Le projet WISE-Man : réalisations et premiers résultats · 2020. 2. 12. · Take home messages...

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

Forum des Sciences de la Mer 2

Landsat-8

Radiative Transfer Equations (RTE)


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


Flight plan


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)


• 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)


• Moderate to strong wind• 19 stations• Hydroball transect in River

Important geometric corrections required

Shallow water experiment

Challenge : bottom reflectance measurement, Rb

• Spectroradiometer deployed by divers (SVC)

• Compact Optical Profiling System (C-OPS)


Divers in work…


Diver

Cops

COPS profiles in shallow waters

Video 1

looking up



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


Downwelling irradiance at each wavelength in Zostera M.


COPS profiles in shallow waters

Video 2

looking down

Upwelling radiance

above bottom

• Increasing or decreasing with depth

• Large variability if seagrass is absent or present

• Absorbed PAR quantification


Sand

Zostera Marina


Upwelling radiance at each wavelength above Zostera M.


Upwelling radiance at each wavelength above sand


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)


Fieldwork team*

* Excluding some members of the inter-tidalteam Forum des Sciences de la Mer 21

!! Announcement !!


Summer school in Optical remote sensing of coastal waters

and littoral habitats

In august 2020 in Ile VerteWelcome to HQPs from QO

Le projet WISE-Man : réalisations et premiers résultats · 2020. 2. 12. · Take home messages...

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