le projet wise-man : réalisations et premiers résultats · 2020. 2. 12. · take home messages...
TRANSCRIPT
Le projet WISE-Man : réalisations et premiers résultats
Simon Bélanger
C. Araujo, J-P Ardouin, P. Bernatchez, C.Blot, R. Côté, M. Cusson, F. Danhiez, J. Desrochers, C.G. Fichot, G. Fournier, Y. Gendreau, J. Harrington, J. Hedley, G. Ifimov, J. Laliberté, M-F Lavoie, B. Légaré, R. Léger-Daigle, J. Lemarchand, R.
Mabit, J. Mayrand, S. Mukherjee, F. Noisette, C. Nozais, A-S Sean, R. Soffer, S. Velasquez, M. Wieser
WaterSat Imaging Spectrometer Experiment (WISE) for optically shallow coastal waters
assessmentThe WISE-Man project
The overall long-term objective wasto demonstrate the potential of WISE, and more generally hyperspectral imagery, for
coastal ecosystem mapping: • bathymetry,
• water column quality (or inherent optical properties) and • bottom properties
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Landsat-8
Radiative Transfer Equations (RTE)
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Should you have any questions, please ask Soham Mukherjee, PhD student
2019 Fieldwork at a glance
• July 30th to August 26th in Baie-Comeau/Manisouagan• 30 participants including, ~ half students• Four boats (FJ Saucier, Kildir, Machiatic, small zodiac)• 1 lab team in CEGEP de Baie-Comeau• 6 professional divers• NRC’s flight team with a Twin Otter and two hyperspectral
cameras (WISE and CASI-1500)• > 6 hours of flights with simultaneous in situ observations• > 50 stations and 84 water samples for constituents
(pigments, carbon, nuts, etc) • 1 Special « optical » experiment in optically-shallow water
with all boats
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Flight plan
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High tide Low tide
High Altitude (3000 m) => 1.5-m pixels resolution
Low Altitude (1000 m) => 0.5-m pixels resolution
High Tide WISE acquisition (18/08)
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• Clear sky• No wind• 29 stations for sampling and
optics• Transects with hydroball +
HOCR + BB3 (bathy, opticalproperties) in opticallyshallow waters
19:40:15SZA=51.5°AZI=241.5°
21:24:10SZA=68.1°AZI=264.5°
Low tide flight (20/08)
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• Moderate to strong wind• 19 stations• Hydroball transect in River
Important geometric corrections required
Shallow water experiment
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Challenge : bottom reflectance measurement, Rb
• Spectroradiometer deployed by divers (SVC)
• Compact Optical Profiling System (C-OPS)
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Divers in work…
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Diver
Cops
COPS profiles in shallow waters
Video 1
looking up
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Downwellingirradiance profiles
• Decreasing with depth, positive Kd ~dEd/dz
• Variability just above the bottom due to depth, water column IOPs and surface variability
• Green light survival
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Downwelling irradiance at each wavelength in Zostera M.
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COPS profiles in shallow waters
Video 2
looking down
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Upwelling radiance
above bottom
• Increasing or decreasing with depth
• Large variability if seagrass is absent or present
• Absorbed PAR quantification
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Sand
Zostera Marina
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Upwelling radiance at each wavelength above Zostera M.
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Upwelling radiance at each wavelength above sand
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Bottom reflectance method comparison
RrsCOPS_Eu= Eu/Ed Rrs
COPS_Lu= pi*Lu/Ed RrsSVC= pi*Lu/Lpanel
Chlorophyll a
Take home messages
• Light transmission and reflection in optically-shallow is not intuitive and complex: – Theory versus measurements still required
– Great potential for quantification of PAR absorbed by vegetation => net primary production
• Flights and fieldwork conducted in August 2019 was a great success, surpassing the initial objectives of the project (e.g., high versus low tide; the experiment with divers)
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Fieldwork team*
* Excluding some members of the inter-tidalteam Forum des Sciences de la Mer 21
!! Announcement !!
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Summer school in Optical remote sensing of coastal waters
and littoral habitats
In august 2020 in Ile VerteWelcome to HQPs from QO