IAFE   05512
INSTITUTO DE ASTRONOMIA Y FISICA DEL ESPACIO
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Satellite detection of a dredging plume by the spectral slope of Coloured Dissolved plus Non-Algal Particle absorption (Scdpm)
Autor/es:
DOGLIOTTI, A. I.; RUDDICK, K.
Reunión:
Encuentro; 2019 International Ocean Colour Science Meeting; 2019
Resumen:
In any satellite mission the validation of derivedproducts is essential to assess and ensure high-quality geophysical dataproducts. In the frame of HYPERMAQ and HYPERNETS projects a new network of automatedhyperspectral radiometers is being developed. One of the planned test sites is aneutrophic, turbid, permanently mixed shallow water body called Chascomús lakelocated in the Pampa Plain in the Buenos AiresProvince (Argentina). This lake has beenintensively studied in the last 20 years and new field campaigns have been recentlyperformed in which radiometric measurements using TriOS/RAMSES radiometer were madefor the first time. Measured hyperspectral spectra have shown a dip at 620 nm,the characteristic absorption feature of the photopigment phycocyanin (PC), a marker pigment forCyanobacteria which presence has been confirmed by microscopy. High spectral resolution informationallows for the full potential of the reflectance signal from lakes to beexplored to improve the retrieval accuracy of existing products, like chlorophyll-aconcentration, but also to derive new products and validate any opticalmission, like S2, S3, PROBA-V, MODIS, VIIRS, L8, Pléiades, ENMAP, PRISMA,SABIA/MAR, etc. The MultiSpectral Instrument (MSI) on board ofSentinel-2 mission provides high spatial resolution data which can be relevantfor monitoring coastal and in-land waters because of the high spatialresolution (10 to 20 m) and spectral bands which allows the estimation of totalsuspended matter and chlorophyll concentration, even though they wereoriginally designed for land applications. In turn, OLCI on board Sentinel-3, amission designed to monitor the ocean color, has more bands which might becapable of capturing changes in the reflectance at specific wavelengths ofbiological interest, like the 620 nm and close bands, but with a coarser spatial resolution (300 m) whichmight prevent its use in small water bodies. Even though the few existingmeasurements are not enough to perform a strict match-up analysis, a firstevaluation of Sentinel-2 and Sentinel-3 potential use to identifycyanobacteria-dominated waters is here analyzed. Different processors, likeACOLITE and C2RCC were tested. Reflectance retrieved using ACOLITE showedbetter performance for bands between 510 and 680 nm, overestimating at higherand underestimating at lower wavelengths, but generally reproducing the shapeof the spectra and the dip at 620 band. In turn, C2RCC systematicallyunderestimated in situ values withbetter results in the blue bands compared to ACOLITE, but the dip at 620 nm andcharacteristic peak at 708 nm was not reproduced. For Sentinel-2 ACOLITEretrieved values tend to overestimate while C2RCC tended to underestimate fieldreflectance measurements, but both reproducing in general the spectral shape.