EVI based Green Vegetation Fraction derived from Suomi NPP-VIIRS

A new Green Vegetation Fraction (GVF) operational product system is currently being developed and transitioned to operations by the NOAA/NESDIS Center for Satellite Applications and Research (STAR). The new system is to produce GVF as a NOAA-Unique Product (NUP) from data from the Visible Infrared Imager Radiometer Suite (VIIRS) sensor onboard the recently launched Suomi National Polar-orbiting Partnership (NPP) satellite, for applications in numerical weather and seasonal climate prediction models at the National Centers for Environmental Prediction (NCEP). The new GVF from Suomi NPP VIIRS will provide continuity for the current AVHRR based GVF system and improved spatial and temporal resolution. The new retrieval algorithm uses the following VIIRS top of the canopy (TOC) reflectance bands as input: red (I1), near-infrared (I2) and blue (M3) bands centered at 0.640 μm, 0.865 μm and 0.490 μm, respectively. In the new system, the Enhanced Vegetation Index (EVI) is calculated from the three bands and used to derive GVF; this approach is different from the current NOAA operational GVF system which uses top of the atmosphere (TOA) reflectance bands from AVHRR to produce NDVI which subsequently is used as input to the GVF algorithm. The new GVF will be produced as a daily rolling weekly composite at 4-km resolution (global scale) and 1-km resolution (regional scale).