HYPERNETS water validation site in the Río de la Plata (Argentina)

DOGLIOTTI, A.I.; PIEGARI, E.; RUBINSTEIN, L.; PERNA. P

Simposio; Living Planet Symposium; 2022

Validation ofsatellite-derived products, in particular water reflectance, using in situ data is essential to ensure thequality of derived parameters useful for water quality monitoring, liketurbidity and chlorophyll-a concentration. The use of autonomous systems, likeAERONET-OC, has shown to be effective for increasing the number of validationmatch-ups compared to oceanographic cruises. However, the multispectral natureof the CIMEL instrument used in the AERONET-OC network prevents its use tovalidate hyperspectral missions, such as PRISMA (Hyperspectral Precursor of the Application Mission) andupcoming EnMAP (Environmental Mapping and Analysis Program) and CHIME(Copernicus Hyperspectral Imaging Mission for the Environment), as well asmissions with different spectralband configurations, like Sentinel-2.In the frame ofH2020/HYPERNETS project, a new generation hyperspectral radiometer, theHYPSTAR@ instrument, with a pointing system and auxiliary sensors has beendesigned and is being tested in different test sites to provide waterreflectance at fine spectral resolution (3nm FWHM) in the 350-1100nm region with high quality at lower cost. This system has been installedin one of the test sites in Argentina, located in the turbid waters of Río dela Plata upper estuary, 60 km south of the city of Buenos Aires, an idealscenario to test atmospheric correction algorithms performance.The qualityof the match-ups at a test site will depend on how representative is the pointradiometric measurement at the site compared to the satellite pixel of a givensize which will be influenced by the spatial homogeneity of the water body andalso by the proximity of the site to land (adjacency effect). In thepresent study, we describe and assess the quality of the HYPERNETS water sitelocated in the Río de la Plata through the analysis of satellite-derivedtime-series of turbidity and its spatial variability (homogeneity) and theinfluence of land using the time series of high spatial resolution L8/OLI and S2/MSIdata extracted at the site location. Furthermore, the first HYPSTAR@ data andmatch-ups of different satellite systems are shown and analyzed showing its potentialto validate satelliteproducts in a multi-mission perspective.