The objective of the project is the development of two vegetation Essential Climate Variables: Leaf Area Index (LAI) and the Fraction of photosynthetically active radiation absorbed by vegetation (FAPAR) according to the GCOS requirements along with a feasibility study for Solar-Induced chlorophyll Fluorescence (SIF) Climate Data Record. In addressing these ECVs, the project will perform the necessary R&D required for the generation of high quality, global, long-term (from 1998 to 2022), multi-mission time series, maximising the consistency between products (at 1km and 300m resolutions) from different satellite missions and between different ECVs.

The consortium is led by VITO with EOLAB, FastOpt, HYGEOS and the Faculty of GeoÔÇÉInformation Science and Earth Observation (ITC) of the University of Twente as partners.

HYGEOS provides SMAC-CL, the processor for atmospheric corrections based on the SMAC radiative transfer approximation, enhanced with uncertainty propagation, multiple aerosol models and BRDF corrections as developed in the C3S project (SPOT4/5-VGT1/2, PROBA-V, Sentinel-3A/B OLCI L1B data). HYGEOS will add the capability to process all sensors, i.e. ENVISAT MERIS L1 V4 FR, Sentinel-3A/B L1B data, SuomiNPP / VIIRS L1B, TERRA & AQUA / MODIS L1B data covering the period from 2000 to the present.
The surface reflectances have been validated for Sentinel-3 and PROBA-V during earlier projects using AERONET data (version 3 of inverted Aerosol Optical Depth (AOD), spectral index of refraction and volume particle size distribution) and the 6S accurate atmospheric correction method acting on Top-Of-Atmosphere reflectance extracted around AERONET sites that cover different biomes, locations and meteorological conditions. HYGEOS will reproduce this exercise for new sensors and specifically for overlapping time period between several sensors. This is important for the multi sensor consistency analysis and error budget consolidation.

Funder: ESA
Duration: 2022 - 2025
Contact at Hygeos: Didier Ramon