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Inputs from the GlobCOLOUR team Special thanks to Yaswant Pradhan, Julien Demaria,

In Situ Database and Sensor Characterisation Results Sam Lavender, UoP. Inputs from the GlobCOLOUR team Special thanks to Yaswant Pradhan, Julien Demaria, Gilbert Barrot & David Antoine. Characterisation review. In Situ Data / Database Level-2 Characterisation: In situ

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Inputs from the GlobCOLOUR team Special thanks to Yaswant Pradhan, Julien Demaria,

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  1. In Situ Database and Sensor Characterisation Results Sam Lavender, UoP Inputs from the GlobCOLOUR team Special thanks to Yaswant Pradhan, Julien Demaria, Gilbert Barrot & David Antoine.

  2. Characterisation review • In Situ Data / Database • Level-2 Characterisation: • In situ • Cross Characterisation • Level-3 Characterisation • Overall Conclusions

  3. Types ofIn Situ Data • Chlorophyll (HPLC and fluorometric) • Diffuse attenuation coefficient at ~490nm (not shown in this presentation) • Fully normalised water-leaving radiance primarily at 412, 443, 490, 510, 531, 555, 620, 670 nm • Computed when Lw, Ed, Es, Chl, and solar and viewing geometry available.

  4. Level-2 characterisation data sets BOUSSOLE NOMAD SeaBASS 2002 onwards

  5. L2 (M)LAC In-situ meta Preparation/Generation L3-DDS Generator Extraction Statistics/Result In-situ data L3 DDS Match-up Result L3-DDS Reader GC in-situ Reader Exclude NO match-up Timediff <24 hrs Y Timediff 12 hrs Flagged pixels ( e.g. NO_MEAS) rejected Num Pix >= 13 CV = 0.15 DDS Match-Up N N Locationdiff <=0.02° Y NO match-up N Extract 5x5 kernel Level-2 Data Processing

  6. Level-2 Characterisation Chl-a Results

  7. Pre-merging sensor cross-characterization

  8. Pre-merging sensor cross-characterization Statistics table for the global comparison for year 2003 (annual min/avg/max): To be compared to the one issued by the JRC team based on monthly data over 36 months (July 2002 – June 2005):

  9. Level-3 characterisation data For GlobCOLOUR PPS months (July and October 2002, January and April 2003) a total of 124 in situ data points were available from the OBPG validation database:

  10. Level-3 Characterisation Chl-a Results

  11. Level-3 Characterisation nLw Results

  12. Level-3 characterisation data As the validation using OBPG dataset for the PPS months was strongly influenced by coastal waters, it was decided that a validation would also be performed using the BOUSSOLE data; chlorophyll data from 2002-2003 and radiances from 2003-2006.

  13. BOUSSOLE Level-3 Characterisation Higher median % differences than the OBPG results.

  14. Chl-a Comparisons Target of less than 35%

  15. Overall Conclusions • In Situ Database: data was converted to a consistent format that was easily distributed within the consortium. • Level-2 Characterisation: rather than correcting for the bias in the level-2 data, the results were reflected in the error bar estimates. • In situ: ideally more in situ data is needed, but the limited amount gave sufficient information for the merging process. • Cross Characterisation: The global analysis showed small biases between sensors, especially MERIS and MODIS, while the regional analysis showed that the differences between sensors fluctuates and is seasonally dependant.

  16. Overall Conclusions • Level-3 Characterisation: are highly dependant on the in situ data. • Chlorophyll a: 35% met for OBPG results • OBPG results: smaller errors for the OBPG level-2 characterisation (PPS months only) than GlobCOLOUR unmerged level-3 data. For the merged data, the errors appeared to reduce; especially for the GSM model. • BOUSSOLE results: larger errors than the OBPG data despite it being a predominately Case 1 site, but it is influenced by Saharan dust and seasonal CDOM values. • nLw: The 5% error level is not yet met for either the level-2 or level-3 data (8.5-20.5% excluding 670nm for merged data).

  17. Thank you for your attention

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