Some results from the “ BOUSSOLE ” project

NASA OCRT meeting, Portland, OR, 12-14 April 2005

Some results from the “BOUSSOLE” project

(BOUée pour l’acquiSition de Séries Optiques à Long termE)

David ANTOINELaboratoire d’Océanographie de Villefranche

« short title » :Building a time series of surface ocean optical properties for satellite ocean color cal/val and (bio)optics research


Funding Agencies / Supports

European Space Agency

Centre National d’Etudes Spatiales, France

National Aeronautics and Space Administration of the USA

Centre National de la Recherche Scientifique, France

Institut National des Sciences de l’Univers, France

Observatoire Océanologique de Villefranche sur mer, France


People involvedRESEARCH STAFF (L.O.V., Villefranche sur mer) David ANTOINE, Chief Scientist Marcel BABIN, Natural phytoplankton fluorescence Annick BRICAUD, IOPs Malik CHAMI, Ocean colour vicarious calibration Hervé CLAUSTRE, IOPs, Biogeochemical proxies André MOREL, AOPs X & Y Phd and Post-Doc, starting in 2006TECHNICAL STAFF (L.O.V., Villefranche sur mer) X (under recruitment) Assistant project manager (2005-2008) Alec SCOTT, Responsible for monthly cruises, data processing (2003-2004) Guislain BECU, idem (2004 - ongoing) Bernard GENTILI, Data processing codes Francis LOUIS, Servicing, electronics, design Joséphine RAS, HPLC and ap measurements Dominique TAILLIEZ , CTD + IOPs, monthly cruises David LUQUET, DivingTECHNICAL STAFF, partnership with companies Pierre GUEVEL, ACRI-st-Genimar, Buoy design, hydrodynamics calculations Jean-François DESTE, ACRI-st-Genimar, Engineering work (e.g., reduced scale model), testing Philippe BARDEY, ACRI-st, Expertise Alpha CAMARA, “Avance Conceptuelle”, Buoy design, structure calculations Cyril DEMPSEY Satlantic Inc. Darrell ADAMS Satlantic Inc.


Main collaborations

Stanford B. HOOKER, NASA/GSFC Optics protocols, cal/val operations

Kenneth J. VOSS Univ. Miami Bidirectionality

Oscar SCHOFIELD & co-workers Rutgers Univ. Gliders’ deployments

P. Y. DESCHAMPS LOA, Univ. Lille Above-water versus Below-water

M. LEE and co-workers IFHM, Ukraine VSFs

J. PRENTICE NAVAIR VSFs


In addition to our supporting/funding Agencies,We also express our appreciation & thanks to

The crews and Captains of : the Castor-02 vessel from the Fosevel Marine company (buoy/mooring operations),the INSU R/V Téthys-II (regular monthly cruises), the GG-IX from the Samar company

Pilots of the Valair and Commerçair helicopter companies, for their willingness in accomplishing for us unusual survey missions above the BOUSSOLE site.

The French institute IFREMER and the Norvegian Marintek company are also thanked for their help and fairness in the engineering studies that were ordered to them after the major failure of the buoy in spring of 2002.

The French weather forecast Agency, “Meteo France” (real time data that are of great help in the day-to-day management of the monthly cruises).

The Brockmann Consult company (Germany) for data distribution

The ACRI-in/Genimar (Sophia Antipolis, France) and Satlantic Inc. (Halifax, NS Canada) for the buoy & instrument system designs

Emmanuel Bosc, Maria Vlachou, Guillaume Lecomte, Edouard Leymarie, who have occasionally provided help in collecting data at sea.

Acknowledgements


Motivations

- Science objectives : short-term changes in IOPs and AOPs, relationships between both, role of CDOM, seasonal and inter-annual changes, bidirectionality of the ocean reflectance...

- Operational objective : vicarious radiometric calibration of ocean color observations from space, and validation of the level-2 “geophysical products” (e.g., chlorophyll, normalized radiances).

Establish a time series of inherent and apparent optical properties (IOPs and AOPs), with two parallel objectives :


Strategy

- A deep sea mooring, collecting data on a “continuous” basis

- Monthly cruises for collecting data that are not accessible to the mooring (vertical profiles, water sampling), as well as for servicing the mooring

- A coastal AERONET station, providing the necessary information about the aerosol properties, which are a central element of the vicarious calibration process

Combination of 3 elements :


Measurement suite, instrumentation

- Buoy: Surface irradiance (Es), downwelling irradiance (Ed), upwelling irradiance (Eu) and upwelling radiance at nadir (Lu) at 4 and 9 meters (7 ’s Satlantic’ OCR-OCI 200 Series), attenuation coefficient (Wetlabs C-star), backscattering coefficient (2 ’s, Hobilabs’ Hydroscat), chlorophyll fluorescence (Chelsea MiniTracka). Temp., Pressure, Salinity at 9 meters (SeaBird’ SBE37), buoy tilt and compass.

- Monthly cruises In-water profiles of Ed and Eu at 13 ’s (Satlantic’ SPMR/SMSR), above water determination of Lw, phytoplankton pigments (HPLC), phytoplankton absorption (filtered water), total absorption, scattering and attenuation coefficients at 9 ’s (Wetlabs’ AC9), backscattering profile (Wetlabs’ eco VSF) and CDOM fluorescence (Wetlabs’ CDOM WetStar). Aerosol optical thickness (CIMEL CE-317 or SIMBADA).- Coastal AERONET Station (CE-318 sun photometer) : aerosol optical thickness, sky radiances (aerosol types) and polarization


The site where we collect data :

“BOUSSOLE” site & program“Buoy for the acquisition of a long-term (bio)optical

series”

Monthly cruises (started July 2001) + a new type of optical buoy (since Sept. 2003)

Marine optics, Bio-optics, Ocean color calibration / validation program (MERIS, SeaWiFS, MODIS, POLDER,PARASOL)


Site characteristics(oligotrophic to eutrophic)

Winter, maximum of the water mixingChl up to ~2-3 mg m-3

mixed layer down to 200 meters

Spring, establishment of the deep chlorophyll maximum around 50 metersChl ~ 0.3 mg m-3

Summer, maximum of the stratification. DCM is maximum, with surface Chl ~ 0.05 mg m-3 (up to 1 in the DCM)

Fall, erosion of the thermocline, the DCM progressively disappearsChl ~ 0.5 mg m-3


Feb March Apr May Jun Jul Sept Oct Nov Dec

2001

2002

2003

2004 SeaWiFS/SIMBIOS « diagnostic data sets »(http://seawifs.gsfc.nasa.gov/cgi/seawifs_region_extracts.pl?TYP=ocean)

SeaWiFS chlorophyll 2001-2004(in correspondence with our monthly cruises)


Deployments summary

Monthly cruises started in July 2001, ongoing

Buoy deployments :- July to October 2000 : qualification deployment- May 2002 : first, unsuccessful deployment- Sept 6 - Dec 6, 2003 : 3-month successful deployment- March 4, 2004 - May 2005 : 15-month successful deployment (including a rotation in July 2004)

continuing...

AERONET site, data collection periods :- July 2002 to April 2003- January to November of 2004- February 2005, ongoing

Project should extend at least throughout the MERIS life


Data summary :monthlycruises


Data summary :buoy

Data summary :AERONET


Matchups summary at BOUSSOLE

Obtained from buoy data : 3 months in fall 2003

8 months in 2004 (March, mid May-mid July, Aug - Dec)SPMR data : monthly cruises

MERIS : N = 43 (36 + 7)

MODIS : N = 85 (77 + 8)

SeaWiFS : N = 98 (79 + 19)

Criteria : no glint, not at a cloud border, QC in situ data.

More selective criteria (low AOT, small s, low wind speed etc...) leads to a reduction of these numbers by at least 50%


Matchups examples BOUSSOLE (1/4) : March 22, 2004MERIS

A-MODIS

SeaWiFS

Chl a(865)

Chl a(869)

Chl a(865)


Matchups examples BOUSSOLE (2/4) : May 29, 2004MERIS

A-MODIS

SeaWiFS

Chl a(865)

Chl a(869)

Chl a(865)


Matchups examples BOUSSOLE (3/4) : June 17, 2004MERIS

A-MODIS

Chl a(865)

Chl a(869)


Matchups examples BOUSSOLE (4/4) : October 6, 2003MERIS

A-MODIS

SeaWiFS

Chl a(865)

Chl a(869)

Chl a(865)


0,0001

0,0010

0,0100

0,1000

0,0001 0,0010 0,0100 0,1000

in situ reflectance

ME

RIS

ref

lect

ance

y = 1,0152x + 0,0007

R2 = 0,9455

0,0000

0,0050

0,0100

0,0150

0,0200

0,0250

0,0300

0,0000 0,0050 0,0100 0,0150 0,0200 0,0250 0,0300

in situ reflectance

ME

RIS

ref

lect

acn

ce

MERIS matchups (w’s)BOUSSOLE site

36 points from the buoy7 points from the SPMR (monthly cruises)

Linear scale

Log scale


0,001

0,010

0,100

1,000

10,000

0,001 0,010 0,100 1,000 10,000

in situ nLw

Sea

WiF

S n

Lw

y = 0,9725x + 0,0073

R2 = 0,9496

0,000

0,200

0,400

0,600

0,800

1,000

1,200

1,400

1,600

0,000 0,200 0,400 0,600 0,800 1,000 1,200 1,400 1,600

in situ nLw

Sea

WiF

S n

Lw

SeaWiFS matchups (nLw’s)BOUSSOLE site

79 points from the buoy 19 points from the SPMR (monthly cruises)

Linear scale

Log scale


0,001

0,010

0,100

1,000

10,000

0,001 0,010 0,100 1,000 10,000

in situ nLw

A-M

OD

IS n

Lw

y = 0,9591x + 0,0219

R2 = 0,975

0,000

0,200

0,400

0,600

0,800

1,000

1,200

1,400

1,600

0,000 0,200 0,400 0,600 0,800 1,000 1,200 1,400 1,600

in situ nLw

A-M

OD

IS n

Lw

Aqua-MODIS matchups (nLw’s)BOUSSOLE site

77 points from the buoy 8 points from the SPMR (monthly cruises)

Linear scale

Log scale


MERIS N mean RPD r2 slope interc. RMS

ratio412 20 1,310 30,958 56,038 0,741 0,008467 0,005357 0,005979 0,023599 0,011699 0,028536443 43 1,124 12,370 72,823 0,770 0,005401 0,002715 0,004207 0,023067 0,008782 0,023743490 43 1,085 8,457 71,248 0,666 0,005691 0,001852 0,004630 0,018206 0,008681 0,018421510 43 1,148 14,793 36,048 0,429 0,006940 0,001816 0,004903 0,012225 0,007627 0,012874560 43 1,151 15,123 0,406 0,054 0,005737 0,001189 0,003287 0,006734 0,004349 0,008306620 7 2,111 111,123 4,160 0,669 0,001007 0,000929 0,000499 0,000989 0,000889 0,002592665 43 2,991 199,057 1,762 0,387 0,000748 0,000651 0,000133 0,000754 0,000248 0,001854681 43 5,716 471,620 32,055 1,342 0,000590 0,000770 0,000009 0,001071 0,000407 0,002420709 6 2,449 144,912 34,291 1,229 0,000293 0,000452 0,000132 0,000610 0,000171 0,001149

All 291 94,575 1,034 0,000843

SeaWiFS N mean RPD r2 slope interc. RMS

ratio412 48 0,949 -5,103 76,961 1,159 -0,196 0,169 0,367 1,545 0,263 1,548443 98 0,990 -0,965 79,500 0,960 0,029 0,119 0,280 1,430 0,314 1,525490 98 0,998 -0,198 67,330 0,784 0,189 0,100 0,315 1,194 0,384 1,189510 98 0,985 -1,492 40,341 0,574 0,250 0,078 0,335 0,848 0,359 0,796555 98 1,011 1,078 12,283 0,368 0,194 0,054 0,187 0,498 0,173 0,436670 95 1,367 36,705 2,565 0,224 0,017 0,014 0,007 0,065 0,004 0,061

All 535 94,956 0,972 0,007

A-MODIS N mean RPD r2 slope interc. RMS

ratio412 42 0,954 -4,618 86,353 1,030 -0,062 0,120 0,405 1,605 0,282 1,590443 85 0,979 -2,133 82,443 0,907 0,075 0,094 0,310 1,495 0,286 1,585488 85 0,999 -0,103 79,543 0,789 0,193 0,069 0,354 1,174 0,372 1,228551 85 1,083 8,314 24,169 0,585 0,153 0,049 0,196 0,380 0,208 0,432667 84 1,484 48,438 0,288 0,055 0,019 0,010 0,005 0,048 0,005 0,040

All 381 97,530 0,960 0,020

in situ range satellite range



Matchups statistics at BOUSSOLE(MERIS, SeaWiFS & A-MODIS)

Norm

alized reflectan

cesN

ormalized

water-leavin

g radian

ces


0,000

0,001

0,010

0,100

0,000 0,001 0,010 0,100

Moby w

ME

RIS

w

y = 1,0556x + 0,0004

R2 = 0,9897

0,000

0,005

0,010

0,015

0,020

0,025

0,030

0,035

0,040

0,045

0,050

0,000 0,005 0,010 0,015 0,020 0,025 0,030 0,035 0,040 0,045 0,050

Moby w

ME

RIS

w

MERIS matchups at MOBY(w’s)

24 points from the buoy

Linear scale

Log scale


MERIS matchups statistics at MOBY

MERIS (Moby site) N mean RPD r2 slope interc. RMS

ratio412 24 1,122 12,203 63,941 0,582 0,018453 0,004782 0,026184 0,046314 0,032363 0,045543443 24 1,089 8,858 55,332 0,554 0,014004 0,002925 0,021370 0,034159 0,024258 0,033342490 24 1,073 7,332 26,020 0,373 0,012535 0,001795 0,015153 0,021244 0,016119 0,020771510 24 1,134 13,374 13,493 0,384 0,007420 0,001561 0,008515 0,011254 0,008446 0,012305560 24 1,176 17,627 7,204 0,362 0,003341 0,000889 0,003397 0,004918 0,003076 0,005809620 24 1,700 70,009 0,330 0,125 0,000732 0,000435 0,000279 0,000736 0,000117 0,001535665 24 2,916 191,615 0,061 0,055 0,000513 0,000377 0,000082 0,000376 0,000068 0,001020681 24 3,737 273,717 0,024 -0,037 0,000660 0,000490 0,000081 0,000351 0,000196 0,001063709 22 8,412 741,161 0,494 0,356 0,000331 0,000334 0,000015 0,000112 0,000111 0,000658

All 214 0,000 0,000 98,905 1,077 0,000380 0,000000 0,000000 0,000000 0,000000 0,000000



Chlorophyll matchupsMERIS SeaWiFS A-MODIS

With the radiometry QC

All matchups


Conclusions / Ongoing & future work- Quasi-operational system, including two complete moorings (mooring line +

buoy + instrumentation) ==> continuous sampling is at reach.==> About 80 to 90 matchups per year for MODIS & PARASOL

40 to 50 matchups per year for MERIS==> A-MODIS looks pretty good (low bias, low dispersion) SeaWiFS shows a significant underestimation and a slightly larger dispersion MERIS shows a significant overestimation, pb in the red, and a larger dispersion

- Still a lot of work to reduce satellite versus in situ scatter(1) Further interpret the matchups’ results(2) Further QC the buoy data, (3) Introduce corrections, e.g., for self-shadow and buoy shadow, tilt on Es(4) Improve the data processing, e.g., surface extrapolation(5) Introduce SQM-II relative calibrations(6) Improve bio-fouling elimination

- Vicarious radiometric calibration of OC sensorsThe tools (inversion procedures & RT codes) & the data (AERONET) are nearly Ok ==> results by fall of 2005.

- Optics / bio-optics2nd half of 2005 & 2006 : data exploitation


2001-2004 time series for Kd(490)


Thank you for your attention

Some results from the “ BOUSSOLE ” project

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