VNP13A1: VIIRS Vegetation Indices 16-Day 500m (NOAA/VIIRS/001/VNP13A1)

The Suomi National Polar-Orbiting Partnership (S-NPP) NASA Visible
Infrared Imaging Radiometer Suite (VIIRS) Vegetation Indices (VNP13A1)
data product provides vegetation indices by a process of
selecting the best available pixel over a 16-day acquisition period
at 500 meter resolution. The VNP13 data products are designed
after the Moderate Resolution Imaging Spectroradiometer (MODIS)
Terra and Aqua Vegetation Indices product suite to promote the
continuity of the Earth Observation System (EOS) mission.

The VNP13 algorithm process produces three vegetation indices: (1)
Normalized Difference Vegetation Index (NDVI), (2) the Enhanced
Vegetation Index (EVI), and (3) Enhanced Vegetation Index-2 (EVI2).
(1) NDVI is one of the longest continual remotely sensed time series
observations, using both the red and near-infrared (NIR) bands.
(2) EVI is a slightly different vegetation index that is more sensitive
to canopy cover, while NDVI is more sensitive to chlorophyll. (3) EVI2
is a reformation of the standard 3-band EVI, using the red band and
NIR band. This reformation addresses arising issues when comparing
VIIRS EVI to other EVI models that do not include a blue band. EVI2
will eventually become the standard EVI.

Along with the three Vegetation Indices layers, this product also
includes layers for near-infrared (NIR) reflectance; three shortwave
infrared (SWIR) reflectance—red, blue, and green reflectance; composite
day of year; pixel reliability; view and sun angles, and a quality layer.

For additional information, visit the VIIRS Land Product Quality
Assessment website and see
the User Guide.