The HYPERNETS Project ? A prototype network of hyperspectral automated radiometers for land and water optical missions validation

BIALEK, A.; DOXARAN, D.; RUDDICK, K.; GOYENS, C.; BRANDO, V.; PIEGARI, E.; ORIGO, N.; DOGLIOTTI, A.I.; SPENGLER, D.; KUUSK, J.

Toulouse

Encuentro; 3rd Sentnel-2 Validation Team Meeting; 2019

Networking of automated instruments on unmannedplatforms has proved to be the most effective way toprovide validation data for earth observation missions.The re-use of data from each site for many opticalmissions (S2, S3, PROBA-V, MODIS, VIIRS, L8, Pléiades,ENMAP, PRISMA, SABIAMAR,etc.) gives a hugeeconomy of scale. The existing networks (e.g.AERONET-OC, RADCALNET, ...) are based onmultispectral instruments requiring modellingassociated uncertainties to cover all spectral bands ofall sensors. Therefore, the general objective of theHYPERNETS project is to ensure that high quality in situmeasurements are available at all spectral bands andfor a wide range of water and land types for thevalidation of the surface reflectance data issued from allearth observation missions. HYPERNETS is expected tofill the very important gap in the current Sentinel-3&2Validation plans and the in situ component of theCopernicus program and become the main source ofsurface reflectance validation data for all spectral bandsof all optical missions for at least the next 10 years.The HYPERNETS instrument design of the new lowercost hyperspectral radiometer for automatedmeasurement of water and land bidirectionalreflectance is presented as well as the associated pointing system and embedded calibration device.Sensor and system designs of the instrument complieswith requirements gathered from the water and landcommunity. In order to test and demonstrate theperformance of the developed system and instrument,about 22 sites have been selected covering a wide rangeof water and land applications and a variety ofenvironmental (cold/hot, wet/dry, calm/windy,biofouling, etc.) and logistical conditions(accessible/remote, standalone/heavily instrumentedsite, well protected/vulnerable to humans and/oranimals). Figure 1 shows the location of the 24 sitesselected for the HYPERNETS prototype network. Theprototype network design is presented. Sitecharacteristics, including spatial and temporalsspecificities, are described and challenges with thesystem set-up are discussed.