Copernicus Ground-Based Observations for Validation service (GBOV): overview and latest updates for EO data Cal/Val

Copernicus Ground-Based Observations for Validation (GBOV) is a project funded by the European Commission and is part of the Copernicus Land Monitoring Service (CLMS). The project has two main purposes: to support yearly validation efforts of core CLMS products (BRF, Albedo, FAPAR, LAI, FCOVER, LST, Soil Moisture, GPP, NPP, LSP and Evapotranspiration), five of which are listed among GCOS Essential Climate Variables (ECV); and to maintain a data portal making these validation products available. GBOV has reached a broad user community, with about 1700 users, including ESA optical MPC.

A large number of ground-based measurement networks disseminate publicly available data such as NEON, ICOS, TERN, BSRN and ISMN. Within GBOV, long-term datasets are needed in order to maximise the number of matchups between ground-based measurements and satellite data.

GBOV produces both ground-based, point-scale observations (the so-called “Reference Measurements”), and Analysis Ready Validation Data (ARVD) which are spatially upscaled to match the resolution of CLMS products (the so-called “Land Products”). Those GBOV products cover more than 150 sites and are made available to the community via a data portal freely accessible on https://gbov.land.copernicus.eu/. Available Land Products variables include Surface Bi-directional Reflectance Factors (BRFs), Surface Albedo, Leaf Area Index (LAI), Fraction of Absorbed Photosynthetically Available Radiation (FAPAR), Fraction of Vegetation Cover (FCover), Land Surface Temperature (LST), Surface Soil Moisture (SSM). Gross Primary Production (GPP), Net Primary Production (NPP), Land Surface Phenology (LSP) and Evapotranspiration are new products and are not yet available, their release is planned for the end of 2026.

The networks providing GBOV initial input data are unfortunately not evenly distributed. In an attempt to reduce the thematic and geographical gaps, GBOV is developing its own network as part of a collaboration with existing networks. In GBOV phase 1, six ground stations have been upgraded with additional instrumentation. In GBOV phase 2, two ground stations monitoring vegetation variables have been deployed in 2023, one at the Fuji Hokuroku research station in Japan as part of a collaboration with NIES (National Institute of Environmental Studies) and one in 2024 at the Fontainebleau research station (France) as part of a GBOV/ICOS collaboration. In addition, two LST stations were deployed in Fuji Hokuroku and Litchfield (TERN network Australia) in 2024.

Over the past year, several updates have been implemented in the GBOV database to better respond to CLMS and general user requirements. This includes new procedures for specific land cover types in vegetation products, improved uncertainty estimates for soil moisture, and enhanced processing procedures for LST products. Procedures are being developed for the new products: Gross Primary Production, Net Primary Production, Land Surface Phenology and Evapotranspiration.

This presentation will focus on the current status of GBOV products and highlight recent developments and evolutions.