Hyperspectral remote sensing of water quality is anticipated to improve the accuracy of water quality retrievals through differentiating between optical characteristics of various algal pigments and optically active water constituents. This study investigates the challenges of synergistically using hyperspectral and multispectral satellite images for retrieving water optical characteristics (e.g., chlorophyll-a concentration; Chla). PRISMA images, and multispectral satellite datasets from MSI and OLCI onboard Sentinel-2A/B and Sentinel-3A/B, respectively, were acquired over five European water bodies. Chla field data were collected concurrently with the satellite observations. The ACOLITE model was employed to reduce the atmosphere interferences in all images. Mixture Density Networks (MDNs) was applied to ACOLITE-corrected data to estimate Chla concentration. Preliminary results show that ACOLITE-estimated remote sensing reflectance (R_rs) spectra for the three satellites follow similar patterns, while PRISMA R_rs spectra contain noise across the visible/near-infrared bands. In general, Chla derived from both MSI and OLCI better match in situ Chla data than from PRISMA. The next steps include examining the application of the POLYMER atmospheric correction algorithm in combination with MDN in retrieving Chla. A few spectral indices, such as MCI and NDCI, will also be tested in conjunction with POLYMER- and ACOLITE-corrected R_rs data to fully demonstrate opportunities and challenges in merging future global hyperspectral and multispectral satellite observations.

Primary Presenter: Kiana Zolfaghari, University of Waterloo (kzolfagh@uwaterloo.ca)

Authors:

Nima Pahlevan, 2 NASA Goddard Space Flight Center, Greenbelt, MD 20771 USA AND Science Systems and Applications Inc., Lanham, MD 20706 USA   (nima.pahlevan@nasa.gov)

Amir Masoud Chegoonian, Department of Geography and Environmental Management, University of Waterloo, Waterloo, ON N2L 3G1, Canada AND Department of Biology, University of Regina, Saskatchewan, Canada  (amchegoonian@uwaterloo.ca)

Arun Saranathan, NASA Goddard Space Flight Center, Greenbelt, MD 20771 USA AND Science Systems and Applications Inc., Lanham, MD 20706 USA  (arun.saranathan@ssaihq.com)

Claudia Giardino, National Research Council of Italy, 80124 Napoli NA, Italy  (giardino.c@irea.cnr.it)

Claude Duguay, Department of Geography and Environmental Management, University of Waterloo, Waterloo, ON N2L 3G1, Canada AND H2O Geomatics Inc., Kitchener, ON N2G 1H6, Canada  (crduguay@uwaterloo.ca)