Colour of the Ocean by satellite Methods Exchanges in the...

The COMETE project:

« Colour of the Ocean by

satellite Methods Exchanges in the Tropical Environment»

Cécile DUPOUY 1

Elisabeth HOLLAND 2

1 Mediterranean Institute of Oceanography,

IRD

2 PACE-SD, USP

GIS-RS 2017, Suva, Fiji

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Nouvelle-Calédonie

Représentant : Édouard Hnawia, Director

Links with partners of Fiji Islands, Samoa, PNG, Vanuatu, Wallis & Futuna

(MOU with USP, JEAI COPRA).

100 persons

20 oceanographers

2000 persons


http://www.ird.fr/

http://www.ird.fr/l-ird-dans-le-monde

http://www.ird.fr/l-ird-dans-le-monde/pacifique

http://nouvelle-caledonie.ird.fr/

http://www.ird.fr/var/ird/storage/images/media/images/illustrations/photographies/soin-des-enfants-au-senegal2/37186-1-fre-FR/soin-des-enfants-au-senegal1.jpg

•COMETE Project•Objectives•Algorithm results•Applications•Collaboration•Validation•What’s up in 2018•COMETE contacts


• Objectives:

“promote the exchange of methods and pool energies and

resources between researchers and students interested by the

utilization of massive ocean colour satellite data for

understanding primary production of phytoplankton in the

tropical Pacific islands and archipelagos”

• Partners :

International Collaborations

• IRD

• PACE-SD University

• of South Pacific

• JAXA H. Murakami

• NASA R. Frouin

………

COMETE Project


Distinguish Chlorophyll, sedimentary sources, CDOM in coastalareas by regionally adapted algorithms

Mean SeaWiFS Surface Chla in the South Western Pacific

5

Why study ocean colour in the Pacific ?

Multiple threats on lagoons of Pacific Islands


Fanga Niu’iHihifo

Courtesy Vailala Matato, Antoine N’Yeurt

Harmful algal and red tides, exotic speciesincrease


Planche 1 Fiji 12 April 1998

Crédit photographique BAN

Trichodesmium and other

filamentous algae

*

Trichodesmium bloom forming 1998

SeawifsNitrogen fixation and carbon sink


Batral Jacques

Cartier

Planche 2 New Caledonia Fiji 9 March 2004

2004

Seawifs


2010

MODIS

**

Batral Jacques

Cartier

Gardian

Planche 3 New Caledonia Fiji 9 Febuary 2010


Vanuatu

New-Caledonia Loyalty Is.

Viti Levu Fiji Is.

https://earthobservatory.nasa.gov/IOTD/view.php?id=85073

2014

MODIS

Planche 4 New Caledonia Fiji 15 december 2014


"Sea Sawdust" in the Southwest Pacific

Ocean

January 16, 2015

https://earthobservatory.nasa.gov/IOTD/view.php?id=85073

COMETE objectives

– Join/or build an international research program centered on Pacific Islands

– Use all ocean colour sensors MODIS, Sentinel 2, 3, Himawari-8, GCOM-C around the Pacific Islands

– Apply the most performant algorithms for lagoons and coastal zone surveys

• Study low frequency variability (El Nino/La Nina cycle impacts) as well as extreme meteorological events

• Analyse long-term series…in relation with climate change, fisheries surveys

• Estimate nitrogen fixation and carbon sink


Absorbed and scattered light

Absorption

Phytoplancton

absorbe la lumière

bleue

Eau absorbe

la lumière

rouge

Absorption

Phytoplancton

absorbe la lumière

bleue

Eau absorbe

la lumière

rouge

Rétrodiffusion

Lumière bleue rétrodiffusée

efficacement

Rétrodiffusion

Lumière bleue rétrodiffusée

efficacement

Backscatter absorption

Spectral dependency

Ocean colour : the sea is not blue!

Phytoplankton species

Trichodesmium Minerals + detritus

CDOM


CDOM : Dissolved organic matterUV absorbingassociated with metals and pollutants

Turbidity : particles density in F.T.U. Scatters in the yellow

Chlorophyll: phytoplankton biomass (mg.m-3)Absorbs in the blue

Retrieve 4 Optical components

Trichodesmium absorbs in the Blue & gives a red edge


▪ Turbidity estimation from reflectance ratios in situ

Ouillon et al., 2008, Remote Sensing

▪ Error on bathymetry retrieval (Lyzenga’s) Meris

Minghelli-Roman and Dupouy, 2013, JSTARS

▪ Bottom color classification Meris

Minghelli-Roman and Dupouy, 2014, JSTARS

▪ Chlorophyll inversion AVNIR2

Murakami and Dupouy, 2013, Appl. Optics

▪ Trichodesmium slick detection SeaWiFS, MODIS

Dupouy et al., 2011, Biogeosciences

Rousset et al., submitted, Biogeosciences

▪ Chla retrieval lagoons MODIS

Wattelez et al., 2016, Remote Sensing

▪ Turbidity retrieval shallow waters MODIS

Wattelez et al., 2017, Water

• Modelling

Fuchs et al., 2012,

Algorithm results from COMETE


Trichodesmium cycle in the SWTP decrypted ?

El Nino years

Blooms in Jan-Feb, El Nino years favourable…


Tricho b

loom

pix

el (%

)

97 98 99 00 01 02 03 04 05 06 07 08 09 10

Reproduced by a 3D coupled model….

Chlorophyll increases after rain x 3 !!! January 2008 March 2008


Turbidity increases by a factor of 2 !!

Raw Modis image Turbidity classes

GIS Map 1 Gis map 2

Lagoon transparency drives coral reefs growth….Detection of turbid plumes !GIS-RS 2017, Suva, Fiji

MODIS shows the seasonal phytoplankton cycle…

Bays/open ocean

M33 OC1GD10

J M M J S N D J M M J S N D J M M J S N D

Mars

Septembre

M33 OC1GD10


M33 OC1GD10


M33 OC1GD10


Mars

Septembre

0.4

0.55

0.30


• About nitrogen fixation

Will the ocean be a bigger carbon sink ? Will there

be more CO2 fixation fueled by nitrogen fixing

blooms ?

Some questions arise…


Will the amount of

harmful algal and red

tides increase, exotic

species increase due

to increasing

exchanges ?

• About toxic invasive species



• About overfishing and pollutions

Will we better protect our lagoons ? Will the

fisheries still sustained ?



• Use of satellite for lagoon surveys, plume detection, case studies … GIS-RS 2017, Suva, Fiji

From satellite to decision makers

Products prepared for management

Research and Valorization

South Pacific Ocean Time Series (PI BIEGALA)


MOISE

MOISE station (lagoon) (PI DUPOUY RODIER)

COMETE validations

C Chl a (mg m-3) D Turbidity 1

2

A CDOM (m-1) B bbp (m-1) 1

2

Collaborations

Characterizing Chlorophyll Plumes in Fiji Waters using Remote Sensing of Ocean Colour and spectrofluorometry

Timoci Koliyavu PHS student : 2018-2020Jérôme Lefèvre, Awnesh Singh, Cécile Dupouy


COMETE network

will benefit from

•expertise in Ocean colour remotesensing (SWP algorithms !)

• experience in communicatingresearch results to decision

makers

•new sensors Sentinel2-3, Himawari 8 GCOM-C


Thanks to all collaborators !

IRD: Jérôme Lefèvre MODIS data base (Sentinel3)Guillaume Wattelez (algorithms)Chloe Martias (CDOM, spectrofluorescence)Rosalie Fuchs (modelling)

LSIS Toulon: Audrey Minghelli-Roman

Scripps Institution of Oceanography: Robert Frouin

JAXA: Hiroshi Murakami

HZG: Rüdiger Röttgers

Bluecham: Rémi AndréoliUSP: Awnesh Singh

…


For the COMETE Workshop (2018)Elisabeth Holland & Cécile Dupouy

For observations /cruisesCecile Dupouy, Isabelle Biegala

For observations around FijiTimoci Koliyavu

For algorithmsGuillaume Wattelez

For applicationsBluecham

COMETE Contacts

THANKS TO WOLF FORSTREUTER AND EVERYBODY FOR LISTENING

VINAKA !


Sentinel 3 01/17 Sentinel 3 01/17

Colour of the Ocean by satellite Methods Exchanges in the...

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