Real-time weekly global green vegetation fraction derivedfrom advanced very high resolution radiometer-based NOAAoperational global vegetation index (GVI) system

摘要

To provide quality-improved and consistent real-time global green vegetation fraction(GVF) data products that are suitable for use in operational numerical weather, climate,and hydrological models, necessary processing steps are applied to the output data streamfrom the advanced very high resolution radiometer (AVHRR)-based NOAA operationalglobal vegetation index (GVI) system. This paper reviewed the NOAA GVI data anddescribed the algorithm to derive weekly updated real-time GVF from the normalizeddifference vegetation index (NDVI). The methodology description focuses on algorithmjustification in an operational production context. The described algorithm was implementedin the global vegetation processing system (GVPS). The new global GVF data sets includethe multiyear GVF weekly climatology and the real-time weekly GVF. Compared to theold 5 year GVF monthly climatology currently used in the operational National Centers forEnvironmental Prediction (NCEP)/Environmental Modeling Center (EMC) weather andclimate models, the new data sets provide an overall higher vegetation value, real-timesurface vegetation information, and numerous other improvements. The new GVF dataset quality was partially assured by validation against Moderate Resolution ImagingSpectroradiometer (MODIS) NDVI at a few EOS land validation core sites and comparisonwith another independently processed NDVI data set. Impact of the new GVF data setsin numerical weather prediction (NWP) model was investigated using EMC mesoscalemodel simulations and concluded overall positive.