Validation of turbidity products EuroGOOS Conference, May 20-22, 2008, Exeter Session Observations – OBS17 May 22, 2008 Validation of turbidity products in the Baltic derived from multi-sensors observations of ocean colour Antoine Mangin 1, Seppo Kaitala 2, Stéphane Maritorena 3, Odile Fanton d’Andon 1, and Philippe Garnesson 1 (1) ACRI-ST, (2) FIMR, (3) ICESS UCSB Session Observations – May 22, 2008 Validation of turbidity products in the Baltic derived from multi-sensors observations of ocean colour

Validation of turbidity products EuroGOOS Conference, May 20-22, 2008, Exeter Session Observations – OBS17 May 22, 2008 Outline of this presentation  Background of Marcoast  Background of GlobColour  Validation over Baltic Validation of turbidity products in the Baltic derived from multi-sensors observations of ocean colour Gulf of Finland

Validation of turbidity products EuroGOOS Conference, May 20-22, 2008, Exeter Session Observations – OBS17 May 22, 2008 MarCoast Project: Presentation SERV10, 21 May by Planetek GMES Service Element project (ESA Funding) The main goals are: – the surveillance and monitoring of the marine and coastal environment – to deliver services at a European scale. – integration and Sustainability was launched in 2005 and will be completed at the end of Background, Marcoast Project

Validation of turbidity products EuroGOOS Conference, May 20-22, 2008, Exeter Session Observations – OBS17 May 22, 2008 Background, MarCoast Project ACRI-ST activities within Marcoast project: -Ocean Colour Delivery Service (NRT/Archive MERIS/MODIS data) to other service providers -Pan-European service of eutrophication statistics information -Water quality indicator for EEA: see EuroGOOS poster P19 -Validation activities: Regional consistency assessment with in situ data over Baltic sea in collaboration with FIMR More on Marcoast:

Validation of turbidity products EuroGOOS Conference, May 20-22, 2008, Exeter Session Observations – OBS17 May 22, 2008 Background, Globcolour project  GlobColour: ESA DUE project i.e. driven by end users: IOCCG, IOCCP,UK Met-Office,  Achievements  Provision of a long time-series ( ) of consistently calibrated and merged global ocean colour products MERIS (ESA), SeaWiFS (NASA), MODIS-AQUA (NASA)  Validation and characterisation performed with available in situ observations  Future development: Global Ocean Colour Thematic Assembly Centre of the future EU GMES Marine Core Service (MyOcean) More on Globcolour: ( Data available on line )

Validation of turbidity products EuroGOOS Conference, May 20-22, 2008, Exeter Session Observations – OBS17 May 22, 2008 Validation with FIMR observations Validation of turbidity products in the Baltic derived from multi-sensors observations of ocean colour

Validation of turbidity products EuroGOOS Conference, May 20-22, 2008, Exeter Session Observations – OBS17 May 22, 2008 Towards the turbidity validation …. through the In situ monitoring route: Helsinki - Travemûnde Turbidity is routinely measured and recorded during cruises The Nephelometric Turbidity Unit (NTU) that is used is directly comparable to the scattering of particulate matter b p Helsinki Travemûnde Validation of turbidity products in the Baltic derived from multi-sensors observations of ocean colour

Validation of turbidity products EuroGOOS Conference, May 20-22, 2008, Exeter Session Observations – OBS17 May 22, Travemûnde Helsinki Åland Illustration of turbidity mapping Well identified seasonal increase of turbidity Spatial and temporal uniformity of turbidity Validation of turbidity products in the Baltic derived from multi-sensors observations of ocean colour Issues: High dissolved organic matter (CDOM) and Turbidity High variability

Validation of turbidity products EuroGOOS Conference, May 20-22, 2008, Exeter Session Observations – OBS17 May 22, 2008 Chl-a - Gulf of Finland – In situ obs. – Source : FIMR Issues: High dissolved organic matter (CDOM) and Turbidity High variability Validation of turbidity products in the Baltic derived from multi-sensors observations of ocean colour Spring bloom 2005

Validation of turbidity products EuroGOOS Conference, May 20-22, 2008, Exeter Session Observations – OBS17 May 22, 2008 Chl-a - Gulf of Finland MODIS/SeaWiFS standard algorithms – Issues: High dissolved organic matter (CDOM) and Turbidity High variability Validation of turbidity products in the Baltic derived from multi-sensors observations of ocean colour Spring bloom is not captured False summer bloom of Chl

Validation of turbidity products EuroGOOS Conference, May 20-22, 2008, Exeter Session Observations – OBS17 May 22, 2008 Chl-a validation - Gulf of Finland in situ / MERIS case 2 Validation of turbidity products in the Baltic derived from multi-sensors observations of ocean colour The Meris-Chla algorithm for Case 2 waters gives quite good fit with in situ data for the Gulf of Finland But … Spatial and temporal coverage issue

Validation of turbidity products EuroGOOS Conference, May 20-22, 2008, Exeter Session Observations – OBS17 May 22, 2008 GlobColour Data merging Validation of turbidity products in the Baltic derived from multi-sensors observations of ocean colour Why do ocean color data merging ? Several simultaneous global ocean color missions Several versions of the same product Benefits: Development of unified, consistent ocean color time-series from multiple sensors Improved spatial and temporal coverage More diverse ocean color products with lower uncertainties GlobColour : Access to products uncertainties Exploitation of all spectral bands from 412 nm to 670 nm.

Validation of turbidity products EuroGOOS Conference, May 20-22, 2008, Exeter Session Observations – OBS17 May 22, 2008 GlobColour GSM algorithm MERIS, MODIS, SeaWiFS LwN + Estimates of the uncertainties on input LwN (from sensors obs. characterisation) Estimates of the model error (from NOMAD Database) Estimates of Chla, bbp, cdm + uncertainties on outputs (Co-variance matrix) Validation of turbidity products in the Baltic derived from multi-sensors observations of ocean colour

Validation of turbidity products EuroGOOS Conference, May 20-22, 2008, Exeter Session Observations – OBS17 May 22, 2008 Inputs: In situ observations (Nomad) Results: very close to expectancy – no significant bias Inputs: GC products Results: very close to expectancy – a small bias is detected – the error estimates by GSM (with ad hoc inputs) is slightly underestimated. Validation of turbidity products in the Baltic derived from multi-sensors observations of ocean colour GlobColour Error estimates - Validation If the Chla error estimates is reliable should be close to a standard normal distribution

Validation of turbidity products EuroGOOS Conference, May 20-22, 2008, Exeter Session Observations – OBS17 May 22, 2008 GlobColour Example GlobColour Chla-merged product – May, GlobColour Chla-merged product relative uncertainties – May, Validation of turbidity products in the Baltic derived from multi-sensors observations of ocean colour

Validation of turbidity products EuroGOOS Conference, May 20-22, 2008, Exeter Session Observations – OBS17 May 22, % GlobColour Example Validation of turbidity products in the Baltic derived from multi-sensors observations of ocean colour bbp Error August 7, 2007 – bbp

Validation of turbidity products EuroGOOS Conference, May 20-22, 2008, Exeter Session Observations – OBS17 May 22, % GlobColour Example Validation of turbidity products in the Baltic derived from multi-sensors observations of ocean colour bbp Error March 26, 2007 – bbp

Validation of turbidity products EuroGOOS Conference, May 20-22, 2008, Exeter Session Observations – OBS17 May 22, 2008 Some empirical laws are proposed between particle backscattering coefficient (bbp) and particle scattering coefficient (bp), e.g., bbp≈0.015 bp (in MERIS ATBD) In other words it is there admitted that it exists a linear relationship between the two coefficients. The challenging objective here is therefore to make the bridge between measured b p (through NTU) and EO-derived b bp in order to bring novel insights about the linearity of the relationship and wherever possible its suitability with respect to turbidity ranges. Turbidity in Baltic – elements of validation Validation of turbidity products in the Baltic derived from multi-sensors observations of ocean colour However, it should vary with size and nature of particulate matters, and consequently could vary with time and space.

Validation of turbidity products EuroGOOS Conference, May 20-22, 2008, Exeter Session Observations – OBS17 May 22, 2008 Travemûnde Helsinki Extraction of a 3x3 GC macro-pixel each 10 km for available in situ truth Turbidity in Baltic – elements of validation EO side In situ side Filtering: Bp<1,5 + removal of « obvious » artefacts NTU Month Validation of turbidity products in the Baltic derived from multi-sensors observations of ocean colour 2006

Validation of turbidity products EuroGOOS Conference, May 20-22, 2008, Exeter Session Observations – OBS17 May 22, 2008 Turbidity in Baltic – elements of validation Validation of turbidity products in the Baltic derived from multi-sensors observations of ocean colour 2006

Validation of turbidity products EuroGOOS Conference, May 20-22, 2008, Exeter Session Observations – OBS17 May 22, 2008 Turbidity in Baltic – Confrontation EO (bbp) against in situ (bp) GSM - GlobColour (EO) bbp vs In-situ bp Validation of turbidity products in the Baltic derived from multi-sensors observations of ocean colour

Validation of turbidity products EuroGOOS Conference, May 20-22, 2008, Exeter Session Observations – OBS17 May 22, 2008 Turbidity in Baltic – Confrontation EO (bbp) against in situ (bp) Validation of turbidity products in the Baltic derived from multi-sensors observations of ocean colour GSM - GlobColour (EO) bbp vs In-situ bp Monthly scale Correlation exists … Still high (spatial) variability

Validation of turbidity products EuroGOOS Conference, May 20-22, 2008, Exeter Session Observations – OBS17 May 22, 2008 Turbidity in Baltic – Confrontation EO (bbp) against in situ (bp) ….. and other sources for validation (Babin, Maritorena, personal com.) to be compared to GSM (in situ) vs In-situ Validation of turbidity products in the Baltic derived from multi-sensors observations of ocean colour September 2006 Bbp= bp R2=0.39 N=1012 GSM - GlobColour (EO) bbp vs In-situ bp Bbp= bp R2=0.15

Validation of turbidity products EuroGOOS Conference, May 20-22, 2008, Exeter Session Observations – OBS17 May 22, 2008 Turbidity in Baltic – Confrontation EO (bbp) against in situ (bp) First conclusions: 1.A simple linear relationship between bp and bbp cannot blindly be used as is in the Baltic sea. 2.On a monthly basis, a linear relationship between bbp and bp can be used to cross-check « observed bp » against « EO-derived bbp » 3.Still some work to sort out « valid » EO-derived information (e.g. by using exclusion threshold on standard deviation) and « valid » observation (e.g. by checking spatial and temporal consistencies). 4.Work will be expanded to previous observations (2003/2004/2005) Validation of turbidity products in the Baltic derived from multi-sensors observations of ocean colour

Validation of turbidity products EuroGOOS Conference, May 20-22, 2008, Exeter Session Observations – OBS17 May 22, 2008 FIMR feedback on the service “The Meris-Chla algorithm for Case 2 waters and by extension GSM method gives quite good fit with in situ data for the Gulf of Finland (… quite problematic due to high variation of water quality parameters).” Validation of turbidity products in the Baltic derived from multi-sensors observations of ocean colour

Validation of turbidity products EuroGOOS Conference, May 20-22, 2008, Exeter Session Observations – OBS17 May 22, 2008 FIMR feedback on the service ” The service gives valuable information for the water quality evaluation of the Baltic Sea and reporting to HELCOM about the water quality status of the Baltic Sea.” Validation of turbidity products in the Baltic derived from multi-sensors observations of ocean colour _GB/secchi/ ringbloom/