Day 4

Detailed paper information

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Paper title ACIX-Aqua: A global assessment of atmospheric correction methods for Landsat-8 and Sentinel-2 over lakes, rivers, and coastal waters
  1. Antoine Mangin ACRI Speaker
  2. Nima Pahlevan NASA Goddard Space Flight Center
  3. Krista Alikas Tartu Observatory, University of Tartu, Estonia
  4. Kohei Arai Department of Information Science, Saga University
  5. Claudio Barbosa Brazilian National Institute for Space Research - INPE
  6. Simon Bélanger ARCTUS INC.
  7. Caren Binding Environment and Climate Change Canada, Burlington, ON, Canada
  8. Sundarabalan Balasubramanian NASA and Goddard Space Flight Center
  9. Mariano Bresciani CNR (National Research Council of Italy)
  10. Claudia Giardino National Research Council of Italy, Institute for Electromagnetic Sensing of the Environment, CNR-IREA
  11. Daniela Gurlin Wisconsin Department of Natural Resources
  12. Yongzhen Fan Department of Physics and Engineering Physics, Stevens Institute of Technology, Hoboken, NJ, USA
  13. Tristan Harmel GET - CNRS - Magellium
  14. Peter D. Hunter Earth and Planetary Observation Sciences (EPOS), Department of Biological and Environmental Sciences, University of Stirling, Stirling, UK
  15. Evangelos Spyrakos University of Stirling, Stirling, United Kingdom
  16. Andrew Tyler University of Stirling
  17. Joji Ishikaza Institute for Space-Earth Environmental Research (ISEE), Nagoya University, Nagoya, Japan
  18. Susanne Kratzer Stockholm University, Stockholm, Sweden
  19. Moritz K. Lehmann Xerra Earth Observation Institute and the University of Waikato, New Zealand
  20. Martin Ligi University of Tartu
  21. Ronghua Ma Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography and Limnology, Chinese Academy of Science, Nanjing, China
  22. Leif Olmanson University of Minnesota
  23. Natascha Oppelt Kiel University
  24. Steef Peters Water Insight BV
  25. Thierry Tormos
  26. Lino A. Sander de Carvalho Meteorology Department, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
  27. Stefan Simis Plymouth Marine Laboratory
  28. François Steinmetz HYGEOS
  29. Kerstin Stelzer Brockmann Consult GmbH
  30. Sindy Sterckx VITO
  31. Nathalie Reynaud RECOVER - Pôle ECLA, INRAE, Aix-en-Provence, France
  32. Quinten Vanhellemont Royal Belgian Institute of Natural Sciences
  33. François-Régis Martin-Lauzer ACRI-ST / ARGANS / adwäisEO / ARCTUS
Form of presentation Poster
  • A7. Hydrology and Water Cycle
    • A7.06 EO for monitoring water quality and ecological status in inland waters
Abstract text Atmospheric correction over inland and coastal waters is one of the major remaining challenges in aquatic remote sensing, often hindering the quantitative retrieval of biogeochemical variables and analysis of their spatial and temporal variability within aquatic environments. The Atmospheric Correction Intercomparison Exercise (ACIX-Aqua), a joint NASA – ESA activity, was initiated to enable a thorough evaluation of eight state-of-the-art atmospheric correction (AC) processors available for Landsat-8 and Sentinel-2 data processing. Over 1000 radiometric matchups from both freshwaters (rivers, lakes, reservoirs) and coastal waters were utilized to examine the quality of derived aquatic reflectances (ρ ̂_w). This dataset originated from two sources: Data gathered from the international scientific community (henceforth called Community Validation Database, CVD), which captured predominantly inland water observations, and the Ocean Color component of AERONET measurements (AERONET-OC), representing primarily coastal ocean environments. The volume of our data permitted the evaluation of the AC processors individually (using all the matchups) and comparatively (across seven different Optical Water Types, OWTs) using common matchups. We found that the performance of the AC processors differed for CVD and AERONET-OC matchups, likely reflecting inherent variability in aquatic and atmospheric properties between the two datasets. For the former, the median errors in ρ ̂_w (560) and ρ ̂_w (664) were found to range from 20 to 30% for best-performing processors. Using the AERONET-OC matchups, our performance assessments showed that median errors within the 15 – 30% range in these spectral bands may be achieved. The largest uncertainties were associated with the blue bands (25 to 60%) for best-performing processors considering both CVD and AERONET-OC assessments. We further assessed uncertainty propagation to the downstream products such as near-surface concertation of chlorophyll-a (Chla) and Total Suspended Solids (TSS). Using satellite matchups from the CVD along with in situ Chla and TSS, we found that 20 – 30% uncertainties in ρ ̂_w (490≤λ≤743 nm) yielded 25 – 70% uncertainties in derived Chla and TSS products for top-performing AC processors. We summarize our results using performance matrices guiding the satellite user community through the OWT-specific relative performance of AC processors. Our analysis stresses the need for better representation of aerosols, especially absorbing ones, and improvements in corrections for sky- (or sun-) glint and adjacency effects, in order to achieve higher quality downstream products in freshwater and coastal ecosystems.