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Gilbert Barrot, Julien Demaria ACRI-ST

Gilbert Barrot, Julien Demaria ACRI-ST. 1 The GlobColour products. What are the GlobColour parameters ? FPS, DDS and DDS_insitu products Grids and files format. 2 Processing status. Which products are currently available ?. 3 Data access. Where and how to get the data ?.

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Gilbert Barrot, Julien Demaria ACRI-ST

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  1. Gilbert Barrot, Julien Demaria ACRI-ST

  2. 1 The GlobColour products What are the GlobColour parameters ? FPS, DDS and DDS_insitu products Grids and files format 2 Processing status Which products are currently available ? 3 Data access Where and how to get the data ?

  3. The GlobColour Parameters Parameters and merging methods Not all parameters are available for all merging methods Methods selected at WS1 Weighted average +GSM for CHL1 All products include error bars and flags

  4. Jan Feb Mar Apr CHL1 AVW 2003 May Jun Jul Aug Sep Oct Nov Dec The GlobColour Parameters CHL1 weighted average pre-processing Inverse formulation is available in the Product User Guide

  5. CDM (m-1) The GlobColour Parameters 2002/07 CDM_GSM monthly mean 2003/05 CDM_MERIS monthly mean CDM is the coloured dissolved and detrital organic materials (m-1). Two GlobColour products are generated for FPS: A merged CDM concentration is generated using the GSM model from the daily L3 radiance products of the 3 instruments if available. The other one comes from the MERIS products. MERIS-derived CDM product GSM-derived CDM product

  6. BBP (m-1) The GlobColour Parameters 2003/05 2003/05 GSM-derived bbp product bbp is the particulate back-scattering coefficient (in m-1) at λ0 = 443nm. The merged bbp concentration is generated using the GSM model. From the initial GlobColour bbp merged product, we have therefore the possibility of generating the following products: bp (m-1) = bbp/0.015 TSM (g.m-3) = 1.73*bp = 1.73*bbp/0.015

  7. Nov. 2003 May 2003 Kd(490) is the diffuse attenuation coefficient at 490 nm (m-1). It is one indicator of the turbidity of the water column. The merged Kd(490) is computed directly from the merged CHL1, using the following equation: with: Kw(490) = 0.0166 m-1 = 0.08349 e(490) = 0.63303 The GlobColour Parameters (Morel, 2006)

  8. The GlobColour Parameters Lxxx is the fully normalised water leaving radiances at xxx nm (in mW/cm²/µm/sr). Spectral values are: 412, 443, 490, 510, 531, 550-565, 620, 665-670, 681 and 709 nm. MERIS reflectances (L2 products) are converted into fully normalised water leaving radiances (normalisation is not applied to the MERIS 681 nm fluorescence band and to the 709 nm band.). MODIS-only - MERIS-only - Preprocessing

  9. L555 July 2002 Weighted average 2002/05 The GlobColour Parameters The 550-565 bands are submitted to a specific processing just before averaging to prepare a more consistent merging between the instruments. First of all, all bands are spectrally re-affected to 555 nm, using inter-spectral conversion rules, which are functions of the CHL1 concentration.

  10. The GlobColour Parameters EL555 is the relative (%) excess of radiance at 555 nm, above a given threshold. The EL555 parameter is computed from the L555 fully normalised water leaving radiance and the CHL1 products. The daily products are computed for each instrument using the associated daily water leaving radiance and daily CHL1, while the merged product is computed from the merged L555 and the merged CHL1 concentration. Details in User Guide

  11. The GlobColour Parameters CF July 2002 Takes into account clouds, ice and high aerosol load contamination CF is the “cloud fraction” (expressed in %). daily products: percentage of input pixels per bin flagged as cloudy in the original L2 products 8-days and monthly products: percentage of merged days per bin where the daily cloud fraction is greater than a specified threshold (50% in current processor conf.)

  12. The GlobColour Parameters The flags

  13. The GlobColour Parameters Complete details are available in the GlobColour Product User Guide Information stored in the products (1): stdev is not computed in the nearest neighbour interpolation process (2): before merging step, error is not provided pixel-wise, but the global relative error (%) coming from the characterisation is saved in metadata (3): stdev is not defined at the output of the merging module. Only error is estimated. (4): error is the output of the weighted average merging model. Only products merged using this method contain the error pixel-wise field; other products does not contain this field. (5): for merged daily, 8-days and monthly products, count is not the number of L2 binned pixels, but the number of days contributing to the bin. So for merged daily products, it is always set to 1. (6): computed from the quadratic sum of the inverse errors of the parents products. (7): quicklook product does not contain any geophysical variable

  14. FPS, DDS and DDS_insitu FPS, DDS and DDS_insitu FPS: global products one parameter per file DDS: local products on specific areas (100x100 km2) all parameters in a single file systematic production DDS_insitu: local products on specific areas all parameters in a single file production linked to in-situ data availability

  15. Grids and Files Format GlobColour products are netCDF files CDL representation in the PUG

  16. Grids and Files Format GlobColour grids

  17. Grids and Files Format The row(), col(), center_lat(), center_lon() and lon_step() arrays allow an easier conversion of the bin index into geographical coordinates. Equations to compute center longitude and latitude for a bin b: • index = row(b) – first_row (first_row is a global attribute) • lat(b) = center_lat( index ) • lon(b) = center_lon( index ) + col(b) * lon_step( index )

  18. Grids and Files Format Tools to browse/plot ISIN and PC products are available on the GlobColour web site and any external tools using netCDF reader and ISIN / PC grid definition

  19. 1 The GlobColour products What are the GlobColour parameters ? FPS, DDS and DDS_insitu products Grids and file formats 2 Processing status Which products are currently available ? 3 Data access Where and how to get the data ?

  20. DDS Merged DDS Not merged MODIS 1.1 Day ISIN - 4km Track PC - 1km ISIN – 4km Level 2 products MERIS DDS Not merged 2.0/Q Day ISIN - 4km SeaWiFS 5.1 GlobColour processor DDS in-situ Not merged Day ISIN - 4km 1997 … 2006 DDS in-situ Not merged DDS in-situ Merged Track PC - 1km ISIN – 4km Day ISIN - 4km Processing Status

  21. ftp server FPS Merged 8-days Monthly ISIN – 4km FPS Merged Day ISIN - 4km Disk storage GlobColour processor Archive FPS Merged FPS Merged Day PC – 25km PC – 100 km 8-days Monthly PC – 25km PC – 100km web server Processing Status

  22. Processing Status fps dds dds_insitu

  23. Processing Status FPS 1.0 MERIS data 04/2002 – end 2006 MODIS data 06/2002 – end 2006 SeaWiFS data 09/1997 –end 2002 Merged products 3 instruments only for 2002

  24. Processing Status FPS 1.1 MERIS data 04/2002 – end 2006 MODIS data 06/2002 – end 2006 SeaWiFS data 09/1997 – end 2006 Extention to end 2006 on distribution servers before Xmas

  25. Processing Status FPS 2.0 MERIS data 04/2002 – end 2007 MODIS data 06/2002 – end 2007 SeaWiFS data 09/1997 – end 2007 Available in 2008 Start of NRT service demonstration

  26. 1 The GlobColour products What are the GlobColour parameters ? FPS, DDS and DDS_insitu products Grids and file formats 2 Processing status Which products are currently available ? 3 Data access Where and how to get the data ?

  27. Data Access Data Access

  28. Any ftp client Wget Unix command All CHL1 monthly quicklooks at 25 km resolution wget -r -l10 -t10 -A "L3m*_25_*CHL1_MO*.gz" -w3 -Q1000m \ ftp://globcolour_data:fgh678@ftp.fr-acri.com/FPS/CHL1 ./ GlobColour products filenames are described in the PUG Data Access ftp data access 2 ways… at least…

  29. Thank you for your attention

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