Preparation of Next Generation Hyperspectral Radiometric Validation Networks for Water and Land Surface Reflectance – the HYPERNETS Project

RUDDICK, K.; KUUSK, J.; BIALEK, A.; BRANDO, V.; CONCHA, J.; CORIZZI, A.; DE VIS, P.; DOGLIOTTI, A.I.; ET AL.

Bonn

Simposio; Living Planet Symposium; 2022

The HYPERNETS project is preparing the next generation of hyperspectral radiometer with associated pointing and acquisition system and network processing for validation of water and land surface reflectance derived from satellite missions.Spaceborne optical imaging missions such as Sentinel-2 and Sentinel-3 are used routinely to provide data for environmental monitoring of water and land surfaces via products such as chlorophyll and suspended particulate matter concentrations in water and Fraction of photosynthetically active radiation absorbed by vegetation (FAPAR) and Land cover over land. Validation of the water and land surface reflectance products is needed to ensure reliability of all such satellite data products.For water reflectance, the AERONET-OC network is currently the main source of radiometric validation data. This network is mature and operational but only multispectral. A new radiometer, the HYPSTAR®, has been designed and is being tested to provide finer spectral resolution (3nm FWHM for the range 380-1020nm) at lower cost. The new radiometer is mounted on a commercially-available pan-tilt unit and is controlled by a rugged PC with purpose-built electronics and software. Data is transmitted in near-real time for standardised processing and distribution.For land surface reflectance measurements, there are few automated systems. The new instrumentation that has been designed and is being tested within the H2020/HYPERNETS project will provide land surface reflectance measurements at high spectral resolution including spectral coverage extended to 1700nm (with 10nm FWHM resolution) and with angular/spatial variability.The progress of the H2020/HYPERNETS project will be summarised briefly here. In situ data from the validation sites (7 in Nov 2021, 14 expected by May 2022) will be presented. The in situ data will be compared with water and land surface reflectance data from various satellites, including Copernicus missions Sentinel-2 and Sentinel-3 but also hyperspectral satellite data (e.g. PRISMA) and metre-scale satellite data (Planetscope Doves).