Fraction of Absorbed Photosynthetically Active Radiation 2013-2024 (raster 20m, 300m), Ground-Based Observations for Validation project sites - version 3.5.0, Dec 2025

The Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) corresponds to the amount of radiation at wavelengths of between 400 nm and 700 nm that is absorbed by the canopy. FAPAR is a dimensionless quantity that ranges from 0 to 1 and depends on illumination geometry and the proportion of direct and diffuse radiation.

The GBOV service (Ground-Based Observations for Validation) is a project funded by the European Commission. Its objective is to provide analysis-ready validation data to support the evaluation of Earth Observation products. The core aim of GBOV is to generate upscaled products derived from ground-based measurements.

This dataset consists of Land Products (LPs) generated using Digital Hemispherical Photographs (DHP) collected from in-situ stations located in North America, Europe, Australia, and Asia. These DHPs are used to extract ground measurements of FAPAR over Experimental Sample Units (ESUs) provided in the "Fraction of Intercepted Photosynthetically Active Radiation Reference Measurements 2013-2024 (20m), Ground-Based Observations for Validation project sites - version 2.0, Dec 2025" dataset. ESU size is comparable to the spatial resolution of Sentinel-2 Level 2 surface reflectance products, which are used for the upscaling.

Each Land Product is distributed at two spatial resolutions: one matching the Sentinel-2 Level 2 surface reflectance resolution (~20 m), and one aggregated to the Copernicus Global Land Service (CGLS) resolution (~300 m).