.gov/documents/194/VNP43_ATBD_V1.pdf).
The VNP43IA4 product includes six SDS layers for BRDF/Albedo mandatory quality and nadir reflectance for VIIRS imagery bands I1, I2, and I3. A low-resolution browse image is also available showing NBAR bands I1, I2, and I1 as an RGB (red, green, blue) image in JPEG format.
Resources
| Name | Format | Description | Link |
|---|---|---|---|
| Download this dataset through APPEEARS | HTML | The Application for Extracting and Exploring Analysis Ready Samples (AρρEEARS) offers a simple and efficient way to perform data access and transformation processes. | Open resource |
| This dataset's landing page | HTML | The LP DAAC product page provides information on Science Data Set layers and links for user guides, ATBDs, data access, tools, customer support, etc. | Open resource |
| Download this dataset through a directory map | HDF | LP DAAC Data Pool provides direct access to available products via HTTPS. | Open resource |
| Get a related visualization | HTML | Browse image for Earthdata Search | Open resource |
| View this dataset's product quality assessment | HTML | Quality Assessment provides information regarding the usability and usefulness of the data product. | Open resource |
| The dataset's project home page | HTML | The LP DAAC website provides detailed information on discovery, distribution, access, and support of land data products. | Open resource |
| View this dataset's algorithm theoretical basis document | The ATBD provides physical theory and mathematical procedures for the calculations used to produce the data products. | Open resource | |
| Use OPeNDAP to access the dataset's data | HTML | OPeNDAP provides direct access to data via HTTPS. | Open resource |
| Google Scholar search results | HTML | Search results for publications that cite this dataset by its DOI. | Open resource |
| Download this dataset through Earthdata Search | HDF | Earthdata Search allows users to search, discover, visualize, refine, and access NASA Earth Observation data. | Open resource |
| View this dataset's science data product validation documentation | HTML | Validation at stage 2 has been achieved for the VIIRS BRDF/Albedo product suite. | Open resource |
| View this dataset's science data product validation documentation | HTML | Further details regarding VIIRS product validation and maturity status are available from VIIRS Land Product Quality Assessment site. | Open resource |
| View this dataset's user's guide | HTML | The technical information in the User's Guide enables users to interpret and use the data products. | Open resource |